Aston Martin advice from Bamford Rose independent specialist
Discussion
BamfordMike said:
Pressure charging Aston Martin V8 Vantage:
Snip
I am sure this response will generate comments from those running pressure charged Vantages, and without doubt, to fit a blower and to even get the car driving means a lot of hard work. I am happy for any discussion surrounding this subject to take place here if you wish.
Excellent as ever MikeSnip
I am sure this response will generate comments from those running pressure charged Vantages, and without doubt, to fit a blower and to even get the car driving means a lot of hard work. I am happy for any discussion surrounding this subject to take place here if you wish.
This is an area I am (was
) very interested in on the Vantage. I did it successfully on a Honda S2000 getting 420 BHP with no issues. But as you rightly point out there are many pitfalls that have not even been considered on the currently available kits. Unfortunately I doubt they ever will.I think this is a shame as a well enegineered low pressure (~6 psi) supercharger kit would transform the V8.
Quote Bamford Mike
"K+N air filters, above the AM airbox update will return very little additional gain. The better modification onward from AM power pack airbox would be to remove the air induction system altogether and fit air filters similar to N24 / GT4 race cars."
I was considering the AM power pack but if better gains can be achieved for less with the N24 /GT4 are there any drawbacks? Where can the filters be purchased?
Cheers
Glenn
"K+N air filters, above the AM airbox update will return very little additional gain. The better modification onward from AM power pack airbox would be to remove the air induction system altogether and fit air filters similar to N24 / GT4 race cars."
I was considering the AM power pack but if better gains can be achieved for less with the N24 /GT4 are there any drawbacks? Where can the filters be purchased?
Cheers
Glenn
alex2 said:
Thanks for your various interesting technical contributions Mike.
Out of interest and given your experience with engine development at Aston Martin, is there any performance advantage to be gained from using higher octane fuel in the recent V8 and V12 engines?
Good question, I understand this is a topic which is often discussed.Out of interest and given your experience with engine development at Aston Martin, is there any performance advantage to be gained from using higher octane fuel in the recent V8 and V12 engines?
The V12 engine has no adaptive knock control / spark control hardware (sensors) or software (ECU program).
This means there is no mechanism to advance the spark angle if high (97 or greater) Octane fuel is used, or retard the spark if low (<95) Octane is used.
Higher the Octane rating number means the detonation limit is reduced, reduced detonation means that the spark can be re-advanced to gain additional power. The lower the Octane rating means detonation is increased and if the spark is not retarded, severe damage is likely (holed or cracked piston or failed sparkplug leading to damage from debris).
The basic mapping on all current V12's was conducted by the factory on 95 Octane. As there is no hardware or software present to re-advance the spark angle if higher Octane fuel is used, means there would be no performance benefit to be had, whatsoever, if high Octane fuel was used. Conversely, in markets (such as the States) where low fuel grades are available, if, say, 91 Octane was filled and the engine was held at high speed and load for prolonged periods, severe damage might occur. For this reason there are not many manufactures today that release engines to the market without knock control.
To give you an idea of the value of knock control, an industry standard charts an extra 1.5 degrees spark per additional octane rating. The same standard releases approx. 2.5 bhp per 1 degree spark. Meaning that when knock control technology is present, running 97 Supergreen will return an additional 7.5 BHP over 95 Octane performance.
So, until the day knock control is available on V12, save your money and fill with 95 Octane as there is no benefit whatsoever to be had from the higher octane fuel.
Onto the V8
The V8 does have knock control (thanks to great hardware from Jag and a fantastic cal job from someone on this forum..)
The base mapping was conducted on 97 Octane, meaning 380BHP for 4.3L and 420BHP for 4.7L is achieved using 97 Octane. If 95 Octane is used then the quoted performance levels will not be achieved. Using the same standard above; 372.5 BHP for 4.3L and 412.5 BHP for 4.7L will be returned. Furthermore, if 91 Octane fuel was used then the knock control system would re-adjust spark so that no damage to the engine would occur, causing the loss of over 10 BHP (yes, this number doesn't follow the same rule stated above re performance loss / retardation of spark, as it is not a linear relationship over the entire fuel octane range).
This is one reason the AM power upgrade option works quite well. As discussed previously on this thread, the kit consists of valves in the airbox which open (outside noise drive-by regulations) to return lower induction system losses, worth approx. 10 BHP. Together with, and ONLY when 100 octane fuel is used, the remainder of the 10 BHP comes from advanced spark, re-adapted to the higher Octane fuel. However, you pays your money you takes your choice... The kit is £2k and to get the final 10BHP you need to fill with 100 Octane (if you can find it), meaning a very expensive fuel fill to get that last little bit of performance. So the debate would be... is there a better performance upgrade option for the outlay of around £2k..??!!
Hope this answers your questions..
Mike.
mikey k said:
Excellent as ever Mike
This is an area I am (was ) very interested in on the Vantage. I did it successfully on a Honda S2000 getting 420 BHP with no issues. But as you rightly point out there are many pitfalls that have not even been considered on the currently available kits. Unfortunately I doubt they ever will.
I think this is a shame as a well enegineered low pressure (~6 psi) supercharger kit would transform the V8.
Ta...This is an area I am (was
) very interested in on the Vantage. I did it successfully on a Honda S2000 getting 420 BHP with no issues. But as you rightly point out there are many pitfalls that have not even been considered on the currently available kits. Unfortunately I doubt they ever will.I think this is a shame as a well enegineered low pressure (~6 psi) supercharger kit would transform the V8.
let me get my note paper and pen... well engineered....~6PSI boost.... maybe one day....
glugcom said:
Quote Bamford Mike
"K+N air filters, above the AM airbox update will return very little additional gain. The better modification onward from AM power pack airbox would be to remove the air induction system altogether and fit air filters similar to N24 / GT4 race cars."
I was considering the AM power pack but if better gains can be achieved for less with the N24 /GT4 are there any drawbacks? Where can the filters be purchased?
Cheers
Glenn
Hi."K+N air filters, above the AM airbox update will return very little additional gain. The better modification onward from AM power pack airbox would be to remove the air induction system altogether and fit air filters similar to N24 / GT4 race cars."
I was considering the AM power pack but if better gains can be achieved for less with the N24 /GT4 are there any drawbacks? Where can the filters be purchased?
Cheers
Glenn
The AM power upgrade kit (see above post discussing ignition) produces 10 of the 20 BHP from valves which open in the air induction system to reduce losses which zap performance.
When the valves are open, the only other part of the induction system which causes any system loss of any significance is the air-filter element. So, my original comment stated that if a car had the AM power valves (£2k kit), the addition of low loss filters (such as K+N), in reality, would return very little cumulative gain.
Now, coming onto your question; A way to replicate the AM power upgrade kit at a fraction of the price would be to remove the airbox, air pick-up pipes and fit directly onto the Mass Airflow tubes low loss filters such as K+N, or, as per GT4 cars, ITG foam filters.
There are two points of concern I can identify; Water ingress (very bad thing) and disturbance to Mass Airflow sensors leading to false readings at sensitive conditions such as idle, which might cause the engine to stall. As far as additional airflow is concerned, the EMS will re-adapt to the new condition so this is not a concern.
Re water ingress, when we fit the foam filters we use shielding to prevent from this worry. The sign-off for me that this modification was / is robust was the 2006 Nurburgring 24 hour race - EXTREMELY wet, the cars could have towed water skiers..! Re error state airflow readings - I have never encountered this condition, but I mention it here as it would be a concern that springs to mind.
Personally, I would never recommend the air filter upgrade in isolation. I really like a 'joined-up' series of measures to produce an end result of real value. What I mean here is a benefit in terms of both vehicle acceleration times and drivers perception of performance increase which comes from another attribute, such as sound.
So, instead of AM power upgrade at £2k, which is 10BHP on 97 Octane, only delivering the full 20 BHP when using 100 Octane fuel, with no 'sound' increase as the kit doesn't include an exhaust.. I would recommend a more joined-up measure - Sports exhaust system (silencer, sports catalysts and the icing on the cake, more optimum exhaust manifold), together with GT4 style air filter system.
From reading other posts, I understand your car has sports cats and silencer already? so you are already halfway there. So yes, and in direct response to your question, for around one/fifth of the price of the AM power upgrade kit, you can get the same effect by simply fitting quality air filter elements to the Mass Airflow tubes - But make certain whoever fits them considers the same care points I mention above.
Hope this helps.
Mike.
This is just the answer I was hoping for.
I would like to fit these ITG filters and keep the original pipework for the next owner.
I am keen to fit the sports headers you are preparing to offer to complete the package and give a few more bhp.
Will you be in a position to supply and fit the filters and the headers to ensure that the the weather proofing aspect is taken care of?
Cheers
I would like to fit these ITG filters and keep the original pipework for the next owner.
I am keen to fit the sports headers you are preparing to offer to complete the package and give a few more bhp.
Will you be in a position to supply and fit the filters and the headers to ensure that the the weather proofing aspect is taken care of?
Cheers
glugcom said:
This is just the answer I was hoping for.
I would like to fit these ITG filters and keep the original pipework for the next owner.
I am keen to fit the sports headers you are preparing to offer to complete the package and give a few more bhp.
Will you be in a position to supply and fit the filters and the headers to ensure that the the weather proofing aspect is taken care of?
Cheers
Yes, perfect opportunity as when the inner wheel arch liners are removed to fit the headers it is easy to correctly fit the filters, with care points, at the same time. I will give you a nod when the preparing is done.. I would like to fit these ITG filters and keep the original pipework for the next owner.
I am keen to fit the sports headers you are preparing to offer to complete the package and give a few more bhp.
Will you be in a position to supply and fit the filters and the headers to ensure that the the weather proofing aspect is taken care of?
Cheers
BamfordMike said:
flinder said:
Hi Mike, You guys are the reason I joined Pistonheads. Is there an easier way, that is, without taking or significantly loosening the rear bumper cover to remove the small left and right grilles under the rear bumper? A special tool or technique? My cars fit and finish are exceptional...I would hate to disturb it if it can be avoided. I want to change the diffuser appearance and function on this car.
Hi.I am happy you like what you see at Bamford Rose..!
Speaking from memory, the grilles are held on with push on barbed clips which you have to damage to get off and bolted to the diffuser.
But I will check one of our cars tomorrow to properly answer your question.
Mike.
BamfordMike said:
Hi.
Thanks to rmrmd1956 for posting the fuel supply data / graph...!
The graph shows that @ 4000 rpm 12.75:1 AFR or about 0.87 lambda should be delivered.
Your dyno run data shows 0.853
Meaning your engine is running approx 2% rich (additional) fuel
The graph shows that @ 6000 rpm 11.0:1 AFR or about 0.753 lambda should be delivered.
Your dyno run data shows 0.716
Meaning your engine is running approx 5% rich (additional) fuel
The graph shows that @ 7250 rpm 10.6:1 AFR or about 0.726 lambda should be delivered.
Your dyno run data shows 0.68
Meaning your engine is running approx 5% rich (additional) fuel
A rich fuel profile like this is not uncommon and is not a problem.
You say there are no fault codes present and no other problems.
If you are able to look at OBDII port data, look at variable FADPT, this is the fuel adaption value learnt by the system to return lambda 1 (~14.65:1 AFR) in closed-loop conditions.
It would be my guess that the number would be around 1.05, meaning it is taking around 5% fuel out to maintain lambda 1 in closed-loop conditions. But, when the fuelling goes open loop (for maximum performance when you open the throttle fully), the adaptions are not always carried across with reliability from closed to open-loop conditions.
So in this scenario, the reason the system might take 5% out, means it is now over fuelling by ~5%.
The reason in most cases is the MAF meters themselves being out of tolerance (meaning they return a value which is either higher or lower than the actual airflow).
This is not a problem, this is something expected from manufacturing.
However, if the MAF meters measure higher airflow than is actually being consumed by the engine, open loop, when fuelling corrections are not reliably carried across, a higher than needed amount of fuel will be delivered than is actually needed-but this is normal and expected in these conditions.
If there was a blockage or dirt in the system, it would be pre MAF meters, meaning this would cause a measured, lower, airflow and the correct lower amount of fuel would be delivered.
In most cases, lean running is due to an air leak (post MAF meters), as un-metered air is additionally introduced to the fuel diluting the mixture. Whereas rich running is more to do with a higher than actual measurement of air, although injector leakage could also be the cause, amongst a few other quirky conditions.
Under no circumstances blow the MAF meters out with compressed air to clean them, they are very sensitive components.
I can not really make comment on the power result as I do not know the dyno in question, and can not be certain the results are reliable.
However, put the dyno result to one side;
There are no problems you can report (fault codes / error states or any comments from technician)
So what exactly do you think is wrong with this car?
What made you go to dealer to check the car out?
I need a little more information to be of any further help, but the slightly rich fuel is of no immediate concern. Clearly you are running rich, and a small amount of power will be lost as a result. For this reason I test all MAF meters for my motorsport cars to ensure the exact and correct flow of air is being measured, this way I know that the car will not run rich, and if anything I prefer MAF meters which read low, as this will run the engine lean and produce more power. This attention to detail is needed in the motorsport world but will mean very little in road cars.
I hope all this makes sense?
All the best.
Mike.
MikeThanks to rmrmd1956 for posting the fuel supply data / graph...!
The graph shows that @ 4000 rpm 12.75:1 AFR or about 0.87 lambda should be delivered.
Your dyno run data shows 0.853
Meaning your engine is running approx 2% rich (additional) fuel
The graph shows that @ 6000 rpm 11.0:1 AFR or about 0.753 lambda should be delivered.
Your dyno run data shows 0.716
Meaning your engine is running approx 5% rich (additional) fuel
The graph shows that @ 7250 rpm 10.6:1 AFR or about 0.726 lambda should be delivered.
Your dyno run data shows 0.68
Meaning your engine is running approx 5% rich (additional) fuel
A rich fuel profile like this is not uncommon and is not a problem.
You say there are no fault codes present and no other problems.
If you are able to look at OBDII port data, look at variable FADPT, this is the fuel adaption value learnt by the system to return lambda 1 (~14.65:1 AFR) in closed-loop conditions.
It would be my guess that the number would be around 1.05, meaning it is taking around 5% fuel out to maintain lambda 1 in closed-loop conditions. But, when the fuelling goes open loop (for maximum performance when you open the throttle fully), the adaptions are not always carried across with reliability from closed to open-loop conditions.
So in this scenario, the reason the system might take 5% out, means it is now over fuelling by ~5%.
The reason in most cases is the MAF meters themselves being out of tolerance (meaning they return a value which is either higher or lower than the actual airflow).
This is not a problem, this is something expected from manufacturing.
However, if the MAF meters measure higher airflow than is actually being consumed by the engine, open loop, when fuelling corrections are not reliably carried across, a higher than needed amount of fuel will be delivered than is actually needed-but this is normal and expected in these conditions.
If there was a blockage or dirt in the system, it would be pre MAF meters, meaning this would cause a measured, lower, airflow and the correct lower amount of fuel would be delivered.
In most cases, lean running is due to an air leak (post MAF meters), as un-metered air is additionally introduced to the fuel diluting the mixture. Whereas rich running is more to do with a higher than actual measurement of air, although injector leakage could also be the cause, amongst a few other quirky conditions.
Under no circumstances blow the MAF meters out with compressed air to clean them, they are very sensitive components.
I can not really make comment on the power result as I do not know the dyno in question, and can not be certain the results are reliable.
However, put the dyno result to one side;
There are no problems you can report (fault codes / error states or any comments from technician)
So what exactly do you think is wrong with this car?
What made you go to dealer to check the car out?
I need a little more information to be of any further help, but the slightly rich fuel is of no immediate concern. Clearly you are running rich, and a small amount of power will be lost as a result. For this reason I test all MAF meters for my motorsport cars to ensure the exact and correct flow of air is being measured, this way I know that the car will not run rich, and if anything I prefer MAF meters which read low, as this will run the engine lean and produce more power. This attention to detail is needed in the motorsport world but will mean very little in road cars.
I hope all this makes sense?
All the best.
Mike.
thank you for your response so complete.
In fact, the problem of wealth came from the sports catalysts that have been removed now because the car to a basic problem.
Currently, my Aston a reinforced clutch and a short bridge (not original Aston). I went to the dyno and power and found that the engine is 330 hp instead of 385 hp normally.
Like all items mentioned in my first message were controlled, have you any idea where the problem may come? Do some have a problem with Aston carthographie the original? Are there any things I should / can check?
Thank you very much for your help.
Vincent
The curve:
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Edited by vince1972 on Thursday 14th April 19:08
BamfordMike said:
Pressure charging Aston Martin V8 Vantage:
Between 380 BHP V8 Vantage to near 500 BHP V12 Vantage, and between 450 BHP DB9 to 510BHP DBS, the factory upgraded the cooling system for capacity and performance for each model.
I thought the V12 Vantage had the same 510bhp as the DBS?Between 380 BHP V8 Vantage to near 500 BHP V12 Vantage, and between 450 BHP DB9 to 510BHP DBS, the factory upgraded the cooling system for capacity and performance for each model.
Mike,
I have modified the intake tract on my V8V different from discussion above. Would appreciate your comments.
The OE air path is convoluted and constricted at several points. My change to overcome these difficulties in 2 words is "ram air".
The Vantage intake is located high on the C/L of the car's upper grille. The OE opening in the plastic tube assembly is about 3"x6.5". The path then turns downward 90 degrees then splits in half, left and right, on its way to the air boxes/air cleaners.
My mod has me sawing down from the OE opening, left and right, to the top of the bumper bar. Joining these 2 vertical cuts with a horizontal cut along the bumper surface allows removal of the front of the tube. The new, larger opening is approximately 7'x 6.5", more than twice the area of the OE opening. Let the air ramming begin! Note, all 3 water drain points are undisturbed.
I have also installed RSC air cleaner elements and a British Quicksilver Supersports muffler. Next on the agenda would be 200 cell cats. I look forward to details of your Bamford headers.
I have modified the intake tract on my V8V different from discussion above. Would appreciate your comments.
The OE air path is convoluted and constricted at several points. My change to overcome these difficulties in 2 words is "ram air".
The Vantage intake is located high on the C/L of the car's upper grille. The OE opening in the plastic tube assembly is about 3"x6.5". The path then turns downward 90 degrees then splits in half, left and right, on its way to the air boxes/air cleaners.
My mod has me sawing down from the OE opening, left and right, to the top of the bumper bar. Joining these 2 vertical cuts with a horizontal cut along the bumper surface allows removal of the front of the tube. The new, larger opening is approximately 7'x 6.5", more than twice the area of the OE opening. Let the air ramming begin! Note, all 3 water drain points are undisturbed.
I have also installed RSC air cleaner elements and a British Quicksilver Supersports muffler. Next on the agenda would be 200 cell cats. I look forward to details of your Bamford headers.
flinder said:
Mike,
I have modified the intake tract on my V8V different from discussion above. Would appreciate your comments.
The OE air path is convoluted and constricted at several points. My change to overcome these difficulties in 2 words is "ram air".
The Vantage intake is located high on the C/L of the car's upper grille. The OE opening in the plastic tube assembly is about 3"x6.5". The path then turns downward 90 degrees then splits in half, left and right, on its way to the air boxes/air cleaners.
My mod has me sawing down from the OE opening, left and right, to the top of the bumper bar. Joining these 2 vertical cuts with a horizontal cut along the bumper surface allows removal of the front of the tube. The new, larger opening is approximately 7'x 6.5", more than twice the area of the OE opening. Let the air ramming begin! Note, all 3 water drain points are undisturbed.
I have also installed RSC air cleaner elements and a British Quicksilver Supersports muffler. Next on the agenda would be 200 cell cats. I look forward to details of your Bamford headers.
Yep, you are on the right lines, a smart low cost mod that will have an immediate effect.I have modified the intake tract on my V8V different from discussion above. Would appreciate your comments.
The OE air path is convoluted and constricted at several points. My change to overcome these difficulties in 2 words is "ram air".
The Vantage intake is located high on the C/L of the car's upper grille. The OE opening in the plastic tube assembly is about 3"x6.5". The path then turns downward 90 degrees then splits in half, left and right, on its way to the air boxes/air cleaners.
My mod has me sawing down from the OE opening, left and right, to the top of the bumper bar. Joining these 2 vertical cuts with a horizontal cut along the bumper surface allows removal of the front of the tube. The new, larger opening is approximately 7'x 6.5", more than twice the area of the OE opening. Let the air ramming begin! Note, all 3 water drain points are undisturbed.
I have also installed RSC air cleaner elements and a British Quicksilver Supersports muffler. Next on the agenda would be 200 cell cats. I look forward to details of your Bamford headers.
Here is the reason why, and the reason air induction system modifications return performance increases...
When the engine is being driven on part throttle, there is a vacuum in the inlet manifold - the engine is being 'throttled' or held back from producing maximum performance.
When the driver requests full performance, Wide Open Throttle (WOT) to achieve the full performance potential the engine can deliver. The vacuum in the inlet manifold should turn into a pressure which is equal to atmospheric ambient pressure.
However, the air needs to be filtered, the air needs to be collected from a position which is outside the heat build up from the under-bonnet area, and finally, 'induction roar' (noise from the throttle) needs to be silenced so that the car passes legislative requirements regarding noise drive-by sound level limits.
Each of these considerations mean pipework and filters, which cause restrictions or 'induction system losses'. These losses cause a slight vacuum within the inlet manifold which means that when the throttle is wide open, the pressure within the inlet manifold is not equal to atmospheric = a power loss. So, when we modify the air induction system it is done to get closer to the optimum, which is no vacuum within the inlet manifold when the throttle is wide open.
The typical induction system loss of most modern engines at wide open throttle, the Aston is no different, is 3.0 KPa. The relationship between a reduction of 1.0 KPa inlet manifold depression = approx. 4.0 BHP improvement.
So, when the ITG filters are fitted, like to my GT4 cars, around 0.5KPa depression / vacuum is measured in the inlet manifold, hence a power increase of 10BHP (inline with my sports air intake element of my performance kit due for release anytime soon).
So, you have certainly got closer to the optimum which is atmospheric ambient pressure within the inlet manifold at wide open throttle. I am sure you are aware of the care points, but for anybody else considering doing something in the home garage remember; the air must be collected from an area away from heat source, it must be metered by the Mass Airflow sensors within their original housing / pipework, the pick-up pipe must ensure against water ingress and the air must be filtered.
And you are also right in that 'ram-air' is an important factor, but is a phenomenon which can not really be measured in terms of its effect on flywheel power output as manufacturers are not permitted to quote power figures with a ram-air effect, even if the system is designed supremely to take advantage of this 'free BHP'. But, in gears 1 through to 4, where realistically is the region most people drive 'fast' ram-air has less effect when the car is in, say, 6th gear when the ram-air effect really starts to take effect.
Mike.
BamfordMike said:
For those owners who have undertaken this mod already, but are still in search of a ‘different’ exhaust note, the next stage is the fitment of an aftermarket silencer system. Regarding sound quality, there is no right or wrong answer here, its personal preference and each brand does something different; from American muscle car V8 burble to a more European ‘refined’ racing note. As the exhaust note from aftermarket silencer will inevitably be louder than removal of fuse 22, the driver will yet again perceive greater engine performance, but, in reality the performance gain is something quite different. Reduced (louder) silencing is achieved by internal design changes which cause a reduction in exhaust system back pressure. The result of this increase in engine breathing is increased performance, however, the drivers perception of performance is greater than the actual flywheel / road wheel performance gain, and many aftermarket tuning companies prey on this fact by claiming more performance than is actually true. These days, it is pretty much industry standard concerning engines which produce close to 100BHP per litre to report that a silencer causes an exhaust back pressure rise of circa 10 Kilopascal (KPa), the same industry standard reports about a 0.7BHP increase per 1Kpa reduction of system backpressure. This means that even if you were to remove the silencer completely, with the intermediate pipes venting to atmosphere, the performance increase would be in the region of 7BHP. However, this is with no silencer box present, so with some form of silencing present, no matter how loud, there will be a small amount of additional back pressure increase. Given an average silencer backpressure rise of, say, 5 KPa, the true increase of performance would be (5x0.7) 3.5BHP. Anybody claiming more than this is preying on the fact the loud exhaust note is worth a perceived performance increase, should their systems come with ‘power test results’ claiming more, scrutiny of the test conditions must be made to verify claims.
So the Quicksilver exhaust by itself should make about 3-4BHP?Question for you, Mike.
With the introduction of the Vantage S, is the different kit a significant upgrade, and is it worth the money? Better off getting a new V8V and modding?
Is the new SportShiftII a significant upgrade, or can a remap of the V8V SportShift accomplish the same thing?
Thanks for your answer.
With the introduction of the Vantage S, is the different kit a significant upgrade, and is it worth the money? Better off getting a new V8V and modding?
Is the new SportShiftII a significant upgrade, or can a remap of the V8V SportShift accomplish the same thing?
Thanks for your answer.
I was contemplating this question yesterday.
Two things not so obvious from the S info;
1) Decent jump in power to weight as there is a decent weight reduction
2) Power losses through the 7 speed transmission are lower so whilst it is only 10 BHP more at the flywheel this is going to be more like 20-25 bhp at the wheels
I would presume adding sports cats, header and intakes would net another gain but I'm sure Mike will tell us how much
Two things not so obvious from the S info;
1) Decent jump in power to weight as there is a decent weight reduction
2) Power losses through the 7 speed transmission are lower so whilst it is only 10 BHP more at the flywheel this is going to be more like 20-25 bhp at the wheels
I would presume adding sports cats, header and intakes would net another gain but I'm sure Mike will tell us how much
Quick question about the windows in a V12 Vantage..
(very dull topic - sorry)
Once you pull out the ECU the windows can still be closed using the buttons for about 1 minute. Is there a way to modify that to say 2 or 3 minutes? I know this may sound dull but I have a very narrow garage and I need to have the window open to exit the car. Getting out in one minute can be a bit tricky...
(very dull topic - sorry)
Once you pull out the ECU the windows can still be closed using the buttons for about 1 minute. Is there a way to modify that to say 2 or 3 minutes? I know this may sound dull but I have a very narrow garage and I need to have the window open to exit the car. Getting out in one minute can be a bit tricky...
BamfordMike said:
Pressure charging Aston Martin V8 Vantage:
In response to several requests, here are some considerations to be made if contemplating pressure charging your V8. It must be stressed that this discussion concerns pressure charging in general, without specific reference to any supplier of such equipment.
Concern should be raised if suppliers of forced induction kits do not remove and strip the engine and rebuild with parts suitable to withstand additional loads, pressures and temperatures associated with forced induction engines. Specifically; pistons, rods, bearings, cooling system and calibration should be revised.
Piston; bulk metal piston crown temperature, cylinder pressure maximum and knock over pressure limits were signed-off by manufacturer, naturally aspirated, @ 89BHP per litre. A ‘CLAIMED’ peak power output of ~550 BHP from forced induction must mean that BMEP (brake mean effective pressure) has risen from ~12 to ~16 Bar. Using industry standard rules that chart combustion gas temperature and pressure rise per 1.0 bar BMEP, would indicate that elevated forced induction combustion temperatures and pressures are highly likely to exceed the in-built safety factor / margin the manufacturer engineered-in to prevent failures for application of the piston in the standard engine. This means that the risk for pressure failure (cracked piston) and holed piston is high. My feeling is that there are so few forced induction kits in the marketplace, and those few have been used so little, is the only reason there is not an epidemic of piston failures in engines fitted with forced induction kits.
Connecting rod; The first 1000 4.3L Vantage engines were built with steel (expensive and strong) connecting rods, from then onwards normal production utilised sintered connecting rods (cheaper and weaker but nonetheless fit for purpose). ~16 Bar / 540BHP forced induction cylinder pressures and temperatures on steel rod = probably OK, but nonetheless unproven. The same conditions sintered rods = failed rod and written-off block highly likely. Remember the comment so few being used so little..
Crank; The crankshaft is bulletproof, the OE supplier is top quality. Weak link is big-end bearings and the concern would be delamination of bearing surface material due to increased heat. This is because Forced Induction heat output to oil is significantly greater than naturally aspirated. The concern would be that at prolonged maximum engine speed / peak power operating conditions, the oil temperature and aeration levels rise to the point where film thicknesses in bearing journals might become compromised. Between 380 BHP V8 Vantage to near 500 BHP V12 Vantage, and between 450 BHP DB9 to 510BHP DBS, the factory upgraded the cooling system for capacity and performance for each model. So why when going from 380BHP to 540BHP is the cooling of the standard car retained and is deemed sufficient by those who supply Forced Induction kits? On the V8 vantage the oil temperature going into the engine is, say, 90 degrees C (after being cooled), and comes out at approx. 130. Bearings start to delaminate at approx. 150 degrees. So, under prolonged running conditions when the additional heat output of the Forced Induction engine pushes the inlet temp from 90 to 110 (a strong likelihood) – Game over.
Calibration; Lost features… DSC is lost (yes, no traction control with more power – go figure..!!??), perhaps ABS, perhaps security (alarm) and perhaps elements of the dashboard too. Some kits I have seen are better at retaining these features than others.
Failure modes and detection / avoidance; Simple example, as far as I can see the failure mode for running out of water injection is that you will run out of fuel before running the water tank dry, ok as long as you remember to fill it up, blown-up engine if you don’t. Even if a light comes on to warn driver of low water level, the suppliers of these kits cannot talk to the original ECU, they cannot program revised ‘limp-home’ modes should error states occur. So in this example water runs dry but the engine can still be operated in a condition that would cause damage.
Another example, and one which worries every manufacturer who produces cars with drive-by-wire throttle systems. Should an electronic error cause the throttle blade to snap open wide with no driver pedal demand input, the OE ECU will safely put the car into limp-home / shutdown mode. A third-party ECU will never have this same level of robustness / intelligence. There are some systems I have seen which run an additional ECU alongside the OE ECU, here there are problems of general calibration competency when a ‘jumper’ ECU is fitted or OE ECU is replaced; calibration of electrical and other loadings like aircon (put aircon on with full battery loading from electrical drain, will engine stall out on return to idle?). Cold starts; at low altitude, at high altitude, using poor volatility fuel (for that time you go on holiday and find nothing but crap fuel in a remote place).
Summary; I think I have done the so little used by so few line to death… so here is another example. When I finished working on BMW mini Cooper supercharged program, I watched an episode of Top Gear where two upgraded models were tested. The John Cooper S works kit survived several laps around the circuit and would last a lifetime in reality, as the engineering behind that upgrade kit was as robust as the original manufacturer. The other car (who I forget the name of the tuning company) blew-up without posting a lap time as the engine was pushed too far by people who didn’t know what they were doing.
I am sure this response will generate comments from those running pressure charged Vantages, and without doubt, to fit a blower and to even get the car driving means a lot of hard work. I am happy for any discussion surrounding this subject to take place here if you wish. But I guess the only way to really prove otherwise is simple – give me the car for an hour around Silverstone...!
Mike.
In response to several requests, here are some considerations to be made if contemplating pressure charging your V8. It must be stressed that this discussion concerns pressure charging in general, without specific reference to any supplier of such equipment.
Concern should be raised if suppliers of forced induction kits do not remove and strip the engine and rebuild with parts suitable to withstand additional loads, pressures and temperatures associated with forced induction engines. Specifically; pistons, rods, bearings, cooling system and calibration should be revised.
Piston; bulk metal piston crown temperature, cylinder pressure maximum and knock over pressure limits were signed-off by manufacturer, naturally aspirated, @ 89BHP per litre. A ‘CLAIMED’ peak power output of ~550 BHP from forced induction must mean that BMEP (brake mean effective pressure) has risen from ~12 to ~16 Bar. Using industry standard rules that chart combustion gas temperature and pressure rise per 1.0 bar BMEP, would indicate that elevated forced induction combustion temperatures and pressures are highly likely to exceed the in-built safety factor / margin the manufacturer engineered-in to prevent failures for application of the piston in the standard engine. This means that the risk for pressure failure (cracked piston) and holed piston is high. My feeling is that there are so few forced induction kits in the marketplace, and those few have been used so little, is the only reason there is not an epidemic of piston failures in engines fitted with forced induction kits.
Connecting rod; The first 1000 4.3L Vantage engines were built with steel (expensive and strong) connecting rods, from then onwards normal production utilised sintered connecting rods (cheaper and weaker but nonetheless fit for purpose). ~16 Bar / 540BHP forced induction cylinder pressures and temperatures on steel rod = probably OK, but nonetheless unproven. The same conditions sintered rods = failed rod and written-off block highly likely. Remember the comment so few being used so little..
Crank; The crankshaft is bulletproof, the OE supplier is top quality. Weak link is big-end bearings and the concern would be delamination of bearing surface material due to increased heat. This is because Forced Induction heat output to oil is significantly greater than naturally aspirated. The concern would be that at prolonged maximum engine speed / peak power operating conditions, the oil temperature and aeration levels rise to the point where film thicknesses in bearing journals might become compromised. Between 380 BHP V8 Vantage to near 500 BHP V12 Vantage, and between 450 BHP DB9 to 510BHP DBS, the factory upgraded the cooling system for capacity and performance for each model. So why when going from 380BHP to 540BHP is the cooling of the standard car retained and is deemed sufficient by those who supply Forced Induction kits? On the V8 vantage the oil temperature going into the engine is, say, 90 degrees C (after being cooled), and comes out at approx. 130. Bearings start to delaminate at approx. 150 degrees. So, under prolonged running conditions when the additional heat output of the Forced Induction engine pushes the inlet temp from 90 to 110 (a strong likelihood) – Game over.
Calibration; Lost features… DSC is lost (yes, no traction control with more power – go figure..!!??), perhaps ABS, perhaps security (alarm) and perhaps elements of the dashboard too. Some kits I have seen are better at retaining these features than others.
Failure modes and detection / avoidance; Simple example, as far as I can see the failure mode for running out of water injection is that you will run out of fuel before running the water tank dry, ok as long as you remember to fill it up, blown-up engine if you don’t. Even if a light comes on to warn driver of low water level, the suppliers of these kits cannot talk to the original ECU, they cannot program revised ‘limp-home’ modes should error states occur. So in this example water runs dry but the engine can still be operated in a condition that would cause damage.
Another example, and one which worries every manufacturer who produces cars with drive-by-wire throttle systems. Should an electronic error cause the throttle blade to snap open wide with no driver pedal demand input, the OE ECU will safely put the car into limp-home / shutdown mode. A third-party ECU will never have this same level of robustness / intelligence. There are some systems I have seen which run an additional ECU alongside the OE ECU, here there are problems of general calibration competency when a ‘jumper’ ECU is fitted or OE ECU is replaced; calibration of electrical and other loadings like aircon (put aircon on with full battery loading from electrical drain, will engine stall out on return to idle?). Cold starts; at low altitude, at high altitude, using poor volatility fuel (for that time you go on holiday and find nothing but crap fuel in a remote place).
Summary; I think I have done the so little used by so few line to death… so here is another example. When I finished working on BMW mini Cooper supercharged program, I watched an episode of Top Gear where two upgraded models were tested. The John Cooper S works kit survived several laps around the circuit and would last a lifetime in reality, as the engineering behind that upgrade kit was as robust as the original manufacturer. The other car (who I forget the name of the tuning company) blew-up without posting a lap time as the engine was pushed too far by people who didn’t know what they were doing.
I am sure this response will generate comments from those running pressure charged Vantages, and without doubt, to fit a blower and to even get the car driving means a lot of hard work. I am happy for any discussion surrounding this subject to take place here if you wish. But I guess the only way to really prove otherwise is simple – give me the car for an hour around Silverstone...!
Mike.
Great info. Thats about what I thought. Failure rate seems to be about 10% per 10K mile (personal knowledge). This is acceptable to me because of the immense increase in power but of course would be completely unacceptable for OEM. Our gas is AKI not RON so that 93 US AKI = 98 RON. I run 105 RON when I drive hard.
The huge safety margin dialed into modern engine production is the only reason we can "get away with this". My hat is off to Aston Martin, they have built a strong engine!
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