Aftermarket ECUs
Discussion
I'm not sure there would be much benefit without an electric water pump too. The rad would get cooled. I'm not convinced (from a simple point of view) that there would be much heatsinking through the supply pipes.
That said VW, for one, used piggyback electric pumps to give low flow. Adding one to the out pipe of the rad would work. They are pretty cheap.
Of course, pointless with out the overrun facility.
That said VW, for one, used piggyback electric pumps to give low flow. Adding one to the out pipe of the rad would work. They are pretty cheap.
Of course, pointless with out the overrun facility.
mk1fan said:
Fair enough, if it works it works.
I think I'd fit both to just have one cycle rather than an on-off cycling of a (heavy) electrical load.
The idea certainly has potential merit on paper, so some time ago I fitted a Davies Craig electric booster water pump (EBP) that runs on the fans circuit, I've run this system on both a permanent live setup and an ignition switched live. Theory suggests running the fans and keeping the coolant moving after engine switch off should reduce heat surge, but I like to test theories as that's the only way to find out what really happens for sure.I think I'd fit both to just have one cycle rather than an on-off cycling of a (heavy) electrical load.
I've carefully monitored what happens when the engine is switched off to test both setups, to create the most testing situation in each case I turned off the engine just as the fans chimed in, I conducted the tests on a hot summers day when ambient tempts were in the high 80's. True coolant temp readings were taken at the top hose using the Davies Craig temp sensor and at the inlet manifold using my Canems ECU software, I also used my IR gun on the same spot on each head and the thermostat housing.
To be honest the results surprised me.... running the EBP and fans after engine switch off made little to no difference when compared with a traditional switch off that also turns the fans off at the same time.
As Steve_D quite rightly points out this is because of the well known principle of thermosypon, even with the engine off and the engine driven water pump not moving, coolant still circulates. Just like air, hot liquids rise and cool liquids fall, this creates a directional flow and so the coolant circulates without any help whatsoever. The radiator is just a heat exchanger, so while increasing airflow helps it's the surface area of the core and the volume of coolant the system holds that has a greater bearing of efficiency. Obviously, when you turn the engine off it stops making heat, so while you definitely need the rad fans and water pump at idle on a hot day, as it turns out you need neither when the engine is switched off
Being all aluminum the engine seems extremely good at shedding heat by itself, it's already pretty effective operating as an aircooled engine when compared with cast iron block & head arrangements. You can see this air cooling effect as we enter the winter months, on a fast motorway run on an icy cold day my 88 degree thermostat will be virtually completely closed, the engine effectively becomes a closed circuit, like this my Canems software will show the engine running at 83 degrees.
Put quite simply I found after properly testing and gathering real world data there's very little benefit in running the fans after switch off even on the hottest day right at the point my fans come on and at idle (no natural airflow). The Davies Craig EBP made naff all difference too, I left it fitted as it has potential benefits in forcing coolant around my LPG vaporiser so reducing the time it takes to switch from petrol to LPG on cold start, but to be honest the car cold starts on LPG just fine without it, but it's nice to be able force it on as it also helps improve heater efficiency in the winter months.
Following the results of my tests I decided to return to a switched live for the fans and EBP, when I switch the engine off the fans and EBP go off too, I just let thermosyphon do it's thing because it's electrically safer that way, on the permanent live setup as I walked away from the car with the fans & EBP running I couldnt help feeling if fan relay was stuck I could easily return to a car with a flat battery. Actually that would never happen as I have a Battery Brain that cuts the battery if voltage falls below a certain level.
But with it proven there's no real benefit in running the fans and EBP after switch off, I decided to return to the simpler and safer switched live setup. In summary..... another good idea in theory debunked in the real world by testing it and studying the data
ChimpOnGas said:
mk1fan said:
Fair enough, if it works it works.
I think I'd fit both to just have one cycle rather than an on-off cycling of a (heavy) electrical load.
The idea certainly has potential merit on paper, so some time ago I fitted a Davies Craig electric booster water pump (EBP) that runs on the fans circuit, I've run this system on both a permanent live setup and an ignition switched live. Theory suggests running the fans and keeping the coolant moving after engine switch off should reduce heat surge, but I like to test theories as that's the only way to find out what really happens for sure.I think I'd fit both to just have one cycle rather than an on-off cycling of a (heavy) electrical load.
I've carefully monitored what happens when the engine is switched off to test both setups, to create the most testing situation in each case I turned off the engine just as the fans chimed in, I conducted the tests on a hot summers day when ambient tempts were in the high 80's. True coolant temp readings were taken at the top hose using the Davies Craig temp sensor and at the inlet manifold using my Canems ECU software, I also used my IR gun on the same spot on each head and the thermostat housing.
To be honest the results surprised me.... running the EBP and fans after engine switch off made little to no difference when compared with a traditional switch off that also turns the fans off at the same time.
As Steve_D quite rightly points out this is because of the well known principle of thermosypon, even with the engine off and the engine driven water pump not moving, coolant still circulates. Just like air, hot liquids rise and cool liquids fall, this creates a directional flow and so the coolant circulates without any help whatsoever. The radiator is just a heat exchanger, so while increasing airflow helps it's the surface area of the core and the volume of coolant the system holds that has a greater bearing of efficiency. Obviously, when you turn the engine off it stops making heat, so while you definitely need the rad fans and water pump at idle on a hot day, as it turns out you need neither when the engine is switched off
Being all aluminum the engine seems extremely good at shedding heat by itself, it's already pretty effective operating as an aircooled engine when compared with cast iron block & head arrangements. You can see this air cooling effect as we enter the winter months, on a fast motorway run on an icy cold day my 88 degree thermostat will be virtually completely closed, the engine effectively becomes a closed circuit, like this my Canems software will show the engine running at 83 degrees.
Put quite simply I found after properly testing and gathering real world data there's very little benefit in running the fans after switch off even on the hottest day right at the point my fans come on and at idle (no natural airflow). The Davies Craig EBP made naff all difference too, I left it fitted as it has potential benefits in forcing coolant around my LPG vaporiser so reducing the time it takes to switch from petrol to LPG on cold start, but to be honest the car cold starts on LPG just fine without it, but it's nice to be able force it on as it also helps improve heater efficiency in the winter months.
Following the results of my tests I decided to return to a switched live for the fans and EBP, when I switch the engine off the fans and EBP go off too, I just let thermosyphon do it's thing because it's electrically safer that way, on the permanent live setup as I walked away from the car with the fans & EBP running I couldnt help feeling if fan relay was stuck I could easily return to a car with a flat battery. Actually that would never happen as I have a Battery Brain that cuts the battery if voltage falls below a certain level.
But with it proven there's no real benefit in running the fans and EBP after switch off, I decided to return to the simpler and safer switched live setup. In summary..... another good idea in theory debunked in the real world by testing it and studying the data
I’ve read some interesting stuff about valve lapping in and how the valves heat is dissipated through this contact with the head, it’s vital to have a good seal all the way round for this very reason but also as it will effect inlet vacuum pressure.
If you have leakage at a valve or two this is going to effect the ability of any Ecu to control things I’d expect.
Regardless of Ecu your engine needs to be in tip top shape to get the best from it.
I’ve got a MAP sensor plumbed into the inlet manifold that coupled with the other sensors controls ignition and fuelling as we know.
Vacumn pressure and understanding the load on the engine is very useful for adjusting timing, the weathers getting cold and damp at first light but whilst it’s dry I’ll drive it to work here and there,
As I don’t have a stepper motor I’m amazed how well the engine will tickover from cold and how the temp sensor with the map sensor adjusts the cold start mix, it’s seemless as if it doesn’t really do anything. It runs the same as when it’s hot.
Cold morning, start and run engine for 20-30 seconds, drive away at 1000 revs with timing doing its thing as like any other day.
Someone once said you don’t need steppers on the RV8
I agree if it’s mapped right.
Mbe rocks my world.
If you have leakage at a valve or two this is going to effect the ability of any Ecu to control things I’d expect.
Regardless of Ecu your engine needs to be in tip top shape to get the best from it.
I’ve got a MAP sensor plumbed into the inlet manifold that coupled with the other sensors controls ignition and fuelling as we know.
Vacumn pressure and understanding the load on the engine is very useful for adjusting timing, the weathers getting cold and damp at first light but whilst it’s dry I’ll drive it to work here and there,
As I don’t have a stepper motor I’m amazed how well the engine will tickover from cold and how the temp sensor with the map sensor adjusts the cold start mix, it’s seemless as if it doesn’t really do anything. It runs the same as when it’s hot.
Cold morning, start and run engine for 20-30 seconds, drive away at 1000 revs with timing doing its thing as like any other day.
Someone once said you don’t need steppers on the RV8
I agree if it’s mapped right.
Mbe rocks my world.
Edited by Classic Chim on Thursday 2nd November 17:55
Recently I've started using scatter spark idle control in conjunction with my existing Canems air bleed based idle management using the excellent Bosch rotary idle valve, which is way better than a stepper motor in itself. It turns out in the case of the Canems system these two strategies actually work extremely well together. In my experience idle air control seems preferable for cold start, and scatter spark is a better idle management strategy when the engine is fully warmed and not under load.
The Canems system offers closed loop idle, this feature works to ensure I always hit my specified target idle speed of 1050rpm, if I put my power steering equipped Chimaera in full lock when parking, or the radiator fans chime in at idle, the engine is placed under load which ordinarily would result in a drop in RPM. With my twin ignition and air system, the closed loop idle strategy will advance or retard my ignition timing to fine trim the idle to the target speed adding or subtracting just 3 degrees either side of the base idle timing figure. If the situation requires greater intervention than the 3 degrees can provide, the idle air control valve will step in to ensure the 1050 RPM target is always precisely maintained.
What I've found is both the ignition based idle management and air bleed idle strategies have their pros & cons, but interestingly when you activate both and run them together with the Canems system you end up with just the pros from each, the best of both worlds if you like. IE better cold start/warm up and engine load idle management using the idle air control valve, and then for the bulk of the time when the engine is fully warmed and under no real load it falls back on the more precise fine idle trimming effects of scatter spark.
The Canems system offers closed loop idle, this feature works to ensure I always hit my specified target idle speed of 1050rpm, if I put my power steering equipped Chimaera in full lock when parking, or the radiator fans chime in at idle, the engine is placed under load which ordinarily would result in a drop in RPM. With my twin ignition and air system, the closed loop idle strategy will advance or retard my ignition timing to fine trim the idle to the target speed adding or subtracting just 3 degrees either side of the base idle timing figure. If the situation requires greater intervention than the 3 degrees can provide, the idle air control valve will step in to ensure the 1050 RPM target is always precisely maintained.
What I've found is both the ignition based idle management and air bleed idle strategies have their pros & cons, but interestingly when you activate both and run them together with the Canems system you end up with just the pros from each, the best of both worlds if you like. IE better cold start/warm up and engine load idle management using the idle air control valve, and then for the bulk of the time when the engine is fully warmed and under no real load it falls back on the more precise fine idle trimming effects of scatter spark.
I need to read up on scatter spark.
As it suggests moving the moment of ignition around which in turn will effect the mixture
A simple way of describing it is if you advance your timing your engine revs will rise thus negating the need for idle control so much.
The Ecu uses set tables etc for this operation if my 5 mins reading is correct. Actual crank position and memory set positioning is being calculated to give accuracy of piston position as advancing can as we know be very dangerous.
The scatter spark is a calculator that’s deciding where best to advance spark to. Is that about right?
As it suggests moving the moment of ignition around which in turn will effect the mixture
A simple way of describing it is if you advance your timing your engine revs will rise thus negating the need for idle control so much.
The Ecu uses set tables etc for this operation if my 5 mins reading is correct. Actual crank position and memory set positioning is being calculated to give accuracy of piston position as advancing can as we know be very dangerous.
The scatter spark is a calculator that’s deciding where best to advance spark to. Is that about right?
Edited by Classic Chim on Thursday 2nd November 20:51
Classic Chim said:
I need to read up on scatter spark.
As it suggests moving the moment of ignition around which in turn will effect the mixture
A simple way of describing it is if you advance your timing your engine revs will rise thus negating the need for idle control so much.
The Ecu uses set tables etc for this operation if my 5 mins reading is correct. Actual crank position and memory set positioning is being calculated to give accuracy of piston position as advancing can as we know be very dangerous.
The scatter spark is a calculator that’s deciding where best to advance spark to. Is that about right?
It's just trimming the idle fractionally by (in my case) subtracting or adding an absolute maximum of just 3 degrees to the base idle timing figure, should the idle rise above or fall below my user defined target idle speed of 1050 RPM. The way I've calibrated my Canems Scatter Spark system is to only add or subtract 1 degree if the idle over or under shoots the target by 50rpm, 2 degrees if idle over or under shoots the target by 100rpm, and 3 degrees if the idle speed is over or under my defined target by 150rpm. I've also configured it so it can only ever add or subtract an absolute maximum of 3 degrees either side of my 1050rpm target, this helps ensure the system is only really fine trimming which delivers a super smooth idle with no surging or over/under shooting of my 1050rpm target.As it suggests moving the moment of ignition around which in turn will effect the mixture
A simple way of describing it is if you advance your timing your engine revs will rise thus negating the need for idle control so much.
The Ecu uses set tables etc for this operation if my 5 mins reading is correct. Actual crank position and memory set positioning is being calculated to give accuracy of piston position as advancing can as we know be very dangerous.
The scatter spark is a calculator that’s deciding where best to advance spark to. Is that about right?
Edited by Classic Chim on Thursday 2nd November 20:51
If I put my power steering in full lock and the rad fans chime in at the same time, which is quite common when I'm parking, engine speed may well fall more than the max scatter spark controlled 150rpm either side of my target, in this situation it's a bit much to expect just 3 degrees of advance to pull the idle up to my 1050rpm target so this is when the idle air control valve steps in to help. The Bosch rotary idle valve will bleed in just enough air to get the idle back up to the target without overshooting it, at which point the less aggressive Scatter Spark strategy steps back in.
If you've ever set the ignition timing on a car running a distributor you'll notice when you rotate the distributor one way you'll be advancing the timing and the idle speed will increase, rotate the distributor the other way and you'll be retarding the timing and the idle speed will fall. Scatter Spark idle management is just a computer controlled version of you turning the distributor one way and then the other very slightly and super quickly to hit your target idle speed.
What many don't realise is, Scatter Spark idle management in it's most basic form is as old as the internal combustion engine itself, on vintage cars and motorcycles it was quite common to have a lever on the steering wheel or handlebar to allow the driver/rider to adjust the engine's ignition timing from the comfort of his seat. It was also normal to have an idle lever that worked independently of the main throttle, which if you think about it is just the ancient manual equivalent of an PWM idle air control valve. With both the advance/retard lever and the idle lever a skilled driver could achieve the perfect start and idle management, as well as allowing him to perform the function of centrifugal and vacuum automatic advance/retard offered by later distributor ignition systems.
In the case of a vintage car the driver's brain was effectively performing the function of a modern ECU, obviously computer controlled Scatter Spark idle management works way faster than any driver could ever hope to achieve with an advance/retard lever, but the truth is the basic principle is exactly the same as it was back in the 1920's and 30's. In practice Scatter Spark is checking and fine trimming my idle speed against my target every 0.35 of a second or roughly 174 times a minute, and only adding or subtracting a maximum of 3 degrees at any given moment which is really quite a small ignition adjustment. In practice, most of the time because it's working so fast it only ever needs to add or subtract a degree or two to hit my target, the result of these super rapid and tiny changes in ignition timing being an extremely stable idle, especially when combined with a closed loop idle AFR target of 13.3:1 and the right base idle ignition timing in the first place.
For the purposes of fine trimming idle speed when there's no load on the engine my preference is always to control the idle speed by altering ignition timing slightly, rather than the air bleed method. No matter how clever and fast the ECU is, the idle air control valve its controlling is really just creating a managed vacuum leak, and for many reasons on any internal combustion engine all vacuum leaks (even managed ones) should be considered a bad thing, and so should be avoided wherever and whenever possible. Yes I have an idle air control valve fuel correction table that helps ensure I don't go lean when air is being bled in, but even with this feature the truth is managing my idle using ignition timing is (up to a point) simply a better strategy, mostly because it works faster, makes finer and more subtle adjustments, and has less of an effect on my carefully calibrated base idle air fuel ratio than the cruder and clumsier air bleed method.
Cold start is different, in the case of applying the advantageous fast idle condition during cold start the idle air control valve works better than ignition, because during cold start you wouldn't want to advance your ignition timing by the amount it would take to hit my 1250rpm cold start fast idle target. Idle air control also works better when the engine suddenly comes under load (power steering on full lock or rad fans coming on), but in all other situations fine trimming my idle by 50,100 or 150rpms is better performed by Scatter Spark. To get all this working correctly it's essential the base idle setting is tuned perfectly when the engine is warm before you even plug your laptop into the ECU, this is achieved using the base idle screw and throttle butterfly rest position with all closed loop features turned off. You can then turn your attention to getting the calibration perimeters setup correctly on both the air and ignition closed loop idle strategies. Get it all right and the air/ignition strategies work brilliantly together, what I end up with is my closed loop idle target being maintained perfectly 95% of the time by merely adding and subtracting just a few degrees of timing, the more aggressive air bleed system only being required during cold start or when the engine comes under heavy load spikes at idle.
Like I say, it's the best of both worlds
I really want to get into this subject more and a few lessons off the Mbe master as in Jay at Powers on negotiating around the software so I can start to understand and contribute to these threads with more than just the experience of using it seems like a good idea to me.
The one thing I can’t question is how good it does it’s job.
I can sort of feel-it all work now, understand enough to appreciate what’s its doing rather than just enjoy it.
Sooner or later a coil pack or a sensor might play up, I need to be able to work on the system with base knowledge at least.
The way I see it, it will be just like fixing the CUX but once every 10 years rather than every other drive I do like the CUX by the way, but it ain’t this is it.
As someone else said it’s all in the timing.
A multi point trigger wheel is keeping a close eye on the crank position so we have a good indication of where the piston top is, this is what’s allowing mappers to use scatter spark to take advantage of advancing the ignition and maximising fuelling and gaining bang for buck.
In all honesty my car feels a lot faster since MBE
Just everywhere it’s instant and deep routed power.
Not so much in a flat out drag test but as in cruising along at low revs then asking of it, it’s just gruntier everywhere.
Weirdly flat out on a drag strip even at high revs it feels like the sparking system is under employed. 6000 revs ain’t a lot these days is it.
I’ve enjoyed the honeymoon period,, 2 years now of almost complete ignorant bliss...
Check the plugs. Change the oil and filters that’s about it.
It’s about time I learnt about the Ecu and it’s functions.
I think it was Stevesprint who said, the biggest thing you’ll notice is you use less revs to pull away and parking can be done using tickover just about.
Up hills they sort of don’t exist,,,, Power.
It’s more able to hold a set speed on motorways which is something that used to annoy me, I’d have to check and regulate throttle as I’d be speeding up or even slowing down slightly, it’s now rock solid set at the throttle settings you ask for which to me is really important. It’s like magic at any setting, fabulous.
I could imagine a bloke who knows his onions on a damp skid pan with such fine throttle responce could do some clever things sideways for hours without spinning,,,,, now that’s a challenge, I have some old hard road tyres that need destroying,,, whens the next Skid pan morning session
It’s important to me the car feels like a precision instrument and boy does it.
The shocks are tired out but hey,,
The one thing I can’t question is how good it does it’s job.
I can sort of feel-it all work now, understand enough to appreciate what’s its doing rather than just enjoy it.
Sooner or later a coil pack or a sensor might play up, I need to be able to work on the system with base knowledge at least.
The way I see it, it will be just like fixing the CUX but once every 10 years rather than every other drive
I do like the CUX by the way, but it ain’t this is it. As someone else said it’s all in the timing.
A multi point trigger wheel is keeping a close eye on the crank position so we have a good indication of where the piston top is, this is what’s allowing mappers to use scatter spark to take advantage of advancing the ignition and maximising fuelling and gaining bang for buck.
In all honesty my car feels a lot faster since MBE
Just everywhere it’s instant and deep routed power.
Not so much in a flat out drag test but as in cruising along at low revs then asking of it, it’s just gruntier everywhere.
Weirdly flat out on a drag strip even at high revs it feels like the sparking system is under employed. 6000 revs ain’t a lot these days is it.
I’ve enjoyed the honeymoon period,, 2 years now of almost complete ignorant bliss...
Check the plugs. Change the oil and filters that’s about it.
It’s about time I learnt about the Ecu and it’s functions.
I think it was Stevesprint who said, the biggest thing you’ll notice is you use less revs to pull away and parking can be done using tickover just about.
Up hills they sort of don’t exist,,,, Power.
It’s more able to hold a set speed on motorways which is something that used to annoy me, I’d have to check and regulate throttle as I’d be speeding up or even slowing down slightly, it’s now rock solid set at the throttle settings you ask for which to me is really important. It’s like magic at any setting, fabulous.
I could imagine a bloke who knows his onions on a damp skid pan with such fine throttle responce could do some clever things sideways for hours without spinning,,,,, now that’s a challenge, I have some old hard road tyres that need destroying,,, whens the next Skid pan morning session
It’s important to me the car feels like a precision instrument and boy does it.
The shocks are tired out but hey,,
I dont have before and after figures but mine certainly had quite a niticeable power increase in the top rpm range.
I think the general consensus is because of the better fueling and spark timing you will definately gain bhp. How much obviously depends how far off your original setup was.
I think the general consensus is because of the better fueling and spark timing you will definately gain bhp. How much obviously depends how far off your original setup was.
I would rather have a sweet running road car that I track now and then than go all out for bhp I'm sure Mat and Joolz will deliver that for me. I just thought it would be great to break the 300bhp in a 4lt. Having said that once the Emerald is fitted it would be much easier to fit a turbo in the future.
trev4 said:
Although I am having the Emerald system fitted for reliability reasons I was wondering if I will gain any more hp I need another 16hp to get my 4lt to 300, thoughts please.
I wouldn't count on it, I'm assuming your target of 300hp is a peak power figure?When talking engine tuning, peak power figures are such a tiny part of the story they really shouldn't be our sole focus, because lets face it you can easily make the engine's peak power with a carb and a dizzy. You just need the dizzy to give the right number of degrees of advance and the carb to deliver the right AFR.
The exact AFR & timing figures settled on by your mapper to produce peak power will be determined by the octane of fuel used, elevation above sea level, the air temp on the day, and your engine specification. The peak figure and everything in between idle and peak should be found using a dyno. if your compression ratio is still in the region of 9.5:1 you'll probably end up with an absolute maximum of 36 degrees @ 4,000rpm and staying there until 5,500rpm , after 5.5k (poss 6k) you'll be pulling timing slightly as you fall away from peak power. On the fueling side you'll probably find 12.8:1 showing 98kPa @ WOT is about where you'll end up, any richer and you'll likely make no more power so just be wasting fuel.
So if it's peak horsepower pub bragging rights you're shooting for you can easily achieve all the above with with a distributor and a carb, the 14CUX offers better fueling control than most carbs as will your Emerald, but neither will give you any peak power benefit because the engine doesn't know or care if it's getting 36 degrees and 12.8:1 from a dizzy and carb or the worlds most sophisticated engine management system.... 36 degrees and 12.8:1 @ 6k WOT is still 36 degrees and 12.8:1 no matter how its achieved.
However, the 14CUX airflow meter is in itself a small restriction, when you move to Emerald you'll be doing away with this restriction as you'll be binning your hot wire AFM for a straight through pipe with an air temp sensor in it, which is zero restriction. This reduction in intake restriction may give you 3-5% more power at the very top end if you're lucky.... but that's about it.
But here's the thing, fixating on peak power figures is not really what engine tuning is all about, like I say you can easily achieve the timing and air fuel ratio you need to achieve peak power with a basic distributor and carb setup. Beyond the tiny 3-5% that removing the AFM will give you, what you're properly mapped Emerald is going to deliver is better cold and hot starts, a smoother idle, lower engine and exhaust temps at idle, better throttle response, better low speed drivability and a measurable increase in fuel economy.
The holy grail for any engine designer and tuner is to deliver peak power over the widest possible rev band, producing peak power at maximum RPM and wide open throttle is the easy bit, because the truth is you could actually achieve that with locked timing and a bucket of petrol with the right sized hole in the bottom of it
Try not to fall into the peak power bragging rights arms race, it BS really, what you're buying with your new Emerald system is greater efficiency through far superior control of timing and fueling, not a bigger peak horsepower number. Quite simply you should end up with an engine that's nicer and more rewarding to use everywhere from idle to peak power. And it's that big fat world of loveliness between idle and peak power you spend your time in, in fact the uncomfortable truth none of us want to admit is if you really analyze your driving on our crowded UK roads the important area of benefit will be found where you spend 95% of your time.. and that is between idle and 2,500rpm with a bit of 3,000rpm motorway cruising thrown in.
Step away from the peak power arms race for a moment, and try to focus on the true benefits your Emerald will deliver...
- Better cold & hot starts
- Better idle quality
- Lower engine & exhaust temps at idle
- Better throttle response
- Better drivability
- Better fuel economy
- Potentially better overall reliability
ChimpOnGas said:
trev4 said:
Although I am having the Emerald system fitted for reliability reasons I was wondering if I will gain any more hp I need another 16hp to get my 4lt to 300, thoughts please.
I wouldn't count on it, I'm assuming your target of 300hp is a peak power figure?When talking engine tuning, peak power figures are such a tiny part of the story they really shouldn't be our sole focus, because lets face it you can easily make the engine's peak power with a carb and a dizzy. You just need the dizzy to give the right number of degrees of advance and the carb to deliver the right AFR.
The exact AFR & timing figures settled on by your mapper to produce peak power will be determined by the octane of fuel used, elevation above sea level, the air temp on the day, and your engine specification. The peak figure and everything in between idle and peak should be found using a dyno. if your compression ratio is still in the region of 9.5:1 you'll probably end up with an absolute maximum of 36 degrees @ 4,000rpm and staying there until 5,500rpm , after 5.5k (poss 6k) you'll be pulling timing slightly as you fall away from peak power. On the fueling side you'll probably find 12.8:1 showing 98kPa @ WOT is about where you'll end up, any richer and you'll likely make no more power so just be wasting fuel.
So if it's peak horsepower pub bragging rights you're shooting for you can easily achieve all the above with with a distributor and a carb, the 14CUX offers better fueling control than most carbs as will your Emerald, but neither will give you any peak power benefit because the engine doesn't know or care if it's getting 36 degrees and 12.8:1 from a dizzy and carb or the worlds most sophisticated engine management system.... 36 degrees and 12.8:1 @ 6k WOT is still 36 degrees and 12.8:1 no matter how its achieved.
However, the 14CUX airflow meter is in itself a small restriction, when you move to Emerald you'll be doing away with this restriction as you'll be binning your hot wire AFM for a straight through pipe with an air temp sensor in it, which is zero restriction. This reduction in intake restriction may give you 3-5% more power at the very top end if you're lucky.... but that's about it.
But here's the thing, fixating on peak power figures is not really what engine tuning is all about, like I say you can easily achieve the timing and air fuel ratio you need to achieve peak power with a basic distributor and carb setup. Beyond the tiny 3-5% that removing the AFM will give you, what you're properly mapped Emerald is going to deliver is better cold and hot starts, a smoother idle, lower engine and exhaust temps at idle, better throttle response, better low speed drivability and a measurable increase in fuel economy.
The holy grail for any engine designer and tuner is to deliver peak power over the widest possible rev band, producing peak power at maximum RPM and wide open throttle is the easy bit, because the truth is you could actually achieve that with locked timing and a bucket of petrol with the right sized hole in the bottom of it
Try not to fall into the peak power bragging rights arms race, it BS really, what you're buying with your new Emerald system is greater efficiency through far superior control of timing and fueling, not a bigger peak horsepower number. Quite simply you should end up with an engine that's nicer and more rewarding to use everywhere from idle to peak power. And it's that big fat world of loveliness between idle and peak power you spend your time in, in fact the uncomfortable truth none of us want to admit is if you really analyze your driving on our crowded UK roads the important area of benefit will be found where you spend 95% of your time.. and that is between idle and 2,500rpm with a bit of 3,000rpm motorway cruising thrown in.
Step away from the peak power arms race for a moment, and try to focus on the true benefits your Emerald will deliver...
- Better cold & hot starts
- Better idle quality
- Lower engine & exhaust temps at idle
- Better throttle response
- Better drivability
- Better fuel economy
- Potentially better overall reliability
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