Discussion
spitfire4v8 said:
I remain unconvinced
The stepper motor is just an air bleed, an electronic base idle screw if you like, while it is controlled by the same ECU the computer isn't really directly sharing mass air flow information with the stepper motor function as suggested, the stepper is just instructed to open by X number of steps based on the target idle speed and or coolant temp (cold start).The one and only reason Land Rover plumbed the stepper motor into the throttle body is simply because it ensures the air it draws is filtered, the problem with plumbing it into the throttle body (and its only a slight issue by the way) is it's drawing on turbulent fast moving air. In my humble opinion it would be far better to simply let it draw still filtered air from true atmosphere. it certainly doesn't matter a jot if it's drawing on air that's had it's mass measured by the ECU, because the ECU only does this to allow it to make fueling corrections. The important bit as far as I'm concerned is the air is filtered, oh and that air is not turbulent or moving fast over the port the stepper is pulling it from.
On the subject of ignition timing I can only share my own experience of running different timing numbers at idle, obviously with a stand alone engine management system you enjoy the privilege of being able to run what ever number you wish and changing that number in seconds with a few key strokes on your laptop. Within moments I can run 8 degrees, 10 degrees, 15 degrees, 18 degrees, 22 degrees ect ect ect, quite simply this gives the very real advantage of picking whatever number genuinely works best. This supported by a good ear for these things and experience of 1960's engines including V8s that all tended to run manifold vacuum to the vac advance unit is what ultimately gave birth to the idea of the distributor crowd experimenting with running a bit more timing at idle.
If 18-22 degrees on my Canems equipped 4.0 Chimaera running a V8D Stealth camshaft definitely works better than the 10-12 degrees you get with the standard distributor setup, which it definitely does, there's absolutely no reason why people still on a distributor shouldn't also look to run 18-22 degrees too. All the theory clearly points to them enjoying the same benefits so of course the easiest way by far to add the 8-10 degrees at idle on a distributor setup is simply ditch the emissions based ported vacuum strategy and apply full manifold vacuum to the vac advance unit, which is exactly how it was done back in the good old pre emission days.
But I'm not pushing the idea on anyone, even though there's an overwhelming body of evidence to suggest the concept would work well for others what we really needed was someone still running a distributor to step up to the plate and test the idea out. This challenge was kindly taken up by Stuart Knight (StuVT) who I'd like to point out I've never met before or even shared a PM with, luckily for us all Stuart conducted the tests in a very clinical way and from what I can tell he honestly recorded and communicated his findings without being influenced in either direction.
So in summary I can only quote StuVT, because the truth is as far as I can tell he's the only person to have tried the idea of switching from ported vacuum to full vacuum, but I have to say his comments seem pretty conclusive to me and are best summarised by this exchange....
ChimpOnGas said:
Q: Now you've experienced the effects of full vacuum to your vac advance unit, will you be going back to the standard ported vacuum setup or leaving it as it is?
StuVT said:
I can answer your question easily... 'No way Jose!!.... Maybe for 1 hour a year for the MOT if its absolutely necessary when the main cat is back in.
Clearly we could do with a few more TVR enthusiasts trying the idea and reporting back on their findings, but that's a pretty sound endorsement from StuVT right there if you ask me, to be honest it didn't really surprise me it worked so well because like I say I can at a press of the key run whatever timing I choose. The fact I choose to idle on petrol at 18 degrees and at 22 degrees when I'm burning LPG hopefully (and supported by Stuart's findings with his distributor equipped Chim)..... says everything we need to know.If others remain unconvinced then that's fine, they should simply stick with ported vacuum and the 10-12 degrees at idle, I'm not a trader so unlike others I'm not selling anything here, all I'm doing is freely sharing concepts and ideas with fellow enthusiasts because that's exactly what the forum is for
The point of the stepper being connected to the throttle body is so that when the stepper opens the extra airflow is seen by the air flow meter and the fuelling adjusted accordingly. To have it open to fresh air means when it opens the plenum sees extra air, but the fuelling isn't altered because the air flow meter doesn't see the extra air. result is weaker running (until the lambda control can sense and correct for it)
Whether I'm a trader or not doesn't change the fact that suggesting people with a lucas ECU have their stepper drawing from fresh air and bypassing the air flow meter is bad advice.
Whether I'm a trader or not doesn't change the fact that suggesting people with a lucas ECU have their stepper drawing from fresh air and bypassing the air flow meter is bad advice.
Hmmmmm 
If that's the case then I stand corrected, does it also measure both the air/blowby mix from the O/S rocker cover and the air from the throttle body that both go directly into the plenum completely bypassing the throttle butterfly?
I guess at least one of the two has passed through the airflow meter
I'd put money on the benefits of letting the stepper breath nice still air from atmosphere will outweigh any negative impact, because at the end of the day the the lambda sensors would pick up any leaning and the ECU will correct accordingly. One of the early lessons drummed into me was 'fundamentally all induction leaks are bad for engine behavior', and the engine doesn't care if they are managed induction leaks or accidental ones either.
I still stand by this good advice given to me by the very experienced time served mechanics I worked with, and I can certainly understand why the Powers MBE engine management system doesn't even come with an idle air control valve, it's perfectly clear to me why they exclusively chose to use scatter spark to manage idle speed instead. To some degree I myself followed their lead by activating scatter spark on my Canems system, and with good results, when I did so I couldn't help hearing the "all induction leaks are bad" lesson ringing in my ears again. It also prompted me to look again at the crankcase breathing system which if you study it, links full vacuum in the plenum directly to atmosphere at the throttle body and with no control valve at all.
You've picked on one tiny point in my long list of suggested improvements, the timing idea for example definitely does seem to work and has been proven to do so by others too. I've also been saying for years the plug extenders are a point of failure and most now seem to accept this, the NGK B7ECS plugs TVR specified were also a bad choice and there are definitely better solutions out there that people are finally warming too as well.
All I'm saying here is there are a number of things people can do themselves with their TVR that can genuinely help them achieve a better driving experience, and without always needing to pay a professional for their services. This fits nicely with the owner maintained enthusiast theme of the forum and the cars themselves. These car's are famous for drivability issues born out by the huge number of posts on the subject on Piston Heads, there's definitely a pattern here.
Lets be honest now, the 14CUX isn't what you'd call a great system, but recruiting a specialist to work on it may not be prove to be the best option for some either, so I'm just sharing ideas with my fellow enthusiasts. I'm almost embarrassed to say it now, but in the early days I myself trusted my 14CUX Chimaera to MA who as it turned out wasn't the engine tuning guru he'd been held up as. Apart from finding him kipping in my car and trying to sell me a completely unnecessary injector cleaning service of my newly reconditioned injectors, he completely failed to solve the hunting and even admitted he was defeated by it. I'd also assumed his mapping session meant he'd burn me a new bespoke chip but apparently I was mistaken, what I actually got was a very expensive serious of basic ignition timing, throttle pot, throttle butterfly gap checks ect.... none of which demanded adjustment because I'd already done all that myself.
The bottom line is there's lots of things enthusiasts can do themselves to make there TVR run better, I've just tried to share a few that clearly worked for me, all I hope is my sharing might serve to help others in some way as this is my only reward, because ultimately this is not a business for me... as it is for some.
If that's the case then I stand corrected, does it also measure both the air/blowby mix from the O/S rocker cover and the air from the throttle body that both go directly into the plenum completely bypassing the throttle butterfly?
I guess at least one of the two has passed through the airflow meter
I'd put money on the benefits of letting the stepper breath nice still air from atmosphere will outweigh any negative impact, because at the end of the day the the lambda sensors would pick up any leaning and the ECU will correct accordingly. One of the early lessons drummed into me was 'fundamentally all induction leaks are bad for engine behavior', and the engine doesn't care if they are managed induction leaks or accidental ones either.
I still stand by this good advice given to me by the very experienced time served mechanics I worked with, and I can certainly understand why the Powers MBE engine management system doesn't even come with an idle air control valve, it's perfectly clear to me why they exclusively chose to use scatter spark to manage idle speed instead. To some degree I myself followed their lead by activating scatter spark on my Canems system, and with good results, when I did so I couldn't help hearing the "all induction leaks are bad" lesson ringing in my ears again. It also prompted me to look again at the crankcase breathing system which if you study it, links full vacuum in the plenum directly to atmosphere at the throttle body and with no control valve at all.
You've picked on one tiny point in my long list of suggested improvements, the timing idea for example definitely does seem to work and has been proven to do so by others too. I've also been saying for years the plug extenders are a point of failure and most now seem to accept this, the NGK B7ECS plugs TVR specified were also a bad choice and there are definitely better solutions out there that people are finally warming too as well.
All I'm saying here is there are a number of things people can do themselves with their TVR that can genuinely help them achieve a better driving experience, and without always needing to pay a professional for their services. This fits nicely with the owner maintained enthusiast theme of the forum and the cars themselves. These car's are famous for drivability issues born out by the huge number of posts on the subject on Piston Heads, there's definitely a pattern here.
Lets be honest now, the 14CUX isn't what you'd call a great system, but recruiting a specialist to work on it may not be prove to be the best option for some either, so I'm just sharing ideas with my fellow enthusiasts. I'm almost embarrassed to say it now, but in the early days I myself trusted my 14CUX Chimaera to MA who as it turned out wasn't the engine tuning guru he'd been held up as. Apart from finding him kipping in my car and trying to sell me a completely unnecessary injector cleaning service of my newly reconditioned injectors, he completely failed to solve the hunting and even admitted he was defeated by it. I'd also assumed his mapping session meant he'd burn me a new bespoke chip but apparently I was mistaken, what I actually got was a very expensive serious of basic ignition timing, throttle pot, throttle butterfly gap checks ect.... none of which demanded adjustment because I'd already done all that myself.
The bottom line is there's lots of things enthusiasts can do themselves to make there TVR run better, I've just tried to share a few that clearly worked for me, all I hope is my sharing might serve to help others in some way as this is my only reward, because ultimately this is not a business for me... as it is for some.
cog said : does it also measure both the air/blowby mix from the O/S rocker cover and the air from the throttle body that both go directly into the plenum completely bypassing the throttle butterfly?
earlier I said : adding air to the plenum that ISN'T going through the air flow meter. (notwithstanding the fact that the std breather hoses do this anyway, but putting the breather upstream of the air flow meter was presumably the worse of two evils ...)
earlier I said : adding air to the plenum that ISN'T going through the air flow meter. (notwithstanding the fact that the std breather hoses do this anyway, but putting the breather upstream of the air flow meter was presumably the worse of two evils ...)
spitfire4v8 said:
cog said : does it also measure both the air/blowby mix from the O/S rocker cover and the air from the throttle body that both go directly into the plenum completely bypassing the throttle butterfly?
earlier I said : adding air to the plenum that ISN'T going through the air flow meter. (notwithstanding the fact that the std breather hoses do this anyway, but putting the breather upstream of the air flow meter was presumably the worse of two evils ...)
Understood and agreed, more evidence the 14CUX is a very challenged system with plenty room for improvement, the poor thing clearly doesn't even really know exactly how much air the engine is ingesting, even the ancient but elegantly simple SU carburetor does a better job than that!earlier I said : adding air to the plenum that ISN'T going through the air flow meter. (notwithstanding the fact that the std breather hoses do this anyway, but putting the breather upstream of the air flow meter was presumably the worse of two evils ...)
Revealingly I had a close look at a friends VW Syncro the other day, for those that don't know a VW Syncro is a 4x4 T3 bus manufactured in limited numbers from 1985-1992 that also used the Bosch L-Jetronic injection system and a distributor, and as we know the Lucas 14CUX is really a licensed copy of this L-Jetronic Bosch system.
Anyway, my point is it made an interesting comparison and what I discovered was there were actually some key differences, just studying the crankcase breather and idle valve arrangement convinced me the guys at Lucas and Land Rover decided they knew best and had set about making changes to what the Germans had carefully developed
. Of course this VW Syncro with it's pure un-messed with original Bosch L-Jetronic injection system and a distributor ran like a Swiss watch, further proof of how adept the Brits were at ballsing up a perfectly good injection system
. Just another example of why we lost our motor industry as we foolishly persevered with an ancient old Buick lump designed in the late 1950's and tried to make it meet modern emissions standards using a messed with Bosch injection system.No wonder BMW walked into Land Rover and took it over in 2000
Dave your mates VW should be running the Bosch Digifant system which is a flapper set up with mapped ign but a bare bones dizzy with just the hall switch fitted and batch inj but does monitor knock too, regarding air leaks only unmetered ones are bad its all the butterfly or stepper/ICV really are is an air leak 
but ..... a metered/monitored one , advance at idle and low speeds are often conservative on production stuff because lots of advance is bad for NOx levels when combined with other factors
but ..... a metered/monitored one , advance at idle and low speeds are often conservative on production stuff because lots of advance is bad for NOx levels when combined with other factors Sardonicus said:
Dave your mates VW should be running the Bosch Digifant system which is a flapper set up with mapped ign but a bare bones dizzy with just the hall switch fitted and batch inj but does monitor knock too, regarding air leaks only unmetered ones are bad its all the butterfly or stepper/ICV really are is an air leak but ..... a metered/monitored one , advance at idle and low speeds are often conservative on production stuff because lots of advance is bad for NOx levels when combined with other factors
Simon for fear of turning this into a pishing contest I have to correct you mate. but ..... a metered/monitored one , advance at idle and low speeds are often conservative on production stuff because lots of advance is bad for NOx levels when combined with other factors My mate's VW Syncro actually runs a DH code 1900cc (83 bhp) engine that came with "Digijet" (Digital Jet-tronic)... not Digifant!
And as we all know the Digijet is just Volkswagen's licensed version of the Bosch L-Jetronic system just as the Lucas 14CUX was the Lucas licensed version of the Bosch L-Jetronic system, so I make no apology for referring to my mate's system in my previous post as Bosch L-Jetronic because "Digijet" is Bosch L-Jetronic! It just received a few very minor but clever VW developed add-ons that the Range Rover and our cars probably could have benefited from.
This was my very point in my previous post!
The airflow meter type does not actually define the system, its just a sensor that evolved from the variable resistor air flap type to the 'Hot Wire' MAF type that was actually developed by Hitachi. Getting hung up on the AFM type is irrelevant because essentially they both measure air, it's just the hot wire type can kind of determine it's mass as well as the flow measured by the flap type, the important word here is air which defined the L-Jetronic system because L stands for Luft which means air in German.
Just like the VW Digijet was a VW licensed version of the Bosch L-Jetronic system with a few minor VW developed additions that helps my mate's Syncro run like a Swiss watch.... the 14CUX was the Lucas licensed version of the Bosch L-Jetronic system with a few minor but critically important omissions, because Lucas thought they knew best
The fundamental point to take away here is all the above are Bosch L-Jetronic systems, and we can learn from both Bosh and VW when studying the Lucas 14CUX, unlike VW Lucas most definitely did not enhance the Bosch L-Jetronic when they got hold of it...
The Digifant system you are incorrectly suggesting my mate's bus uses actually arrived with the MV code 2100cc (95hp) engine, Digifant is of course a VW tweaked cousin of Bosch Motronic, there are fundamental differences with this system which is why they were no longer referred to as L-Jetronic.
ChimpOnGas said:
.... And as we all know the Digijet is just Volkswagen's licensed version of the Bosch L-Jetronic system just as the Lucas 14CUX was the Lucas licensed version of the Bosch L-Jetronic system...
And, just for the sake of completeness ... as we all know Jetronic was just Bosch's licensed version of the Bendix Electrojector system - so simply another case of we'll copy that but engineer it better!
ChimpOnGas said:
Sardonicus said:
Dave your mates VW should be running the Bosch Digifant system which is a flapper set up with mapped ign but a bare bones dizzy with just the hall switch fitted and batch inj but does monitor knock too, regarding air leaks only unmetered ones are bad its all the butterfly or stepper/ICV really are is an air leak but ..... a metered/monitored one , advance at idle and low speeds are often conservative on production stuff because lots of advance is bad for NOx levels when combined with other factors
Simon for fear of turning this into a pishing contest I have to correct you mate. but ..... a metered/monitored one , advance at idle and low speeds are often conservative on production stuff because lots of advance is bad for NOx levels when combined with other factors My mate's VW Syncro actually runs a DH code 1900cc (83 bhp) engine that came with "Digijet" (Digital Jet-tronic)... not Digifant!
And as we all know the Digijet is just Volkswagen's licensed version of the Bosch L-Jetronic system just as the Lucas 14CUX was the Lucas licensed version of the Bosch L-Jetronic system, so I make no apology for referring to my mate's system in my previous post as Bosch L-Jetronic because "Digijet" is Bosch L-Jetronic! It just received a few very minor but clever VW developed add-ons that the Range Rover and our cars probably could have benefited from.
This was my very point in my previous post!
The airflow meter type does not actually define the system, its just a sensor that evolved from the variable resistor air flap type to the 'Hot Wire' MAF type that was actually developed by Hitachi. Getting hung up on the AFM type is irrelevant because essentially they both measure air, it's just the hot wire type can kind of determine it's mass as well as the flow measured by the flap type, the important word here is air which defined the L-Jetronic system because L stands for Luft which means air in German.
Just like the VW Digijet was a VW licensed version of the Bosch L-Jetronic system with a few minor VW developed additions that helps my mate's Syncro run like a Swiss watch.... the 14CUX was the Lucas licensed version of the Bosch L-Jetronic system with a few minor but critically important omissions, because Lucas thought they knew best
The fundamental point to take away here is all the above are Bosch L-Jetronic systems, and we can learn from both Bosh and VW when studying the Lucas 14CUX, unlike VW Lucas most definitely did not enhance the Bosch L-Jetronic when they got hold of it...
The Digifant system you are incorrectly suggesting my mate's bus uses actually arrived with the MV code 2100cc (95hp) engine, Digifant is of course a VW tweaked cousin of Bosch Motronic, there are fundamental differences with this system which is why they were no longer referred to as L-Jetronic.
so not much similarity to the Lucas hotwire system 
its not a pissing contest by the way purely because I couldn't give a monkeys 
just trying to keep things in perspective is all Edited by Sardonicus on Tuesday 20th March 15:37
Definitely all variants of the Bosch L-Jetronic family, the VW version had some good additions and the Lucas one had some omissions.... because either Lucas didn't quite understand the system fully or they were simply trying to cut costs. Either way they are all Bosch L-Jetronic, neither VW or Lucas invented the system... Bosch did. Both VW & Lucas just licensed Bosch's excellent L-Jetronic system and both fiddled with it very slightly with very different levels of success.
I dont care what anyone says, the hose that directly links the plenum under full vacuum with atmosphere at the throttle body is not a great idea, just as the 10-12 degrees at idle and the emissions based ported vacuum idea that supports it is poor idea for drivability too. I also don't buy the brilliance of the 14CUX hot wire MAF and it's ability to accurately measure every last gram or air that passes into the engine, I guarantee you it's missing a lot. The 14.7:1 the 14CUX shoots for isn't ideal either but that's far less important, it's really the ignition timing and vacuum leaks that are the issue. Lift the throttle just off idle on any 14CUX TVR, keep the butterfly open a fraction and hold it there, and in my experience most Chims/Griffs demonstrate a clearly audible lean misfire like this, mine did it on the 14CUX and others do it too.
Everyone knows lean mixtures are harder to strike, and the flame front propagates the combustion chamber slower when you run lean mixtures too.... because quite simply a lean mixture burns slower. Both of these unavoidable characteristics of the lean mixture demand that ignition is initiated earlier. LPG is 110Ron so is extremely resistant to detonation, but that's not why we run more timing on this fuel, LPG actually behaves in a very similar way to a lean petrol mixture which is why just like a lean petrol mixture it's advantageous to run more timing when you're burning gas.
When StuVT switched from ported vacuum to full manifold vacuum he didn't change his lean AFR at all, what he did was initiate combustion a full 10 degrees earlier at idle and just off idle as he pulled away which helped him burn the lean mixture more completely by the time the crank had reached 15 degrees ATDC, in turn this helped him deliver something far closer to Maximum Brake Torque timing. This is why he reported feeling more torque and a smoother drive, the system is still shooting for 14.7:1 and sucking air where it shouldn't too, but at least now that lean mixture is being burnt more completely.
There's no question more timing at and just off idle while eliminating all erroneous induction leaks definitely delivers a smoother running 14CUX TVR, and all this without even touching the fueling. Actually as StuVT found out, the benefits go higher up the rev range all the way through the shunting zone before you reach 2,000rpm where these things become way less important, this is because the vac advance unit doesn't only add timing at idle and cruise, it's adding some timing around the shunting zone too.
Now of course if you're looking for better low speed drivability you could always lob in a bit more fuel, and most with an after market ECU will do just that, lets face it (up to a point) this strategy has been the tried and trusted path to smoother engine operation since time in memorial. Richer mixtures burn easier and faster so you need less timing, so if you're still running a retarded 10-12 at idle it stands to reason it'll work better with a richer mixture, this is how the richer 14CUX chips help... a bit.
However, while the more fuel strategy is indeed very effective, its also a very crude approach to engine tuning, clearly it would be a far far more efficient approach to initiate the burn of a slightly leaner mixture at the right moment so you burn it completely and so extract the maximum work from it..... and of course the truth is your average 14CUX RV8 TVR is absolutely crying out for this very approach
I dont care what anyone says, the hose that directly links the plenum under full vacuum with atmosphere at the throttle body is not a great idea, just as the 10-12 degrees at idle and the emissions based ported vacuum idea that supports it is poor idea for drivability too. I also don't buy the brilliance of the 14CUX hot wire MAF and it's ability to accurately measure every last gram or air that passes into the engine, I guarantee you it's missing a lot. The 14.7:1 the 14CUX shoots for isn't ideal either but that's far less important, it's really the ignition timing and vacuum leaks that are the issue. Lift the throttle just off idle on any 14CUX TVR, keep the butterfly open a fraction and hold it there, and in my experience most Chims/Griffs demonstrate a clearly audible lean misfire like this, mine did it on the 14CUX and others do it too.
Everyone knows lean mixtures are harder to strike, and the flame front propagates the combustion chamber slower when you run lean mixtures too.... because quite simply a lean mixture burns slower. Both of these unavoidable characteristics of the lean mixture demand that ignition is initiated earlier. LPG is 110Ron so is extremely resistant to detonation, but that's not why we run more timing on this fuel, LPG actually behaves in a very similar way to a lean petrol mixture which is why just like a lean petrol mixture it's advantageous to run more timing when you're burning gas.
When StuVT switched from ported vacuum to full manifold vacuum he didn't change his lean AFR at all, what he did was initiate combustion a full 10 degrees earlier at idle and just off idle as he pulled away which helped him burn the lean mixture more completely by the time the crank had reached 15 degrees ATDC, in turn this helped him deliver something far closer to Maximum Brake Torque timing. This is why he reported feeling more torque and a smoother drive, the system is still shooting for 14.7:1 and sucking air where it shouldn't too, but at least now that lean mixture is being burnt more completely.
There's no question more timing at and just off idle while eliminating all erroneous induction leaks definitely delivers a smoother running 14CUX TVR, and all this without even touching the fueling. Actually as StuVT found out, the benefits go higher up the rev range all the way through the shunting zone before you reach 2,000rpm where these things become way less important, this is because the vac advance unit doesn't only add timing at idle and cruise, it's adding some timing around the shunting zone too.
Now of course if you're looking for better low speed drivability you could always lob in a bit more fuel, and most with an after market ECU will do just that, lets face it (up to a point) this strategy has been the tried and trusted path to smoother engine operation since time in memorial. Richer mixtures burn easier and faster so you need less timing, so if you're still running a retarded 10-12 at idle it stands to reason it'll work better with a richer mixture, this is how the richer 14CUX chips help... a bit.
However, while the more fuel strategy is indeed very effective, its also a very crude approach to engine tuning, clearly it would be a far far more efficient approach to initiate the burn of a slightly leaner mixture at the right moment so you burn it completely and so extract the maximum work from it..... and of course the truth is your average 14CUX RV8 TVR is absolutely crying out for this very approach
what i dont understand here:
if i use a valve in the hose going from the t-piece to the throttle for stopping this vacuum "leak"...i could also remove that hose, seal the connection on the t-piece, seal the connection on throttle-body.?
what i have done so far is: let the stepper motor suck fresh-air from enginebay via a filter and seal the corresponding connection on throttle-body
but what happend: the idle (cold start) was next to zero. why this?
do i need to increase base-idle after this "littlle" modification?
if i use a valve in the hose going from the t-piece to the throttle for stopping this vacuum "leak"...i could also remove that hose, seal the connection on the t-piece, seal the connection on throttle-body.?
what i have done so far is: let the stepper motor suck fresh-air from enginebay via a filter and seal the corresponding connection on throttle-body
but what happend: the idle (cold start) was next to zero. why this?
do i need to increase base-idle after this "littlle" modification?
Thread revival, sorry, not sorry. Referring back to CoG's earlier post (I know he's not on here any more), and other people's inputs:
Even though my car doesn't give me much shunting (though this might be down to the way I drive with the clutch), I'm going to implement the shift from ported vacuum to manifold, having sourced some suitable adapters from a hose specialist. Quite simply, I like the idea of a smoother running car and nicer pick up from low revs.
So, two questions:
I might implement the carbon canister re-routing to the induction pipe, but not sure how to do this - can anyone advise?
The crankcase gas hose point where it can pull air back from the throttle body - I'm interested to see if that makes a difference, though cannot find a suitable fitting. The Jeep PC849 that CoG refers to doesn't come up on searches, so does anyone know what this thing is? Alternatively a suitable 15mm one way valve that could be chopped into the silicone 15mm ID hose that's already there?
I don't want to be reversing lots of things for the MOT test unless it's easy - I'm not clear on which bits beyond the vacuum routing needs to be reversed - can anyone advise?
Even though my car doesn't give me much shunting (though this might be down to the way I drive with the clutch), I'm going to implement the shift from ported vacuum to manifold, having sourced some suitable adapters from a hose specialist. Quite simply, I like the idea of a smoother running car and nicer pick up from low revs.
So, two questions:
I might implement the carbon canister re-routing to the induction pipe, but not sure how to do this - can anyone advise?
The crankcase gas hose point where it can pull air back from the throttle body - I'm interested to see if that makes a difference, though cannot find a suitable fitting. The Jeep PC849 that CoG refers to doesn't come up on searches, so does anyone know what this thing is? Alternatively a suitable 15mm one way valve that could be chopped into the silicone 15mm ID hose that's already there?
I don't want to be reversing lots of things for the MOT test unless it's easy - I'm not clear on which bits beyond the vacuum routing needs to be reversed - can anyone advise?
If its the pcv valve your after its a very common part on American V8 engines.
I may have one in my magic shed if you want it posted foc i can take a look, no promises made as i cant remember when i last saw it!
Places like real steel will sell them, think they are pretty standard sizes.
OR here.
https://www.ebay.co.uk/itm/285220208256?var=0&...
Save your pennies though and go for an aftermarket management system, best money you will ever spend.
I think it cost me around £600 to diy a megasquirt install and it was a very interesting project, car felt night and day afterwards.
I may have one in my magic shed if you want it posted foc i can take a look, no promises made as i cant remember when i last saw it!
Places like real steel will sell them, think they are pretty standard sizes.
OR here.
https://www.ebay.co.uk/itm/285220208256?var=0&...
Save your pennies though and go for an aftermarket management system, best money you will ever spend.
I think it cost me around £600 to diy a megasquirt install and it was a very interesting project, car felt night and day afterwards.
Edited by Belle427 on Wednesday 6th September 07:33
Edited by Belle427 on Wednesday 6th September 07:43
I am honestly so keen to do that, and would certainly look at DIY for both cost and involvement/understanding.
I just need to get the £££ past the wife LOL.
In the meantime, I'm just adopting simple tweaks.
My car runs pretty well, though I don't want to get to a point of break before fixing/upgrading things.
Thank you kindly for the offer, I can get hold of a PCV valve (I contacted Real Steel), it will probably just require a bit of faffing to get it to fit between the 15mm T connector and the hose.
I also spoke with my local hose specialist, and they have a lovely one-way valve that would work, but it was coming in a £65 which feels a bit steep for a tweak.
I just need to get the £££ past the wife LOL.
In the meantime, I'm just adopting simple tweaks.
My car runs pretty well, though I don't want to get to a point of break before fixing/upgrading things.
Thank you kindly for the offer, I can get hold of a PCV valve (I contacted Real Steel), it will probably just require a bit of faffing to get it to fit between the 15mm T connector and the hose.
I also spoke with my local hose specialist, and they have a lovely one-way valve that would work, but it was coming in a £65 which feels a bit steep for a tweak.
So I dug around quite a bit, and found that PCV valves are awkward in that corner of the breather hose arrangement.
So I decided to try a breather one way valve which I found through Car Builder Solutions (part no NRV14A), also bought a new section of breather hose from Rimmer Bros (part no ERR4763P) to chop up, with the intention to retain the existing section of hose in case I need to reverse the idea.
All told around £20 delivered.
The parts look like this
With a bit of chopping and actually ended needing to use the straight section of the original hose to accommodate both the T connector and the valve tail (but that hose was about £8 delivered), and now it looks like this
I might add some jubilee clips, though the fit was grippy enough when I tugged at it.
Not sure how to rotate the photos...
So I'm exercising the theory, and have no idea if I'll notice the difference, but maybe this is part of a bigger process, as I now have the parts to add full manifold vacuum to the vac advance module on the dizzy - I'm just waiting to get my hands on a timing strobe gun to check the settings before I wade in.
Just in case it's useful for anyone out there.
So I decided to try a breather one way valve which I found through Car Builder Solutions (part no NRV14A), also bought a new section of breather hose from Rimmer Bros (part no ERR4763P) to chop up, with the intention to retain the existing section of hose in case I need to reverse the idea.
All told around £20 delivered.
The parts look like this
With a bit of chopping and actually ended needing to use the straight section of the original hose to accommodate both the T connector and the valve tail (but that hose was about £8 delivered), and now it looks like this
I might add some jubilee clips, though the fit was grippy enough when I tugged at it.
Not sure how to rotate the photos...
So I'm exercising the theory, and have no idea if I'll notice the difference, but maybe this is part of a bigger process, as I now have the parts to add full manifold vacuum to the vac advance module on the dizzy - I'm just waiting to get my hands on a timing strobe gun to check the settings before I wade in.
Just in case it's useful for anyone out there.
So i added a jubilee clip to either end of the one way valve, the other fittings feel solid enough (compared to the original set up).
Drove to work this morning (a 20-odd mile run of slow, then motorway), and noticed a whistle sound around 1500-2000 revs. Not big, and nothing else has been changed.
Should I add more jubilee clips all round, or could it be something else?
I'm going to implement the full manifold vacuum change soon too, and actually in investigating the parts for that I had to take out and measure the plug that holds the PAS reservoir bracket to the manifold, and refitted with a new crushable copper washer.
So it could be that, but assuming that's fine, any ideas?
plenum plug
breather hoses and valve
Drove to work this morning (a 20-odd mile run of slow, then motorway), and noticed a whistle sound around 1500-2000 revs. Not big, and nothing else has been changed.
Should I add more jubilee clips all round, or could it be something else?
I'm going to implement the full manifold vacuum change soon too, and actually in investigating the parts for that I had to take out and measure the plug that holds the PAS reservoir bracket to the manifold, and refitted with a new crushable copper washer.
So it could be that, but assuming that's fine, any ideas?
plenum plug
breather hoses and valve
It’s only done this since I added that valve.
I’ve just added a jubilee clip to every join, and I noticed that when I turn the engine off I can hear a hissing that sounds like depressurisation. I can squeeze the breather hose and it is clearly through that.
If the stepper is howling, is there a cure?
It’s never done this before…
I’ve just added a jubilee clip to every join, and I noticed that when I turn the engine off I can hear a hissing that sounds like depressurisation. I can squeeze the breather hose and it is clearly through that.
If the stepper is howling, is there a cure?
It’s never done this before…
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