Going Further For Less - I give you The 51mpg Chimaera
Discussion
'Ol Gasbag' just gets better and better
She's hitting her best average fuel economy figures ever, and now with the problematic idle valve disconnected she's driving smoother than I ever thought possible
A genuine LPG range of 317 miles at a very pocket friendly £0.11p a mile and she still pulls to 150mph and gets to sixty in 5 seconds, name we one other classic open British sports car that can do all that while turning in an average petrol fuel economy figure of 51.28mpg?
carsy said:
Good work Dave. It’s an impressive project.
What’s wrong with the idle valve.
Read this Ian...What’s wrong with the idle valve.
https://www.pistonheads.com/gassing/topic.asp?h=0&...
It explains everything mate
This is where I was up to untill recently Ian, but I have to say my new sealed system is way way better. I understand why you wouldnt want to mess with what you have but you really should try it, do'nt forget this could just be a simple reversable experiemnt, save your current map and you can always reinstate the idle valve and go back to the idle valve map easily and in no time at all.
I'm absolutely loving the drivability and AFR stability improvements my 'throttle butterfly only sealed syem' delivers, I can litterally 25mph trickle through town at 1,000rpm in 5th now, to be honest thats exactly what a 4.0 litre V8 pulling just 1,100kg should do. The fact so many TVRs dive like ship at low speed is absolutely redicoulous, these cars should litterally glide along on a whiff of throttle, mine now does and throttle response is massively enhanced too.
Just as I was always taught.... "All vacuum leaks are bad"....... and this rule very clearly applies to ECU managed vacuum leaks too! I'm not a fan of idle air control valves, full stop
, if you can do without one it'll only make for a nice driving car.
By the way, while I do need to tickle my throttle slightly for the first 30 seconds I also found with no idle valve I needed to pull out a huge amount of fuel out of my cold start map too, this makes sense as less air means you need less fuel which is only a good thing as throwing less fuel into an engine is always a desirable improvement for many obvious reasons. After the first cold start of the day it needs no throttle input for all subsiqent starts, it's the very definition of 'Turn Key'. I've tried turning off Scatter Spark and the truth is it makes very little difference, this tells me just how little this engine actually needed that damn air bleeding idle valve anyway.
I conclude the Canems system, which is all I have experience with, is trying to do something very sophistacated with all this idle valve control business when in truth 99% of the time the engine really does'nt need or benefit from all that fancy closed loop PWM air bleed idle management anyway, indeed if my findings are anything to go by the old Rover V8 actually benefits greatly from not having all this interference at all. This also indicates to me a lot of the driveability issues with the 14CUX may well as commonly reported be caused by errant stepper motor behaviour, the wonderfull drivability I'm enjoying on the standard plenum now also tells me the well peddled charge robbing theory is mostly a Red Herring too.
Perhaps the Emerald system makes a better job of managing the idle valve than the Canems ECU does, but my guess is the people who created the RV8 MBE system made all the same discoveries as I have which is why it doesn't use an idle air controll valve at all. All I've really done here is used what I was taught years ago, then copied what Powers Performance do with the MBE system, try it for yourself and see what you think
I'm absolutely loving the drivability and AFR stability improvements my 'throttle butterfly only sealed syem' delivers, I can litterally 25mph trickle through town at 1,000rpm in 5th now, to be honest thats exactly what a 4.0 litre V8 pulling just 1,100kg should do. The fact so many TVRs dive like ship at low speed is absolutely redicoulous, these cars should litterally glide along on a whiff of throttle, mine now does and throttle response is massively enhanced too.
Just as I was always taught.... "All vacuum leaks are bad"....... and this rule very clearly applies to ECU managed vacuum leaks too! I'm not a fan of idle air control valves, full stop
, if you can do without one it'll only make for a nice driving car.By the way, while I do need to tickle my throttle slightly for the first 30 seconds I also found with no idle valve I needed to pull out a huge amount of fuel out of my cold start map too, this makes sense as less air means you need less fuel which is only a good thing as throwing less fuel into an engine is always a desirable improvement for many obvious reasons. After the first cold start of the day it needs no throttle input for all subsiqent starts, it's the very definition of 'Turn Key'. I've tried turning off Scatter Spark and the truth is it makes very little difference, this tells me just how little this engine actually needed that damn air bleeding idle valve anyway.
I conclude the Canems system, which is all I have experience with, is trying to do something very sophistacated with all this idle valve control business when in truth 99% of the time the engine really does'nt need or benefit from all that fancy closed loop PWM air bleed idle management anyway, indeed if my findings are anything to go by the old Rover V8 actually benefits greatly from not having all this interference at all. This also indicates to me a lot of the driveability issues with the 14CUX may well as commonly reported be caused by errant stepper motor behaviour, the wonderfull drivability I'm enjoying on the standard plenum now also tells me the well peddled charge robbing theory is mostly a Red Herring too.
Perhaps the Emerald system makes a better job of managing the idle valve than the Canems ECU does, but my guess is the people who created the RV8 MBE system made all the same discoveries as I have which is why it doesn't use an idle air controll valve at all. All I've really done here is used what I was taught years ago, then copied what Powers Performance do with the MBE system, try it for yourself and see what you think
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