Rolling road day fail!
- Thread starter Evo8
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I know very little about tuning but that would be my guess. The injection will be metering the fuel according to rpm (and various other things) But if fuel pressure is not being maintained then it's gonna start running lean.
Dunno, I would have thought the chap running the rolling road would have a clue. If he doesn't he's stealing your money.
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He did have a clue, he said it was running crazy lean, it should be just below 12 on the graph. He asked if I had my standard air box so he could swap it back in to see if it made a difference but I never had it with me.
Potential fuel pump problem?
Potential fuel pump problem?
Fairly easy I think, I'm sure I've seen trick fuel rails with a gauge already fitted, but it's all extra money. Plus I think they also have a fuel regulator valve??
I know nowt about Evo's. But if I were in your position I'd have the car in "standard" fettle first so I could get a baseline for the car. Basically see if all the bits that should be working are as they should be. (You could have something dodgy like a mass airflow meter to begin with) Then you can see if any of the bits you are bolting on actually make the performance better or worse. Your rolling road chap doesn't sound that clued up to me. He's stating the obvious about it running lean, you can read it for yourself from the print-out. I would have thought he would have at least had a clue about what is throwing the fuelling off. Unless I'm doing him an injustice and he's just trying to be polite and knows it's down to the induction kit already.
What does a run on a rolling road cost?
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Not sure if the same applies to EVOs or not but induction kits need to be specifically mapped for on Imprezas as it alters the MAF scaling in a big way.
I wouldn't be go anywhere near 6k with it running like that, if anything I wouldn't be going anywhere near boost at all. I wouldn't be surprised at all if the engine was close to destruction through detonation already, 14:AFR on boost onset is not good (closer to 12.5:1 is "normal")
My MX5 is richer than that with no boost yet
I wouldn't be go anywhere near 6k with it running like that, if anything I wouldn't be going anywhere near boost at all. I wouldn't be surprised at all if the engine was close to destruction through detonation already, 14:AFR on boost onset is not good (closer to 12.5:1 is "normal")
My MX5 is richer than that with no boost yet
I'm convinced he thought it was the induction kit because he wanted to test it again with the standard air box. It was a rolling road day a guy I know organised and it was £35 for 2 power runs measuring boost etc.
Frozen, it's pretty hard to stay away from boost as my turbo is small and spools quickly. Boost is sitting at 1.1 bar. The AFR should be sitting roughly at 12.
I've be talking to a guy who works at a closer dyno place and he can get me in in a few weeks, the place I went was 90 minutes away. I might get a full service with new plugs and fuel filter and see if that does the trick.
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Pfft! I was hoping to see a big flash and loads of steam and tyre smoke and a car struggling to get free.
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Boost is about right for an FQ300 then.
Did he check AFRs at idle/cruise at all? If it was fuel pump/injector related I'd expect AFRs to lean out as RPM/Load increase as additional duty on injectors/required fuel flow would put exaggerate an issue there.
What induction kit is it? Does it use the original MAF housing or is it a different housing?
Did he check AFRs at idle/cruise at all? If it was fuel pump/injector related I'd expect AFRs to lean out as RPM/Load increase as additional duty on injectors/required fuel flow would put exaggerate an issue there.
What induction kit is it? Does it use the original MAF housing or is it a different housing?
That was through the rev range, uses the rpm from the graph above.
It's a HKS induction kit (that I want to change for an A'PEXi anyway) and the MAF sits in the cast you get with the induction kit. It's totally possible the MAF is dirty as the HKS has poor filtration but a dirty MAF shouldn't cause this or could it?
It's a HKS induction kit (that I want to change for an A'PEXi anyway) and the MAF sits in the cast you get with the induction kit. It's totally possible the MAF is dirty as the HKS has poor filtration but a dirty MAF shouldn't cause this or could it?
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I know that's through the rev range but that's only WOT did he check it at part throttle at all?
Dirty MAF would cause misfuelling but not to this extent.
But as you say the HKS kit comes with a different cast for the MAF that will more than likely be the cause. The different diameter means the airflow the MAF is reading and the actual airflow through the MAF are two different things.
What people seem to forget on highly string motors is that even simple "bolt on" mods are not actually bolt and and will require mapping to suit. Throw a decat on an otherwise standard turbo charged car and watch peak boost go through the roof, potentially dangerously as the boost solenoid will now need considerably less duty cycle to reach the same boost levels
Dirty MAF would cause misfuelling but not to this extent.
But as you say the HKS kit comes with a different cast for the MAF that will more than likely be the cause. The different diameter means the airflow the MAF is reading and the actual airflow through the MAF are two different things.
What people seem to forget on highly string motors is that even simple "bolt on" mods are not actually bolt and and will require mapping to suit. Throw a decat on an otherwise standard turbo charged car and watch peak boost go through the roof, potentially dangerously as the boost solenoid will now need considerably less duty cycle to reach the same boost levels
When I go to the rolling road place in a few weeks I'll take my standard air box and test it with the HKS and then clean the MAF and put on the air box and see if that sorts it out. The other option as you said is get it mapped to suit.
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If you have the stock airbox theres a fairly crude way you can check if that's the cause if you have an OBDII Adapter with something like Torque on Android you could take the car out and hold the car at a steady load state ( light throttle 2.5k rpm in 3rd for example) and make a note of the "Mass Airflow Rate" swap the induction kit out for the stock airbox and do the same again.
Providing you are on the same bit of road, same throttle position and ambient temperatures are as close for both as possible a large difference between the two MAF rates would indicate this was a problem.
Again I'm not too familiar with the EVOs ECU but does if have any way of viewing its long terms fuel trims, if its anything like Subaru you could use these to also help diagnose
Providing you are on the same bit of road, same throttle position and ambient temperatures are as close for both as possible a large difference between the two MAF rates would indicate this was a problem.
Again I'm not too familiar with the EVOs ECU but does if have any way of viewing its long terms fuel trims, if its anything like Subaru you could use these to also help diagnose
I'm not familiar either as it's my first Evo and I've never had a need to do anything engine related because it's been running sweet as a nut.
It sometimes doesn't start straight away either and I replaced the battery so it's probably due new plugs anyway.
It sometimes doesn't start straight away either and I replaced the battery so it's probably due new plugs anyway.
If the Evo is anything like the Galant VR-4, then the MAF is very sensitive to air flow patterns - replacing the stock air box with other types of filter means that you do not get a consistent, straight, even, air flow through all parts of the MAF - and this messes with your fuelling.