Autech Pulsar GTi

Cheers Rob. Im hanging on to the N1 cover, just keeping as a spare. Its not in the best condition now anyway.
 
Well i took the car in for tuning, with not so good results.
Ignoring the lowish peak hp numbers, the car is faster.

I have run into problems with audible pinging / detonation from around 5000-7000rpm with a bad missfire developing after 7300rpm, I thought ignition timing could have been tweaked to resolve this but all that happened was the power dropped masssively with only a couple of degrees taken out.

I noticed the detonation as soon as i fitted the N1 cams. No detonation was heard prior to this when using the regular 16VE cams.

The current setup is:
SR20DE Block / 16VE Head
SR16 Pistons
SR16 N1 Cams
Custom Intake Manifold
Q45 Throttle Body (80mm) with 73mm Intake Pipe
Custom 4-1 Exhaust Manifold (shortened mazworx header)
OEM CAT
2.25" Mandrel Exhaust (2" backbox)2014-09-03 17.39.44.jpg
 
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So now im looking at ways to eliminate the detonation and missfire.

I find it odd that the detonation occured after fitting the n1 cams and i think this might be key to resolving the issue.
Perhaps altering the cam timing might help??

Compression is over 300psi per cylinder.

Could be a weak spark? Worn Dizzy cap/rotor. Too hot heat range plug?
 
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The N1 cams are fitted straight up on OE cam gears. Retarding the intake cam might help reduce cylinder pressure, but not sure about that at higher RPM's??? Also havent got adjustable gears to test.

Running on 99RON fuel as always.
 
What was the fueling / AFRs like?
I assume N1 cams can make power up to 8k? If so on that graph you would make around 225-230hp. Is that a more reasonable figure? Liking the flat torque.
 
The fuelling was setup on this MAHA rolling road, using steady state mode at different RPM intervals. We held the motor at 7400 to get a good reading, it was a little rich but not enough to cause a missfire etc.

Yeah the N1 cams can make power upto 8-8.5k.

Well id consider this dyno as reading low, when you consider a bone stock SR20VE is 190bhp.
This 211bhp should be more like 211WHP for this setup but Im not too concerned about the numbers, im happy with the torque curve and theres a little bit more power to be found to 8000rpm if i can sort out the issues.

Im almost tempted to put the regular 16ve cams back in.

Has anybody got adjustable cam gears for sale?
 
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The inlet cam was retarded loads on the stroker when i first got it because the compression was so high.
 
They are SR16VE Springs, proven to at least 8500 so it shouldnt be float.

The noise is audible from 5k and gets worse upto 8k.
 
damienga15de said:
Are you going on us power figures?

There totally exaggerated

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Click to expand...

For comparison sake, i would refer to dynojet numbers, which gives the most consistent/comparable results.
I would need to put my car on a dynojet to be able to compare.
 
Can I say this is near textbook what happened when mine hit the RR? Same HP figure near enough an all. The compression is a ball ache it's just too much I think unless race fuel is used?

I don't know if cam gears are the answer a lot with these builds found 0, 0 to be best? Or at least adjusting them to not yield so much?
 
^ they'll be needed to bleed of some cylinder comp.

what did the afr look like?
what's the afpr set too?
what management you using?
surely your drivetrain isn't loosing 40hp+?
dd
 
yet bhp is a derivative of whp, not the other way round as you know. with such a stunning build, this warrants better management i feel.

like you say these whp and bhp aren't the issue *as a dynojet is a much better gauge, its the issue of det that you'll address shortly im sure.
 
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