Dyno numbers with a T3/T4 and weird lean condition

[JaeTea]

7psi wastegate spring, got up to about 8.2psi. Without the silencer in the exhaust the boost got up to about 10psi and made 210 hp and 225 ft/lb torque but it was running a little lean in some areas.



Not sure why my numbers are so low..I should be making about 250 hp on my set up.

I'm also concerned about how lean it was running just by removing the exhaust silencer.

Its a JGS starter kitSOHC JWT ECU for fuel and timingExternal Wastegate (7psi spring)t3/t4 50 trim, .63 a/rJGS Downpipe3" exhaust550cc injectorsWalbro Fuel PumpStock FPRZ32 Maf

Car was tested for boost leaks and compression and everything checked out fine.

Any ideas?
Modified by JaeTea at 11:27 AM 1/27/2010

[biggie]

Since my setup is 'similar' that hurts my feelings.

Possible not enough FP with the stock FPR?

Granted with the 7psi spring, I'm only seeing 5psi at the intake mani.

[PuNcHdRuNk]

timing/tuning issue? your afrs are way unstable........have you put a timing light on it?

[JaeTea]

I sent the ECU back to JWT once before and it checked out fine and had timing set to stock.

I'm going to be taking it into a shop soon so I'm just trying to figure out what could possibly be wrong with it.

I've been running on this set up for about 3 years now (events, daily driving) and compression checks out fine.
Modified by JaeTea at 1:25 PM 1/27/2010

[biggie]

Just noticed, but to confirm this is a KAE?

[PuNcHdRuNk]

I sent the ECU back to JWT once before and it checked out fine and had timing set to stock.

I'm going to be taking it into a shop soon so I'm just trying to figure out what could possibly be wrong with it.

I've been running on this set up for about 3 years now (events, daily driving) and compression checks out fine.

Modified by JaeTea at 1:25 PM 1/27/2010

the cam timing could be on (giving you good compression numbers) but your ignition timing could be off, this could be due to distributor replacement or adjustment (just one tooth the wrong way would simulate the conditions you are describing). this would cause weird afrs and low power. i would put a timing light on it just to be sure.......

[JaeTea]

Yep SOHC

[lancet913]

I have a similar set up:DOHCt3/t04e .48 JGS kit3"DP, 3"TP2.5" catback550cc injectorsJWT tunez32 mafbig fmicstock FPR255 fuel pump

I put down 221HP 237TQ @7psi 236HP 250TQ @ 9psiafr's 10.8 at WOT

[Chris28]

Change your FPR to an aftermarket unit, that could be causing the lean condition. Do you have a wideband o2 sensor? Your ignition timing might be off as well, check it with a timing light as previously suggested.

The numbers do seem a little low, I made 293 at 13 psi with a t2.

[JaeTea]

I thought JWT tunes are meant to run on 3 bar stock FPRs?
Modified by JaeTea at 6:02 PM 1/28/2010

[Chris28]

Well really any tune should work with a stock FPR, but if you are running a Walbro or an aftermarket fuel pump it can cause the diaphragm in the stock FPR to fail. If you are running a stock fuel pump you should change that out.

Not sure what impedance means, but are you running the correct impedance injectors?

Do you have any exhaust leaks? Any exhaust leak pre-sensor will cause a lean o2 reading.

[biggie]

As far ast the tune I'm having no issue with JWT, but do have Nismo FPR, with in-line FP gauge and set to stock pressure. But is a DOHC.

[WDRacing]

Well, the KAE is under powered compared to the DE from the jump IIRC. Something like 20whp...anyone? However, with that turbo and fuel management you should be close to 300whp at 8 psi with those AFRs.

Honestly, those AFR's are so erratic that I think the probe was jacked up, perhaps broken or uncalibrated. The only way to run AFR's like those without knocking would be massive timing retard.

So I see 2 possibilities.

1, The AFR's shown on the dyno are incorrect due to "something" with the probe most likely.

2, The timing is so retarded on boost it's jacking up your AFR's, or the base timing itself is off. JWT used to be known for far to much timing retard on boost, but has since changed their tunes.

I suppose the FPR could be bad, but if you are truly running that lean I would think you'd hear some knock. You'll need a fuel pressure gauge to verify, and while you're messing with the fuel you might as well install an aftermarket FPR.

Also, check your plugs and wires. I was tuning my car...forever ago...and one of my wires was worn in a spot and was slightly grounding out. Caused some really weird AFR readings.

WD

[JaeTea]

1, The AFR's shown on the dyno are incorrect due to "something" with the probe most likely.

2, The timing is so retarded on boost it's jacking up your AFR's, or the base timing itself is off. JWT used to be known for far to much timing retard on boost, but has since changed their tunes.

I suppose the FPR could be bad, but if you are truly running that lean I would think you'd hear some knock. You'll need a fuel pressure gauge to verify, and while you're messing with the fuel you might as well install an aftermarket FPR.

WD

Well the probe measuring the AFR's was just put in the exhaust. It wasn't in the downpipe. Not sure if that would make a difference.

I'm going to have the timing checked.

If it was the FPR wouldn't the AFR's go up as the boost and rpm's increase rather than going down?
Modified by JaeTea at 9:38 AM 1/29/2010

[biggie]

Well, the KAE is under powered compared to the DE from the jump IIRC. Something like 20whp...anyone?

15 crank hp less from factory specs E vs DE. 140 vs 155.

[PuNcHdRuNk]

this could also be due to one fouled injector, giving lean or rich condition in one cylinder, but you would be able to see this on the plug.......

[KFL]

Well the probe measuring the AFR's was just put in the exhaust. It wasn't in the downpipe. Not sure if that would make a difference.

I'm going to have the timing checked.

If it was the FPR wouldn't the AFR's go up as the boost and rpm's increase rather than going down?

Modified by JaeTea at 9:38 AM 1/29/2010

Probably a bad probe.. it doesn't matter most dyno shops put it in exhaust.

If you need timing checked I can do that, i'm in NJ. That dyno shop RT is in PA i know, not sure how far you are. Also considering thats a dynojet with cf, the numbers would be a bit lower on a dynapack/mustang/dd.