Lower than expected dyno numbers from LS2 402. HELP!!!
Lower than expected dyno numbers from LS2 402. HELP!!! OK guys, I did a really long write-up of my LS2 402 install into my 98 Z28 M6 some time ago. Since then I have been working on the Speed Density tunning and I am confident that I got my VE Tables set properly and my Idle Correct. Today I went and put it on a Dynojet to compare my stock O2 sensor readings to a WBO2. Unfortunately, the shop that I went to does not have the Wideband connected to the dyno (don't ask) so I can't show the fuel curve as I did not get one. I did watch the wideband and saw that the AFR was reading like 12:1 until about 6200 and then started getting rich 11:1 to the 6800-7000RPM rev limiter that I set. I am using HPTuner software. When I took a look at the dyno sheet, I almost threw up right there on the spot even though I could tell that I was not getting the power that I should in the seat of the pants. I really expected just under 500 HP from this setup when I bought it. My problem is that there doesn't seem to be a problem with the way that the car is running. I am not throwing any codes besides the MAF code. The car is not sputtering or missing. There isn't alot of blow-by. Is there something in the tune that I may have messed with that would cost me 100 HP and 80+ torque? I am over this. PLEASE HELP ANY SUGGESTIONS ARE WELCOME AS ARE ANY QUESTIONS.
I would imagine you would find some power with a 90/90, and 1 7/8" headers, but i doubt you will find the numbers you are looking for with those mods and/or a tune.
Where you having any KR or did you try tweaking your timing while you were on the dyno?
Where you having any KR or did you try tweaking your timing while you were on the dyno?
I had some KR at the top end (like 2*). I have been told that that is normal with the 98 sensors. That should not cost me 100 hp. I have never seen a 402 under 440hp. Specially not one with stock 3.42 gears and an M6 tranny. Something is mechanically wrong or there is a setting in my tune that is f**ked in WOT.
Originally Posted by DrkPhx
I can't believe you're still on stock injectors. If so, what is the duty cycle? You really need a printed AFR on the dyno sheet. Also, what is the total timing at WOT?
Not sure and not sure. I will answer both of these tomorrow after I can log a bit more. I think that I overwrote the log with this info.
Originally Posted by ninobrn99
he beat me to it! Injectors are probably max'd out on that motor! Did you get a log of your dyno run?? (please say yes)
Btw, '98 knock sensors are not a problem if you know the software. They need to match the PCM.
That graph looks like a car detonating, or a knock retard problem.
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it was pulling between 1-3* of timing from 4400 and up. Not sure if I should pull tinming out or put in some race fuel to see if it still happens and then numb my sensor some. My knock sensors are relocated so that could be picking up false Knock.
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Originally Posted by 98Z28CobraKiller
it was pulling between 1-3* of timing from 4400 and up. Not sure if I should pull tinming out or put in some race fuel to see if it still happens and then numb my sensor some. My knock sensors are relocated so that could be picking up false Knock.
I have to agree about the injector size not being the problem.
Do you know what your actual compression is? What size chambers?
Originally Posted by white2001s10
Well if you know how much it pulled out, then tell us what the total was during the test.
I have to agree about the injector size not being the problem.
Do you know what your actual compression is? What size chambers?
I have to agree about the injector size not being the problem.
Do you know what your actual compression is? What size chambers?
The compression should be at about 11:1 with the flat top pistons and the 65 cc combustion chamber on the heads.
Originally Posted by RedHardSupra
post your bin/logs then we'll tell you what ails you
I did verify that my narrowband O2's are close compared to the WB. What is tough is that I originally tuned the WOT AFR against 2nd gear but it was different in 4th gear. Because of my gears, a WOT 4th gear pass takes me over 130MPH and is difficult to do on the street. Not sure how to get around this.
Thanks again.
First I'd question the a/f with those injectors. Your stokcers are only 26 lbs. I maxed my 30s (which are actually 35 on our cars) with my 9.3 CR 402 with a smaller cam and have 60s in there now with the blower. I think you need to recalibrate the WB sensor & get some 42 lbers & start over. The other thing to take into consideration is your printout is in WinPep7, so your numbers WILL be a little lower.
And I think your problem starts down around 4k. Your lines should be climbing like crazy there. I attached my NA stroker dyno sheet for comparison. (tires broke loose on 1 run) And I have an auto/stall & a Ford 9"....
And I think your problem starts down around 4k. Your lines should be climbing like crazy there. I attached my NA stroker dyno sheet for comparison. (tires broke loose on 1 run) And I have an auto/stall & a Ford 9"....
I dasabled the TPS test as noted in the description on the HPTuners software. LTFTs all went way positive and I adjusted it. The funny thing is that know my LTFT's and STFT's are all 0. This would be ok if it wasn't for the fact that they are ALL ZERO. They were reading positive but I haven't seen one even jump into the negative for a second. Any idears?
I disabled the TPS test as noted in the description on the HPTuners software. LTFTs all went way positive and I adjusted it. The funny thing is that know my LTFT's and STFT's are all 0. This would be ok if it wasn't for the fact that they are ALL ZERO. They were reading positive but I haven't seen one even jump into the negative for a second. Any idears?
The car is running very smooth though. Feels a little stronger maybe 10-20 HP. It might just be because it is more responsive right now.
The car is running very smooth though. Feels a little stronger maybe 10-20 HP. It might just be because it is more responsive right now.