#s seem low. Looking for help.
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From: NW Chicago Subs
#s seem low. Looking for help. I have a 2002 Z28 M6 with a T-Rex cam and supporting mods. Car has a 9" with 4.11s and locker. She just put down 388/373 on a Mustang loaded dyno. Best trap is 119 and change so far. Car is 3600lbs RW. I am still running the LS6 with ported TB so I have about 15-20hp on the table here with 90/90 but still feel like it is not as strong as it should be. Strangely though, my torque curve is amazing. Great under the curve power and mid and low range torque. She starts to fall off about 6300rpm. Fuel is right on. I have the stock timing set. Is it possible I am off a tooth or something? How many degrees would it be off if I was off a tooth? I had it tuned on the same dyno back in Sep and it did 391/374 so it is consistant. Also, this is not a low #s dyno. On the same day vettes were putting down dynojet numbers. I shimmed the springs too and no change. Any advise would be helpful.
Last edited by BADSZ28; May 15, 2007 at 06:23 PM.
The 9" and 4.11s won't help with the dyno numbers at all! Shoot trapping at 119 with cam only is pretty good IMHO, dyno is just a tuning tool the track is where it shows.
BTW, take into account your rear and the fact it is a Mustang Dyno. If you are really worried about the superficial number you should just find a nice generous Dynojet...
Badass car BTW!
BTW, take into account your rear and the fact it is a Mustang Dyno. If you are really worried about the superficial number you should just find a nice generous Dynojet...
Badass car BTW!
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From: NW Chicago Subs
I am well aware of how MDs work and that my rear is hurting the numbers. I feel 119 is kind of slow though and wanted to post dyno numbers to back it up. I really don't care about the numbers as long as it traps. And I still feel I am missing something only making power till 6300. Most cars with similar cams are into the 120s. Even A4s! If my car was A4 trapping this I would be happy. But as an M6 I feel I should be like 122+ in the same air.
Thanks for the compliment.
Thanks for the compliment.
Doesn't sound too low for a mustang dyno, considering the LS6 intake and 9" rear.
What kind of exhaust are you running? The TRex is really dependant on exhaust flow and this could have a pretty big effect on peak power.
If the cam was off one tooth it would be something like 28 degrees out. Highly unlikely that it would hold together as PTV contact is a definate w/ the cam that far off.
The only thing I find strange is the 6300 peak. Does it start to fall off at this point or will it carry?
What kind of exhaust are you running? The TRex is really dependant on exhaust flow and this could have a pretty big effect on peak power.
If the cam was off one tooth it would be something like 28 degrees out. Highly unlikely that it would hold together as PTV contact is a definate w/ the cam that far off.
The only thing I find strange is the 6300 peak. Does it start to fall off at this point or will it carry?
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From: NW Chicago Subs
I have SLP headers and ORY with flowmaster merge and 3" cut-out. I drop the cat-back when I race most of the time.
28*! Wow. Can't be that then. I feel better knowing about that I guess. But not so much as it can not fix my problem.
Starts to drop but not hard. Maybe 5hp per 100rpm. Most I have seen make power to 6700-6800 and hold it past 7k.
28*! Wow. Can't be that then. I feel better knowing about that I guess. But not so much as it can not fix my problem.
Starts to drop but not hard. Maybe 5hp per 100rpm. Most I have seen make power to 6700-6800 and hold it past 7k.
If you could post the dyno graph I'm sure it would help. Most of the guys on here will request it(I'm surprised they haven't already).
Also, what do you shift your car at?
Also, what do you shift your car at?
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From: NW Chicago Subs
Graph added. From dyno tune session, but looks the same. You will notice it shows lower numbers. Not sure why. Something happened with the correction factor when they print it from what it shows on the screen. But you get the idea. Just move the graphs up the difference in the peak numbers. I did notice it goes slightly rich at peak and I am making changes for that. Did the same thing last time. Should add a couple HP. Timing is already at about 29.
Last year I shifted at 7k. This year I am going for 6500.
Last year I shifted at 7k. This year I am going for 6500.
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Verdad Gallardo I would say the graph looks good. I went to Thunders website for a comparison, and it also shows peak between 63-6400.
I agree w/ the 6500 shift points. It should make better trap speeds than winging up to 7000. Give that a shot and post up some results.
I agree w/ the 6500 shift points. It should make better trap speeds than winging up to 7000. Give that a shot and post up some results.
Your AFR might be a little lean if the lowest the WB ever picked up was 12.8:1 and averaged 13.3:1. Where was your timing at?
I'd try to shoot for 12.5:1 around peak torque, and 12.8:1 around peak HP. Timing should probably be in the area of 28* from 2400 on up backing off a little (to 26* maybe) for peak torque...then returning to 28*~30* for peak HP. That's how I'd start tuning it.
I'd try to shoot for 12.5:1 around peak torque, and 12.8:1 around peak HP. Timing should probably be in the area of 28* from 2400 on up backing off a little (to 26* maybe) for peak torque...then returning to 28*~30* for peak HP. That's how I'd start tuning it.
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From: NW Chicago Subs
It is a little lean on the low end and fat at the higher end. I have since made changes. and will give that a try. Have not had a chance to even load the file. lol. It hits 12.5 on the peak HP curve for referrence (at least on my last dyno run). I am waiting on a WB to get to me and will do more tweaking and see what my changes did.