quake
Member
3.2 mtx,bbb,cams,48#injec,80maf,3.27 S/C pully,10psi of boost.Whats wrong with this picture.Afr is even across the board 
dyno 300 s/c 3.2 wtf!
- Thread starter quake
- Start date
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SHOspazz92
Banned
First of all, on a S-Trim with a 3.27'' Pulley 10psi is pretty low. That pulley should net you 15lbs, easy (I saw 14+ on a 3.33''). With that being said, you must have massive belt slip. Also, what RPM are they taking it to? What were your AFR's?
-Sam
-Sam
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88GTA92SHO
aka NCtaurusSHO
nothing...you went supercharged...
Off Road SHO
Moderator
I'm guessing 350/350 at the crank.
Tom
Tom
SHOspazz92
Banned
That car should be making a LOT more power. It obviously has a ton of belt slip.
-Sam
quake
Member
Yep
We found belt slip at dyno. The afr is good cross the sheet.Got the belt slip take care of while i was there.6300 power fell off at that point.My setting rev 7800,bbb set at 3400,idle 1000,And far as boost 10 was what the donor car was pushing.It was dyno at at 312fwhp. Afr 11 to 13
We found belt slip at dyno. The afr is good cross the sheet.Got the belt slip take care of while i was there.6300 power fell off at that point.My setting rev 7800,bbb set at 3400,idle 1000,And far as boost 10 was what the donor car was pushing.It was dyno at at 312fwhp. Afr 11 to 13
jayro
SHO Member
I thought with FI you wanted to run a little richer than that....could be wrong though. 312 fwhp is 376 at the crank. Mathmatically a stock SHO should make 377 chp on 10psi. Sounds like you are about in line. What exhaust are you running?
Which cams are you running? Obviously not stage II, but I think you are just meaning mtx cams. If so, your power is not too low. Comp check? What tune? And if you fixed the belt slip, you should see more thsn 10psi. Sure you don't have a large leak at the bypass valve? What size filter?
SHOspazz92
Banned
You are still getting belt slip if all you can get is 10lbs from that pulley. That is why power is falling off after 6300 RPM. Or like Tim said your bypass valve may only be letting you see 10lbs. You can adjust that by tightening the bolt on top (you'll need to loosen the nut on the bottom of the bolt to do so)....adjust it in small increments.
As far as an Air Filter, If you are using that small little round filter that sits on the blower that is a huge restriction. You will need to construct a CAI that runs in to the fender (Where the washer reservoir was) and run at least a 4'' long cone filter. 13's @ WOT is a little lean, especially on a stock internal engine running a S/C with no intercooler.
-Sam
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Seeing AFRs that lean with no intercooler sounds like you were getting detonation and the computer was pulling timing.
My recommendation is to have it tuned correctly and some type of charge cooling, methanol or an intercooler. You will make more power and add some safety for your ring lands.
My recommendation is to have it tuned correctly and some type of charge cooling, methanol or an intercooler. You will make more power and add some safety for your ring lands.
shomethe$$$
SHO Member
Whats your timing and spark plug gap?
On my old M90 setup, when I set the timing at 24 degrees over 5000rpm it would pull it back to 19 degree's on the top end, we were running 15psi. I have it set at 20 or 22 degree's now. Spark plug gap was .044" I think i have it set at .040" now.
and
looks like the wide-band went real rich for an instant.
I believe the all the sea-level spark tables have to be changed.
On my old M90 setup, when I set the timing at 24 degrees over 5000rpm it would pull it back to 19 degree's on the top end, we were running 15psi. I have it set at 20 or 22 degree's now. Spark plug gap was .044" I think i have it set at .040" now.
and
looks like the wide-band went real rich for an instant.
I believe the all the sea-level spark tables have to be changed.
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Yea, you're after stoich or slightly richer under full boost. His car is either pulling timing or he doesn't have enough fuel.
Edit: Michelle will run the ink pen out in here
quake
Member
Here
Thanks for the feed back guys.There a few things that i have to changeView attachment 1365
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View attachment 1367
Thanks for the feed back guys.There a few things that i have to changeView attachment 1365
View attachment 1366
View attachment 1367
quake
Member
Sorry cant get pics any larger
Yea, you're after stoich or slightly richer under full boost. His car is either pulling timing or he doesn't have enough fuel.
Edit: Michelle will run the ink pen out in here
Definitely not. Stoich is 14.7 and I would recommend between 11-12:1
Fuel=safety
Running no intercooler gets things real hot, even more so with 10psi or more. When you have stock pistons and charge air temps, you need more safety. The two things that keep your pistons from melting or cracking is cooler air temps or pulling timing. Since you didn't give it cooler air temps the computer took out timing. My car ran VERY well, and it did so on stock pistons over 13psi. It was intercooled with between 10.5-11.5:1 AFRs and lots of timing pulled.
SHOspazz92
Banned
I still say there is a ton of belt slip but agree with andrew none the less.
SHOspazz92
Banned
Crank the ****** down as tight as possible. Not that it is really the right way, but it's what I had to do for a while when I was tuning my car to safely run 15lbs.
Otherwise, most folks move the Idler closer to the stock tensioner/idler pulley for more belt wrap around the S/C pulley.
-Sam
I agree, fuel does equal safety, too much "safety" is also nearly as bad.....granted, most of my experience is with intercooled turbo setups.....most of them run between 13.0-13.5 when under full boost.
13-13.5:1 at WOT is too lean for any application.
nearly all internal combustion engines develop maximum torque at a/f of 12-12.5:1
supercharged or turbo-supercharged engines need to run a little richer for the reasons outlined above.
nearly all internal combustion engines develop maximum torque at a/f of 12-12.5:1
supercharged or turbo-supercharged engines need to run a little richer for the reasons outlined above.
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