hey i am working on a 00 trans am with a
Forged 393
TREX cam
Absolute Speed 5.3L heads
Fast 90/90
kooks 1 7/8" long tubes
12.5:1 compession
Those are the basics. The problem is we just put this motorin out of another car that ripped so hard it put my nitrous car to shame. Now in the new car we are working in it cant hardly get out of it own way. It is still on the origanil break in tune. The heads were changed and the compression raised 1.5. Also the headers went from 1 3/4 to 1 7/8. The car we put the motor and tranny in was originally a auto and it has 2.73's. Any clues on to why the car is not going ? It free revs niceand quick so i am leaning towards gears. Any ideas ?

 

You realize that the TREX cam is designed to work best with the stock heads. Have you checked the compression? The 2:73 gears will make quite a difference in how the enginew pulls. Good luck and let us know how it turns out.

 

Well with the livernois ls6 heads and 11:1 compression on 3.42 gears it put 512 to the ground on a safe tune and pulled like a raped ape. It still needs the final tune but the car just pulled so hard. Now i think my four banger honda will keep up.

 

Did u mean check it to see if it is running on all eight cylinders ?

 

2.73's and a trex=

 

try some 4.11 or 4.10 gears , also wouldnt hurt to have some more converter with the t rex and more cubes than stock

 

Check your DCR, 12.5 on T-Rex is a lot. You could be detonating like crazy
Also 2.73 is nono

 

2.73 probably hurting even more if it's detonating because of the extra load.

 

give me the mtor specs so I can calculate DCR:
Bore
stroke
rod size
piston > deck
valve reliefs
gasket compressed thickness
head chamber size

also .006 cam specs and LSA, ICL

 

^WORD. The timing is probably crap with a ton of detonation from high compression both static and dynamic and the fact that the car is loaded up a lot more all the time with 2.73s. In my car I can run pretty lean for a 1-3 and a little 4th gear drag pull. But I will knock like crazy if I tried to floor it in 5th with the same tune.

Granted thats on a DSM, but the principals are similar. Besides, I'm on a 100MM stroke, and thats about 4 inches, so its not as hugely a far off comparo as you would think interms of timing advance.

 

Is this an auto? If so what stall? trex doesnt pull until 3500 rpms anyway. I dont think that 3400 is a good verter for that cam but I dont really know to much about verters.

Sounds to me like a combination of things. Trex cam, small stall and the wrong gears for that cam. Its a drag strip cam and really isnt going to be impressive on the streets unless your keeping the rpms in the range it needs to make power.
Even with KR all over the place I made good numbers. Not as good as when we tuned the KR out but they were still good. We gained maybe 10 hp by retarding the timing until we got rid of kr.

 

No sorry its in a six speed car. We are running 113 race fuel in it cause i was thinking the same thing and that did not help one bit. This car is actually not mine but maybe steve (nogamesls1) can post all thise motor specs. Thanks guys. O by the way it feels like it wants to pull hard but it cant. I know were the powerban is on this cam and it starts to want to go and it just wont its so weird.

 

Darn, well good luck with it. Maybe its a fuel issue? Do you have hptuners? You need to do some logging and see whats happening.

Those are still the wrong gears for that cam. Does it pull in 1st gear at all?
With those gears I wouldnt expect any thrust until your around 4500 rpms maybe, not sure I've not had the trex in my car. Full weight car as well?

 

No i think we are planning to take it to force fed to do some tuning on friday. Hopefully we will have some gears in it by then also.

 

2.73 in a m6. Yeah, I'd say drop to 4.10 with that cam. Should be able to spin the sh:t out of it. Assuming the rest can take it.

 

How does it sound sitting there idling? Looks like a nasty combo, bet it sounds real mean

 

Yeah it sounds mean all right. True duals dumped through little tiny magnaflows.

 

ALRIGHT got it. The car was only running on four cylinders. We did not have power to the main harness that drivers side coil plugged into. The fuse that controls that side when tested would show good on both sides. But then we would not have power anywhere on that system. So we figured out that when testing the fuse just the slightest pressure was giving us full power. So it ended up being the holder that held the fuse. Sometimes you just have to go back to the basics. This car pulls so hard and its only on the 2.73's still