I have a 1999 Trans Am LS1. When I first got it I put it on a dyno (245.5 max power @ 5250 rpm, and 280.8 max torque @4000 rpm).

After the test I was told to put new exhaust on and it would make a big difference. I put a new Excelerator exhaust on and took out the cats. I also used a hypertech programmer but all it did was slow my car down lol.

I was running a 14.3 in the 1/4 so I was told my car may have been programmed with a programmer already and I was writing over a program and it confused the computer.. So I took it in and had it reflashed to stock. Now it feels like there is no top end? Can anyone help out please as I’m not doing well on my own..lol

{edited a bit, was a late night last night, lol}

 

That's the lowest dyno I've ever heard of for an LS1.

Did you dyno on a Mustang dyno or a Dynojet? Maybe your car is in need of a good tune and maybe a few other things.

 

I've been trying to help a bit on this problem.

LoL, if I didn't know the situation I'd probably put foot to ***** for using the Caps hehe. But I'm pretty sure that this situation warrents Caps Lock hehe. (Gentle reminder as my ears are bleeding from all the yelling hehehe :P).

Any help on this problem would be greatly appreciated. We are at altitude (3750') and that is costing some of the performance. About a month ago we went to a 1/4 mi track and IIRC the best time was around a 14.3 @ 98.

What are you guys getting stock out of LS1's for 1/4 mi times? His numbers correct (NHRA, .9543 correction for ET and 1.0486 correction for MPH) to 13.646 @ 102.76. This looks to me like the bottom end is pretty good but just not getting the MPH out of the top end. Shoot, he *should* trap 104+ stock shouldn't he? Full exhaust (no headers) and drop-in are the other power mods.

I just don't know much about LS1s to help pinpoint the problem.

Also, what are you LS1 guys using to Scan with? I've been using Datamaster for my LT1 for a couple years and love its functionality, but we can't find anything comperable for an LS1. If we could scan, I think the problem would become pretty evident.

Thanks for any further help guys, really would appreciate it as I'm trying to keep one of the few FBody buds in the area from getting out of his FBody . But it sure is frustrating.

 

TTT, as L8ER is out of town.

Any input on this would be appreciated.

 

those numbers aren't horrible considering the elevation.

somebody must have the sea-level calculation...i looked but couldn't find it.

it could just be that the altitude is starving you of air at high rpms.

have you checked your fuel pressure?

 

i ran 13.5 @ 104 stock with nittos....

nothing done...

 

I used a Mustang Dynamometer. The ele, was 3500.

 

I am 75% sure that the dyno (dynojet anyways) compensates for temp,density ,humidity and alt. A dragstrip wont though. (Off the subject, I stay in Sheridan once a year in te end of March on our snowmobile trips to the Big Horns, cool little town, went down to Dairy Queen and had ice cream but didnt see any F-Bods cruising. Just a bunch of trucks with glass packs.)

 

LOL yes there are a ton of trucks here. i would like to get more f-bodies here but everyone wants imports.

 

Altitude really kills et's.

At our local 4,100 ft altitude track, stock LS1's are low 14 to mid 14 cars. If well driven, high 13's. So L8er's T/A is in range, if slightly slow.

 

sounds like u got one of those phantom ta's ls1's

 

phantom ta's ls1's ?? What do you mean?

 

Ok I have done a pressure test and it came up with 50 with engine off and 60 with engine on. Is this good or bad?

 

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