LT1 vs. Mach1

**secondgearscratch** · 07-27-2007, 10:09 AM

stock for stock mach 1 takes it. an auto in an lt1 is pretty sluggish without a stall.

**2000T/A Guru** · 07-27-2007, 11:50 AM

Friend nick has exhaust, intake, 3.23 rear gears a tune and a slipping tranny and he ran a 13.4 with his 95 z28. With a good tranny could prob due lower 13s and he now has a 75 shot on it but thats beside the point lol. He doesnt have a stall. He ra na 14.0something bone stock.

**JwMonE99** · 07-27-2007, 04:26 PM

So wait an LT1 puts down only 265? I thought they had 275 cept for the 97 when they had 285? (f-bodies that is im not sure about the corvettes)

I also thought that LS1 is 350 to the crank and 305 to the wheels and LT1 was 315 and 275-285 to the wheels.

**secondgearscratch** · 07-27-2007, 04:29 PM

Originally Posted by JwMonE99

So wait an LT1 puts down only 265? I thought they had 275 cept for the 97 when they had 285? (f-bodies that is im not sure about the corvettes)

I also thought that LS1 is 350 to the crank and 305 to the wheels and LT1 was 315 and 275-285 to the wheels.

i dont think an lt1 puts down 275 though ive been wrong many times....

**JwMonE99** · 07-27-2007, 05:09 PM

Overall a 97 Trans Am with 3200 stall, shift kit, 3.73 gears, filter, cowl hood and a tune beat a mach1 A4 with an H pipe right?

BTW is kind of off track but is it possible to get 25 hp and 30 lbs of torque from a single tune in one hour?

**secondgearscratch** · 07-27-2007, 05:11 PM

Originally Posted by JwMonE99

Overall a 97 Trans Am with 3200 stall, shift kit, 3.73 gears, filter, cowl hood and a tune beat a mach1 A4 with an H pipe right?

BTW is kind of off track but is it possible to get 25 hp and 30 lbs of torque from a single tune in one hour?

yes to the lt1 with mods...

would need to know mods about your tuning issue and various other tuning parameters, program used balh blah

**preston1980** · 07-27-2007, 08:03 PM

The 93 LT1 f-bod was rated at 275 crank hp, the 94-97 were rated at 285 crank, except the 95-97 WS6 Ram Air cars were rated at 305 crank hp. The ram air had a less restricted air intake box, and differant exhaust. which put it at the hp rating equal to the 91-96 Corvettes.

In 98 the LS1 F-bods were rated at 305 crank and the WS6 was 320, for the exhaust and more opern air boxes. In 2001 the hp was bumped up to 310 and 325 for the WS6, because of the differant intake.

Realisticly the 98-00 F-bods have 345 hp at the crank and the 01/02 has 350 at the crank, wich was what the Vettes were rated at.

All though the Vettes always seem a little higher on the hp #'s, (5-10 hp) I believe its because the tune was a little better and the true dual exhaust. But in a few cases they have had comparisons of a f-body with more hp than a vette LS1. Not very often though, but it has happend.

**N20LT4** · 07-30-2007, 04:54 AM

Originally Posted by BLKCLOUD

Ok. How do you measure HP at 80 mph, especially down to 1 or 2 HP?

LT1s were not underrated, at least not by much.

LS1s in F-bodys were severely underrated.

LS1s in GTOs were rated just about spot on.

LS1s in Corvettes were rated just about spot on.

LS2s in GTOs and Corvettes were just about spot on.

LS6s were just about spot on.

So.....we all know the LS1 in the F-body was under-rated, badly, by GM. Once everyone figured that out, the internet world went crazy and everything except the 99 Cobra suddenly became "under-rated". Most especially everything GM.

1st, LT1's are underated. For example a stock '97 M6 in GMHTP magazine dyno'd @ 249rwhp, while rated @ 285fwhp. You tell me? 2nd, I thought by now everyone would know that GM underrated the F-bodies so that they wouldn't screw with the 'vette. It was simply a marketing scheme, and despite the fact that the Corvette had the same exact LS1 in it, they had to make it "look" more potent than the F-bodies to charge and extra $10-20 grand more. Chevy's always done that with the Corvette. Put the F-body @ the Corvettes 350hp, it's that simple. And last, '99 Cobra's are over-rated. Naw, just kidding.

**BLKCLOUD** · 07-30-2007, 09:41 AM

Originally Posted by N20LT4

1st, LT1's are underated. For example a stock '97 M6 in GMHTP magazine dyno'd @ 249rwhp, while rated @ 285fwhp. You tell me?

A couple of things...

First, 249 RWHP on a 285 rating might be a bit under-rated, but not significantly so. Some math would suggest 285 at the flywheel to 249 at the wheels is about a 13% loss. Pretty close to what most folks use as 'typical'.

Second, GMHTP uses STD correction vice the more common SAE. STD corrects to a standard atmosphere at sea level (59F, 0%, 29.92"/hg), while SAE corrects to a more 'typical' day in anywhere USA (77F, 0%, 29.32"/hg). STD corrections will show ~3% more power than SAE, which would have brought your example down into the 242-243 RWHP, and right in line with what would be expected of a 285 HP motor.

Finally, some cars dyno more, some less. This is based on so many factors that the only way to get a reasonable idea of how close the cars are rated is to take an average over a very large population.

My conclusion: They may have been slightly under-rated, but not much. I'll stick to my original assertion.

2nd, I thought by now everyone would know that GM underrated the F-bodies so that they wouldn't screw with the 'vette. It was simply a marketing scheme, and despite the fact that the Corvette had the same exact LS1 in it, they had to make it "look" more potent than the F-bodies to charge and extra $10-20 grand more. Chevy's always done that with the Corvette. Put the F-body @ the Corvettes 350hp, it's that simple.

I'm not sure why you put this statement below my quote, as I never said anything to the contrary.

And last, '99 Cobra's are over-rated. Naw, just kidding.

LOL. As delivered, they generally were, hence the performance recall (commonly known as "the fix").

Some of us "fixed" it a little bit more than others.

Bob

**N20LT4** · 07-30-2007, 01:25 PM

That was exactly my point. I never said they were "majorly" underrated. You said they were "not" underrated, meaning @ all, and off the top I knew that wasn't true. The Corvette point wasn't directed towards you. I'm pretty sure you already knew that, but some didn't.

**BLKCLOUD** · 07-30-2007, 03:58 PM

LOL. Ok, if we want to really really really be sticklers, this is what I said, and I quote myself...

Originally Posted by BLKCLOUD

LT1s were not underrated, at least not by much.

emphasis added.

Truth be told, I don't think the LT1 was "over-rated" (or over-rated) any more than any other engine of the time. But you have one, so I understand why you might disagree.

**N20LT4** · 07-30-2007, 08:45 PM

Originally Posted by BLKCLOUD

LOL. Ok, if we want to really really really be sticklers, this is what I said, and I quote myself...

emphasis added.

Truth be told, I don't think the LT1 was "over-rated" (or over-rated) any more than any other engine of the time. But you have one, so I understand why you might disagree.

My apologies. I didn't see that. I better read the entire comment next time