Stock performance

[Dragkid1917]

Ive been looking around and getting varried results, do any of you know the stock times for a 98 - 02 trans am, and not the Ws6 just the 305/310 hp versions, and Automatic. (yes i know they will be a bit different depending on the year)

[ryan34]

well depending on you elevation, you can probably expect mid 13's.

[casey02ws6]

http://www.ls1tech.com/forums/showthread.php?t=458711

They are good for < 6 sec 0-60 and mid 13 sec 1/4s

[fastTa]

The '98-'00 A4's are good for 13.4-13.5. The '01-'02 A4's are just a hair faster due to the LS6 intake manifold.

The '01-'02 M6's have gotten into the 12's bone stock on a number of occasions.

The factory M6 cars have a big advantage in the 1/4 mile by being able to leave the line on a clutch drop, the drivetrain is more efficient and soaks up less power, they are lighter, and they have a greater torque multiplication selection due to the gear ratio relationships.

LS1 RWHP numbers can vary anywhere between 285 and 315 depending on the drivetrain type. Most of the LS1's are between 350-360 HP at the crank on average. The factory ratings are vastly underrated to keep from adversely affecting Corvette sales.

[Dragkid1917]

Really?, so your saying that instead of the advertized 305 / 310 hp they have more like 340?, that would make sence since the tq is up there someware. So basically what u can expect from a z28 and a trans am is about a 13.5 (not SS or WS6).

[Joe K. 99 Zeee!!]

Really?, so your saying that instead of the advertized 305 / 310 hp they have more like 340?, that would make sence since the tq is up there someware. So basically what u can expect from a z28 and a trans am is about a 13.5 (not SS or WS6).

Yes...HP loss through the drivetrain comes to about 20% for an auto and 15% for a manual. These are estimates though not actuals. Anyway, as was mentioned before dyno measurements at the rear wheels show between 285 and 299 HP for stock cars. Over 300 for some 01-02 cars. If you do the math it comes to around 340-350HP or more. The cam was slightly more aggressive for 98-00 cars, but the 01-02 cars got an LS6 intake manifold and less restrictive exhaust manifolds that more than made up for it.

As far as drag racing...one could argue that the Auto is easier to launch and therefore may get a jump on an manual tranny car. It'll also have more consistent times.

The WS6 got some enhancements, but nothing you couldn't do with a few aftermarket parts. The main reason for getting the WS6 is if you prefer the style and exclusivity of the car.

Maybe that's more than what you were asking for, but it's a nie brief overview of 98-02 performance.

[Dragkid1917]

when people say Z28 M6, or SS M6 what do they meen by m6, are all of them M6 or is M6 a special upgrade or sumthing cuz be4 i read this forum i never herd of that at all.
And another thing is about the link that is above about hp gains. It says that long tube headers will yeild only 15-20 rwhp, when slp claims 41hp/58tq. Now i know that 41 is a high number but spending a grand (headers, Ypipe, gastets and whatnot) for only 15 hp is rediculus. What do u think the avg yeild of headers are? (4x1.75" into a 3" collector per header).

[Joe K. 99 Zeee!!]

M6 is short for 6-speed manual transmission. A4 would be 4-speed auto.

I would suppose the SLP claims for HP gains are attainable, but that would depend on the setup of the car that they're installed in. For example, header gains on a supercharged car would be greater than gains on a stock car. I would view all advertised claims with a grain of salt. Spend the time to do some research and read about other's experiences before jumping in on something. That said, long-tube headers on an LS1 show some good gains. It's a good mod if you don't have to worry about emissions laws.

[Dragkid1917]

I think is should be good, in Nj there are emisions laws but i also plan to put on a LM ex that comes with a catback and is said to be 50 state legal. However my frend told me that i can get a peice that is just a straight pipe connector so after inspection i can swap out the cat with a straight pipe which should give me more h/p. With the full exaust redone claims to the products say that gaining 60 hp and 80tq are possible. (40hp from headers 20 from the LM) I just hope its someware around there.

[Craig 94 TA GT]

IMHO, to gain 60 hp just on exhaust is impossible. I would say even 50 is a stretch. Also, because one claims 40 and the other claims 20, doesn't mean they'll yield 60. It doesn't really work that way. I think a very reasonable goal is 25-40 hp from a full exhaust.

[fastTa]

And another thing is about the link that is above about hp gains. It says that long tube headers will yeild only 15-20 rwhp, when slp claims 41hp/58tq. Now i know that 41 is a high number but spending a grand (headers, Ypipe, gastets and whatnot) for only 15 hp is rediculus. What do u think the avg yeild of headers are? (4x1.75" into a 3" collector per header).

In the link they are discussing RWHP gains. Gains measured at the rear wheel. And 15-25 RWHP is about right for just LT headers on a LS1. SLP is advertising their gains in HP measured at the crankshaft which doesn't account for drivetrain losses and is obviously a higher number. It sounds better to advertise the bigger crank HP numbers.

On an internally stock LS1, you can expect anywhere between 340-360 RWHP from just headers, catback, lid, and tuning.

[Trash man]

Question - why would you pull the cat? fred on the board i think(correct me if im wrong) but has said it only cost 5hp on a 800hp motor

[Dragkid1917]

Question - why would you pull the cat? fred on the board i think(correct me if im wrong) but has said it only cost 5hp on a 800hp motor

Oh i didnt know.. then never mind with that...

[Injuneer]

Question - why would you pull the cat? fred on the board i think(correct me if im wrong) but has said it only cost 5hp on a 800hp motor

Fred never said that

Lingenfelter claimed less than 5HP on his 383 LT1's. The dual cats on the LS1 cars are probably extremely efficient. A buddy of my with a 98 TA ran consistantly quicker with a pair of high flow CarSound cats on his headers than he did with the "off road" pipes (Mufflex did the swaps for him, to get some data on the CarSounds).

Here in NJ, you're totally screwed if you get pulled over by one of the mobile inspection teams that sets up on the side of the road, pulls cars over "at random" (sure) and does a full visual inspection - by people who know exactly what to look for - and a roadside emissions test on a portable dyno. If you get caught without cats, you're screwed. They seem to be focusing mostly on diesel trucks these days though.

I ran cats on my setup when it was still street driven, and only dropped the cats and replaced them with Borla XR-1 mufflers for running at the track with leaded fuel.

[casey02ws6]

On a side note - never underestimate the amount of sound the cats control. They are very good mufflers. If you decide to run without cats be ready for your car to become LOUD in an instant - no matter what exhaust you have.