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LS1 guestimate power....

1531 Views 2 Replies 2 Participants Last post by  Gamikatsu
Ok... my 02 firehawk LS1 Auto trans.... looking to get some good opinions on what flywheel and rear wheel hp might be at. It will never see a race track (maybe once just to save the slip... but wont be beat on) and i dont really hotrod it. Just food for thought... and to create good friendly discussion.

Engine mods:
Long tube ceramic coated headers.
Full 3 inch exhaust with cat delete; resistored rear 02 sensors (i think); y pipe of unknown brand; single in dual out muffler unsure of brand but im told it sounds like slp loudmouth..... not sure has no visible markings.

Stock air box lid was modified by removing all the baffles and sanding smooth. Silencers still installed until i find a pipe to delete them.

Superchips cortex 2950 91 performance tune with 5 mph higher shift points and slightly higher line pressure. Fan speeds lowered (oem thermostat still... will get a 160 thermostat and drop fan speeds to 175/185 i think)

The tuner made a huge difference... three friends verified... it really did feel a LOT better... even if its all in my head... but it is a good bit quicker so i believe the hp gains...(roughly 20). Oh yeah... i was given it locked by a friend... he bought it used on craigslist and it was vin locked... so he gave it to ke instead of paying the 100 dollars on top of what he paid. I felt it was worth it. Also had another friend say if i didnt like it he would give me 150 for it unlocked.... win win.

So 335 flywheel hp stock. Add in long tubes... full exhaust... lets say 10-20 hp gain? A lid is good for 8-10 hp... i just modified mine so lets say 5 hp. Then the tuner... lets say 10 hp just to curb the mass of people who are smarter than me to waste money on a worthless handheld tuner and cut the advertised gains in half.. i will say.... 360-370 engine hp... 315 rear wheel...

How far off am i?

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Oh crap! Let me get out my HP calculator.

First you can't start off basing things off of the factory rating. I've seen LS1 4th gens make between 285-320ish whp for the M6 SLP optioned ones. Most are 300-310. A firehawk is a SLP optioned fbody. The Firehawk came with a 3" dual out the left or dual dual SLP catback. It also should have came with the blackwing airlid. 2 more reasons why you can't add those to the stock HP rating. If you have the silencers and the lid doesn't say SLP, you got screwed with a stock LS1 lid someone put on. Yes a lid does generally make 8-10hp. A lide without the ribs doesn't make yours an aftermarket design with improved flow characteristics. Maybe 3-5 hp if anything for the modded stocker. Your only real addition are headers. The effetiveness of a handheld is very debatable. So with an A4, I'll speculate 335 at the wheels on a dynojet. Add 18% for bhp. And I'll say stop cutting corners on your mods if you really care about HP, and don't worry about driving it hard. The things were made to drive. It won't be a collectors items for 20 or more years, if ever. It already sounds like it is missing the SLP options so its collector value has decline. Might as well enjoy it. My wife daily drives a car that only 1829 were made for half a year, and hers is a even more rare M6. Drive the car and enjoy it!!!
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my car, was an early production firehawk, and was a "Base model". SLP told me it got Rims, a hood, and decals. did not get an exhaust, or a lid. It used the factory GM parts. this is all verified by calling SLP.
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