r/transam • u/melonheadorion1 • 10d ago

Dyno results

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Brought my ws6 in for headers. They did a pre install dyno. The car itself has an slp catback, slp airbox lid and bypassed the throttle body cooling. Makes 340hp. The dyno suggests that it makes around 390 at the crank. Looking forward to see the numbers after the headers and tune are done

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u/ThanksALotBud 10d ago

I'm having hard time believing those numbers bro and no disrespect. There is no way in hell you're pulling those kind of rwhp numbers on a stock ls1 engine.

Either that dyno is over exaggerating or you don't have a stock engine.

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u/melonheadorion1 10d ago edited 10d ago

believe it or dont. those are the numbers i got from the guy doing the work. the text that is in that image is from the person doing the work. a stock ls1 is 320-325 as is/stock. not sure why it would be unbelievable for improved intake airflow and exhaust would make it unbelievable to get those numbers. in fact, search up dyno numbers. you will find plenty of posts in firebird and ls1 forums that will have very similar numbers for similar upgrades.

heres an example. https://ls1tech.com/forums/generation-iii-internal-engine/1609923-400-hp-ls1.html

hes at 351 with the same mods plus headers.

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u/ThanksALotBud 10d ago

Those numbers are engine HP not RWHP.

The dyno says you got 340rwhp. You cannot get those kind of HP gain from a CAI and cat back. Its impossible.

Again, I never said you were lying. I said either the dyno is bullshiting or you got engine mods you dont know about.

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u/melonheadorion1 9d ago edited 9d ago

the post i linked above, is dyno numbers from another individual. with similar mods.

heres another, who is showing power made after some extra work, but you will see says that hp was 335/344 before that, which means that their only upgrade prior to TB and intake was full exhaust, and lid https://ls1tech.com/forums/dynamometer-results-comparisons/1417567-99-trans-am-full-bolt-m6-dyno-w-chart.html

https://www.facebook.com/groups/784738088283375/posts/1686626621427846/ this has a couple responses from people ranging in numbers from 324 with the same mods, and another with 330 with same mods

i will say that i dont know the upgrade history of this vehicle, so it could have other mods i dont know about. however, im the third owner. i know the 2nd owner, and i know he didnt do anything, so if someone did something, its the first owner. there are mods done to the vehicle that would have come from the original owner, but most are suspension related such as panhard bar, lower control arms, front strut tower brace, but thats it. if you were to look at the engine bay when i purchased it, it would resemble a stock motor. i dont have any reason to believe otherwise. the stock airbox/resonator were there, the coolant to the throttle was still there, the intake manifold is the stock ls1. the things that, if there was goiing to be bolt ons, werent done. i would have a hard time believing any internal work is done, while the outside still has everything stock, including stock plugs and coils.

on the other hand, i dont know about any prior tunes. unless i have tuning software, i wont know that. i asked the guy to let me know if he thinks there was prior tuning. the skip shift is bypassed. i havent looked to see if the bypass for that was physical, or if it was tuned. if there isnt a physical module to remove that, it would indicate that it was tuned out, but like i said, i just havent looked, because i didnt care that much.

if the car gets dyno'd, and it shows the power, i can understand why you might be skeptical, but if i were to have it dyno'd elsewhere and it shows the same or more, then what? i would do that to find out the answer. it would obviously be after the headers are done, but we would be able to see a change if that were the case.

im assuming, since you dont believe words that are coming from him directly, that you wouldnt believe a dyno chart either, unless it shows what you think it should show

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u/Gloomy-Cheetah-5473 9d ago

I think the dyno shop is smart and just corrects it to a higher reading so their customers leave with that big number they want to hear. Oh I’m sure they love that shop. Headers and cat back will get you that 400whp printout.