hp gain
- Thread starter 04gtboy
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Maybe 7-8 from the midpipe. The catback is a toss-up. Some say 0...others claim 4-5HP. You will not "gain" flywheel HP meaning you will still be at 260 but you will free up some that is lost at the wheels.
streetstang03
unModerator
SOTP meter definetly will feel the midpipe...i know i did. like coramprat said ~10hp from midpipe and no more than 5hp from the catback.
keep in mind the 260hp rating from the factory is fly wheel hp, not rear wheel hp.
keep in mind the 260hp rating from the factory is fly wheel hp, not rear wheel hp.
ponysarepretty
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- Jul 25, 2005
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coramprat said:
you are gaining flywheel HP, the only time you will free up parasitic loss is when you change a component of the driveline. think about it.
It's just numbers though...I barely felt anything from my swap (still have the stock catback) but my dyno numbers say different.Kilgore Trout said:
I based my findings on this: Went to a dyno day. There were two other NPI GT's besides mine. One had no mods except K&N and American Thunder catback. He dyno'd at 174HP...
Second car had mods similar to mine except the PI intake and he had full Bassani exhaust w/an X and 3.73's...197HP.
My car...PI Intake, Mac Prochamber, fenderwell CAI, TB and plenum Screamin' Demon Coils, 4.10's...213HP.
I think the difference in cars 1+2 was the X...mine made the power with a combination of the midpipe and the upper air flow. I haven't dyno'd since my cam install but thinking I'm around 235 now. Keep in mind these were NPI cars (mine being a PI intake swap only with stock heads). Your results on the PI car will probably be a little better.
But all you are doing is increasing the output air flow with a midpipe? The engine is rated at 260 (Mine is 215 :roll: )and you are restricting that with cats in relation to your RWHP. That will decrease your RWHP. Pull them off and you increase your RWHP but the FWHP won't go up until you make increases in upper airflow. Maybe I have my info wrong...ponysarepretty said:
03ghoststang
Well-Known Member
you will see increase in both WHP and FWHP since the cars are rated at 260HP at the fly the parasitic loss is roughly about 15-20%. So if you gain RWHP then the HP at the fly should go up also, since the engine is not forcing the exhaust out like when it had the Stock mid pipe, now it will flow more freely.
ponysarepretty
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coramprat said:
I think you have your logic a little wrong. How much air goes in and out of your engine does effect how much power it makes. Because an engine is basically a massive air pump, the more air that is moves, the more power it will make, in theory. The cats restrict air flow, thus dampening your motor's ability to produce power. However something liek the tranny and the sound energy it gives off eats up power as it goes from your motor to the ground.
I have to agree. I guess you can look at it like this: It is the same thing as doing an engine buildup and dynoing the motor with different headers/mufflers before you put it in the car (Car Craft and Hot Rod do these tests frequently). The horse power and torque figures change and there are no wheels.03ghoststang said:
ponysarepretty
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But for all intensive purposes RWHP is the figure you want to remember, because if your motor produces 1000 hp and 50% of it reaches the ground, its no better than a car that produces 700 hp and 70% of the hp reaches the ground.
jstreet0204
Active Member
The 260 hp is SAE net hp which is rated at the flywheel with all accessories and exhaust systems intact. So the answer is, Yes you will gain FW hp. If the standard used was gross hp where no accessories and open manifolds were used then you wouldn't.
03ghoststang
Well-Known Member
ponysarepretty said:
that is true its all on how much of it you can lay to the ground effectively :Word:
Mossberg
Active Member
streetstang03
unModerator
Mossberg said:I hope you like an extremely raspy exhaust note, because you just bought one!
w/o a doubt.
BBK
ponysarepretty
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jstreet0204 said:
its not all accessories, its all accessories now, but when the 260 was claimed it wasn't. also back then they could use some super slick lubricants, very cold inlet temps etc.
