A number of folks have replaced the stock pulley with a 2.7" pulley and increased the HP by about 100 (with a tune). My question is do you really notice the difference other than the shorter E.T. / MPH. That is to say, does the car really feel different with the extra HP.
Pulley Change - Real Effect
- Thread starter hboyle2003
- Start date
Actually, what you’ll feel is the added torque. Torque at the flywheel is multiplied through the transmission and differential (by the overall gear ratio) to an even larger torque at the rear wheels, (rwTQ = fwTQ*GRtot). The torque at the rear wheels results in a force at the contact patch, which goes as the torque divided by the radius of the tire, (F = rwTQ/Rtire). The higher this force, the larger the acceleration (a = F/m). The acceleration, and hence torque, is what you feel. Torque represents the ability to do work. Power is just the rate at which work is done, (P = TQ*angular_velocity). Putting a smaller pulley on the supercharger forces in more air at any given engine speed, (which also means more fuel gets injected), so torque goes up. Therefore, the answer to your question is yes…you will definitely “feel” the difference!
Fubar
Totally ****** Up
I think Cobra is saying that HP is a function of torque (of course I failed quantum physics so Cobra might have just said that HP stands for Hokey Pokey and we should all turn ourselves around but I digress). So consequently, whatever you feel must be torque. We laymen prefer the use of the term Horse Power because it has the word "Power" in it.
At any rate, the general consensus is you can feel the pulley in the seat of your pants. 100 HP or 100ft/lbs torque is roughly a 23% increase in engine output.... that’s huge.
At any rate, the general consensus is you can feel the pulley in the seat of your pants. 100 HP or 100ft/lbs torque is roughly a 23% increase in engine output.... that’s huge.
SLF360
GT Owner
Big Carrot
GT Owner
- Aug 25, 2006
- 4,436
Yes; HP is an extrapolated number.
As for the pulley swaps and the HP gains; likely I have seen and yet I ask; what is the torque increase and where in the power curve does it come into play. I suspect being a mechanical air pump that comes in sooner and runs a bit longer.
All the best
Shadowman
As for the pulley swaps and the HP gains; likely I have seen and yet I ask; what is the torque increase and where in the power curve does it come into play. I suspect being a mechanical air pump that comes in sooner and runs a bit longer.
All the best
Shadowman
what exactly is done to acheive 100 hp?what is the stock supercharger psi putting out?what is the psi after the pully?any exhaust mods and ecu tunning to acheive the 100 hp gains?where do you get all the parts from?
thanks
thanks
If you go to the Kenne Bell web site there is a chart that shows hp/tq with different pulley size, good info.
B O N Y
MODERATOR & FGT OWNER
pulley, chip, acufab exhaust = 602rwhp
see dyno chart on other pulley thread
big whipple,chip,aufab = 750rwhp :cheers :banana :cheers
see dyno chart on other pulley thread
big whipple,chip,aufab = 750rwhp :cheers :banana :cheers
californiacuda said:
I'll agree 100% with this statement... my car now feels like I was expecting it to feel outta' the box. Still is very drivable down low, but now the boost comes on more quickly and makes a big difference in the acceleration factor.
mardyn
Just for comparisons sake, a stock GT takes about 19 seconds to hit 250kph according to this test. With the 2.7" and tune, it can be done in about 15. You can see this is significantly faster than any other car in this test except for the Veyron. Unfortunately, I haven't got a chance to verify the 300kph time, but I suspect the gain in time is even more significant. The difference in how hard the car pulls over 155 is astronomical.
