What kind of HP gains are you seeing between the 5% and 10%? Nothing exact just your best guess. I am concerned about traction and pushing the motor to hard on the 10%. Also is the 10% overkill for someone without your exhaust?
You also mentioned a add on heat exchanger in another thread. Do we need one for these?
Last edited by CadV; 05-28-09 at 10:50 AM.
Granted, take my thoughts with a grain of salt, as I'm not nearly as experienced as many on this forum, especially Jesse, but that's my preliminary guess.
He had the airbox mod, stock exhaust and tune done at the time. Crank should give us more boost.
I am predicting 560-580 with the 5%. 10% is probably overkill until the fuel stuff is sorted.
I am doing the same as you and going with the 5%.
Here is his baseline before the blower pulley.
Is there a mathematical equation that would nail down peak HP at the crank using 560-580 figures? I love the RWHP but any ideas of the BHP? Or is there only estimates.
Any one know where that thread was? Or knows the Math?
I took some pictures when I got it:
Handheld is the only way to get the trans tune without going to his shop.
I dynoed at ~470 rwhp stock, then went to ~520 rwhp from a tune alone. That's about 50 rwhp from a tune alone. If Jesse got that much, that would leave the pulley swap generating another 30 rwhp, which seems in the ball-park.
I'll shot-in-the-dark estimate that I'll get 30-40 from the crank pulley and end up around 550-560 from the pulley alone. However, I'm also doing the American Racing headers, and Corsa, exhaust system, as well as Hennessey's cold-air intake, so I'm hoping for a tad more than that.
Jesse--what % overdrive does the 2.55" pulley equate to so we can compare the crankshaft pulley to the 2.55" blower pulley? Thanks!
Most of the time, I see people using 15% losses for the drivetrain and that makes decent sense assuming that 556 as a starting point and what people are seeing at the tires.
Last edited by Luna.; 05-28-09 at 06:46 PM.
Well you know people like to here the bigger numbers and i like to tell them. When they hear 556 they just about fall over. So why not add it up. Isn't that what Hennessey is doing with his V700 package? That 15% math sounds fairly just as everyone who has put up their numbers has seen similar RWHP with just a tune or some kind of combo. If that figure is correct 556BHP x 15% = 473 RWHP
I dynoed at ~470 rwhp stock, then went to ~520 rwhp
This would equate to about 612 HP if you ad back the 15%. Add a pulley and you could be looking at around that 700 magic number. All the other breath better goodies, Heads and cam should should easily take you there. No doubt.
Just curious...why interested? The number at the tire seems to be the truly important one.
Most of the time, I see people using 15% losses for the drivetrain and that makes decent sense assuming that 556 as a starting point and what people are seeing at the tires.[/QUOTE]
Just to help also on this. The cars are VERY different when you dyno them cold vs hot, vs different intake air temps, vs time running before floored. This could account for people gaining more power from tunes vs others...
This is a motor, just like any other motor. Timing can only be so high, and fuel can only go so lean before you have problems....
If you watch all my dyno vids, the car is run on the rollers until the car hits EXACTLY the same coolant temp, which in my case is 180degrees, And the same intake air charge temps. Sometimes it takes 5 minutes of running on the rollers to hit that... THEN WE DO A PULL. If you just do a startup and then dyno pull after sitting for 3 hours, your horsepower goes up, but only for the dyno and not real world conditions.. REAL world conditions are you driving down the highway and or thru the city and letting some poor sap with a m5 get his feeling hurt as you show him he paid too much for his car.... If you do a pull in our cars when they are completely cold, of coarse you will make alot more power on the dyno, but when is it really going to be that way when you are on the street...
If you look at timing tables, based on coolant, and intake air, you can see that they are able to apply alot more timing during that time. To be fair for horsepower gains, you need to have exact coolant temps, and exact intake 2 temps.. Then it is a fair honest gain.....