28HopUp

Before my C&L (cold air induction) and tune from Evolution, my car dyno'd (Mustang Dyno) at 180 rwhp (4.0L/auto). That was with a GT take-off muffler. After the tune, I was at 190 rwhp (93 Extreme tune), but that was with zero miles on the new parts/tune and we did not reset the car per instructions in the manual after reconnecting the battery. Within a day, my car was even stronger than when I left their shop. So my next time on the dyno should generate better numbers (it will be cooler outside too), and then I'll know for sure. Also looking to get some 1/4 mile times soon!!!

As stated previously, having the throttle lag virtually gone is enough reason to get a tune (and CAI). These cars have a torque management program in the PC too, and most tunes fix that. My car has much better low end torque getting to the ground, which increases the smile-factor exponentially.

And BTW, you didn't ask a stupid question (per subject line)

v6stanggoddess

It really makes that much of a difference huh?

jericho73

That sounds right. That would be 20 over stock rwhp, they may be going by manual numbers but lets run with 190...that would be a little over 230 at the crank, up from the stock 210 chp.

so it's...

170 rwhp--> 190 rwhp

or you could say

210 chp--> 230 chp

28HopUp

Before the tune, my car would not spin the tire at all unless the road wa slippery. Nadda peep from the tire. Pulling out in front of traffic had to be timed in such a way that the car spooled up into the power band before I'd get hit. No fun whatsoever.

After the tune, the car seemed to be awakended. Some folks say it feels like a different car. That's not how I would describe it. With a tune, the car feels like it is running the way Ford should have built it in the first place. MUCH MORE FUN TO DRIVE!

v6stanggoddess

Ok, well since you guys put it that way it is VERY much worth it. 230 HP is good I feel. I really do not understand the rwhp at all. I know it is at the rear wheels and it is better than HP. But I just, well, everything in HP makes more sense to me for some reason. So 230 HP is really awesome! That is almost at my friends G35 I think?

Black Stang 3200492

my car wont start now with the custom tune, it starts but then the car dies. Is it because I have to put the cold air intake in first because i think the tunes are for the cold air intake.

joshetc

I was always under the impression that rwhp was Real World Horse Power, I've seen people use RWHP on AWD and FWD vehicles as well.

Anyway, its pretty simple. The engine is rated at 210 at the crankshaft (before resistance from transmission and driveshaft and other factors). The HP left after all of those things is RWHP or the horsepower given to the wheels themselves. Apparently the stick loses about 15% of its horsepower through the process of converting it to the wheels (also known as drivetrain loss) The auto loses roughly 20%.

So a 210 HP car would be

210 x 0.8 = 168 HP -- Auto
210 x 0.85 = 178.5 HP -- Manual

The main reason this is done as its MUCH easier to measure the HP from the wheels than from the crankshaft, which is how they do it at the factory. It would be much less confusing if the manufacturers would rate the RWHP instead of CHP but CHP is always higher so it looks more appealing to consumers.

jericho73

You're mixing up ratings again...let's just stick with chp for now, since you seem more comfortable with that.

G35- 280 chp <stock auto>

Mustang v6-230 chp <w/ tune>

so its still quite a difference.

Rwhp and chp are the same things, just different measurments of it. Rwhp is a more accurate measurment of the power you're really getting. The g35 would be at about 230 rwhp stock, while, as said, you'd be at 190 rwhp. New edge v6's were 190 chp, but like 150 rwho for example. Every car is going to show a much lower rwhp # then chp #, that's why car companies use chp.

28HopUp

To clarify, rwhp = Rear Wheel Horse Power. And you are right, I've seen people use the term on FWD cars too.