Dyno results before & after homefries

[Dingo]

one of the first things I did when I got my car was to bang it on the rollers just to see if everythings as it should be, it was completely standard and came back with no surprises, all three runs are very close with no peaks or troughs and bang on 230 hp.
Anyway had it a while and its now got a Milltek (cats removed) K&N panel & homefries, so I took it back to the same place but look at the results.
Its been done in wheel HP (245), I showed him the first graph and he said it was set up the same, I know it was a hotter day but this car'nt be right can it ?
But apart from that everythings good, seems more power at the top end, he also measured boost this time, hitting full boost 1.4 bar @ 2,500 rpm and tailing of slowly.
So what do you recon and how much does this work out at the fly wheel.

[Rusty]

Mine was loosing 70bhp so sounds like you've got a good'un there. I'd say that's well over 290bhp which is correct for a car of that spec that's running correctly.

[Dingo]

Thats just made my day,
Cheers Andy

[S2central.net]

So the standard graph is estimated at flywheel and the 2nd one is at the wheels ?

240bhp and 300lbft at the wheels (ATW) is good - very good. Adding something like 25% for rolling losses is about the norm and you are knocking on for ~300bhp on this setup.

My car ran about 210bhp ATW on 98RON with stock exhaust on Maha rollers and the G-Tech shows ~220bhp on 97RON (nett ATW on the move) with the lower portion of RS2 airbox installed.

240bhp ATW is good - proves the Milltek is good at that level !

[andyg plym]

i may just get mine on the rollers to sort this long debate out,ive got a similar spec but plus a few extra goodies:mischeif:
i MUST be knocking on the door of 300 now with my stock k24

[EspenW]

Remember that these pulls were made on a Dynojet (extremely popular in the US, not very common in Europe). Numbers from a Dynojet are usually approx. 13% higher than those generated on a Mustang or Dynapack. ATW numbers from a MAHA are normally even lower than that.
Torque is way up in the after runs (312 vs 275 lb-ft), but horsepower has only increased by 15hp. Fuel delivery problem?

[T2Andy]

The hp is at the wheels on the second graph i would add 25% to the 245hp =306bhp

[A80Avant]

i dont know how the 25% is thought for 4wheel drive cars.I think the add on the wheel power of 25% is a bit high for a crank hp figure.

[Rusty]

Without the estimated power / torque at the wheels it's all a guessing game and even then it's hardly ultra-accurate. As long as you're getting 1.5 bar peak dropping to about 0.8 and your afrs are about 11.5 to 12:1 all the way through on full boost it's running healthily and that's what you want

[EspenW]

25% drivetrain loss isn't all that unheard of for 4wd, but remember that different dynos will give wildly different numbers for power at the wheels. Trying to correct atw numbers for power at the flywheel just makes things even more inaccurate.
To find estimated flywheel power with assumed 25% drivetrain loss, divide the atw number by 0.75. Thus, in this case, pulling 245 at the wheels with 25% drivetrain loss would put the crank figure to 326. However, the number is generated on a Dynojet, and those are famous for high numbers, usually somewhere in between the real ATW number and flywheel power.