If our cars pick up 8 wheel hp how much is that at the crank?
 

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We lost about 20% give or take

looks like drivetrain losses are ~17.5% on the twins (manual trans).

Therefore,

CHP = WHP/(1-0.175)

so a 8 whp gain is 9.69hp gain at the crank.

That's what I've seen more often than not. Depends on the dyno. Possibly quality of fuel..

How did you pick up these extra 8whp?

I would like a 8whp on the cheap.

i bought a chip off ebay...

:laughabove: jk. that seems to be about what you can expect from a drop in filter and catback

I suspect our engines don't make the full 200 hp until somewhere after 5000 miles (i.e., fully broken in). DD Performance demonstrated that their stock FR-S dyno'd at:

- 166 whp with 250 miles
- 171 whp with 2500 miles
- 174 whp with 8500 miles

on their dynojet. Based on that, I'd guess the drivetrain loss on the twins is a bit lower, probably 13-15%.

http://www.ft86club.com/forums/showt...?t=7319&page=3

I just hit 5k the other day...not sure I noticed any difference but about a thousand miles ago I'd say it's picked up a little bit. :) Has anyone else seen this and can confirm it or just those guys?

I think it'd be hard to find more of these kinds of dynos. I don't know of anyone else dynoing their cars stock every few thousand miles.

It is pretty common knowledge that most cars gain some hp after the break-in period (you see it sometimes when magazines do 0-60/quarter mile tests at the beginning and end of long-term tests).

Why would u need to know that? "At the crank" hp would always be an estimate unless u took the motor out. Dyno it, get baseline whp, then stick on the bolt on and dyno it on the same exact dyno in similar temperature.