Thread: Comments on this dyno sheet please

Engine and Transmission spec as follows:

Engine

UK 10:1
Hotshot CAI with Z32 MAF
Port matched + polished throttle body
Port matched + polished inlet manifold
Ported and polished head
Piper Ultimate Road cams (268/268 Duration and 11.1/11.1mm lift - weak!)
Adjustable cam gears currently at stock
Hotshot Gen VI Manifold, wrapped
3" 100cpsi CAT
3" mandrel bent CAT back with centre and rear resonator (high flow)
Decibel insert in tailpipe
Fuelling controlled by an Apexi SAFC Neo
Superchip running advanced ignition timing
Walbro 255l/ph
FSE Adjustable FPR with pressure set to 58psi i think

Transmission

Fidanza 8lb flywheel
ACT HD PP
ACT 6 puck unsprung ceramic clutch plate
Redline shockproof heavy (has wrecked my synchro's!!!)
Toyo R888 tyres (205/50 R15) which are road legal track tyres
Energy front and rear poly mounts


The dyno sheet to me just doesn't add up, ~36hp lost in transmission losses???
190hp seems too high, and 154whp sounds more like it, possibly low?
Power seemed to still be climbing at 7.5K
They were getting about 0.5AFR leaner at the tailpipe compared to my Innovate wideband in the downpipe.
And it seems to have the legendary torque dip at 3.5K, but i've forgotten the reason for that...

Are you at sea level?

Yup, the place where the run was done is less than 1/2mile from the sea, with minimal elevation between the two places.

Dastek dyno's are usually very accurate and a bit stingy. What exactly bothers you about the graphs? The 18% power loss from flywheel to wheel?


I suggest maybe contacting dastek (they're a South African company) and asking them how their dyno's convert hp at the fly to wheel hp.

What gear was this done in?

I wouldn't pay any attention at all to the flywheel horsepower numbers/calculation. It's all useless anyway except to compare (inaccurately) to manufacturer's output claims.

You've made 34 WHP more than stock. I'd bet there's more to be had, and it's more than likely hidden in the ignition timing (smoother fuel delivery couldn't hurt). I use my own results as a reference:

http://www.sr20-forum.com/showthread.php?t=7064

Your horsepower curve looks much more skewed to the higher revs than stock which can be expected due to your porting, and aftermarket cams. Not sure how you compare to others with similar mods but from what I gather your results are maybe a tad low.

Thanks for the replys.
Yup, it was first of all the higher than expected fly hp that surprised me (i was expecting 170-180hp), then secondly the amount of loss between the fly and wheels.
I was just curious as to whether 18% loss is average for an RS5F32A 'box?
I would also be inclined to take the whp figure as much more of an accurate value for the very reasons you've touched on above...fly hp is a backward calculation and therefore not so accurate.
So i guess all in all, it's the lower than expected whp figure that has me asking...does it look about right for the setup described above?

Ben, thanks for the input, you posted while i was replying to Doctor G's post.
Ah, THAT thread, been dipping in on that whenever i get a minute, good work

4th gear, and you kind of answer a question right there, so 120whp is about right for stock? Is that on a 9.5:1 compression ratio?

The ignition timing is locked in to the piggyback chip and it's definitely something i'd like to have a chance to mess with, but there's no way i'll be able to modify that chip program as the hardware is way out of date and i can't get a cable or software. Will have to look in to other options for that.

The fuel delivery i definitely agree on, done by myself with an Innovate wideband and DL-32 datalogger and Apexi SAFC Neo. Just never spent the time to get it really finetuned and ran out of funds to point it at the dyno.

Only dyno'd it now as i'm about to tear it down.
Been running this setup for about 2years.

120 WHP seems about average for a stock SR20DE with 9.5:1 compression.

You should have been able to get that fuel delivery smoother I bet with ton more hours put into it just on the street. It's hard to know what AFR will give best power without a dyno though. Were you aiming for 12.8:1?

13-15% drivetrain loss is typical for FWD cars and we'd probably lay in the 13% side of things. 15-18% is for RWD cars, and even then 18% is usually a bit high.

Doing the calculations, stock flywheel output is 140 HP, and typical measurements at the wheels result in 120 WHP so that's a 14.3% loss. Nowhere close to 18%.

Seems like you either need an 8K rev limit and or use the cam gears to help the mid range pull a bit to help the street drivability. The cams are a degree or 2 too advanced?

Also the Gen6 header has a bad mismatch on one of the pipes length to the other 3 because of space issues.

Mike

Isn't the Gen VI header meant for very high flow engines putting out upwards of 200 WHP with peak power made past 7.5k rpm?