Thread: Dissapointing dyno

My first build was off by one tooth - ran smoothly, idled just fine, but was down on power/wtq, especially on the low end. Retiming the engine netted much better economy, and about 9whp / 11wtq

Setup: DE, S4, Hotshot G5, 3" exh., K&N panel filter.

Ok so lets look at what youve done here.

Stock cam timing - reasonable HP


Now, did he go 2.5 advance on intake and 2.5 retard on exhaust? Which way are the cams set at now?


My guess is that whoever has played with the cam gears has screwed up, and youve lost a heap of dynamic compression. Have you bothered to do a compression test? Did you have a vacuum guage fitted during the dyno run to see how the inlet is flowing?

But, youve lost HP from your original dyno - nearly 20% worth. Theres something a miss! The AF's although being over the place, are within spec, but should certianly be more linear and smoother.

Ediy: Your power curve looks to be identicle, except the dyno run has been cut short at 6k. Double check your map yourself, or get himt o reload the original base map and work from there!

I used non RR...Valves, Springs, retainers, rockers and oil squirters(with the longer bolt)...and a Non RR Cam cover.



Thanks, This is looking the culprit now.



He did +2.5 on intake and -2.5 on exhaust yes...the car is now back to 0 0.

Unfortunately I wasn't there when this was being done...I dropped it off in the morning and had to go to work. I then picked it back up after work, but never asked him if a guage was on there. I haven't done a comp test.

Im gonna lift the engine out and double check the cam timing, I have a funny feeling it's not right.

Cheers everyone.

This motor was originally a UK-RR? What was the compression and what is it now?

Comp was 10:1 as a UK RR,now it's 11.7:1...same engine but no RR.

^I thought the SR16 pistons would put it at 11.8:1........? Anyway I would double check the timing like you plan on doing and give her another run on the dyno. You should be making around 165-170WHP I would say with a full 2.5" exhaust system.

Ok, before I go to through the hassle of pulling the engine out...I did a quick check of the timing this is what the dowell pins look like when piston 1 is at TDC.



You can just make out number 1 on the cam sprockets...that's where the dowell pin is.


There at 10 o'clock and 12 o'clock....is it still best to do it properley with the engine out.?

You dont have to pull the engine out to change the cam settings. Besides at the current settings, everything looks to be perfect as there are 11 links.

Yeh, it's a wierd one, that is fine isn't it. Im now wondering if the cams have anything to do with it? There BC stage 3's...so should be ok but maybe a dodgy ground?

Any help or input would be great.

I made mid 180s hp and 147 Tq with stg 3's and sr16ve pistons. Somethings going on. Possible the wrong settings, maybe the small exhaust bottling everything up.
I saw a few ponys going from 2.5" to 3"