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3500-3700rpm is a typical lowered vtec point for this car out of the box if you have a test pipe. So nothing out of the ordinary there, unless you still have the stock cat still in place, and then i would be further suspect of the cam timing being off.
I'm not understanding what you mean about running out of gear on the dyno. It doesn't matter what your rear end gearing is, your only task is to run the car up to redline, hell you could do it in 1st gear if you wanted. But i find it curious that your run went up to 144 in 4th and down to 126 in 6th, something to consider there. Did you run the car up to redline in 4th gear? If not, why exactly?
A hub dyno reads higher then a typical roller dyno just fyi, because less drivetrain loss. Not to pour salt in the wound, but we are just trying to figure out if there is a problem or not. We dont do KW here, we do whp. So all we can do is take your word for it on what the stated average power output is on this tuners dyno for an s2000. 144 seems a lot closer then 125kw though. The power curve on dyno looks pretty normal though. Just down on peak power yield.
Test pipe, no cat as per OP. The 144kw is 4th gear to redline, I have a blurry pic on my phone (my fault) which shows very similar torque and power plots to the 6th gear pull. I've noted to my tuner that when I return after doing my mech checks to re-run it in 4th, 5th and 6th.
My initial impressions with driving after the tune is that the mid-range torque different is vastly improved.
Also, I am grateful for your input and help thus far - no hurt feelings here, I just want to get to the bottom of it as it is a car I intend on keeping and using for trackdays for a very long time. I will keep in mind the power measurement - hp v kw; we use both here and 99% of the time its at the wheels/hubs. I don't think we have many roller dynos in NZ come to think of it - there are definitely more hub dynos than roller dynos.
I will do the usual tests as mentioned above in the coming week and report back.
Test pipe, no cat as per OP. The 144kw is 4th gear to redline, I have a blurry pic on my phone (my fault) which shows very similar torque and power plots to the 6th gear pull. I've noted to my tuner that when I return after doing my mech checks to re-run it in 4th, 5th and 6th.
My initial impressions with driving after the tune is that the mid-range torque different is vastly improved.
Also, I am grateful for your input and help thus far - no hurt feelings here, I just want to get to the bottom of it as it is a car I intend on keeping and using for trackdays for a very long time. I will keep in mind the power measurement - hp v kw; we use both here and 99% of the time its at the wheels/hubs. I don't think we have many roller dynos in NZ come to think of it - there are definitely more hub dynos than roller dynos.
I will do the usual tests as mentioned above in the coming week and report back.
No problem, happy to help. These motors respond the most in the mid range after tuning because of its stock vtec engagement point. Sometimes the top end feels a little flat afterward, just because of the gain in mid, the vtec hit is gone and it sometimes the perception feels like the top end never comes on, even though it does. But as going back to my original post further back, you can always do a leakdown test to confirm the health of the engine, and double check the timing mark on the cam wheel when checking the valve lash to insure its at factory timing. Until then we are all just grabbing straws.
4th gear run 144kW x 1.36 = 196whp which doesn't seem that far off. That big dive just after 8000rpm is a bit weird though.
6th gear run 169Nm x 0.74 = 125lbft, looks like the torque is dropping way fast after 6000rpm which also seems a bit odd.
Check your valves and timing marks and do some new runs, hopefully you pick up all those lost kilowatts
Here is an old dyno from my AP1 with boltons just for comparison, this is also a dynapack and I think we used 4th gear (maybe 5th) but that shouldn't matter much.
Using a Berk HFC on this run which I later found did rob me 8-10whp up top.
flanders - I've been reading your build thread, it's very impressive and I actually stumbled across it awhile ago when I was looking at the air pump delete.
My car is with my race mechanic now for a compression and leakdown test. I've asked him to take some photos of the timing and to check the cam timing itself. Fingers crossed!
For reference, my 2001 AP1 @ 161,000kms got 130rwkw on a roller dyno - 4th gear pull / stock diff. Only mod was Injen cold air intake and it was on shitty 18" wheels. I think it had 225/30 tyres on it at the time.
MCM's s2k achieved a similar result. I believe they got 132rwkw when they did their initial tests with a CAI as well. Stock wheels / tyres. Not sure if this was before or after exhaust.
If you want i can dig around for a picture of my run if you want.
Last edited by Bruunz; 03-01-2018 at 02:16 PM.
Reason: Typos
It looks like we have found the culprit - timing was out. I'm surprised the factory ECU ran with the timing being slightly out. It had no problems starting up or running through the revs so it's interesting that it's come this way
Compression has been retested - 225-225-225-220 on their gauge. He said that's what he would expect from a high compression motor on his gauges. Valves being adjusted this afternoon. I won't be able to book my tuner for at least a couple of weeks from now, but it's all looking positive.
Hopefully I'm not speaking too early but the takeaway from this is to double check the basics especially if an engine has been rebuilt.
Video screenshot attached from the mechanic - apologies for sizing/quality etc. but clear to see its not quite right here.
02-28-2018, 04:29 PM
