Dissect my dyno graph please...
Melting Slicks
Joined: Feb 2006
Posts: 2,007
Likes: 1
From: Eastern PA:ECS Paxton Novi 1500(676rwhp,585tq on stock engine),LG headers, 410's, Corsa Sports, ECS Alky Kit
St. Jude Donor '08-'09
http://www.youtube.com/watch?v=_REQ1...eature=related
Someone sent this link to me today, a video of valve spring rotation and valve float happening. Pretty intense to actually watch it happening.
Someone sent this link to me today, a video of valve spring rotation and valve float happening. Pretty intense to actually watch it happening.
Le Mans Master<br><img src="/forums/images/ranks/5k-6k.gif" border="0">
Joined: May 2007
Posts: 5,404
Likes: 1
St. Jude Donor '08-'09
Le Mans Master
Joined: Oct 2007
Posts: 6,149
Likes: 11
From: Greater Detroit Metro MI, when I'm not travelling.
http://www.youtube.com/watch?v=_REQ1...eature=related
Someone sent this link to me today, a video of valve spring rotation and valve float happening. Pretty intense to actually watch it happening.
Someone sent this link to me today, a video of valve spring rotation and valve float happening. Pretty intense to actually watch it happening.
Thread Starter
Drifting
Joined: Feb 2007
Posts: 1,844
Likes: 12
From: Alpharetta Georgia
Tech Contributor
Joined: Mar 2003
Posts: 12,094
Likes: 197
From: Colorado Springs, CO
St. Jude Donor '08-'09-'10-'11
The lS3 doesnt seem to like being 13:1 @tq peak and tends to like being richer in the TQ peak area with more timing there. I have seen 2 degrees make 10rwtq there. Did you use the same PE ratio through the entire rpm band or did you add more fuel in the 4800 rpm range?
Safety Car
Joined: Sep 2007
Posts: 4,359
Likes: 6
From: Los Alamitos California
St. Jude Donor '09
http://www.youtube.com/watch?v=_REQ1...eature=related
Someone sent this link to me today, a video of valve spring rotation and valve float happening. Pretty intense to actually watch it happening.
Someone sent this link to me today, a video of valve spring rotation and valve float happening. Pretty intense to actually watch it happening.
San
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Thread Starter
Drifting
Joined: Feb 2007
Posts: 1,844
Likes: 12
From: Alpharetta Georgia
The lS3 doesnt seem to like being 13:1 @tq peak and tends to like being richer in the TQ peak area with more timing there. I have seen 2 degrees make 10rwtq there. Did you use the same PE ratio through the entire rpm band or did you add more fuel in the 4800 rpm range?
The car is pretty noisy as is and the stock knock sensors damn near pick up anything, which usually causes false knock. As such, I haven't really been able to run much ignition around peak tq. I am commanding 24deg at peak tq and the knock sensors usually pull .5 a degree or so. Hell on this pull, A/F's were actually in the low 12's now that I am looking back through my log. I am commanding 25deg at redline.
I have read about relaxing the attack setting and advancing the decay setting, but the car is making some power, so I wonder if its worth the added safety
Safety Car
Joined: Jun 2004
Posts: 3,563
Likes: 2
From: Dallas Tx
Sometimes an open exhaust will give that tq dip at 3K. A good X pipe and mufflers with some backpressure can help that low RPM tq. Same reason the NPP opens the exhaust valve at 3500, helps the tq below that to keep it closed. The ZR1 can open the NPP sooner because of the supercharger, don't need the backpressure to help fill the cylinders.
I see that a lot in Harley tuning. Put in a cam and straight pipes and they can have quite a tq dip at 3000. Some backpressure from putting baffles in the pipes helps it, but often it's just overcammed and over exhaust flow'd to be efficient in that range.
I wouldn't think the intake would make it flat line like that on the top end. Seems like it is hitting a wall in the tuning- timing. You could see if the ignition timing is doing that by running some octane boost or mix in some race gas and bumping the timing up in that RPM range.
I'd call the company that makes the cam and ask what type of timing mapping they run with that cam. I've had good luck doing that with Harley race cams. The cam grinders generally know exactly what compression and ignition curve works best with that cam. Often, they've had that cam on the dyno many times and will give some tips.
I see that a lot in Harley tuning. Put in a cam and straight pipes and they can have quite a tq dip at 3000. Some backpressure from putting baffles in the pipes helps it, but often it's just overcammed and over exhaust flow'd to be efficient in that range.
I wouldn't think the intake would make it flat line like that on the top end. Seems like it is hitting a wall in the tuning- timing. You could see if the ignition timing is doing that by running some octane boost or mix in some race gas and bumping the timing up in that RPM range.
I'd call the company that makes the cam and ask what type of timing mapping they run with that cam. I've had good luck doing that with Harley race cams. The cam grinders generally know exactly what compression and ignition curve works best with that cam. Often, they've had that cam on the dyno many times and will give some tips.
