PCM Diagnostics & Tuning HP Tuners | Holley | Diablo

head and cam swap= no power increase

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Old Dec 17, 2003 | 10:48 PM
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Default head and cam swap= no power increase

added stage I heads and 218/224 cam.
Tuned it on the dyno, and made 13 hp 40 tq over
the stock heads and cam. AFR was 12.5 on the
wide band. From .8 gms/cyl @5200-8000 rpms rpms
up to 1.2 gms/cyl @5200-8000rpms is at 23 * in
the high octane table. I am still running the stock
exhaust, and I know that will kill power,but it would
seem that I would have made more power. It seems
to run pretty good except for idle is a little rough. LT's
were -4 to -7 at part throttle, IAC was at about 90.
Max Torque was around 3600 rpms and then drops
pretty fast. I have everything record and can send the
excel files to anyone that would like to look. Also went
to the track and was a tenth or so faster and abouth
2 mph faster. Hope this wasn't confusing!
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Old Dec 18, 2003 | 12:32 AM
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The timing should be 26 degree's minimum.I ussually run 28-30 from 2400 rpm and up.
The exhaust could definitly be choking the top end.
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Old Dec 18, 2003 | 06:05 AM
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your definately choking off your system with the stock exhuast setup. honestly more power could of been had with stock heads, new cam, and some more bolt ons.

was the numbers tuned or untuned, do you have the graph. something is way off if your peak tq is a 3600. and your timing is low as well. also what was the power under the curve gain as opposed to just peak.
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Old Dec 18, 2003 | 07:25 AM
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the gains were with tuning. On the first pull the numbers were almost the same. Ill have to go back and print a comparision. As far as timing I usually see somewhere around 26-30*@ WOT, when scanning so I don't know if I should add any more timing. I did a search on the cam being 1 tooth off, and my power seems to be better than what is described in that scenario. I will scan the Dyno graphs and post later, and again I have excel files of the scan if anyone wants to see.
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Old Dec 18, 2003 | 07:33 AM
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What both have said above , you need more timing , and you need headers and exhaust for that to breath ok.
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Old Dec 18, 2003 | 08:09 AM
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Originally Posted by boomcase
What both have said above , you need more timing , and you need headers and exhaust for that to breath ok.
I know as well as anyone else that Headers & exhaustwill make a world of difference. My point is I should have made some power gains, even if minimal. The gains I made were from tuning.
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Old Dec 21, 2003 | 06:54 PM
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Originally Posted by jrp
your definately choking off your system with the stock exhuast setup. honestly more power could of been had with stock heads, new cam, and some more bolt ons.

was the numbers tuned or untuned, do you have the graph. something is way off if your peak tq is a 3600. and your timing is low as well. also what was the power under the curve gain as opposed to just peak.
Went back and got a print out comparing the stockheads/cam to the Stage I heads/218/224 cam. The peak Tq is @ 3600 and is below the stock curve most of the pull. If you like I can scan the dyno graphs and email them to you.
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Old Dec 21, 2003 | 07:02 PM
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I would like to see the graphs too please

My email is buff2761@bellsouth.net

BTW who did the heads & what do they flow etc?
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Old Dec 21, 2003 | 07:26 PM
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Originally Posted by 99 Black Bird T/A
I would like to see the graphs too please

My email is buff2761@bellsouth.net

BTW who did the heads & what do they flow etc?
They are JPR heads, and flow 270 @550lift. From what I have been told the can flow good numbers on a flow bench, but still not perform if they weren't ported right. I ll send later.
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Old Dec 21, 2003 | 09:40 PM
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I would first get the timing back up.. Hell I run more than 23* on a 180shot! I try running my current 25* on NA and the car feels sick. Truely need the timing fixed, as well, sounds like you have some KR, reason for the timing being lower than with stock setup. Lower timing will kill ET and Dyno reads. Your stall is small and gears wont help much for dynos. In comparison, my TR224 setup only gained 16hp over stock, but at track after a month or so of "learn time" (cant explain it otherwise) I dropped about .3 off my time.
-timing
-check for KR
-check regap plugs
-Exhaust
-beats the hellouttame!

Hope this helps
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Old Dec 22, 2003 | 01:20 AM
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Don't worry about the 0.8-1.2g/cyl range - unless you are FI or big cubic inch I doubt you will get up there. WOT is probably going to be around 0.6g/cyl for you, though you need to log it to see for yourself.
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Old Dec 22, 2003 | 02:03 AM
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FWIW, I went from 320 to 393rwhp with heads/cam, stock exhaust, stock cats, stock exhaust manifolds, stock everything from the heads to the tailpipes, so the exhaust isnt whats causing you to not see the performance gain. Something is definitly wrong, and it seems like its hardware related. Even a bone stock tune should pick up power with heads/cam, people made 400+rwhp before ls1edit even existed.

Maybe try going back to the stock tune and see what it does.
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Old Dec 22, 2003 | 09:12 AM
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To clear up a couple of things the EC in my sig stands for extended cab. I have done this to my truck, and thats the reason for the timing being so low. I raised the timing up to 28* and really didn't see much of a difference, so I will add more in the .6 range. I go back to the dyno tomorrow, and if I can't get anymore out of it i am going to check the cam and geometry.
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Old Dec 22, 2003 | 09:26 AM
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I hate my JPR heads. Good luck on your troubleshooting. I went from 320HP, all stock to 370, with all in my sig., and 470 on a 100 shot. I expected at least to break 400RWHP and didn't even come close. I blame my heads!
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Old Dec 22, 2003 | 01:10 PM
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You really need to log your vehicle and see what range you are in, not just add timing to arbitrary ranges.
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Old Dec 22, 2003 | 06:56 PM
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Originally Posted by ChrisB
You really need to log your vehicle and see what range you are in, not just add timing to arbitrary ranges.
I was logging it on the dyno, idle and cruising. Would you like to take a look and see what you think.
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