Dyno Results GTP S2 LT4's and GTP-6 cam
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Joined: Sep 1998
Posts: 458
From: Newark, DE.
Dyno Results GTP S2 LT4's and GTP-6 cam
I finally was able to run my car on the dyno today. I did not tune it...just made 5 passes. 3 Na and 2 on the spray. It was freezing out today so my bottle pressure was down. I had 900 psi on the first N2O pass and 850 on the second. I was running pump gas in the tank and C16 in the fuel cell.
The results were:
Best NA: 351rwhp 337ftlb My air fuel ratio started around 16 then immediately dropped to a steady and constant 14.7 A/F ratio.
Best 150 shot N20: 535rwhp@5600 rpms 504 ftlb@5600 My air fuel ratio on this pass was all over as well as the rpms on the graph. The converter spiked and went down and then doubled back. Basically it was all over. When I first hit the spary the tach jumped to 6000 rpms and stayed there for about 3 seconds and then started to climb up to 6300 rpms. Must be something with my converter. Anyway, A/F ratio spkied really high at 17-1 at 5200 rpms and then went down to 13-1 by 5500rpms and continued to go down to around 12-1. I am not really sure the A/F ratio spiked as high as it did at first as the fuel line was purged on the fuel system.
The numbers are SAE corrected.
Looks like I have to get to tuning this thing. I was really surprised at the little amount of horepower it made NA but that could be attributed to the tall slicks and th400/loose converter. I was very surprised that it jumped up so high on the bottle. I was not expecting it to jump that high. I gained basically 184rwhp on the 150 shot. The numbers seem low NA but I run the numbers in the sig so rwhp doesn't always match what the ET and mph show.
It was a cool experience and I got to ride in an 800rwhp supra.....man what a hell of a ride. The thing pulled from 60mph to 145mph in what seemed like 3-4 seconds. I never felt something pull that hard up top.
Matt
The results were:
Best NA: 351rwhp 337ftlb My air fuel ratio started around 16 then immediately dropped to a steady and constant 14.7 A/F ratio.
Best 150 shot N20: 535rwhp@5600 rpms 504 ftlb@5600 My air fuel ratio on this pass was all over as well as the rpms on the graph. The converter spiked and went down and then doubled back. Basically it was all over. When I first hit the spary the tach jumped to 6000 rpms and stayed there for about 3 seconds and then started to climb up to 6300 rpms. Must be something with my converter. Anyway, A/F ratio spkied really high at 17-1 at 5200 rpms and then went down to 13-1 by 5500rpms and continued to go down to around 12-1. I am not really sure the A/F ratio spiked as high as it did at first as the fuel line was purged on the fuel system.
The numbers are SAE corrected.
Looks like I have to get to tuning this thing. I was really surprised at the little amount of horepower it made NA but that could be attributed to the tall slicks and th400/loose converter. I was very surprised that it jumped up so high on the bottle. I was not expecting it to jump that high. I gained basically 184rwhp on the 150 shot. The numbers seem low NA but I run the numbers in the sig so rwhp doesn't always match what the ET and mph show.
It was a cool experience and I got to ride in an 800rwhp supra.....man what a hell of a ride. The thing pulled from 60mph to 145mph in what seemed like 3-4 seconds. I never felt something pull that hard up top.
Matt
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Joined: May 2003
Posts: 724
From: Regina,Sask,Canada
Umm read you post and it doesn't make any sense you airfuel na.
Na cars need af around 13.1 roughly would think nitrous should be slighty richer to be safe..like 12.5 to 1.
14.7 is cruising air fuel ratio for best economy.So not sure whats up with that but any car putting down 14.7 at full throttle is going to be super lean and not make any power and likely knock like crazy..must be a mistake there..
Na cars need af around 13.1 roughly would think nitrous should be slighty richer to be safe..like 12.5 to 1.
14.7 is cruising air fuel ratio for best economy.So not sure whats up with that but any car putting down 14.7 at full throttle is going to be super lean and not make any power and likely knock like crazy..must be a mistake there..
Thread Starter
Registered User
Joined: Sep 1998
Posts: 458
From: Newark, DE.
Hey 80Ta,
The A/F was right around 14.7-15 the whole pass WOT. It is very lean and very dangerous but I wasn't knocking. I am leaving a lot of power on the table with it running that lean. I can't beleive it ran the numbers in the sig with it so lean NA. I just got some 36lb injectors and I am going to be running a new tune so I should make somewhere around 380-390rwhp NA and about 560rwhp on the 150 shot. And you are dead on by what I need as my ideal A/F ratio.
Matt
The A/F was right around 14.7-15 the whole pass WOT. It is very lean and very dangerous but I wasn't knocking. I am leaving a lot of power on the table with it running that lean. I can't beleive it ran the numbers in the sig with it so lean NA. I just got some 36lb injectors and I am going to be running a new tune so I should make somewhere around 380-390rwhp NA and about 560rwhp on the 150 shot. And you are dead on by what I need as my ideal A/F ratio.
Matt
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