Dyno Data & A/F ratio variations??
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From: SE NY
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Dyno Data & A/F ratio variations??
I just returned from Dyno Day at TT Performance in Saddle Brook, NJ; even with adjusting my AFPR I could not keep the A/F ratio at WOT below14:1. It would drop from 14.7:1 when he went to WOT at 3,200rpm but climb back to 13:1 by 3,600rpm and was up to nearly 14:1 by 5,800rpm.
The best numbers were:
233rwhp & 289 ft-lb
Which is 10rwhp off my prior pulls of 243rwhp & 308 ft-lb.
So I'm thinking fuel delivery at WOT is not up to par and wonder which of the three elements (injectors, regulator or pump) is most likely the problem, the filter is about 1yr old so I don't think that is the source of problem. I've done a resistance check on the injectors and all pass.
Has anyone had a similar problem and can come with the solution??
The best numbers were:
233rwhp & 289 ft-lb
Which is 10rwhp off my prior pulls of 243rwhp & 308 ft-lb.
So I'm thinking fuel delivery at WOT is not up to par and wonder which of the three elements (injectors, regulator or pump) is most likely the problem, the filter is about 1yr old so I don't think that is the source of problem. I've done a resistance check on the injectors and all pass.
Has anyone had a similar problem and can come with the solution??
Last edited by 65Z01; Dec 18, 2004 at 08:05 PM.
Race Director
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Originally Posted by 65Z01
I just returned from Dyno Day at TT Performance in Saddle Brook, NJ; even with adjusting my AFPR I could not keep the A/F ratio at WOT below14:1. It would drop from 14.7:1 when he went to WOT at 3,200rpm but climb back to 13:1 by 3,600rpm and was up to nearly 14:1 by 5,800rpm.
The best numbers were:
233chp & 289 ft-lb
Which is 10chp off my prior pulls of 243chp & 308 ft-lb.
So I'm thinking fuel delivery at WOT is not up to par and wonder which of the three elements (injectors, regulator or pump) is most likely the problem, the filter is about 1yr old so I don't think that is the source of problem. I've done a resistance check on the injectors and all pass.
Has anyone had a similar problem and can come with the solution??
The best numbers were:
233chp & 289 ft-lb
Which is 10chp off my prior pulls of 243chp & 308 ft-lb.
So I'm thinking fuel delivery at WOT is not up to par and wonder which of the three elements (injectors, regulator or pump) is most likely the problem, the filter is about 1yr old so I don't think that is the source of problem. I've done a resistance check on the injectors and all pass.
Has anyone had a similar problem and can come with the solution??
i cant answer your question, sorry!!
Race Director
Joined: May 2003
Posts: 10,749
Likes: 41
Originally Posted by 65Z01
I just returned from Dyno Day at TT Performance in Saddle Brook, NJ; even with adjusting my AFPR I could not keep the A/F ratio at WOT below14:1. It would drop from 14.7:1 when he went to WOT at 3,200rpm but climb back to 13:1 by 3,600rpm and was up to nearly 14:1 by 5,800rpm.
The best numbers were:
233chp & 289 ft-lb
Which is 10chp off my prior pulls of 243chp & 308 ft-lb.
So I'm thinking fuel delivery at WOT is not up to par and wonder which of the three elements (injectors, regulator or pump) is most likely the problem, the filter is about 1yr old so I don't think that is the source of problem. I've done a resistance check on the injectors and all pass.
Has anyone had a similar problem and can come with the solution??
The best numbers were:
233chp & 289 ft-lb
Which is 10chp off my prior pulls of 243chp & 308 ft-lb.
So I'm thinking fuel delivery at WOT is not up to par and wonder which of the three elements (injectors, regulator or pump) is most likely the problem, the filter is about 1yr old so I don't think that is the source of problem. I've done a resistance check on the injectors and all pass.
Has anyone had a similar problem and can come with the solution??
Race Director
Joined: Sep 2000
Posts: 17,298
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From: The Top of Utah
Originally Posted by 65Z01
So I'm thinking fuel delivery at WOT is not up to par and wonder which of the three elements (injectors, regulator or pump) is most likely the problem,
RACE ON!!!
Thread Starter
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From: SE NY
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Thanks Rick my bad; I've corrected it to RWHP. But you are right, peak power was indeed down for the season, as I saw from trap speeds.
CFI-EFI, good idea. I really hate to just throw parts at a problem. Maybe on a short WOT burst with a FP gauge on the windshield I can get the answer.
BTW, I've plotted up the pull data in Excel and see that going deeper than 1" (on this set of pulls it is at 2" deep) on the siamese base gave no improvement in top end, as the 1" deep and the 2" deep pull power curves are pretty much parallel. Though that may be in part due to stock heads & cam limitations. Guess I'll have to get the fuel delivery issue resolved first and get another set of pulls to verify that.
CFI-EFI, good idea. I really hate to just throw parts at a problem. Maybe on a short WOT burst with a FP gauge on the windshield I can get the answer.
BTW, I've plotted up the pull data in Excel and see that going deeper than 1" (on this set of pulls it is at 2" deep) on the siamese base gave no improvement in top end, as the 1" deep and the 2" deep pull power curves are pretty much parallel. Though that may be in part due to stock heads & cam limitations. Guess I'll have to get the fuel delivery issue resolved first and get another set of pulls to verify that.
Burning Brakes
Joined: Mar 1999
Posts: 858
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From: Fl,USA
Are you running closed loop? This is normal in closed loop. Before you change anything you should run scan software to confirm the ECM is not pulling fuel out in BLM cell 15. If it is it will pull out fuel under wot. The ECM will pull fuel out as you increase the fuel pressure. You can dump the memory every time you adjust fuel pressure but as soon as you drive it it will try to lean it out again.
John
John
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From: SE NY
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I didn't have the scanner on it at the dyno but a few months ago I did some WOT runs on the highway which showed BLM cell #15 & Int both at 128. At that time I was getting a little knock retard, so I'm thinking that it may have been going lean, though the O2 readings didn't indicate such.
However, that is another item to check out, thanks.
I'll have the scanner hooked up when I check out fuel pressure at WOT early next year.
However, that is another item to check out, thanks.
I'll have the scanner hooked up when I check out fuel pressure at WOT early next year.
Team Owner
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From: Bergen County, NJ Democrats, doing for the country what they did for Michigan
boy, this is killing you insn't it. Keep us posted. I'm looking into that manifold we talked about. Can't wait till next time.
If you want to work indoors, let me know.
Sorry about that "short cut" to the parkway. Was playing with something in the car and missed my left.
If you want to work indoors, let me know.
Sorry about that "short cut" to the parkway. Was playing with something in the car and missed my left.
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Thread Starter
Team Owner
Joined: Dec 2000
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From: SE NY
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Thanks for the escort back onto the Pkway, it would have been "fun" finding the path alone in the dark. 
Yea, now that I have some confirming numbers I need to find out what is causing the power/torque loss. I'm even thinking of contacting Matt after I collect some more data on the issue for another copla dyno pulls.
Anyway, that has to go to the back burner for a few weeks as I prep the IROC for the trip to OH and do the Holiday shopping. And thanks for the offer of an indoor working area.
I think that intake set runs about $1,200 new and maybe $700-$800 used on e-bay. As I mentioned, I would also do at least 1.6 RRs along with it though. Since you were running a little rich on the dyno, you may not even need an AFPR nor a chip for tuning.
Have a great Holiday.
Yea, now that I have some confirming numbers I need to find out what is causing the power/torque loss. I'm even thinking of contacting Matt after I collect some more data on the issue for another copla dyno pulls.
Anyway, that has to go to the back burner for a few weeks as I prep the IROC for the trip to OH and do the Holiday shopping. And thanks for the offer of an indoor working area.
I think that intake set runs about $1,200 new and maybe $700-$800 used on e-bay. As I mentioned, I would also do at least 1.6 RRs along with it though. Since you were running a little rich on the dyno, you may not even need an AFPR nor a chip for tuning.
Have a great Holiday.
Safety Car
Joined: Jun 2000
Posts: 4,870
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From: Long Island, NY
Jim - I am glad the dyno confirms that something is wrong. I also noticed you were down about 3 tenths in ET.
We discussed this during the season , but could not come up with anything solid. This A/F ratio seems to point in the right direction.
Maybe the fuel pump is dying ?
Vic
We discussed this during the season , but could not come up with anything solid. This A/F ratio seems to point in the right direction.
Maybe the fuel pump is dying ?
Vic
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From: Bergen County, NJ Democrats, doing for the country what they did for Michigan
I don't want to hijack your thread. But the fact that it's running a little rich it may balance out with a new intake, because I'll be pushing more air.
I think I'll start with the intake then I'll do another dyno day. See where I'm at, then headers.
I think I'll start with the intake then I'll do another dyno day. See where I'm at, then headers.
Thread Starter
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From: SE NY
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Vic, if fuel pressure drops off during testing the FP will be one item on the agenda.
Jsup, maybe we can use the AutoXray to get some O2 sensor & BLM cell data at WOT and during normal driving before and after you do the intake. That will show if it has leaned out enough to warrent an AFPR with the installation of the SR.
Jsup, maybe we can use the AutoXray to get some O2 sensor & BLM cell data at WOT and during normal driving before and after you do the intake. That will show if it has leaned out enough to warrent an AFPR with the installation of the SR.