Disappointing dyno numbers today!! Come give me some advice on what is wrong.
06-16-02, 05:10 PM
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Disappointing dyno numbers today!! Come give me some advice on what is wrong.
Got dynoed today and ended up with some really disappointing numbers, and I am perplexed as to why, so here's the scoop.
Today's temp - 75
My perf mods are:
FMIC
Intake
DP
MP
CB
Non-seq
8.5 mm wires
11.5 R plugs
I dynoed a lousy 317rwhp on 15psi!
Well here is something that is strange because I know a lot of you are saying, wow 15psi is quite a bit. My a/f ratio was 11.5 and my injector duty stayed around 78-81%......how can I boost so much, yet my duty and a/f ratio are fine? Also when we leaned it out a bit on high rpm's, it actually made it worse. This is all on stock fuel system with a filter that has never been changed.
Also another thing, and this has to do with the non-seq, but my boost sometimes builds to 15psi, but then tapers off to 12, but the dyno charts are always the same whether it holds boost or tapers off, it still makes the same power? wtf?
So any advice opinions or feedback would be helpful.
Today's temp - 75
My perf mods are:
FMIC
Intake
DP
MP
CB
Non-seq
8.5 mm wires
11.5 R plugs
I dynoed a lousy 317rwhp on 15psi!
Well here is something that is strange because I know a lot of you are saying, wow 15psi is quite a bit. My a/f ratio was 11.5 and my injector duty stayed around 78-81%......how can I boost so much, yet my duty and a/f ratio are fine? Also when we leaned it out a bit on high rpm's, it actually made it worse. This is all on stock fuel system with a filter that has never been changed.
Also another thing, and this has to do with the non-seq, but my boost sometimes builds to 15psi, but then tapers off to 12, but the dyno charts are always the same whether it holds boost or tapers off, it still makes the same power? wtf?
So any advice opinions or feedback would be helpful.
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06-16-02, 09:41 PM
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Originally posted by Bucrx7
Something is wrong, 15psi with stock injectors your duty cycle should be at 100%.
Something is wrong, 15psi with stock injectors your duty cycle should be at 100%.
your psi indicator must be wrong or something ...
06-16-02, 11:24 PM
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Originally posted by Alpine
are you on basemap? 315rwhp is not bad at all.
are you on basemap? 315rwhp is not bad at all.
06-17-02, 12:01 AM
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That doesn't sound right - 15 psi on the stock fuel system - you would need atleast 1300cc and maybe even 1600cc secondaries for your injector duty to be 78% - something is not reading correctly. 317 rwhp isn't bad - 320 is a number alot of people shoot for with those mods - you are minus a streetport which would put you in the 340-350 range - put it this way - a 320 rwhp FD does 40-70 as fast as a Z06 with 355 rwhp - not bad w/out a streetport - change that fuel filter!! When I changed mine my fuel was almost black. You are right about this run should be more in the 13-14 psi range for those numbers.
06-17-02, 08:34 AM
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Originally posted by kwikrx7
That doesn't sound right - 15 psi on the stock fuel system - you would need atleast 1300cc and maybe even 1600cc secondaries for your injector duty to be 78% - something is not reading correctly. 317 rwhp isn't bad - 320 is a number alot of people shoot for with those mods - you are minus a streetport which would put you in the 340-350 range - put it this way - a 320 rwhp FD does 40-70 as fast as a Z06 with 355 rwhp - not bad w/out a streetport - change that fuel filter!! When I changed mine my fuel was almost black. You are right about this run should be more in the 13-14 psi range for those numbers.
That doesn't sound right - 15 psi on the stock fuel system - you would need atleast 1300cc and maybe even 1600cc secondaries for your injector duty to be 78% - something is not reading correctly. 317 rwhp isn't bad - 320 is a number alot of people shoot for with those mods - you are minus a streetport which would put you in the 340-350 range - put it this way - a 320 rwhp FD does 40-70 as fast as a Z06 with 355 rwhp - not bad w/out a streetport - change that fuel filter!! When I changed mine my fuel was almost black. You are right about this run should be more in the 13-14 psi range for those numbers.
Could I be losing power due to a boost leak? I know that I get a lot of pops and backfires, and sometimes they don't sound like they are coming from the back of the car, more like a muffeled popping underneath the passenger side floor.
07-09-02, 08:11 AM
#13
Re: Disappointing dyno numbers today!! Come give me some advice on what is wrong.
Pressurized
In comparison with my dyno run in red ..i would tend to believe your numbers are somewhat suspect imo...maybe expectations are just high.....
Today's temp - 75 96
My perf mods are:
FMIC stock ic
Intake k&nwith RB inlet duct
DP same
MP resonated
CB RB duals
Non-seq stock twins
8.5 mm wires stock NGKs
11.5 R plugs old 9s around w/ 15k
PFC same
pulley kit
efini ypipe
I dynoed a lousy 317rwhp on 15psi! 260 on 10psi
at better temps and 5psi more...i may question it as well ...
and to add....im hitting high 90s in injector duty on stock 850s
In comparison with my dyno run in red ..i would tend to believe your numbers are somewhat suspect imo...maybe expectations are just high.....
Today's temp - 75 96
My perf mods are:
FMIC stock ic
Intake k&nwith RB inlet duct
DP same
MP resonated
CB RB duals
Non-seq stock twins
8.5 mm wires stock NGKs
11.5 R plugs old 9s around w/ 15k
PFC same
pulley kit
efini ypipe
I dynoed a lousy 317rwhp on 15psi! 260 on 10psi
at better temps and 5psi more...i may question it as well ...
and to add....im hitting high 90s in injector duty on stock 850s
Last edited by amp; 07-09-02 at 08:17 AM.
07-09-02, 08:36 AM
#14
fart on a friends head!!!
nonseq and stock twins will produce the same peak horsepower. check your ignition timing. have the guys run a probe for exhaust temps so you can adjust your timing maps accordingly. i forget what the ideal exhaust temp is though. sorry. be careful about the fuel system. at 15 psi you are pushing it to its limits. upgrade, upgrade, upgrade. you will most definately end up leaning out. the dyno you tuned at might be broken too. haha. you never know. 317 on stock twins is really pretty good man. maybe those cold *** plugs are missing. that maybe why you are getting backfire. stick 9's back in. (im assuming those are ngk's you listed) that cold of a plug isnt made for street driving. way to cold. i dont even know how you are able to start it. haha. i honestly think you might have some plug issues. try diff heat ranges. i would get a tad bid hotter. "9s"
paul
paul
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