need ideas on upper rpm prob
Thread Starter
Joined: Nov 2001
Posts: 7,903
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From: Cleveland, OH
need ideas on upper rpm prob My car runs pretty good at the track in 1/2 gear but in 3rd and especially top of 4th it starts going lean. I have great fuel pressure...enuff injector and can make it pig rich with the maft but nothing helps. I noticed on stock maf that atap showed me at 57lb/min and then the car would go lean and slow down. I thought maybe I hit the maf limit that Ed Wright supposedly took out. Went to screenless maf....reported airflow dropped but it still did the same thing. Could this just be a programming problem? This starts around 5300 rpms.....I shift no later than 5800.
ANY ideas would be appreciated. I'm wondering if my pcm has a funky fuel curve that is causing the leaning out when the airflow goes up...the reported airflow is less in 1st/2nd gear. Thanx guys
ANY ideas would be appreciated. I'm wondering if my pcm has a funky fuel curve that is causing the leaning out when the airflow goes up...the reported airflow is less in 1st/2nd gear. Thanx guys
Re: need ideas on upper rpm prob I have no clue whats going on with your car, but you seem to know how to read those Atap logs. I would be glad to buy ya a 12 pack if ya wanna log some runs on my SS. I work at the Discount in Rex, right outside of Stockbridge. We could meet up sometime.
00 SS M6
H/C/I TNT 100 shot
538RWHP/709.6RWTQ on the bottle
00 SS M6
H/C/I TNT 100 shot
538RWHP/709.6RWTQ on the bottle
Re: need ideas on upper rpm prob Are you monitoring fuel pressure at WOT?
What is the injector pulsewidth at 5300?
What is the MAF reading at WOT?
Are your Ltrims locked?
How big are your injectors?
How fast are you going?
How much boost? (turbo, right?)
RPM dependent leanout is a 'limit' problem.
i.e. something is hitting a limit. Just have
to find out what...
Bob
What is the injector pulsewidth at 5300?
What is the MAF reading at WOT?
Are your Ltrims locked?
How big are your injectors?
How fast are you going?
How much boost? (turbo, right?)
RPM dependent leanout is a 'limit' problem.
i.e. something is hitting a limit. Just have
to find out what...
Bob
Thread Starter
Joined: Nov 2001
Posts: 7,903
Likes: 1
From: Cleveland, OH
Re: need ideas on upper rpm prob Bob my fuel pressure is 60 psi all the way thru the run...injectors are 40# accel...this was happening on 5-8psi of boost. My ltrims are locked at zero due to the single turbo...Ed says the car will do funky stuff if they arent locked. This happens at trap speeds of 119. Maf flow goes to 57lb/min when the car goes lean suddenly.
Re: need ideas on upper rpm prob [quote]Originally posted by cablebandit:
<strong>Bob my fuel pressure is 60 psi all the way thru the run...injectors are 40# accel...this was happening on 5-8psi of boost. My ltrims are locked at zero due to the single turbo...Ed says the car will do funky stuff if they arent locked. This happens at trap speeds of 119. Maf flow goes to 57lb/min when the car goes lean suddenly.</strong><hr></blockquote>
First, i'm not a big fan of the constant fuel pressure setup. It's just not good w/ boost.
Are those 40's at 3 BAR?
funny stuff w/o locked LTRIMS huh? You don't say <img src="images/icons/rolleyes.gif" border="0">
let me guess, you see 57 lb/min and then it sits there? You're hitting the limit, the all mighty Ed, supposedly removed. You're going lean because you PCM is not reading any more air. although, you are still pulling more in.
<strong>Bob my fuel pressure is 60 psi all the way thru the run...injectors are 40# accel...this was happening on 5-8psi of boost. My ltrims are locked at zero due to the single turbo...Ed says the car will do funky stuff if they arent locked. This happens at trap speeds of 119. Maf flow goes to 57lb/min when the car goes lean suddenly.</strong><hr></blockquote>
First, i'm not a big fan of the constant fuel pressure setup. It's just not good w/ boost.
Are those 40's at 3 BAR?
funny stuff w/o locked LTRIMS huh? You don't say <img src="images/icons/rolleyes.gif" border="0">
let me guess, you see 57 lb/min and then it sits there? You're hitting the limit, the all mighty Ed, supposedly removed. You're going lean because you PCM is not reading any more air. although, you are still pulling more in.
Thread Starter
Joined: Nov 2001
Posts: 7,903
Likes: 1
From: Cleveland, OH
Re: need ideas on upper rpm prob Hmm Harlan I can go back to rising rate if needed...i thought you were running constant fp so I did it that way too <img src="images/icons/grin.gif" border="0"> The "mighty Ed" lol....you can imagine how I feel right now...mail order tune sucks. I would buy ls1edit right NOW if it were out....hopefully soon. My 40# are branded "Accel" so i ASSume they are rated at 3 bar.
Thread Starter
Joined: Nov 2001
Posts: 7,903
Likes: 1
From: Cleveland, OH
Re: need ideas on upper rpm prob F#$Ck just got off the phone with the wonderful Ed Wright and his customer service is SH$T!! i mentioned the maf limit at 58lb/min and what my car is doing..his response "dont use lb per minute with me...that don't mean sh$t to me..the pcm uses grams per second. Find out what that is in grams per second and call me back" <img src="graemlins/gr_images/icons/mad.gif" border="0" alt="[very mad]" />
So what does that convert to please...58lb/min...Harlan I know you know this and this idiot should too!!!
So what does that convert to please...58lb/min...Harlan I know you know this and this idiot should too!!!
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Re: need ideas on upper rpm prob it's about 438 g/s <img src="images/icons/smile.gif" border="0">
1:1 rising rate on the fuel pressure is what i recommend. unless he's got the enrichment going way up to compenate for it. Did you tell him to tune for a constant pressure?
1:1 rising rate on the fuel pressure is what i recommend. unless he's got the enrichment going way up to compenate for it. Did you tell him to tune for a constant pressure?
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Verdad Gallardo Thread Starter
Joined: Nov 2001
Posts: 7,903
Likes: 1
From: Cleveland, OH
Re: need ideas on upper rpm prob No..He told ME he tunes for constant pressure...Harlan whats your honest opinion about my problem...My fuel pressure stays at 60psi all the way thru the run so I dont see this as a fuel PRESSURE problem. Its just weird it does it in high gears at the track and with a different MAF (screenless/ported) NOT hitting the 57lb/min
Re: need ideas on upper rpm prob well, first i'm not surprised it does it in the higher gears. You're putting some serious load into the motor at the top of the higher gears. My guess is your air flow is greater there than say in first or second.
W/ the fuel pressure staying constant, i'd agree the pump is holding its own.
OK, so the ported MAF is keeping you below the limit. That makes me tend to agree w/ TurboBob. check your duty cycles. If those are 40# injectors at 3 BAR you got plenty of injector. If those are something else, that equals 40# at 4 BAR (ie 60 psi) you're running out. I'd go static on 40# (@ 4 BAR) at about 8 psi.
can you monitor commanded A/F on a-tap? we can see if Ed really tunes for constant fuel pressure <img src="images/icons/smile.gif" border="0">
W/ the fuel pressure staying constant, i'd agree the pump is holding its own.
OK, so the ported MAF is keeping you below the limit. That makes me tend to agree w/ TurboBob. check your duty cycles. If those are 40# injectors at 3 BAR you got plenty of injector. If those are something else, that equals 40# at 4 BAR (ie 60 psi) you're running out. I'd go static on 40# (@ 4 BAR) at about 8 psi.
can you monitor commanded A/F on a-tap? we can see if Ed really tunes for constant fuel pressure <img src="images/icons/smile.gif" border="0">
Thread Starter
Joined: Nov 2001
Posts: 7,903
Likes: 1
From: Cleveland, OH
Re: need ideas on upper rpm prob I don't know if I can monitor Commanded a/f or not....I'm still learning autotap. I will call accel now and see what their injectors are rated at for certain. I'm thinking now that maybe its the 1:1 rising deal. Maybe I need to increase fp with boost which is simple enuff to do. Thanx guys for all your input. These archives will help someone else in the future I'm sure!
Thread Starter
Joined: Nov 2001
Posts: 7,903
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From: Cleveland, OH
Re: need ideas on upper rpm prob Ok heres is the info I got from jegs..over the phone..couldn't get Accel on the phone. My "40#" injectors are rated at 2.7 bar or 39.7 psi. He mentioned a "static flow rating of 37.6" Can you guys make sense of this? Maybe I need new injectors...sux I sold my 36# lucas to buy these.
If injectors ARE too small I need a reference for which ones to buy
If injectors ARE too small I need a reference for which ones to buy
Thread Starter
Joined: Nov 2001
Posts: 7,903
Likes: 1
From: Cleveland, OH
Re: need ideas on upper rpm prob Went back and looked at several of my logs....the leaning out takes place in every gear ...just not as dramatically as 4th. I assume its just not as noticeable because I'm only in the lower gears for such a short time. I have programming for 36# injectors and am running 40# now. Could this be the sole problem? I think its odd my strims cruising show +40% <img src="images/icons/shocked.gif" border="0"> without the maft.
[ December 10, 2001: Message edited by: cablebandit ]</p>
[ December 10, 2001: Message edited by: cablebandit ]</p>
Re: need ideas on upper rpm prob what a chump <img src="images/icons/tongue.gif" border="0"> <img src="graemlins/gr_judge.gif" border="0" alt="[judgement]" />
here's what i gather from the numbers you got
2.7 BAR, static flow of 37.6 #/hr
at 3 BAR they flow 39.6 #/hr
at 4 BAR they flow 45.8 #/hr
plenty of injector i'd say for 5 to 8 psi.
still, check the pulsewidth to be sure. i still say no no, to constant fuel pressure w/ boost.
here's what i gather from the numbers you got
2.7 BAR, static flow of 37.6 #/hr
at 3 BAR they flow 39.6 #/hr
at 4 BAR they flow 45.8 #/hr
plenty of injector i'd say for 5 to 8 psi.
still, check the pulsewidth to be sure. i still say no no, to constant fuel pressure w/ boost.
Re: need ideas on upper rpm prob work != <img src="images/icons/grin.gif" border="0">
work = <img src="graemlins/gr_barf.gif" border="0" alt="[barf]" />
work = <img src="graemlins/gr_cry.gif" border="0" alt="[whiner]" />
work = <img src="graemlins/gr_bs.gif" border="0" alt="[bullshit]" />
Bob
<img src="images/icons/rolleyes.gif" border="0">
work = <img src="graemlins/gr_barf.gif" border="0" alt="[barf]" />
work = <img src="graemlins/gr_cry.gif" border="0" alt="[whiner]" />
work = <img src="graemlins/gr_bs.gif" border="0" alt="[bullshit]" />
Bob
<img src="images/icons/rolleyes.gif" border="0">
Re: need ideas on upper rpm prob work != <img src="images/icons/grin.gif" border="0">
work = <img src="graemlins/gr_barf.gif" border="0" alt="[barf]" />
work = <img src="graemlins/gr_cry.gif" border="0" alt="[whiner]" />
work = <img src="graemlins/gr_bs.gif" border="0" alt="[bullshit]" />
Bob
<img src="images/icons/rolleyes.gif" border="0">
work = <img src="graemlins/gr_barf.gif" border="0" alt="[barf]" />
work = <img src="graemlins/gr_cry.gif" border="0" alt="[whiner]" />
work = <img src="graemlins/gr_bs.gif" border="0" alt="[bullshit]" />
Bob
<img src="images/icons/rolleyes.gif" border="0">
Re: need ideas on upper rpm prob [quote]Originally posted by TurboBob:
<strong>work = <img src="graemlins/gr_bs.gif" border="0" alt="[bullshit]" />
</strong><hr></blockquote>
LMFAO!!!!
<strong>work = <img src="graemlins/gr_bs.gif" border="0" alt="[bullshit]" />
</strong><hr></blockquote>
LMFAO!!!!
Thread Starter
Joined: Nov 2001
Posts: 7,903
Likes: 1
From: Cleveland, OH
Re: need ideas on upper rpm prob Since work is not so entertaining maybe you could do some more work on that 2 step <img src="images/icons/grin.gif" border="0"> Do you need any more hints <img src="images/icons/smile.gif" border="0">
Re: need ideas on upper rpm prob I bet they are not enough for a constant pressure
setup.
Constant gauge pressure != Constant delta-pressure.
Wonder which Ed is thinking about....
assuming a rising gauge pressure system (like Harlan) = constant deltaP
Harlan says static at 8 psi (assume 6000 rpm...)
But Cables injector size is effectively being reduced by his boost pressure. so the rail pressure is 60 psi, but the manifold is 8.
so he has effectively 52 psi on his injectors.
so they are probably 42# or so. Probably borderline especially if your boost is creeping some.
A T76 moves a BUNCH of air too......
Grab some more data and meet us back here.....
<img src="graemlins/gr_barf.gif" border="0" alt="[barf]" />
^ thought he was cute so put him in my post....
(edit for spelling errors)
[ December 10, 2001: Message edited by: TurboBob ]</p>
setup.
Constant gauge pressure != Constant delta-pressure.
Wonder which Ed is thinking about....
assuming a rising gauge pressure system (like Harlan) = constant deltaP
Harlan says static at 8 psi (assume 6000 rpm...)
But Cables injector size is effectively being reduced by his boost pressure. so the rail pressure is 60 psi, but the manifold is 8.
so he has effectively 52 psi on his injectors.
so they are probably 42# or so. Probably borderline especially if your boost is creeping some.
A T76 moves a BUNCH of air too......
Grab some more data and meet us back here.....
<img src="graemlins/gr_barf.gif" border="0" alt="[barf]" />
^ thought he was cute so put him in my post....
(edit for spelling errors)
[ December 10, 2001: Message edited by: TurboBob ]</p>
Thread Starter
Joined: Nov 2001
Posts: 7,903
Likes: 1
From: Cleveland, OH
Re: need ideas on upper rpm prob Ok I see your point...I will change to rising rate and see what happens (just hook the manifold referenced hose back up ) As far which pressure Ed is thinking of...I dont honestly think he knows...I bet i will be fine raising fp with boost.
Thanks a lot guys....it kicks *** to get this kind of useful info from you guys so quickly <img src="images/icons/smile.gif" border="0">
Thanks a lot guys....it kicks *** to get this kind of useful info from you guys so quickly <img src="images/icons/smile.gif" border="0">