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May 19, 2008 | 06:29 PM

#281

vaticano

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From: Denver Colo.

Quote:

Originally Posted by 2000Firehawk

Hay,
I just did my 1998 Z28 automatic too this past Saturday the 17th

12.7x @ 110MPH on 93 gasoline, "bolt-on" car.

I'm on stock 28.8# injectors right now, & have tested all out, with no power problems.
Injector duty cycle of 118 on top, 6,200RPM ...

but AFR ok....
Feels like 10-20 more HP. added 4 degrees everywhere.

On a full 1/4 mile pass I will be at 100 % + duty cycle for 1 second at the top of 1st gear, & 2 seconds at the top of 2nd gear, after looking at my log files...

I may just go to the track & try it...

I know that I shouldn't , but I did...

until my new 42# injectors come in on Wednesday...

BUT, with the cooling effect of E85 Any stock 'bolt-on' LS1 should be able to get by with the stock 28.8# injectors, because how long are you really over 100%.....

100% duty cycle reached at 5,000 RPM.

I too have hard start/ cold idle issues that need addressed with cranking + cold idle tables.... anyone know which tables to change, & by how much....

If your duty cycle is over 100% then something is off in your tune. You may want to play with the timing a bit as well. When I added 4* to the whole table in my truck it didn't run to well down low, not saying yours doesn't run well but I found less in some areas was better then 4 everywhere. I still have cold start trouble in my car and truck. I haven't figured it out yet. Hopefully someone has and lets us know what they did. It may be to much fuel. My car surges for a minute or so then stops, but runs at 18:1 and gradually richens up as it heats up. Try the RAFIG process to adjust the Desired Air Flow, for the idle. Not sure on the cold start. I thought I had it on my truck, ut the next day turned out I didn't. I have an intake leak in the car, so it doens't quite work for me. But it's a start.

May 19, 2008 | 11:35 PM

#282

2000Firehawk

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No, duty cycle is over 100% starting at 5,000RPM as stock 28# injectors are maxed out on E85...

I need to see what others did too for correct crank/cold idle...

May 20, 2008 | 07:03 PM

#283

vaticano

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From: Denver Colo.

I only repeat what I was told, by a member far more knowledgable than I, when my 42# injectors where seeing a duty cycle of 224%. It is physically imposible for an injector to flow more than what it can at 100% duty cycle. The duty cycle % is calculated from the various paramiters/values entered into the tune. If these values are incorrect then the calculation will reflect that with an innacurate duty cycle %. If your injectors hit 100% at 5000 rpm then would not get the correct amont of fuel past that. This is from ChrisB
Injector Pulewsidth(msec) * RPM / 1200 = Duty Cycle (in percent)
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Chris

https://ls1tech.com/forums/fueling-injection/833273-injector-duty-cycle-explained-good-stuff.html

Last edited by vaticano; May 20, 2008 at 07:14 PM.

May 21, 2008 | 09:21 AM

#284

2000Firehawk

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From: Pittsburgh , PA

Runs like a raped ape...

It's getting correct fueling as my WB readings are a-ok....

Got to take it to the track for testing....

Anyone know what the AFR needs to be for the 1st 30 seconds
after start-up...
It's my only issue......
Some start-up tables need changed, don't know which ones...

May 21, 2008 | 09:34 AM

#285

Irocss85

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From: waterford MI.

I cant help cause Im no tuner but Im pretty sure Ive seen someone talking about the startup tables specificaly in this thread. I do know the fuel in general is harder to start then gasoline. esp. in the cold. but Im not sure how to get around that, or properly tune for it. hopefully when you find out you'll make it part of this thread. one day I will dable in tuning, and I'd like to use this thread and people's exp. tuning for E85 to help out.

Quote:

Originally Posted by 2000Firehawk

Runs like a raped ape...

It's getting correct fueling as my WB readings are a-ok....

Got to take it to the track for testing....

Anyone know what the AFR needs to be for the 1st 30 seconds
after start-up...
It's my only issue......
Some start-up tables need changed, don't know which ones...

May 21, 2008 | 01:23 PM

#286

Runn

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From: Tranås, Sweden

Quote:

Originally Posted by 2000Firehawk

No, duty cycle is over 100% starting at 5,000RPM as stock 28# injectors are maxed out on E85...

I need to see what others did too for correct crank/cold idle...

Why not upgrade?... my afr (measured with WB) went way off when i tried a wot on stock injectors on E85. I did it as a test to see if they could deliver the fuel needed on E85

May 21, 2008 | 01:28 PM

#287

Gold Phoenix

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From: Indianapolis Area

Quote:

Originally Posted by 2000Firehawk

Anyone know what the AFR needs to be for the 1st 30 seconds
after start-up...
It's my only issue......
Some start-up tables need changed, don't know which ones...

Same here. I have noticed that my car on start ups it stumbles going from cranking to idle. It isn't too bad, but it makes it sound like the car needs a tune up. Once it is goin, no problems.

May 21, 2008 | 01:30 PM

#288

Runn

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From: Tranås, Sweden

Quote:

Originally Posted by Gold Phoenix

Same here. I have noticed that my car on start ups it stumbles going from cranking to idle. It isn't too bad, but it makes it sound like the car needs a tune up. Once it is goin, no problems.

Give it more fuel...

Look at the flex-trucks for a olfa that you can try out.

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May 21, 2008 | 04:57 PM

#289

2000Firehawk

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From: Pittsburgh , PA

Quote:

Originally Posted by Runn

Why not upgrade?... my afr (measured with WB) went way off when i tried a wot on stock injectors on E85. I did it as a test to see if they could deliver the fuel needed on E85

My new 42# injectors just got here today from Racetronix..

It runs so well during all my testing, that I 'm going to try it at the track with the stock injectors.

AFR at WOT is a-ok, new at over 100% duty cycle...

May 21, 2008 | 09:00 PM

#290

2000Firehawk

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From: Pittsburgh , PA

Just got back from test-&-tune at the track tonight.

Same ET/MPH as the last time that I was there 12.7x@109.x
Weather, [DA], was worst. Track not preped as well...

I think it's at least a tenth better the 93 gasoline..

I'm really thinking about not changing out the stock injectors...

Got to check my 4 log files tommorow to see where it's at...

May 23, 2008 | 05:41 PM

#291

needaz28

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From: tucson

having an injector thats bigger then you need is never a bad thing. having them be to small is just a bad move. you can never be to safe when it comes to fuel delivery.

May 23, 2008 | 07:15 PM

#292

Bill Bowling

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From: Lawrenceville, GA

There is finally a E85 station near me but it is the only one with 20+ miles. I think I will have to wait until there are at least a couple of them around. I already have 42 injectors and I can do my own tuning.

Bill

May 23, 2008 | 11:33 PM

#293

2000Firehawk

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From: Pittsburgh , PA

Quote:

Originally Posted by needaz28

having an injector thats bigger then you need is never a bad thing. having them be to small is just a bad move. you can never be to safe when it comes to fuel delivery.

Maybe for most , but not all applications with gasoline.....

E85 is a different story...

May 25, 2008 | 12:01 AM

#294

Gold Phoenix

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From: Indianapolis Area

Quote:

Originally Posted by 2000Firehawk

Maybe for most , but not all applications with gasoline.....

E85 is a different story...

I run 96# injectors on my strip car and they work fine. I got them big so eventually I would switch to E85 and agree with better to have too big than too small.

May 25, 2008 | 10:03 PM

#295

SHARKZ33

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From: Roanoke, Virginia

Thankz for the info runn. I live in the states, Virginia to be exact we are a little slow in converting to E85. So my particular problem is that I may not be able to find E85 everywhere I go. Can I set my car up to run both regular fuel and E85?

May 26, 2008 | 01:31 AM

#296

Big Bird WS6

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Quote:

Originally Posted by SHARKZ33

good questions i also want to know

May 26, 2008 | 02:36 PM

#297

Runn

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From: Tranås, Sweden

Quote:

Originally Posted by SHARKZ33

When i dont find any E85 i run gas which works fine if you drive carefully and no wots.

May 26, 2008 | 04:15 PM

#298

Irocss85

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From: waterford MI.

Runn, are you open or closeloop tuned? if closed loop, wouldnt it auto. see the rich exh. (in the scenario above) and just command less fuel for part throttle driving?