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I have a forged 346, D1SC making 15psi, LS6 cam, Stock 241 heads, LS6 intake, Lts.
Running E85
80lb injectors
dual 255 pumps
stock feed line
97-98 corvette rails (has the return built in)
Evap line as my return line
External fuel pressure reg.
Scan is showing 127% duty cycle??
I know I have to take about 10-15% fuel out, but if Im understanding this, Im still going to be over 100% duty.
I wouldnt think my setup would max out these injectors.
What do you guys think?
80's max out pretty easily on E85. 800 crank at 85% IDC is a rough idea, so 680-700whp'ish unless you crank the pressure up but then you need enough pump.
Agree that those injectors wont go near as far on E, but have you logged fuel pressure to confirm its not dropping?
Good idea, Im new to tuning and this is the first time ive ever tuned a car.
I will log the F.P. and see what happens.
My goal with this car was a simple 650rwhp street car that idled and drove like stock, and from what Ive read, 80s on e85 would go 700-750max rwhp, so I was suprised to see 127% on my setup.
I also wanted to check with you guys to make sure my fuel setup looked right and wasnt causing any issues.
you can do 650rear on pump gas. So why go through the fuel system troubles of running e85 for that? I know e85 is magical, but at that power level, its not needed.
my opinion: your stock feed line isnt enough to handle the power you should be making. If you figure on the low side, your 5.7 is making AT LEAST 385-400hp with the ls6 cam and long tubes, naturally aspirated. Now, add in 15lbs boost and that should roughly double the power, minus a little bit from having to turn the supercharger. so estimate around 700ish flywheel. you are likely at your limits of fuel line, fuel pumps and injectors. time to upgrade those items if you want to keep the e85. Definitely check fuel pressure. If you can maintain that, then injectors first. If you are dropping pressure, upgrade fuel lines and rails. when you do that, pressure should be good. Then you may find yourself going up on injector or maybe you can get close enough with more fuel pressure.
Or an alternative is, go pump 93 and turn the timing back down. Sure, you might lose some power, but how much are you leaving on the table because you arent getting enough fuel? could almost end up being a wash. just my .02
btw, why you have the timing so low? i'm running 14 degrees on 16psi on pump 93 with no meth. surely itll take a little more? depending on your compression. Mine is 9.5:1......I see you have a built bottom end so I assume your compression is different from stock?
btw, why you have the timing so low? i'm running 14 degrees on 16psi on pump 93 with no meth. surely itll take a little more? depending on your compression. Mine is 9.5:1......I see you have a built bottom end so I assume your compression is different from stock?
Because I have full 1 month of experience with tuning cars and wanna be safe with it.
I'm having some false knock issues. Once I get that sorted out, I plan on bumping the timing up.
btw, why you have the timing so low? i'm running 14 degrees on 16psi on pump 93 with no meth. surely itll take a little more? depending on your compression. Mine is 9.5:1......I see you have a built bottom end so I assume your compression is different from stock?
I have a full 1 month of experience with tuning
so I'll take all the benefits of e85 I can get.
As for the timing, I'm starting low and working my way up. I'm having a false knock issue so once I get that sorted out I'll bump the timing up.
Because I have full 1 month of experience with tuning cars and wanna be safe with it.
I'm having some false knock issues. Once I get that sorted out, I plan on bumping the timing up.
compression should be around 9.8:1
gotcha. I can respect that. You have forged pistons and they do make noise. You need to desensitize the knock sensors some AFTER you verify it’s false knock. Take a couple degrees out in the knock area. Still there? It’s false. So desensitize it in little increments (with the timing pulled back) until you don’t pick up that false knock. Then add timing back. See if it comes back. No? Then add one degree at a time and check. That’s how I did mine. Make sure you have 7 heat range plugs.
you can do 650rear on pump gas. So why go through the fuel system troubles of running e85 for that? I know e85 is magical, but at that power level, its not needed.
my opinion: your stock feed line isnt enough to handle the power you should be making. If you figure on the low side, your 5.7 is making AT LEAST 385-400hp with the ls6 cam and long tubes, naturally aspirated. Now, add in 15lbs boost and that should roughly double the power, minus a little bit from having to turn the supercharger. so estimate around 700ish flywheel. you are likely at your limits of fuel line, fuel pumps and injectors. time to upgrade those items if you want to keep the e85. Definitely check fuel pressure. If you can maintain that, then injectors first. If you are dropping pressure, upgrade fuel lines and rails. when you do that, pressure should be good. Then you may find yourself going up on injector or maybe you can get close enough with more fuel pressure.
Or an alternative is, go pump 93 and turn the timing back down. Sure, you might lose some power, but how much are you leaving on the table because you arent getting enough fuel? could almost end up being a wash. just my .02
Can easily make 900whp on stock feed line, that is the last thing I would touch on a 650hp car. I agree E85 isn't needed at all under 750hp, especially on a 9.8:1 engine with conservative timing.
have you logged fuel pressure to confirm its not dropping?
This is the FIRST thing you need to check right now. Your Deka 80's actually flow more like 92#/hr if you are actually keeping them at 4bar rail pressure. This should be enough for easy 4-digit power on gas and 800+ on E85, depending on the application. Make sure your regulator is also raising rail pressure 1:1 with boost, so you should see ~73psi in the rail with 15psi of boost.
gotcha. I can respect that. You have forged pistons and they do make noise. You need to desensitize the knock sensors some AFTER you verify it’s false knock. Take a couple degrees out in the knock area. Still there? It’s false. So desensitize it in little increments (with the timing pulled back) until you don’t pick up that false knock. Then add timing back. See if it comes back. No? Then add one degree at a time and check. That’s how I did mine. Make sure you have 7 heat range plugs.
Thanks for the advice.
It was pulling 4 degrees of timing as soon as I would enter P.E. mode. And that was with my starting point of 12 degrees timing and running E85.
I talked to some tuners and they said this is definitely false knock. It threw a P0332 code only once, but would pull 4 degrees each time I went into P.E. mode.
After some reading on the HP tuners site, I read where people were setting the P0332 code to "No error reported"....So I tried that and it worked. No more pulling the 4 degrees. The car ran great.
Then I have some well known tuners telling me, DO NOT set the P0332 to "No error reported" and that I need to replace my knock sensors and pigtail. So thats where Im at.
I hate to buy knock sensors and a pigtail and change them out when all I needed to do was simply adjust my global gain.
But Im sure the sensors and pigtail are old and it would be a good idea to change them out to be safe so I bought some AC Delco sensors and a AC delco pigtail.
My Deka 80s are at 65% at 600whp. They topped out over 800whp.
The duty cycle % is a calculation and takes dead time into that calculation.
You would need to make sure that the injector dead time in HPT is 100% accurate.
Dead time can change slightly with battery voltage, fuel pressure, etc.
So unless you're starting to go lean, don't rely on the duty cycle calculation as anything more than a general indicator.
My Deka 80s are at 65% at 600whp. They topped out over 800whp.
The duty cycle % is a calculation and takes dead time into that calculation.
You would need to make sure that the injector dead time in HPT is 100% accurate.
Dead time can change slightly with battery voltage, fuel pressure, etc.
So unless you're starting to go lean, don't rely on the duty cycle calculation as anything more than a general indicator.
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80lb injectors maxed out on E85? Is this right? 
