I am trying to tune around some knock @ WOT with E85, I am running NGK TR6's and am at .038-.040 on the gap, I am going back to NGK TR 55's (hotter plug) but would like to know if I should run a small gap with E85? Should I even go back to 55's or stay with 6's? Thanks.
2015 Yukon SLT 5.3
Why not keep the stock heat range and pick up the timing in the right places? A hot plug is always hotter.
You might be getting pre-ignition, and not detonation.
this is typical of E85.
You may actually need to go one step colder on the plugs like TR7, because a glowing ground strap on a plug can cause pre-ignition.
just a thought
^Well I swapped to TR5's wish I would have read this I would have kept the TR6's in for now. I am running super lean still but I added the Racetronix hot wire kit and a new fuel filter so I will know later today if that helped out a bit for now till I can get the pump changed out later this year.
2015 Yukon SLT 5.3
What is your injector duty cycle when the pinging happens?
If it shoots up near/past 100% then it might be the pump not having enough.
I calculate that the Stock pump for E85 will maybe support 400hp.
The racetronix pump and wire kit should enable you to hit 450-475 rwhp with E85.
Did you "read" the plugs when you took out the TR6s? what did they look like?
I dont have any pinging.
The TR6's when I took them out yesterday were all light white (lean). I will post back later today to see if the hot wire kit and filter change helped me out any...
2015 Yukon SLT 5.3
K, still lean up top @ 8.1 from 6k-6500k, inj duty @ 112 but down low it helped get me to 7.5 which is what I wanted. I will get a pump in a few weeks.
2015 Yukon SLT 5.3
what did you do? plugs or filter? didn't I sell you an airbridge or something a couple years ago?Originally Posted by Ls1c5vette
Injector duty of 112 doesn't surprise me with only 58's in there on straight E85.
When I was running a 60/40 mix of 91/E85, my 42.5's were pretty close to being maxed out.
Even less surprising on a stock fuel pump. What's your fuel pressure at?
2003 Oldsmobile Alero, 3400 V6, liquid intercooler
You may have. I just did a plug and filter swap a couple days ago.
They are 54lb injectors, I ned to change my sig, pressure at idle is 62 and it drops to 54 @ wot from 5500-6500 rpms. Inj duty goes way up at 5500
2015 Yukon SLT 5.3
when you hit 5500rpm, what's your AFR reading?
With your injector duty cycle running that high, I would think possibly a stronger pump (volume wise) might be the issue. Logic says if your fuel pressure is dropping out that much, your injector demand is out-flowing your pump's volume/pressure output. I'm having similar issues, which is why I'm bumping up to an Aeromotive 1000 pump for next season.
Why not hit some google-time and find out what your existing pump is rated for on flow/volume/pressure, and see if that seems to be a likely culprit? I know the factory pump for my setup is taxed heavily at 300+ hp.
Without really knowing all the components of your entire fuel system, it's difficult to say.
2003 Oldsmobile Alero, 3400 V6, liquid intercooler
From what I have heard the pump change only wont do anything as the FPR is at the back so it wont account for the pressure drop at the fuel rails.
2015 Yukon SLT 5.3
This will take some more research. As I said, I'm not vette specific on knowledge, but I'm reasonably savvy on fuel systems in general.
I've seen a couple of articles where people going into higher horsepower setups have had to move the FPR closer to the engine bay to prevent pressure drops. They seem to allude to this helping to prevent pressure drop over the distance.
Here's one example, though it isn't specifically mounted in a vette, but I believe it was a vette engine/fuel system swap in another type of car:
In particular in this example, post number 7
http://www.ls1tech.com/forums/conver...regulator.html
Good luck, I think I've reached the end of my ability to assist you, and I'm frankly surprised more vette owners haven't chimed in to help out.
2003 Oldsmobile Alero, 3400 V6, liquid intercooler
Did you change your fuel filter after switching to e85. If not it is likely clogged. I did see what pump you had listed, but FWIW I made just dynoed 518rwhp running e85 with a single intank 255.
Also, your fuel filter is also a first level regulator for the return line, but don't forget you have a regulator on the rail as well. I have seen the stock rails well over 600 rwhp on 91/93.
Plug gap is not about fuel, it's about peak cylinder pressure
and how much gap your coils can reliably punch through.
Short of failing to do that, more gap = more energy in the
hole.
If you're screwing with the fuel system anyway, a close-in
return type manifold referenced one can remove a whole
lot of mystery.
I am on stock rails and lines making over 700rwhp/tq.....and a stock fuel filter, lol.
I do nto have 2 FPR's the one at the fuel rail is some sort of "surge dampner".
My fuel filter has been changed.
I am back on 100% gas for now until I dig into this more, might wait till I get my 408 or 427 in later next year and re-do the fuel system to run a retun line.
2015 Yukon SLT 5.3
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