tunedportcj5

iTrader: (18)

I finally made the switch to E85 and I am working on my fueling. I also switched to a boost reference FPR which is requiring me to do some VE work.

Anyways, I am hearing some pinging under heavy acceleration... WHY??

Here is my setup:

'08 LY2 4.8 9.2CR
LS6 springs
TR6 plugs - gaped at .035" (which I need to lower)
mpt70 turbo @13psi
timing is 16*
IATs 80-100*
Commanded fuel 7.35(e85)AFR
Actual WBO2 reading - 6.95(e85)AFR - a little rich, still dialing that in.
ECT 195*

I know i need to lower the plug gap, i am also getting some high RPM misfire.

Ideas?

Thanks,
David

tripblackls1

iTrader: (11)

Plugs are too hot , with e85 you should not be even close to having knock with that amout of timing , my 4.8 has seen 15# w/ 18 degrees of timing on 91 pump and its never once had any sort of knock
BTW I run tr8 plugs

tripblackls1

iTrader: (11)

Also put a colder t-stat in something like 160

Wicked69

Wow! 6's on E85. I am using -9 NGK's. You should be an 8 or 9 on E85. I also agree with a lower thermostat. Mine fires right up with no fouling on a 9 right now. If it does start to foul I will switch to an-8 but nothing hotter than that.

hellbents10

iTrader: (10)

I have run Tr6s at 900hp with no issues on E85, Unless it is non intercooled.

Put the wideband on each bank and compare, sounds like it has a stuck injector or a crank/cam sensor problem.

hellbents10

iTrader: (10)

As for the plugs if the fueling is good you can run a fairly hot plug, we run 9s at 2000hp non-intercooled, 40psi.

tunedportcj5

iTrader: (18)

Thanks for the info. I agree that I should not even be close to seeing/hearing KR at these levels. I sure do see a lot of mixed results on who is running what plug. So, switching to a colder plug (B8EFS) - would that fix my issue? I'm going to do it anyways - just curious...?

Here is a pic of my #1 plug (TR6)

Thanks,
David

tunedportcj5

iTrader: (18)

Besides the obvious, what is your definition of good fueling?

My FPR is set to a static 58psi with a 1:1 rise in fuel. What are you commanding for your WOT E85 fueling?

Thanks!
David

HydroStream6

iTrader: (16)

I find it REALLY hard to believe that you're knocking on E85 at ALL. You sure you're not mistaking it for valve float and plug blow out? LS6 springs aren't going to hold up to much boost especially if you have high back pressure or are revving high. Get some colder plugs (I'd go BR7EF) gapped at .024" in there for good measure and go from there.

HydroStream6

iTrader: (16)

Oh and I'm on E85 with 7s and about 1000fwhp. I like her around 20* and mid-high .7s λ, 20psi.

Fbodyjunkie06

iTrader: (10)

Plug strap heat wise looks good as does the porcelain from what I can see, but the bottom ring on the porcelain matters more than the top and I can't see that in that picture. It's also hard to tell where the actual timing mark is.

I'd go to a BR7EF and wouldn't worry about a colder plug till you upped the boost a good bit.

BTW what's the TSL on?

tunedportcj5

iTrader: (18)

To be honest I have never experienced valve float or plug blow out. Can you hear it when valve float occurs? I've only seen dyno comparisons.

tunedportcj5

iTrader: (18)

Thanks for the info!

tunedportcj5

iTrader: (18)

Tube chassis YJ with an LS3. :-)

98Z28CobraKiller

iTrader: (17)

You will feel it under acceleration. Valve float feels like light surging and blow out feels a bit heavier.

Pull all the plugs. You may have busted a ring land or ring and are getting oil in the cylinder.

foose04

iTrader: (4)

Your timing and boost level is fine, so are the plugs and valve springs. However going to 7 heat range would be a good idea. Might be possible that big gap is causing some blow out and making some odd sounds in the process. I was fine on the ls6 springs up to around 15psi. Past that your going to make good gains swapping to better spring.

Swap in some 7's at .026 and do a compression check as you go around.

Best of luck man.

Also to back it up, this is my graph/ old setup. TR6's, MP70/P .81 a.r, 15psi and 16 degree timing, LS6 springs on a 4.8L.

e30polak

Sweet lord that's one sexy dyno graph!

What are you tuning on?

tunedportcj5

iTrader: (18)

So I pulled the plugs, replaced them with BR7EF@.026. All of the plugs looked ok, just like the pic above. Compression is solid across all 8. Still on the LS6 yellow springs. Maybe I am mistaking it for valve float? This isnt your old school chevy 350 "jingling" ping... its just a mild ticking, mild enough that i probably couldn't record it. You hear it under full load at 5000+ rpm. If you are detonating it bad enough, wouldn't you surely see it as KR in the logs?

I'll toss in some patriot gold springs that I've had for a while - hopefully Sunday, that will certainly fix the valve float questions

I've attached a log if someone wants to take a look. (EFILive)

Thanks ALL!
-David

Sarg

iTrader: (6)

What are you gapping the plugs to? My guess is probably blow out. I have run stock heat range plugs in many E85 turbo cars and never had an issue (stock for Subaru). But when running all the fuel, you can sometimes get spark blow out if you are gapped too wide. We usually run around .024-26 gap.

tunedportcj5

iTrader: (18)

I was at .035 with tr6 plugs. I'm now at .026 with the br7ef plugs.