E85 Power/Boost/Timing Combination

[CMac455]

I was at the track and started having problems with leaking HGs. I pulled the top end apart and found that the head gaskets were torched on two cylinders. At 25PSI and 750ish RWHP, I didn't expect the motor to detonate, but it seems to be what happened. My timing is at 22* and AFR is 10.80-11.00, on the gas scale.

I'm just wondering what everyone else is getting away with?

 

[GNVYUS 1]

This is a GN right or a 455 Ponti/Olds etc?

25psi with 22 degrees and any Intercooler will be enough to squelch detonation on E85 with a 10.8-11 AF/R GS.

Somethings not right there, either the old combo had some issues or the new combo has an injector/fuel system etc problem as traditional cylinder pressure knock doesn't seem to fit here.

More details on the fuel system components like dual feed etc, intake EGR port still in there, Power Plate, what two cylinders torched the gasket 5-6, 1-2 or 1-3?

I'd be dual feeding the rails here or you're asking for trouble with rail volume for sure at your level of HP of 750whp. I couldn't imagine the stock rail even with the feed fitting removed getting enough volume over to 1-3 if 160lb injectors were feeding off her with an engine possibly making 860-880hp.

 

[CMac455]

This is a GN right or a 455 Ponti/Olds etc?

25psi with 22 degrees and any Intercooler will be enough to squelch detonation on E85 with a 10.8-11 AF/R GS.

Somethings not right there, either the old combo had some issues or the new combo has an injector/fuel system etc problem as traditional cylinder pressure knock doesn't seem to fit here.

More details on the fuel system components like dual feed etc, intake EGR port still in there, Power Plate, what two cylinders torched the gasket 5-6, 1-2 or 1-3?

I'd be dual feeding the rails here or you're asking for trouble with rail volume for sure at your level of HP of 750whp. I couldn't imagine the stock rail even with the feed fitting removed getting enough volume over to 1-3 if 160lb injectors were feeding off her with an engine possibly making 860-880hp.

I'm running a factory 3.8L (stroked to 4.2L) Ford V6 from a Thunderbird SC. Nobody has really used E85, so this is the closest comparison I can use. Sorry, I generalized to try and get more responses by removing potential bias. I'm using an Aeromotive A1000 fuel pump with a dual -8 AN feed and -10 AN supply line. The fuel rail is a 1/2" billet.

The cylinders are the driver's side rear (number 6) and the passenger's side front (number 1). Duty cycle was 75% with the 160 lb/hr injectors and the datalog shows a nice constant AFR.

 

[GNVYUS 1]

Not many can truly help you here since we aren't Ford guru's.

If the ID of that rail is .50, you're asking for trouble with one feed at this HP and volume need. Is the feed at the front near #1 or the other side at #2?

2nd, the A1000 isn't a great pump at higher pressures (Bosch is better from about 70psi on) and considering the volume of E85 and 750whp I'm amazed one pump is actually keeping up.

Don't know how the air distribution works with that Ford, but it's possible one or multiple cylinders are getting a bigger % of air vs the others. This is why Widebands aren't the end all in tuning and some do each cylinder EGT's.

I'd see if there's an MLS gasket that FI 3.8 Ford enthusiasts recommend and make sure the heads have the appropriate RA and try again. Could've stretched a bolt etc and then this eventually occurred.

 

[CMac455]

The SC and GN motors are similar, in design. I'm just trying to get some general info as a 3.8L V6 push rod motor. The port configuration is like the GN. The intake also has equal length runners.

I'm going to purchase new head studs since I am skeptic of the ones I have. They have been retorqued about six times. The HGs are leaking between the block and the gasket, not the heads and the gasket. The gaskets are Fel-Pro MLS.

Here are pictures:

Driver's side gasket:

Cylinder six gasket close-up:

Cylinder six:

Passenger side head gasket:

Cylinder one gasket close-up:

Cylinder one:

 

[BEATAV8]

10.8-11.0 may be a bit lean for E85.

I would check the deck and heads for flatness to see if they're damaged where the leak is occuring. Even if the parts were OK before, the heat may have caused some damage now.

Put it back together and richen it up some more.

For comparison, I've been running 28psi and 22 degress of timing for quite a while now, but it's only 450whp, stock motor with E85 and methanol injection too.

 

[CMac455]

10.8-11.0 may be a bit lean for E85.

I would check the deck and heads for flatness to see if they're damaged where the leak is occuring. Even if the parts were OK before, the heat may have caused some damage now.

Put it back together and richen it up some more.

For comparison, I've been running 28psi and 22 degress of timing for quite a while now, but it's only 450whp, stock motor with E85 and methanol injection too.

I'm tuning using the gas scale, on an LC1 wideband. The plugs look very clear, so maybe it still isn't rich enough. I may just go ahead and have the heads decked, although they look good. I'll definitely check the block's deck, too. I'm ordering new head studs. What size are the head studs for the GNs? Also, how many are there per side? I have 8 per side and they're M11.

 

[asloan5]

go to post 32 this guy mark is pretty sharp
E85 + Turbo Question - Page 3 - Yellow Bullet Forums



this complete thread has lots of info
e85 tuning AFR - Yellow Bullet Forums

 

[BEATAV8]

Lots of good info there on yellow bullet..

I couldn't tell you the AFR on my setup. I haven't installed my LC1 on that car yet. All I can say is that it's "pretty rich".

 

[asloan5]

my afr at start up is 9.8. at 150kpa and up I'm at 7.2 across the rpm range

 

[GNVYUS 1]

Drag Chevette has his way and everyone else has theres. Imports literally are running E85 at WOT to low-mid 12 AF/R and making max WHP, to each their own. Do a search on DSMtuners for a guy who laid down over 1k to the wheels with a mid 12 AF/R, it's crazy but it's Max Lean Power so as long as cylinder pressure doesn't overcome the fuel it can be considered a safe AF/R.

If you look closely at the chart you just go down 3 steps from the gas settings and you have the E85 ratio.
Example, Gas stoich - Lambda 1 = 14.7, go down 3 for E85 and it's 14.3 AF/R on the Gas scale.

OP's WOT AF/R is fine, that ratio isn't going to blow headgaskets if DSM's are running low-mid 12 AF/R in the 40psi range.

Air distribution, Injector clogged or harness jacked up, rail volume, bolt stretch etc are way more the culprit than a 10.8 AF/R.

 

[CMac455]

I'm fairly confident in the equilibrium between the each cylinder. My concern is that I may be over powering the 7/16" studs at 90 ftlbs. There are only 8 of them per side. If a head lifts and the flame encroaches the surface of the block, heads, or the gasket, they will become torched. Doesn't necessarily mean there is detonation, but that increases cylinder pressure astronomically.

I just dyno'd yesterday and started at 18 degrees timing, 11.6 afr and 21 psi. It made 660/684. At the track I was running 22 degrees. I turned the timing down to 15 and went to 11.0 afr. It went down to 603.

 

[Quik]

heres some food for thought i run 26* timing with 11psi on a 10.0 motor on e85 and im 816rwhp on a mustang dyno. my AFR is 11.2-11.4 using gas scale no issues here


now with that being said what are your IATs? what were your ECTs? how about EGTs? these 3 are very important

i also use MLS gaskets and they have proven to withstand plenty of power and abuse

25psi is alot of compressed air and has probably high IATs reguardless of using E85 or not. anything over 145* iat i pull timing like a mofo anything over 180* ect i pull timing and add fuel

 

[bison]

I'd want to see egt #'s before i made any calls.

 

[forcefed86]

Why did you decide to run 22* timing? Did you previously make your best MPH at that timing level? Timing is a necessary evil, no reason to run high timing unless you are benefiting from it. I would crank total timing down to a known low safe number like 16*. Then dial in your AFR and boost. At that point bump timing up slowly until your MPH stop raising and lock it down. At the same time your bumping timing up you need to be checking the ground strap on the plug to ensure you have the proper heat range plug.

Each motor will be different and plugs will tell the story best... or so I'm told. This is a great read on alcohol plugs. Alot of good info from one of our own in there too.


turbo alcohole spark plug pictures

Good luck let us iknow what you find....