The E85 Thread

[Manaz]

My bad, thought we're still on the subject of gtbs

I haz ze stoopidz todey.

Welcome back Rob, any updates?

I flew in from the US this morning. Spent a week there, saw ONE Subaru the entire time - it was a Forester, and not even a turbo one.

This week should see some updates. I just wish I could get P100 or E85 easily/reliably here (E85 is common in the US, there's a large number of cars over there running on it).

[KiDo_Tuning]

Does this apply to us N/A H6ers too Mick?
I'm running 85, KiDo, Raptor headers & Raptor CAI (in near future).
So would this set-up benefit from larger injectors -or only for boosted cars?

No injectors needed, have plenty of flow for E85. Not even hitting 90% duty cycle

Not even 90% on what level boost?

Around -1psi since engine is sucking down more air than what the intake can provide so generates vacuum

[Sean82]

Ben you're being robbed of all the gloriousness of E85 by not going bigger injectors and a nice aggressive tune

Do you think bigger injectors would make a difference in power on a stock GTSpecB (which will have a aftermarket dump pipe and DW65c by the time United here gets their E85 tank)? Because I had the feeling Matt thought the stock ones are more than adequate.
I don't mind spending the money, but they're not cheap.

Sean he wants an engine clean out tune hence why stock injectors are fine for that purpose

185Kw@wheels at 4800rpm is nothing too sneeze at but in all seriousness, BBB is not exactly A 5000+RPM guy as he loves the 2000rpm to 4800rpm punch on the VF46

I know it's just a weak clean out...but...E85!!!! It's soooo damn awesome! I need it back and soon!!!

[cynner]

Thought I'd bring the can of worms I started on the H6 E85 thread (http://forum.liberty.asn.au/viewtopic.php?f=16&t=21043&start=165#p376494 over to here (probably a more relevant spot).

In summary, there seems to be mixed opinions about E85 on the GT Libs as far as potentially causing popped heads.

The "caution" opinion: E85 makes serious torque (high cylinder pressures) - making it very easy to pop the heads. Apparently there are several people who have switched to E85 and needed to rebuild their engines within a year.

The "don't worry" opinion: Providing the power is not pushed above 18psi (where there is no feedback knock protection?) - the ECU will detect knock from heads lifting. Apparently 17.6 psi is the safe-spot. On the stock turbo and stock injectors, the peak power boost is only going to be around 12psi (limit of injectors). More boost is not required with E85 as the ethanol chills the air before it enters the inlet valves (I guess this means more air density?)... too much boost only chokes up exhaust side.

I'm curious to know, of the people who have had to do engine rebuilds after switching to E85 - what sort of setup did you have? (bigger turbo and larger injectors?).

Kim

[shav]

Im also keen to know who here has had E85 issues on stock motor too.

[dr20t]

I would rather push more boost and less timing

[tom_kauf]

That's an interesting question cynner. I am also planning to get E85, as soon as the local United gets the upgrade. With a 150,000km engine engine, I will be up for a headgasket at some stage anyway. But ways of running E85 without blowing a hg would be good.

So although the approx $2k-$3k (at an independent subaru specialist) will hurt, I'd also be very interested in ways to avoid a blown headgasket *again after that*. Because that would be acceptable, as long as it's then a long term fix.

Better gasket? Or anything we can do to prevent further hg failures on a stock engine (apart from eg bigger injectors and non-engine mods like dump-pipe). Because repeated failures are not gonna be acceptable on my daily driver family wagon.

[cynner]

Is putting better head studs in an easy thing to do without pulling the engine fully out? (just as a pre-emptive engine hardening?)

[jaydece]

Is putting better head studs in an easy thing to do without pulling the engine fully out? (just as a pre-emptive engine hardening?)

The OEM headstuds/bolts are made to stretch.....mods aside...I believe e85 even with a conservative tune would promote it to stretch & lift cause of its natural ability to give more power/torque Vs say pump fuel and tune

Spending money by just putting headstuds in would be a costly exercise for that reason only....

[tom_kauf]

I just read all 12 Pages of the H6 thread cynner linked to. Interesting read... Still a bit inconclusive though.

At the end of the day, it's all part of modifying. Even on bone stock cars, things will break eventually. With more power, some things will break sooner. I doubt anyone would say you will get the exact same lifespan out of an engine with increased performance, than you would stock.

I'd personally go the route of strengthen the engine before it breaks, coz I can choose when the downtime occurs. If it turns out that's what is needed, I'll accept that as part of running E85 . But deciding on what needs to be done to make the engine stand up to E85 (if anything at all) is another matter - still a bit of a newb in that regard.

And I'd still like to hear more guys with blown HGs on stock engines add their 2c, and who tuned them. It's not a blame game, it's just a risk we all take. Because Matt has a lot of guys running E85 without problems so far, so putting all E85 tunes (incl some that might've pushed the engine too far) in the same basket isn't fair.

[bigBADbenny]

http://forums.nasioc.com/forums/showthread.php?t=803341
Read up on e85 basics

Quote:
5. Peak combustion pressures are actually lower for ethanol than for gasoline but the cylinder pressures stay higher longer, so you have more (longer) crank angle that is usable by the engine. This lower peak cylinder pressure also helps with detonaton control.

6. It will, at proper mixtures lower EGT's by around 200 deg F, but due to the higher quantity of exhaust gas products it produces you do not lose any spool up (in fact I would wager spool up is better).

[tom_kauf]

Sweet! Thanks Ben.
I usually like reading a whole thread from start to end, but I might jut skim the first few pages on this one - 113 pages all up .

[tom_kauf]

Quote:
5. Peak combustion pressures are actually lower for ethanol than for gasoline but the cylinder pressures stay higher longer, so you have more (longer) crank angle that is usable by the engine. This lower peak cylinder pressure also helps with detonaton control.

6. It will, at proper mixtures lower EGT's by around 200 deg F, but due to the higher quantity of exhaust gas products it produces you do not lose any spool up (in fact I would wager spool up is better).

Very interesting...

Anything to do with lower temps is good news for me. Living in tropical North QLD, we don't really have 'cool' days (most days 25-30deg, even in winter mostly 22-25deg). But I guess we don't really have the extreme 35deg+ days either, that eg Melbourne can have....

[bigBADbenny]

It's a very old school thread but the physics is probably sound
So read the first page first...
I totally agree with coyotes approach: 12psi on e85 is what I'd aim for too on my high k engine
If built, that would be a different story altogether

[cynner]

Hm interesting. So with a flex fuel scenario, i guess one could just use sports mode for e85 and s# for petrol (to limit peak boost for e85, if wanting to play it safe)