Lil'John

Title kind of states it.

Short version:
For those who have gone from a 87 to 91 octane tune over to an E85 tune, how much more power were you able to squeeze out of your engine? Preferably with no major upgrades but tune. Ideally no meth but I'll take what data I can get.

Longer version:
I'm building up a turbo 5.3 more for giggles. Not a race vehicle. Not trying for big dyno numbers.

In reading here, it appears from a parts standpoint, E85 requires E85 compatible parts(fuel injectors and fuel pump at minimum, maybe rubber fuel lines) And that E85 compatible parts will do regular old 91 octane with no change aside from tune.

My build is using a set of Deka 80 injectors so I'm compatible there. I'm running new fuel lines as well as new pump/custom fuel tank... the engine is part of a swap into a 70s vehicle(Toyota FJ55) so all the parts were happening no matter what.

I'm getting to the point of needing to tune it so I'm debating tacking on an E85 tune in addition to an 87 octane tune through the use of the fuel composition sensor... sadly this is an offroad vehicle that may not have E85 available on the trail so I need to account for the worst case scenario.

2muchboostNY

iTrader: (8)

Not apples to apples but here is an example:

2JZ inline 6 stock bottom end with some cams & springs made 520rwhp @ 20 PSI on 93 Octane Pump and made 766rwhp @ 33psi on E85. E85 allowed for more boost safely netting these results. Again just a real world example of what a renouned tuner was able to do by literally only emptying out the tank of gas then adding E85 and tuning for that.

coltboostin

On a turbo motor this is like comparing masturbating to a 3some in Vegas with the last 3 playmates of the year.

Just consider E85 race gas- and compare how much fuel you will use a season vs. E85+fuel system upgrades to support it.

svslow

This is a great example.

Longblue

Have a Procharged 5.3. At same boost number, 93 octane made 570rwhp. On E85, made 630rwhp. So 60hp gain with the ability to add more timing with E85.

stevieturbo

Problem is...it's not a great example.

Boost for boost, what was the difference ?

And there is no way that engine was limited to only 20psi on 93. They may have stopped tuning it there, but there is no way it could not have been pushed further.

stevieturbo

Now this is a much better example.

But of course a lot depends on the base motor and all the supporting parts/mods.

If you built it with say 11:1 CR, clearly pump fuel is going to struggle against E85 in a head to head test.

roastin240

iTrader: (13)

My favorite example is an evo I tuned years ago for a friend on the dyno. It made 402whp on 91 octane. We swapped out to E85, KEPT BOOST THE SAME, and increased timing a bunch and picked up 102whp. Then we turned it back down a bit and turned the boost up another 8psi and netted 150whp if I recall. Last thing I did was turn timing up more and the final result was 230whp increase. Car made over 600whp at the end. E85 is gods gift to the budget racer.

pdxmotorhead

Gasoline carries more BTU's than E85 (Thats partially why alchy motors burn 2x the fuel of race gas motors, but you lose the cooling of the alcohol that really is the magic. There have been some good tuners that got crazy numbers out of pump gas, but its WAY more expensive than the E** path. If you want the full monty start with E100 or methanol and add some Nitro.. Its all about stages of spending money...

I've had the chance to convert a few different NA cars to Methanol from Race gas and it just makes life easier... Example, On a Air cooled GSXR1200 motor (Dwarf car) the switch drops the head temps from like 400+ down to 185 We used ot rebuild the head constantly due to heat. After the conversion never touched it again in 3 seasons.. Keihn Carburated

On a Cosworth Twin cam midget, we ran the compression from 12:1 for race gas to 16.5:1 on Methanol. The chamber is only like 20CC's at that point and if you throw a timing belt it makes really really expensive noises.. (Hillborn injected, dry sumped) 1500 CC engine 225 to 240 HP.. Only made 165 on 114 race gas..

BCNUL8R

iTrader: (2)

Is it possible for the budget street/strip racer to build a motor at 11:1 CR running on 93 octane pump one year then add a procharger and make the switch to E85 with a compatible fuel system the next year?

stevieturbo

Given how many people boost totally stock motors which will be in the 11ish ballpark, of course it is. It's been proven thousands of times over.

But then you dont state what sort of power goals for either setup.

BCNUL8R

iTrader: (2)

Long term goal is over 700 rwhp with auto trans and irs in a GTO. I can't get there all in one year financially. So trying to decide...procharger first on stock cam only motor or built motor first then boost later. I originally didn't like the idea of having a built motor with only 10:1 built for boost, but running NA for a year. If E85 will allow 11:1 and enough boost to get to 700+ rwhp safely and reliably that option looks a lot better.

E85 isn't a problem to get here in Iowa it's actually more readily available then 93 octane.

2muchboostNY

iTrader: (8)

Again i had no apples to apples comparison as the tuner would not feel ok bumping the boost on my example past 93 octane safely. Could it be done above 20 psi sure, i have seen a setup pushed further. The tuner was comfortable bumping up the boost up to 33 psi on E85 and some race fuel as well.. Could the tuner have pushed a bit more...no doubt for both ends. Saw the same setup on a different car with bigger fuel capabilities pushed to 38psi on E85 but that guy was trying to squeeze power with little regard for his swtup.

But the guy asked how much power can be extracted given the different fuels with no other change except fuel type and resulting capabilities (ie same motor setup). Dont know too many tuners that would try to push the same PSI for Pump as with E85 but there are out there.

The comparison of using X-psi between Pump vs E85 is great but in general people switch to E85 to push their setups further into its capabilities "safer" and wouldnt ever run the same PSI between thr two....kind of defeats the purpose of E85. And sure we could get into a huge discussion as to why higher PSI and power levels can be attained using E85 but thats not the purpose of the discussion from what i gather.

stevieturbo

But if you're holding back with either fuel, you're holding back.

A comparison of fuels would only be valid if pushing both fuels hard.

neverstop

No direct experience but ive read in other platforms that e85 spools a turbo a bit quicker also for whatever reason. I assume from more dense exhaust given more liquid being pished through the motor?

stevieturbo

No idea...but if there are tuning changes throughout with E85, then it could simply be because of those changes, than the actual fuel content itself.

No E85 here...so never likely to find out lol

Lil'John

Lots of great information. Thank you all.

If this was for me, I have no real set power goals. This is a "run" rig and no competition intended so I'm going to haul it to tuner for a "max" tune run and then have it dialed back a bunch for safety.

kingtal0n

iTrader: (1)

its all about temp. gasoline is more dangerous at high temp than E85. There is no way to directly compare them because each run is different and you have to push knock threshold to find out (and nobody wants to do that, because it might cost an engine). For example I can run a cold engine (pre-warm the oil) that was just started a couple minutes ago, through a single pass on a dynometer, with an ambient temp intercooler and tons of charge pipe on 93 octane up into the 25psi of boost region with a 9.5:1 compression on almost any engine in existence with proper tuning, without having the gasoline fail. The same exact setup, fully warm after driving in Florida traffic for an hour, strapped down to the same dyno could explode violently into little pieces at half that boost pressure. Control the temp, and you control the fuel.

yenkomike

iTrader: (2)

the e85 to me takes away one thing for me to worry about. I don't push the car hard or to the edge I'm sure my 14 psi boost and 14.1* timing whould run on 93 if I watch the temps. but id always be thinking I was close to knock on 93.

my car picked up a tenth or so et with no changes except swapping to e85. no timing or boost changes just fuel settings.

as far as compatability I run the stock steel tank sumpped .aluminum hard line from tank to fuel rail and it all looks good. I do run lucas ethanol treatment from time to time when I park it for extended time.

forcd ind

iTrader: (7)

To kind of add into this, I have the flex fuel sensor (Holley HP) setup, I norm run 93 octane, have added 5 gallons of E85 (tested) to the tank, and saw it up to 24% E85 on the scale. It was adding 8-9% more fuel from the graph, which I can make anything I want. Curious what I am raising the octane to, maybe 95-96? based off what octane 100% E85 is-I think on my graph, if 100% E85 I have it set to about 35-40% more fuel.
Last fill up of 93 I am down to 14%, will go down to 8-10% all 93, where I have it set to 0% fuel added (93 tune)