E85 fuel with carbies

[Darryl]

I was surprised how much the jets had to be opened up to get to 12:1 with E85.

Also when I had the float chamber open the rubber gasket I have had swelled with the e85.
The rubber float chamber gasket is unique to force fed dellortos, usually this is a fibre gasket.
So on a stock carby gasket kit the e85 should be ok in the short term at least.

So to summarise I have increased the idle jets from 55 to 75, a 37% increase
Main jets from 160 to 245, a 54% increase, these increases didn't quite match those I had researched.
I haven't been able to find any dellorto DHLA e85 conversion info, only Holley etc.

Interesting results. Given the vagaries of turbo blow through jetting it's not too much of a shock that it didn't accord with "theory" - but that is massive! Re the gasket - half expected I suppose. I wonder what will happen to the accel pumps... For the simple gaskets getting something cut from EPDM should be ok?

[brook308]

I think a problem you might run into is that E85 is not consistently 85% ethanol, it moves around a bit depending on time of year - this will knock your jetting around. Of course, not a problem on a wideband equipped injected car.

From my research United e85 has been found to be 85%, other suppliers may vary their content.
A question for the fuel suppliers I guess. I have heard that there can be a winter and summer mix to improve cold starting by reducing the ethanol content to say 70%. Not sure if this is required in our Qld climate.

[brook308]

I was surprised how much the jets had to be opened up to get to 12:1 with E85.

Also when I had the float chamber open the rubber gasket I have had swelled with the e85.
The rubber float chamber gasket is unique to force fed dellortos, usually this is a fibre gasket.
So on a stock carby gasket kit the e85 should be ok in the short term at least.

So to summarise I have increased the idle jets from 55 to 75, a 37% increase
Main jets from 160 to 245, a 54% increase, these increases didn't quite match those I had researched.
I haven't been able to find any dellorto DHLA e85 conversion info, only Holley etc.

Interesting results. Given the vagaries of turbo blow through jetting it's not too much of a shock that it didn't accord with "theory" - but that is massive! Re the gasket - half expected I suppose. I wonder what will happen to the accel pumps... For the simple gaskets getting something cut from EPDM should be ok?

When I did my ethanol submersion test I used the old turbo carby gaskets. These showed no side effects.
The new rubber gaskets did swell and I haven't checked the accel pump diaphragm.
Given that I plan to flush with bp98 I won't do too much more testing of carby materials.
Next test is either a dyno or track. The ultimate test is at the track, if e85 saves my motor from detonation damage then it's passed.

[carlo rossi]

Sorry must apologise about my earlier post did not realise it was for a full blown race car
but I believe that certain rubbers will decompose as will other light alloy components
also even thou alcohol does raise the RON it is also 30% less energy per gram
and for Strega Nera I thought  e85 is 15% alcohol 85% petroleum ( ron of 95)
have you tried 95 with 10% alcohol this gives a theoretical ron of 104
I prefer 95 as it has the highest calorific value.
better start base.

[Duk]

Sorry must apologise about my earlier post did not realise it was for a full blown race car
but I believe that certain rubbers will decompose as will other light alloy components
also even thou alcohol does raise the RON it is also 30% less energy per gram
and for Strega Nera I thought  e85 is 15% alcohol 85% petroleum ( ron of 95)
have you tried 95 with 10% alcohol this gives a theoretical ron of 104
I prefer 95 as it has the highest calorific value.
better start base.

The number represents the percentage of Ethanol fuel. The rest makes up a conventional petrol (probably just pissy 91-92RON).

[LaStregaNera]

the number is the *nominal* amount of ethanol - E85 has been found to vary between somewhere around 60% eth and 80% eth.

[brook308]

the number is the *nominal* amount of ethanol - E85 has been found to vary between somewhere around 60% eth and 80% eth.

Have a watch of the MCM episode where they convert a turbo subaru wagon to E85.

https://www.youtube.com/watch?v=NuCUf2Qrzhs

At the 13 min mark the fuel flex sensor reads 79% Ethanol from United E85.

[Duk]

In reality, given the variables of using ethanol fuel, it's only really a decent computer that has a 'flex-fuel' feedback that can safely take advantage of the actual ethanol content.

http://zeitronix.com/Products/ECA/ECA2.shtml

[LaStregaNera]

At the 13 min mark the fuel flex sensor reads 79% Ethanol from United E85.

For that tank full.

[carlo rossi]

So really its pumping 40% plus extra fuel in ( 30% less energy) and the extra  advance (2deg) is where the power is being picked up !
if e85 has a ron of 105 wouldn't avgas at 120'ron and more advance say another (2 deg) about 14-15 deg be even better
injection is so much easier  as he adjusted the timing, the fuel, the knock all from a lap top
very cool

[brook308]

So really its pumping 40% plus extra fuel in ( 30% less energy) and the extra  advance (2deg) is where the power is being picked up !
if e85 has a ron of 105 wouldn't avgas at 120'ron and more advance say another (2 deg) about 14-15 deg be even better
injection is so much easier  as he adjusted the timing, the fuel, the knock all from a lap top
very cool

AVGAS or BP100 is expensive and hard to get hold of, I was getting AVGAS from the local aero club but had to make an appointment and a 2hr round trip. From memory AVGAS was about $2.50 a litre.

E85 is available at Coolum or Doonan United, both about 15 minutes away for $1.15 a litre.

I also like the e85 for it's cooling effect. As I don't run an inter cooler, keeping the inlet air temp as low as possible helps prevent detonation.
I thought running water methanol injection with BP98 would work but still got detonation on very hot days 35 deg C +, hence the experiment with e85.

On a side note, the engine idles the best it ever has on e85, almost as good as an injected motor. The plugs don't seem to foul.

[carlo rossi]

Very interesting I learnt alot about e 85 this week its quite the dark side fuel
Why no intercooler? they work a wonder and simple to apply

[Duk]

An intercooler really is a good idea. I'm sure that you know they provide power and knock reduction. Tho I am surprised that water injection didn't stop the knock. Perhaps post some photos of your old set up??? WI has excellent knock reduction capabilities and will absorb more heat energy than ethanol will (per unit mass).
More info would be needed, but perhaps there was some cylinder to cylinder water variations and only 1 or 2 of them were suffering from knock??? Individual exhaust gas or cylinder temperature measuring would have revealed what was going on.
Measuring the discharge temperatures from the turbo would also be interesting.

As a side note, when I first added the turbo to my supercharged MR2 (twincharger set up), I also modified and fitted a Pulsar GTiR intercooler. But unlike the factory intercooler which sat higher and had the engine lid's rubber seal pressed against it, the Pulsay 'cooler sat lower. Because of this, the engine suffered from noticeable knock under load. With a duct that made sure the air flowed thru the intercooler and out of the engine lid, knock gone. 
You can see the duct (made from 'high performance steel angle'...............  ) sitting above the 'cooler core. The flange of it has the rubber seal on the lid pushed against it when the lid is closed.

[festy]

I'm surprised you haven't installed an intercooler, I would consider one pretty much essential for a turbocharged circuit car - even more so considering you're current concerns with detonation.
Those $150 generic ebay intercoolers are surprisingly effective, and a million times better than no intercooler at all.

If you ever want to look into ditching the carbs and distributor, PM me. You might be surprised just how little a decent EFI setup can cost

[17fitty]

Let me know if you need an intercooler-same one you looked at ages ago--(and not flood damaged)Great thread this as i know nothing about any of it-interesting plus-keep up the good work fellas