E85 on a 4age bigport

[oz_eight6]

Looking to rebuild my 4age for the project car to run on e85.

Just wondering if anyone has set up a 4age maximised to run on e85 ie higher comp, timing etc.

if so was the gain worth it and what engine specs are you running?

How much higher can you go with comp ration, what size injectors? ecu? etc

cheers,

Adam

[Bazda]

Good rule for the injectors, around double the size of what you would normally run to be safe.

[trdee]

in the ballpark of 14:1 seems to be the compression ratio most n/a people aim for on E85. Timing go as aggressive as you can up to the point where it doesnt make you any more power. I forget what point that is at, it's documented somewhere though

[Redmohawk]

I have a 675 cc 4 cyl bike with big cams running 16 to 1 comp and flatslides (used to run straight meth) that I plan to run on E85 soon so very interested in replys myself.

[MWP]

I forget what point that is at, it's documented somewhere though

You can only find that on a dyno. Every engine will be different.

[oz_eight6]

i dont know too much about building up a 4age, if i want to achieve higher comp on my BP can i do this with just shaving the head?

[RT40Corona4AGTE]

agreed with timing needs to be confirmed on a dyno.

agreed, injectors should be twice normal size to be safe.

compression is usually raised through the use of pistons and/or shaving the block/head and/or choice of head gasket thickness.

[oldcorollas]

not much.. domed pistons would be a better bet.
to increase 3 or 4:1, you would need to make the combustion chambers a LOT smaller,
14:1 pistons will nto leave much room in there, so you will want to be very careful with valve clearance on the pistons when you get them custom made

one really good way of maximising a 4AG on E85... would be to turbo it

for example CR -> combustion chamber volume
949.63759.546.717651044.122221139.711236.11333.091671430.546151528.36429

1mm head gasket is about 5cc, so a stock 0.8mm gasket is about 4cc..

if you had NO head gasket, you would reduce CCV by 4cc, so not even enough to go from 10:1 to 11:1.. and then you still need to add another 10cc of piston crown volume

so really, coming from abotu 9.5:1 CR, and keepign a 0.8mm gasket, you need to add about 16cc of dome to the piston

[RT40Corona4AGTE]

OC - speaks the truth!

[oldcorollas]

i'm only guesstimating....

[RT40Corona4AGTE]

LOL

10char

[beerhead]

Here's a spanner in the worx

If your serious about a budget E85 build I'd go for a late 4AFE / 7AFE head. Throw that on a 4AGE bottom end and you have an instant 14:1 motor. Yes it's interference, but it'd dam cheap for the potential with some porting and decent billet cams. Once my 3SGE is on the road I'm planning a similar build with a modified 5SFE camry head and stock 3SGE gen2 bottom end to end up in the 14's compression wise too. Will be a hand grenade, but gen1 3SGE bottom ends are a dime a dozen at the wreckers these days

[Celica RA45]

have been playing with it, pistons on my motor are 14.5 to 1 and the test with the lambda was around 84 to 85 for best power ,and we added about 2 to 3 ign timming over what was 13.5 to 1 on 100 octane /it didnt seem to make more power with more ign timming... the 3sge seems to go to about 28ign max on e85 and about 26 on 100 octane
and tests we did on my 13.5 to 1 only made another 4 kws through the mid range and 2 up at the top end