Thread: High Compression VE

This is for all the high compression VE guys
1 what kind of afr's does these motors like at cruising and wot.
2 whats the timing you guys running on these motors.

setup is 12.5.1 on 2.0 ve on pump.

Cruising afr's are in the 13-14's. Car gets good gas mileage. WOT the car is in the low 12's. This is just off a quick street tune. Depends on weather as well with my car.

I believe peak timing is 30* or so.

This is a 20VE bottom with SR16 pistons, vet headgasket, and milled head. I figure compression is somewhere around 13:1? Who knows. I know she runs hard, lol.

Around here our timing up top is around 25-28 degrees that I've seen with a couple of our motors. As for afr bes is right on with what im running too.

Thanks guys I should be on the dyno during the week.

I was thinking of going the High compression route. So using a SR16 piston on will yield a 12.5 to 1 CR? Do you have to mill the top of the piston down? Are there any pics of where to notch them at? I currently have my AFRs set to 13.2 @ WOT. What you should you set your base (distributor) timing to and AFRs for a 12.5 to 1 motor?

ken, 16ve's straight up will yeild 13:1 fine on pump gas, just have to tune a lil.

a better bet would be 87mm 12:5:1's. youll gain some hp going up a mm and the added compression.

mid 230s are expected for a 87mm high comp ve.

stratton.

Being as the stock bores in sr20's is 86.5mm would going to a 87mm piston require the block to be bored to 87mm or can you get away running a 87mm piston in a stock 86.5mm bore block. Forgive me if this sounds like a stupid question but I know nothing about building motors and stuff like that.

the stock bore is infact 86mm.

fitting a 87mm piston would require a 1mm bore.

no need to be sorry, we all start out in the same place.

if you have any questions feel free.

stratton.

Yeah stock bore is 86mm.

High compression ve's like in the mid to high 12's on the a/f ratio, crusing you can still get away with around 14.5-15:1 a/f, just be sure under any decent load it richens up to avoid any pinging/detonation. Stock compression ve's like right at about 13:1 a/f ratio

As far as timing goes right around 30 seems to be right up top on the high comp motors. Stock ve's like around 32-33 deg up top.

Base timing should be around 15 deg. Do the rest of the tuning using a tunable ecu.

Other than that not much to it.

Make sure you have mint injectors. My old set cost me my motor. I would keep the afr's in the mid 12's just to play it safe with SR16. If you set up the SR16 side by side with a 20ve piston you can see where the bottom of the skirt needs to be trimmed for the oil squirter.