Anyone have experience with increasing compression

[WVcamry3sfe]

I'm interested in increasing the compression on my 3sfe. does anyone have experience with this? Still in the research phase, but it seems like a fairly practical way to bolster engine power without messing with a turbo/forced induction.

[terrastrife]

3s-gte it

unless you have your own workshop that is... then i suppose you could mill the head a bit...

[Variety=Spice]

some VW fanatics will use a thin metal head gasket instead of the thicker fiber gasket to reduce the cylinder volume, thus increasing compression.

You could weld the cup in the top of the piston full...the cup that prevents valves from getting bent when the timing belt blows.

Your best bet, if you're serious, is to have fresh piston rings and well seated valves in your beast to capitalize on the compression you do have.

How much variability do you have in compression between your cylinders currently?

[Tommy]

there is a company that makes high comp pistons for the 3SFE, sure a google search or a TN search would pull it up.

you're not going to gain anything by doing it though, with high compression you need more fuel, more fuel needs more air and so on. by the time your done, youve spent more than its worth on the gains.

Just do a GTE or a GE swap

[dillspy]

I'd prolly go with the gte conversion or the high compression pistons. When you mill an overhead cam engine, you have to start watching how it is going to effect the valvetrain. You could mill a little bit out to get some compression but if you go to far the timing could get messed up. Then if you get more compression, you might have to cam it to get the dynamic compression back down to 7-7.5. Depending on what fuel you are going to run. We are doing a 3sgte swap right now. Picked it up about 100 miles away. Hope this helps. I've also found a 2.2L stroker kit. But that is about $2300.

[marc780]

You can increase compression by the way they said, changing pistons and even boring out the engine if power is your goal. It increase strain on the valve train and crank and what you are really hinting at is a turbocharger installation which does exactly what you describe.

[rustySFE]

It would only be worth it if you did all of the work yourself.

IMO, I don't see why increasing compression would be a bad idea but just don't go overboard. I would stay away from removing layers on a multi-layer steel gasket.

The shop down the street from me does $50 mill and surfacing.
I took .030" and used a thinner HG on my CRX to go from stock 9.2:1 to right at 10:1.
Still run 87 and picked up 3ft-lbs peak on the dynojet but picked up 5-6ft-lbs everywhere under 4000.

I do have an adjustable cam gear however as the cam/cams will be slightly advanced or it could be retarded (cam gear is on drivers side on hondas).

[car_boy_16]

If you mill your head your timing will be off, so you'd need adjustable cam sprokets...I don't know if anybody makes them for the 3sfe, but you'd need them otherwise you're just creating more problems than you'd want.

You don't need to dump more fuel into your car if you increase your compression. All the increased compression does is squish the air:fuel mixture together into a tighter and more compact order. It makes for a quicker and more forceful explansion when ignited. Although, it will run hotter during the top of the compression stroke though so if premium fuel doesn't stop preignition then yes you would have to either back off the intake cam, or add more fuel, or both.

I wonder how much it would take before your milled head, and after you adjust the cam timing, turns the engine into an interference engine.

[rustySFE]

I think on the honda d motors (mine specifically a d15b2) .040" equated to 10 degrees advanced.

My adjustable cam gear is set at 8 degrees retarded as it produced the best curve for my desired peak HP RPM. One tooth = 10 degrees.

You should mill it .040-.050", retard the cam gears one tooth and let us know how it went.
It would probably be pretty easy, measure cranking compression before and see if its close after milling and moving the cam gears back a tooth.

[HomeGrown]

I understand how milling the head could affect valve timing, but not to the extent that it would actually require correction. I did a rough layout on AutoCAD and found that lowering the head .040" would affect the the cam gear angle by only 0.02 degrees. This measurement was based on a 3" dia. gear, a smaller diameter gear size would increase the angular change. If I had the actual gear size I could do a more accurate analysis.