legacycentral bbs

who's running these on the 22T SOHC heads? any noticeable difference in power? I wanna run a VF39 turbo, 440cc or slightly larger injectors, FMIC, at around 17 psi, would the SOHC heads with delta cams be better then all the work and time of 2.5 DOHC heads? what else could be done to the SOHC heads to get better flow from them? any input welcome...


thanks in advance...

You will make more power with stock 2.5 DOHC heads than you would with the SOHC EJ22T heads and cams.
That might not be true after some porting but that's not an apples to apples comparison then. Basically I've heard it put that if you fully port out the EJ22T heads they flow like the stock EJ20G heads. I can't find the flowbench numbers anymore but someone tested it.

The spark plug hole really gets in the way on those SOHC EJ22T heads so you can see looking into the intake ports how much smaller and more restricted they are compared to a DOHC head where the spark plug comes in the middle in between the cams. Also the angle of the valves isn't as good. The DOHC heads would cost twice as much to get cams for but I think you would get more benefit from doing other mods before cams. If you've spent so much on other stuff the cost of delta cams is just a drop in the bucket.

Why not just get the EJ25 or EJ20G heads?

As far as stuff you can do to the SOHC heads...

You could gasket match them to the intake manifold, but even that intake manifold is smaller than the EJ25, EJ20G, or EJ20H manifolds. So you would still have a more restrictive intake than they get stock.
You could knife edge the divider in the intake port where it splits for the valves. Then open up the whole intake port and throat. You could also do a 3 or 5 angle valve grind, 30 degree valve seat, back cut valves, back cut valve guides. You know all the standard head work you can do on any head. It all makes a difference and some of it can be done pretty cheap once you have the head taken apart. I'm sure you could make the EJ22T heads flow as well as a DOHC head and make good power from them.
A lot of people have used these heads and made good numbers, theres no reason you can't. For the turbo you selected, the VF39, these heads are a good match. I'm assuming you're looking for 250-300 HP max. That turbo spools quick and gives you a good low end and even though the EJ22T heads might not be as high flowing as some others, they can give you good torque. The VF39 doesn't flow as well on the top end and the boost starts to drop off more quickly than it would with a TD05H but you're heads have the same problem so you could focus on making low and mid range power instead.
Also you have to think that these heads are 20-30 pounds lighter (for a pair) than DOHC heads and they have less rotating mass so that will be the same difference as taking the battery out of the front end of your car. I mean that's not a deciding factor when choosing an engine, but it is a plus.

Ultimately for power everybody knows DOHC is better, but you can make lots of torque which is good for autocross, rallycross and just daily driving with those heads.

And engine management or piggyback...

The coolant passages on the SOHC 2.5 heads don't match the closed deck blocks either