B20a turbo build valves

[Chrislude1982]

What valves do you guys reccomend for a b20a turbo build? i want to use 15psi with the option of upping the boost furthur if i feel the need afterwards. I was going to use some modified toga b20a5 valves but they are only any good up to 14psi.

Thanks

[RobT5580]

As far as i know the B20A5 valves are not the same. Im running Ferrea B18A exhast valves and custom intake valves because they are much larger than any b-series blanks. Iv run my ferrea valves and dual springs upwards of 17psi without any problems.

[Chrislude1982]

i was going to buy 16 Toga stainless steel inlet valves from B20A5 and have them re-machined from 33mm to 30mm which would still sit on the stock seats nice, i got told this would work well with a turbo setup except Toga only reccommend them upto 14 psi.

[RobT5580]

It was a little more involved than that because you need different seat locators for the exhaust side. My ferrea valve train ran just over $1000 back in 2004 which included their machine shop service and heat treating.

[Chrislude1982]

Thanks rob, il have to look into it a bit more i think, i havent really got that kind of money to spend on the valvetrain but i do need it to be efficient and reliable.

[rjudgey]

Toga B20A5 valves, Chris let me double check again on the valve sizes but i'm sure last time i checked the valve sizes from B20A5 are identical to B20A engines in our cars in the U.K. the stem thickness, length and head size are all the same and the inlet valves have the same stem size and lenght as the exhaust and the collet position is the same as well so i can't see why this cannot be done? Even if we had 8 custom 30mm exhaust valves made would only run £15 a valve but cheaper to buy toga and have it machined to size. Might have to have them heat treated or coated as a precaution i'll ask my engineer see what he thinks. Worse case scenario well use the stock ones and i'll have the other set of inlet valves off you for my engine.

[TWOLOUDNPROUD]

what we need to do is make a new parts list for the B20a and put it in JDM B18A / B20A Swap Tech that will help all of us that have b20a.

[newtuner]

now thats thinking brother!

what we need to do is make a new parts list for the B20a and put it in JDM B18A / B20A Swap Tech that will help all of us that have b20a.

[thegreatdane]

The B20A intake and exhaust vavle stems are 0.03mm different in diameter. Length is different too.

[RobT5580]

I was pretty sure they were not the same but going turbo i would focus on the basics with your pistons, and rods being priority.

[Chrislude1982]

yeah im going with what you suggested on that rob

[RobT5580]

I am not a pro but i would think the stock valves will hold up ok its the rpm's i would be more concerned with.

[rjudgey]

Valves are the same size just the heads are different and as the intake is being modified not a problem, the stems on the valves may be slightly smaller due to the increase heat of exhaust vlave it will expand more, but thats an easy fix as you'd just need to reem out the guide a little more, as the engine will have a few miles on it probably not even needed may have bronze guides custom made and fitted anyways which will be made to the right clearances. I'm suprised you guy's are being so negative about this going from 28mm to 30mm exhaust valve on a turbo setup is a very worth while mod will help spin the turbo up quicker as well as other benefits from flowing more exhaust gas out quicker. Intake valve size is fine you'd have ajob getting bigger in there anyways. The stock valves are very hard and would be fine for a turbo conversion but while the whole heads being worked on in every tiniest detail for the small cost of 8 valves i think it's worth increasing to 30mm from 28mm.