M20 Oversize valves

[Manu329is]

I have found this old forum post when I was looking for oversized valves for my m20b29. Strangely there are more providers in the US than in Germany ... :D

Although I have decided against oversized valves, but i want to show you pictures of my Schrick valves - it could well be interesting for one or the other. I also have a picture of a Dbilas valve, unfortunately the angle of the picture is bad and it´s hard to tell: but i think the Dbilas valve is not very flow optimized. The picture on the dbilas homepage doesnt show a m20 valve (that valve looks very nice!)The price is dbilas typically very high (40 € each) Schrick valves are € 27.50 each.

Intake (72 g):



Exhaust (63 g):



Dbilas:



Wrong picture in dbilas shop:

[matiasz]

do the seats have to be opened up any special way to use +1 valves?

I am wondering this also. Im in progress of rebuilding my engine to 2,76l, my valves are fine but im thinking about doing 1mm oversize on the intake valves. Worth it? Should I do 1mm exhaust also?

[ForcedFirebird]

Wow! Talk about misrepresentation!

I have found this old forum post when I was looking for oversized valves for my m20b29. Strangely there are more providers in the US than in Germany ... :D

Although I have decided against oversized valves, but i want to show you pictures of my Schrick valves - it could well be interesting for one or the other. I also have a picture of a Dbilas valve, unfortunately the angle of the picture is bad and it´s hard to tell: but i think the Dbilas valve is not very flow optimized. The picture on the dbilas homepage doesnt show a m20 valve (that valve looks very nice!)The price is dbilas typically very high (40 € each) Schrick valves are € 27.50 each.

Intake (72 g):



Exhaust (63 g):



Dbilas:



Wrong picture in dbilas shop:

[Manu329is]

I am wondering this also. Im in progress of rebuilding my engine to 2,76l, my valves are fine but im thinking about doing 1mm oversize on the intake valves. Worth it? Should I do 1mm exhaust also?

Is it worth it? Mmmh, if you are planing to use a maf or alpha/N instead of the stock "air flow meter" (i dont know the correct english word - but im sure you know what i mean) - i think: yes! I would go for VAC (but intake valves only are 270 $ - i asked last week) You can use the stock seat, but you need to open them a little.

About the oversize exhaust valves:
Even e21jps uses 36mm exhaust valves (stock size but not stock shape :D) in his 200 kw m20-beast (the reason is here: http://www.e30tech.com/forum/showpos...36&postcount=8 full: http://www.e30tech.com/forum/showthread.php?t=117701) I also think oversize exhaust valves are bad for torque (like a to much ported exhaut-side of the head). Interesting: He tooks 44mm (!) intake valves.

[matiasz]

Is it worth it? Mmmh, if you are planing to use a maf or alpha/N instead of the stock "air flow meter" (i dont know the correct english word - but im sure you know what i mean) - i think: yes! I would go for VAC (but intake valves only are 270 $ - i asked last week) You can use the stock seat, but you need to open them a little.

About the oversize exhaust valves:
Even e21jps uses 36mm exhaust valves (stock size but not stock shape :D) in his 200 kw m20-beast (the reason is here: http://www.e30tech.com/forum/showpos...36&postcount=8 full: http://www.e30tech.com/forum/showthread.php?t=117701) I also think oversize exhaust valves are bad for torque (like a to much ported exhaut-side of the head). Interesting: He tooks 44mm (!) intake valves.

Yeah, already got the Miller MAF that im going to run.
Thanks for the link, ill check out those threads.
I think im going to run stock seats and oversize intake then. Thanks again :)

[ForcedFirebird]

Yeah, already got the Miller MAF that im going to run.
Thanks for the link, ill check out those threads.
I think im going to run stock seats and oversize intake then. Thanks again :)

You will need to do more than just fit a larger valve. The flow bench showed a loss in flow in usable areas by inserting a larger valve without additional work.

http://www.r3vlimited.com/board/showpost.php?p=4240085&postcount=104

[matiasz]

You will need to do more than just fit a larger valve. The flow bench showed a loss in flow in usable areas by inserting a larger valve without additional work.

http://www.r3vlimited.com/board/show...&postcount=104

Yes, of course. Just wondering if the oversize valves was worth doing as well. :)