M20 Oversize valves

[digger]

Here are some pics of VAC's valves. I can't speak personally about any of the other options, but I am very happy with my purchase. The machine work and finish was top notch, my machine shop (whom specialize in billet aluminum CNC'd big blocks) even commented on how nice they were.



+ 1mm Intake Valve (43mm)





+1mm exhaust valve. Here you can see the difference in the head shape on the intake and exhaust valve (intake in the rear of the pic). Like Digger mentioned before, these have a flatter crown on the intake valve to help aid flow. The exhaust valve has a more tradition bell shape to it.




And here are some pics of them installed:

out of curioisty when did you buy those valves from VAC and was the a brand name on the stem?

[SpecM]

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

[tinkwithanr]

Here are some pics of VAC's valves. I can't speak personally about any of the other options, but I am very happy with my purchase. The machine work and finish was top notch, my machine shop (whom specialize in billet aluminum CNC'd big blocks) even commented on how nice they were.



+ 1mm Intake Valve (43mm)





+1mm exhaust valve. Here you can see the difference in the head shape on the intake and exhaust valve (intake in the rear of the pic). Like Digger mentioned before, these have a flatter crown on the intake valve to help aid flow. The exhaust valve has a more tradition bell shape to it.




And here are some pics of them installed:

[einstein57]

Anyone have info on the valves TEP sells?

[E30-325iS]

Thanks Tinkwithanr, looking forward to the pics.

[tinkwithanr]

Glad to hear the IE valves are improved, never hurts to have another quality option for BMW parts.

Also, later today I'll get a picture of my VAC valves. They are slightly different than those in Digger's pictures (coated, maybe a slightly different shape to the head). It would have been nice to have this kind of info in one place when I was shopping around for parts before.

[E30-325iS]

Thanks Digger, it is definitely worth explaining as I don't have as much knowledge as I would like, and any input no matter how trivial or basic it may seem is most welcome, hence the thread.

[digger]

I didn't ask how they were lighter, and what effect it has. You're explaining engine dynamics 101.

Again, similar thought process, differing perspectives

i think it was worth explaining that being lighter wasn't something that should be overlooked when choosing a valve, as eluded to be the case from a different member. Not everyone is aware of engine dynamics or the significance or lack of valve mass so it might help others be in a better position to choose if they want to pay a premium for the last few %. i have edited my post so that it wasn't directed to you.

[SkiFree]

I didn't ask how they were lighter, and what effect it has. You're explaining engine dynamics 101.

VAC and IE cater to slighly different markets

It depends on the immortal question ... Value Vs. Weight, and that's a question that depends on the individual. I think we have a similar mind-set, just differing perspectives.

Again, similar thought process, differing perspectives

[digger]

they are lighter because the the head is flatter (less tulip shaped) which is what the M20 intake port needs due the port geometry (valve port angle) for better flow. This seems to be what schrick did with their valves though i havent held them in my hand.
In a performance engine valve control is very important so you can use faster ramps to give high valve lifts and area under the curve, without needing to use crazy durations which narrows the power band. Being able to use less spring pressure will help the rockers out aswell.

VAC and IE cater to slighly different markets

[whodwho]

The weight of a valve is hardly a concern.

Depends on your target RPM and how much spring it will take to get you there with the added weight to keep from floating all adds up to needing extra spring pressure and the wear associated.

[MR 325]

Exactly Andrew, DOUBLE the price! (Much like everything VAC sells)

The weight of a valve is hardly a concern.

[SkiFree]

\
i maintain that the IE are not significantly lighter than stock.

if i made out that IE were crap then it was harsh, they just arent as good as the VAC and PPF ones but are cheaper

I agree with you, the VAC/PPF are certainly lighter, and they certainly should be for how much they charge as you pointed out. (VAC: $539 for full set, IE: $276 for full set [NOT made in China, Tawain, etc]).

It depends on the immortal question ... Value Vs. Weight, and that's a question that depends on the individual. I think we have a similar mind-set, just differing perspectives.

[E30-325iS]

Thanks everyone for your replies, it's terrific to get every ones views and to be able to see the differences side by side.

[MR 325]

I would not hesitate to run the IE valves, in fact Myster-e is planning to build a head with them soon!