Thread: Supertech over sized valves & N1 Cams

Wow didn't think you still had a VVL it's been ages lol.

well intake air is more dense then exhaust gas. you might want to just go +1, +1 if you go to big they can crack between valve seats. just a thought.

you realize the exhaust gases expand right. the intake is not compressed..

Oversized intake and exhaust valves are not a straight bolt on deal. They require at least a valve job which is head work.

In their defense, "minimal gains" are what modifying naturally aspirated motors are all about. There are no "large gains" when dealing with peak performance without LARGE money. Oversized valves can be just another 1 or 2 HP increase which can take your build above others! Do it!

If done properly it will be more than 1-2 whp gain. Probably more like 5-7whp. But again like they said. Money can be better spent elsewhere. Your looking at 450.00 for the valves and then a massive amount of headwork to install them and have them work like they are supposed to. The seats are gonna have to be cut quite a bit and while your there you might as well have them deshoud the valves and port the inlet just before the valve seat to make it a nice smooth flow through that area of the port coming into the combustion chamber. There is more to it than just throwing larger valves in.

Probably the machine work to install them and do the deshrouding and smoothen out the port and valve opening will cost you another $500 or more in labor. They also have to make sure when doing the valve install that they use the correct install height so the top of the stem is at the proper height. This is done by measuring the valve height with the stock components in and then making sure the new ones come out the same. Its a very lengthy process.

So with a port and polish + N1's and oversized valves at ~$1300 and probably over 10 hp gain, that sounds like a good deal to me. With a good tune, you can probably see 215 whp + without touching the block. If I could, I would.

$/hp gain could very well be acceptable, depending on the level of the rest of the build. If it's a stocker then there is cheaper hp to be had. Well built motor with not much room to build to, this could be a good deal.

In my opinion it is absolutely pointless and a waste of money to do that kind of work for a stock compression and bore VE. The gains would be more noticable on a built high compression motor, 2.2, 2.3, 2.45 and so on. That would be the only time I would go that extensive into headwork is if im trying to make absolutely the most power I can out of a built motor. The money spent to try and gain 5-7whp on a stock internal VE is just not worth it in my opinion.

Agreed



Where I am machine work is not as overpriced as in the US.

This discussion raises good points and different schools of thought, which is always welcomed, but I think we're forgetting the original question, which is not whether if it's a worthwhile gain, but rather a matter of clearance.