3SGTE question

[Mr_X]

Excuse my ignorance, just need to know someone's experience on running over-size valves.
Does it help the turbo spool quicker? And won't there be the problem that the valves will be kissing the piston?

What sort of cams should I run with a Garrett gt3037 and what other mods can I do to increase the air volume?

[Joshstix]

The bigger valves improve volumetric efficiency quite nicely. You can get 1mm oversize valves onto the stock seats.

I don't know about getting the turbo to spool quicker, maybe it will if you setup the cam timing to favour that.

You should make sure that the pistons are flycut correctly for the size of valve you are using.

In my car I'm running Wade cams, 266 degrees advertised and 10mm lift. I suspect these won't fit straight into a Gen2 head though. They would work nicely with a decent size turbo though, on mine with a TO4S I made 203rwkw at 10psi.

If by "increase the air volume" you mean improve flow then look at getting a better intake manifold and head porting.

[Mr_X]

Thanks Joshstix, that’s a good figure for a t04 on only 10psi

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Running over sized valves and high lift cams, you will turn the engine into an interference type as well.

Personally, cams for that size turbo, i'd run 264's with your choice of lift (i'd run stock, to try and keep it non interference). Keep the idle relatively the same, with more topend/torque (depending on how you degree them)