3.2 Valves in 3.0

[whrdnsx]

Has anyone fitted the 3.2ltr Inlet Valves into an OEM 3.0?

Just wondering if there's any issues with the OEM 3ltr piston valve relief & the larger 3.2ltr inlet valves.

Thanks

 

[sparky]

Not many responses, but interesting idea. I guess you're just looking to increase intake air flow rate, then re-tune for more power

 

[BATMANs]

I did look into this when I had my engine project

My machinist said that the larger valves were too close to the cylinder walls and just didn't feel that comfy about it.

http://www.nsxprime.com/forum/showthread.php?t=154679&highlight=Ferrea

 

[whrdnsx]

Ok, Thanks. that's the info I'm after.

Bore will be slightly larger at 90.5 but probably best to leave the intake valves OEM size.

 

[stevenlee]

My engine builder put the 3.2 intake valves in my 3.0 heads to go with the 93mm (3.2 liter) pistons and sleeves.
He thought that the larger intake valves help the performance.
My engine dynoed at 275 whp at no boost, and 505 whp with 7 pounds of boost.

 

[BATMANs]

Ok, Thanks. that's the info I'm after.

Bore will be slightly larger at 90.5 but probably best to leave the intake valves OEM size.

Consider a 3 angle valve job. That will increase power throught ur power band.

My engine builder put the 3.2 intake valves in my 3.0 heads to go with the 93mm (3.2 liter) pistons and sleeves.
He thought that the larger intake valves help the performance.
My engine dynoed at 275 whp at no boost, and 505 whp with 7 pounds of boost.

Yep.

If I did the wider darton sleeves I certainly would have gone with the upgraded valves.

 

[Mac Attack]

If you have a 90.5mm bore, upgrading to 1mm diameter larger valves only places the valve 0.25mm closer to the cylinder wall.
I don't think that's a huge difference IMO.

Since my C30 valves were fine, I just reused them to save money without spending money on the larger ones. Plus, this will be boosted, so I'm not looking for that extra few HP in headwork in exchange for high cost when I can just increase boost to compensate.

Dave

 

[Mark911]

You'd probably loose as much flow due to overshrouding as you'd gain from the larger window area. I've never seen any data that would suggest the stock heads were valve limited (vs port limited) anyway.

 

[stevenlee]

You'd probably loose as much flow due to overshrouding as you'd gain from the larger window area. I've never seen any data that would suggest the stock heads were valve limited (vs port limited) anyway.

Mark, I enjoy reading your detailed and technical posts on Prime. Do you think that the larger 93mm bores with ported and polished intake runners would benefit from larger intake valves?

I modified and opened up my intake manifold and my engine builder seemed to think that the larger intake valves would help. I didn't do a back to back comparison and I made other modifications at the same time so I can't tell what the effect of the larger intake valves is.

Here are a couple of photos of my modified intake manifold and a head modified for the larger intake valves.