windhund116

I wouldn't be surprised if the V-6 NSX engine doesn't weigh that much more than the straight-4 S2000 engine.



Just a thought...

DeeKay

thought someone did an accord v6 engine..

s2000sccaracer

Resurrecting this thread from a couple of years ago. Since then, has anyone tried locking the vtec pins and done any testing? I thinking about this for a race only engine, so a poor idle is not an issue. There are vtec killer cams available, but since SCCA EP race rules limit valve lift to 0.500", the commercially available vtec killer cams cannot be used (my budget has limits, so I am not going to spring for custom cams and even the available ones are not cheap).

DefSport

You can do the same thing via any sort of tuning method, so what's the real gain?

Having a low lobe to occasionally pull you out of a low RPM hairpin might be useful. There's really no benefit to removing one of the cam lobes, since they're each more suited towards their given operational domain.

zeroptzero

Are you allowed to use a vtec controller, that would be easier.
Saying that, I would guess your car would be slower as you would lose power at lower rpms. Remember that the Honda vtec system is not about high rpm power it is about maintaining bottom end torque while also having a high rpm cam. Your air fuel ratios would be way off too on the bottom end, so you would need to tune the fuel delivery. I know on my car it gets leaner as I lower the vtec point, and I can't add any more fuel with my controller so there is a limit to what I can do, unless I increase fuel pressure.

s2000sccaracer

I have a Haltech ECU and have adjusted the vtec engagement down to 4100 rpm and on the track, the car is always above that. The advantage is ensuring oil flow to the bearings, rather then the volume and pressure loss going to the valve train to engage the vtec pins. On the track, it is the high end power that is used. The car, even with vtec, does not have low end torque. Torque is not what the S2000 is known for. Yes for the street vtec is needed, but in a race car not so much.

I would be able to tune the low end to ensure A/F ratio is good

DefSport

I could be off on this for the F20C/F22C, but on most other high revving VTEC engines, when the VTEC pin is engaged, a small oil hole sprays the big VTEC lobe with lots of oil. So you'd be potentially starving the cam lobes of oil flow.

Plus the oil pump at high RPMs is likely bypassing quite a bit of flow anyway, so I'm not sure it'll actually give much if any more pressure to the bearings.

windhund116

OT: But, could be related. All my messing with engine valve timing is with motorcycles. Two-stroke dirt bike engines. I had an old 1986 Honda CR125R. It had a cleaver exhaust port chamber with a valve, controlled by engine rev's. ATAC system. Worked via a centrifugal weights --- like the ones used in old-school distributors.

Anyhow, there was a lot of aftermarket kits to modify this system. Different gear ratios, springs, etc. To change the RPM's when the system engaged. Me, being a dumb kid, bought into the aftermarket gizmos. Everyone of them made the bike worse. I eventually went back to the OEM setup.

Later, I bought CR250 and CR500 bikes. Never fooled with the engines or suspensions (except routine maintenance). Very reliable.

Guess the lesson was Honda spends a lot of time engineering these things. Many are race tested, at the factory. Guess they know what they're doing?

https://en.wikipedia.org/wiki/Two-st...tem#Honda_ATAC

jaymz

Honda did it twice. 3.7L
https://hpd.honda.com/street-perform...projects/s3700

s2000sccaracer

I have thought about the reduced oil flow to the cams, with the vtec locked. This is one reason I am asking if anyone has had any success with locking vtec, before I try it. There are Youtube videos of someone that locked Vtec in an S, but they only had the car idling. No follow up if the engine stayed together.