JClaw

iTrader: (17)

What is the concensus on just how high the Stock VQ35DE oil pump can be revved? Can it be revved to 7700-7800 safely?

I believe at least one or two guys on my350z.com have done mild 8000 Rpm builds while keeping the stock DE oil pump. I believe some have gone as high as 8500 with the RevUp oil pump, where does the revup pump become necessary? 7500? 7800?

Rods vs Rod Bolts

Technosquare tested the stock VQ35 for 15 minutes at 7200 continuously and got rod bolt failure. The other test I have heard is failure at 7600 after 3 minutes continuously.

But its not clear whether they always get ROD BOLT failure or sheer ROD failure, like a BENT rod or something. Has anyone actually BENT a rod NA through sheer revs and not rod bolt failure?

It seems NA problems always come from rod bolts and not the strength of the rods themselves. The rod bolt breaks as it reaches ITS limit, bearing cap detaches itself and the engine is destroyed.

So what prevents me from revving a bone stock VQ35 with just valve springs and ARP rod bolts to 8000? Has this been documented?

doublea

iTrader: (7)

Hey JC Law, I think there might be a safer way to create more power and keep the rev to let say around 7200 rpm. I personally think that the engine doesn't produce that much more power between 7500 - 8000 rpm versus the risk of an engine failure.

I think if you use .020 or .030 oversize piston, pierce the block or sleeve it to have the perfect clearance, then have some custom rod bearing + the arp rod bolts would be a much safer way to start, but another thing that you want to check is the offset of the wrist pin.

I'll try to explain the best I can but I dont know the exact technical english term for that. When I had my custom piston made they have set the wrist pin to be not in the center of the piston but rather a bit more off the center let say the center is set at 5 on a scale of 10, they suggest to set it at 6. My builder was explaining that doing so will prevent the piston from flapping and create vibration. This also keep the concentricity of the cylinder for a much longer period of time. There is a price for that but re-opening and engine and rebuilding it a second time is much pricey. Precise engine tolerances not only provide extended mileage, but add 5-10% more horsepower to any engine, I personally think this is an aspect that we should pay more attention if we want a more durable engine.

On my DEK, my goals was to have a solid 400 HP engine that will last. I'm going to set the cut off at 7100 rpm even though technically speaking the engine is build and good for 8000 - 8200 rpm, but again at that rpm, I know my rod & rod bolts wont last forever. From the beginning I've decided to have more TQ at lower rpm than having a higher revving engine. My DEK is blue-print and balance so time will tell if we where right or wrong.