Low RPM + High boost = Bent rods?

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BennVenn
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Re: Low RPM + High boost = Bent rods?

Post by BennVenn »

Do you think 9psi is reasonable/safe for a stock 80's era motor? the 'experts' in the various forums all say 6psi is the limit of a stock motor. Going higher is rolling the dice every time you hit the loud pedal

I'd be looking for a larger VNT. I've got a borgwarner 2.0L VNT here out of a great wall which is a little larger in the rear housing so it should be better on the 1.6L. I'm thinking of getting a Ford Transit 2.2L VNT for the 1.8L build. It's still a tiny little thing so it'll fit OK, has a .74 rear housing which will be almost no restriction to the 1.8 until the nozzle is closed. It's odd none of these VNT's are water cooled. I guess diesels are just big cold air pumps when they're not under power so they're actively cooled.

I figure larger turbo, less restrictions all-round, higher VE = more power for lower boost
BennVenn
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Re: Low RPM + High boost = Bent rods?

Post by BennVenn »

And then there's this: https://www.facebook.com/marketplace/it ... 4443b57911

For those not on FB, its a n13 1.8L stripped down as a rally car, turbo bolted on, looks like rising rate reg and not much else. $400 up near newcastle
forsale.jpg
Maybe I'm worried about nothing? If this gets thrashed around the bush on the limiter for a half hour at a time maybe there's hope!
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'quipt4it
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Re: Low RPM + High boost = Bent rods?

Post by 'quipt4it »

This was always going to be a test bed, so what better way to test it :twisted:
That 1.8l will still be on the pallet when this gives it up lol.
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antus
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Re: Low RPM + High boost = Bent rods?

Post by antus »

I think 9 will be ok provided timing isnt on the edge and its not pinging (you may not be able to notice it) and if the fuel isnt lean, and if the valves are still closing. Im no expert as to when you'd want to upgrade the valves, but I know its a thing.
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BennVenn
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Re: Low RPM + High boost = Bent rods?

Post by BennVenn »

There's a whole lot of noise from the wideband so I'm not overly confident I could pick up detonation at 5000rpm, low speed knock is easy to pick out but not so much when it's most important. Maybe some dyno time would be best here. I'll ask what the going rates are in Goulburn tomorrow or I'll weld up a hub dyno and do it all at home. Easier to clean up the mess in my garage

The 1.8 swap is easy :-) The day wasted hiring a trailer to recover the mess is what I'm dreading
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Re: Low RPM + High boost = Bent rods?

Post by vlad01 »

Good time to invest in knock ears.
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Re: Low RPM + High boost = Bent rods?

Post by vlad01 »

BennVenn
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Re: Low RPM + High boost = Bent rods?

Post by BennVenn »

That's pretty much what I've got, wideband knock sensor, high impedance high gain pre-amp, sound canceling headphones. You can hear everything from valve train, water moving around the block, ignition. Unless the knock is a lot louder than the background, not sure you'll catch it. Or is it? I might force it to knock to get a gauge on it
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Re: Low RPM + High boost = Bent rods?

Post by vlad01 »

Knock, even mild that you can't hear outside the engine is ear piercingly loud on knock ears. Sounds like popcorn going off in a metal pan.
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Re: Low RPM + High boost = Bent rods?

Post by BennVenn »

That's reassuring! I'll give it a go in the morning