Knock on the VQ37VHR - gear heads step inside

JoeyD · 01-19-2009, 03:58 PM

Yes your car would be tuned. However, a tune won't change your compression ratio. High Compression and FI don't go together well. If the VQ is seeing knock with no boost it is undoubtably pulling timing and that results in a net power loss. Same will be true with FI only more timing will be pulled.

zman1910 · 01-19-2009, 04:09 PM

Quote:

Originally Posted by JoeyD

Yes your car would be tuned. However, a tune won't change your compression ratio. High Compression and FI don't go together well. If the VQ is seeing knock with no boost it is undoubtably pulling timing and that results in a net power loss. Same will be true with FI only more timing will be pulled.

We all know high compression and FI don't go well together. Even then the CR of the 370 is not much different from my turbo'd 350DE, which held up well at 400whp. Combine that with the much beefier internals of HR engines and you've got one stout motor. In the end it all comes down to the tune with a proper EMS.

I am more curious as to where the OP is making his statement. I highly doubt any automobile manufacturer will tune their car to the brink of destruction. It would have to be a variable on the users end or a factory defect causing this phenomenon.

18rgcelica73 · 01-19-2009, 08:27 PM

Quote:

Originally Posted by JoeyD

Yes your car would be tuned. However, a tune won't change your compression ratio. High Compression and FI don't go together well. If the VQ is seeing knock with no boost it is undoubtably pulling timing and that results in a net power loss. Same will be true with FI only more timing will be pulled.

No a tune won't help the compression ratio go down any but actually compression is great with FI as long as it is safely tuned. You can get a lot more power per pound of pressure with higher compression. Just look at rsx-s boosted usually with 11.5:1 compression ratio and turboed making 500whp and safely tuned. It is ALL in the tune.

Clint@Altered · 01-20-2009, 08:24 AM

Quote:

Originally Posted by 18rgcelica73

No a tune won't help the compression ratio go down any but actually compression is great with FI as long as it is safely tuned. You can get a lot more power per pound of pressure with higher compression. Just look at rsx-s boosted usually with 11.5:1 compression ratio and turboed making 500whp and safely tuned. It is ALL in the tune.

I agree. High compression + FI might not always be the best for 93 octane, but it works great in race circumstances.

Anyone have the GTM graph?

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01-19-2009, 03:58 PM	#1 (permalink)
JoeyD Enthusiast Member Join Date: Jan 2009 Location: Raeford, NC Posts: 305 Drives: 09 NISMO 370Z Rep Power: 187	Yes your car would be tuned. However, a tune won't change your compression ratio. High Compression and FI don't go together well. If the VQ is seeing knock with no boost it is undoubtably pulling timing and that results in a net power loss. Same will be true with FI only more timing will be pulled.