I need some general info on rebuilding the VQ engine. I'm approaching 230,000 miles and I intend to keep the car and soon make it track-only...I don't want to go crazy b/c I want the car to meet SCCA guidelines for IT...so no wild cams or different intakes or stuff like that.
question is, do rebuilds confuse the computer? Can the block be bored to .40 over without things going crazy? In general, what kind of money has any of you paid to do a basic rebuild (honing, blueprinting) stuff like that?
Like I said, just looking for general info.
Thanks

 

I don't think a rebuild is going to have any affect on the ecu, unless you do things that affect cam and ignition timing.

With VQ30s being so cheap and plentiful, it is much more cost-effective to swap in a lower mileage used engine rather than rebuild your old one.

 

A rebuild to factory or close to factory specs will not confuse the ecu

The block cannot be bored as uses an aluminum block with steel sleeves. You can get thinner sleeves that will increase the bore. But not by 0.40. That's a pretty big change.

Your best best as stated, is to find a low miler used engine and swap.

 

You can also swap in a VQ35 lower which would put your CR around 11.5:1. The added displacement and CR would really be perfect for a track only car with a JWT advanced ECU.

 

Thanks for the info. Can you give me an estimate of cost of VQ's and what would you consider "low" mileage on these engines?
The 3.5 swap is intriguing but would make my car illegal for the class I'd put it in...Thanks tho...
BTW-"IT" as I refer to in the original post means "Improved Touring"..a regional only SCCA road race class...I used to race a 1985 Honda CRX in that class...

 

Like $300-400... www.car-part.com is your friend.


I'm confused as to what the rules say that would allow you to have larger displacement by way of block boring, aftermarket pistons, etc, but wouldn't just allow the usage of a 3.5L untouched block? Is it just a cap on the displacement or something else?

And jeff I think he meant .040" not .40" hehe. Doesn't the VQ have ductile iron sleeves?

 

[QUOTE=Nealoc187]Like $300-400... www.car-part.com is your friend.


I'm confused as to what the rules say that would allow you to have larger displacement by way of block boring, aftermarket pistons, etc, but wouldn't just allow the usage of a 3.5L untouched block? Is it just a cap on the displacement or something else?

IN SCCA IT, the original engine type that the car was produced with must be used. Even tho the 3.5 is a VQ designation (right??), it's a different engine size with more HP and would not be allowed. There is some flexibility in backdating stuff, (such as if you were running a base Maxima but wanted to use the limited slip from a higher line model, that would be allowed, or using the larger tire size from a 5th Gen on a 4th Gen), but the 4th Gen models are so similar in all ranges, that you wouldn't gain anything by switching parts from one 4th Gen to another.
There are enough differences between the car and the engine that would make a 3.5 swap a NO-NO in SCCA. In NASA tho, a 3.5 swap probably could be done with no issue. That's where the Hybrid Hondas are running.

 

how would they even know oyu were using a 3.5 block since its visibly the same as a 3.0

 

Yeah. If you put 3.0 valve covers with the "Nissan V6 3000" cover and say, a 00 VI, they will think you are running a VQ30 with a 00 VI, while everyone scratches their heads.

 

It's a risk thing. One could get away with it. You'd have to know how to cheat. In other words, if I raced that swap, then I go out and whup EVERYONE and do things like walk a BMW 325IS down the back straight, that would raise some eyebrows, then I could get protested, just like at an autocross. I'd then have to prove that the swap is legal, AND depending on the region, they might even tear down the engine to make sure, and I'd have to pay to tear it down, and they AIN'T putting it back together. It's not worth it to me. Besides, SCCA is amateur racing. No prize $$$ involved.