I'm considering building a VG powered S12 200SX with a supercharger for Rally America's Rallycross series. Problem is that the engine size with the 1.8 multiplier puts it over the 5100cc limit in Open class.

So, my question is has anyone installed shorter rods into a VG30E and got it to around 2.8L's (2833cc's)? Is there a Nissan or other make con. rod that will work?

My calculations put the maximum rod length to 79.42mm's, so anything close to or just under is my limit.

Ever hear of a VG20?

seang wrote:Ever hear of a VG20?

Yeah, just wish I could find one in a pick-your-part.

What is it's rod length?

EDIT: NVM, it's 69.7MM and if I can increase the stroke to 78MM, I'd have a square engine. (78MM bore x 78mm stroke) That would be awesome.
Modified by Drift21_Hardslider at 5:59 PM 3/13/2010

I wonder if you could take a stock VG30 crank, if it is steel, and have it de-stroked by welding material onto the inner facing sides of the journals and then having it re-ground back into spec for the bearing. I know practices like this have been done before, but that is about all I know about it.

Then you might have to deck the block, which in turn might cause the intake manifold not to fit. Hmmm, serious engineering; and serious amounts of work compared to just installing shorter rods like you said originally, given vg20 rods have the same journal size as a vg30.

seang wrote:I wonder if you could take a stock VG30 crank, if it is steel, and have it de-stroked by welding material onto the inner facing sides of the journals and then having it re-ground back into spec for the bearing. I know practices like this have been done before, but that is about all I know about it.

Then you might have to deck the block, which in turn might cause the intake manifold not to fit. Hmmm, serious engineering; and serious amounts of work compared to just installing shorter rods like you said originally, given vg20 rods have the same journal size as a vg30.

<bangs my head on the desk> Well, in my glorious moment of utter stupidity, turns out I read the rules wrong. The multiplier is 1.7, not 1.8. THUS, I can in fact supercharge the VG30E without de-stroking.

But, there might be other series that might have a similar rule to my mistaken 1.8 multiplier. Never know.