John Williams, Sunbelt Preformance & Classic Motorsports Mag.

[rdefabri]

Old thread (I AM utilizing search ) - what ever became of Sunbelt?

I know they were acquired by Kinetic - they now seem to be a BMW focused shop. I was keen on this rebuild, and on other sites I've read about the magic Sunbelt was doing on L24 heads with stock bottom ends. Interestingly, they have a completely different view of generating performance from other Z performance shops, although I don't know all the details.

Do they still do Z work? If not, does someone else do it for them (or similar to what they were doing)?

Just confused, so asking the question...thanks in advance.

[jmark]

^ I am pretty sure they still do Z work. I know member dspillman had a motor redone by them & can probably give you some contact info.

Edited January 13, 2009 by jmark

[John Coffey]

Interestingly, they have a completely different view of generating performance from other Z performance shops, although I don't know all the details.

Yes they did (do)? Jim Thompson developed new cam profiles based on simulation software specific for the N42 and P90 heads that John Knepp at Electramotive researched. Jim had direct access to that data and very detailed information about the dynamics of the L6 valve/cam train. Previous cam profiles (including the Nissan Motorsports cams) were developed from BMW profiles and were a compromise.

The first engine he built using these new cam designs was the NA 3L in my old race car. The engine was good to 8,000 rpm and the valve spring seat pressures were 25% less then stock and 150% less then the typical aftermarket L6 cam.

[rdefabri]

John,

Thanks - that's what I was referring to. It's that level of engineering that really separates "good" from "great". I know they were justifiably proud of their work (some funny comments on other boards from people that work / worked there).

Eventually, I'll need my head redone on the stock L24. I don't have plans to do much to the lower end other than refresh, but I am thinking I can gain some modest power from a great shop. The CM article referenced here is a good example - pretty much what I'd like to do.

Rich