Hello everyone, I have a few questions regarding the VH45 and n/a tuning. I know that the H22 outer valve springs can be used with no modifications (bored out H22 retainers were optional if I understood correctly) allowing a mild cam with identical ramping be utilized (I think? ). I'm guessing unless I went solid lifters like Mr. Dixon my max rpm would be about 7500. From what I understood HLA are superior for non track applications due to less upkeep I believe. So the big question, with mild cams, stock internals (haven't found higher compression pistons yet), and a limited rev limit, are high HP numbers possible? I imagine with itb 350 whp isn't unreasonable, but unless I went with solid lifters, an aggressive cam, and inner H22 springs I don't believe the potential of this motor would be realized until much higher rpm (would the rotating assembly geometry support much higher rpm?). I guess as always forced induction is just too easy and too cheap . If any of my information or assumptions are incorrect please point them out. I guess this wasn't much of a question either, I answered it while writing.

check out http://www.q45.org/vhpower/info.shtml also search the New zealand web sites as they widely use JDM vh41de in speedway and jet boats. In New Zealand, many of the Super Stock racecars use JDM VH41’s. They run those things to about 9000 RPM and 500HP on basically stock motors. Modifications include mostly things like headers, intake and cams/valve springs (note stock hydraulic adjusters are retained).

Thanks nissman, I had seen that page but never read the first paragraph. Now I just need the motivation to reassemble my block instead of fitting a turbo onto the miata. Thanks again for the info.

a tuned ecu will do wonders for the motor, stock mapping sucks.
easy 20-30hp from ecu alone, i've had good luck with tuning these motors...they respond well.

Carl H wrote:a tuned ecu will do wonders for the motor, stock mapping sucks.
easy 20-30hp from ecu alone, i've had good luck with tuning these motors...they respond well.

I wasn't aware that the stock ECU was so tame. I for some reason thought the culprit would be the cams. Is JWT still used or has Wes cornered the market for aftermarket ecu's?

no idea, i guess wes still does ecus.
if you want i can do a custom tune for your setup on a dyno or one of the prefabbed ones that i've done that have proven themselves on the track that several people on this forum are running.