And that's no BS. Cam has had it that fast "racing" on 95 south of Miami.

 

so clean

 

"put the three rotor in it, put the twin turbos on it" bwahahahahahahaha!

 

Something has confused me here, i know its a late post and all but isn't twin turbo only capable of producing like 350-400 HP or less, I can't remember? Thanks.

thewird

 

Pettit claims 500 HP AT THE CRANK, not RWHP. That's about 425-450 RWHP depending on loss. My Pettit twin turbo setup "only" made 400 RWHP as the turbos wouldn't hold anymore than 12 lbs. of boost. Cam (Pettit) swore the car should do better than this but mine never did. I drove in the one he sold, however, and it seemed much faster than mine. I was actually gripping on to the passenger handle while Cam drove the car. Cam tells the story of racing a crotch-rocket biker on I95 and beating him and also racing a guy in a new Porsche turbo. He claims he buried the speedo during these runs. I would think this is true.

 

12lbs in a 3 rotor will yield more power than 12lbs in a 2 rotor won't it? that might account for the extra bump the 20b gets. I'd like to see the cosmo flow maps.

 

Mosty definately. The 3 rotor will generate much more torque (at lower RPM ranges) and HP. The cosmo flow maps are not impressive though, at least not mine. The turbos reach max efficiency at about 5,000 RPM and run out of air from 5,500 RPM forward. The 20B should peak at about 7,000 - 7,500 RPM. The twins definately restrict the engine's performance. Would be interesting to see if the BNRs would work on the 20B.

 

That's something i was thinking. I see a lot of the 20b's are running single turbos so i'd like to compare the 20b flow map to the 13b. change one or both of my stock twins out for its 20b counterpart. maybe bnr would do a rebuild/upgrade on the 20b stockers?

 

If you are thinking of doing this on a 13B, I wouldn't do it. I'm pretty sure about this - the 20B turbos are actually smaller (at least the secondary unit) than the 13B turbos. I also don't think the turbos would be a direct swap for your 13B. There are better ways to go (the BNRs) if you want to stay with the twins.

 

Meh. So much for the novelty. It doesn't suprise me thought that they're smaller. If they were trying to keep the peak power down in the 280-300hp range they'd have to go with smaller turbos...which is probably why yours run out of breath at 5000 where mine i really starting to pull into their prime.

Given the availability of stock twin assy's you shouldn't have much trouble finding a core, and i bet the bolt patterns are the same too.

 

Back when I first got my 20B (about 5 years ago) I gave my stock turbos to Byran to see what he could do with them, but back then the 20b market was still somewhat new and everbody that was doing the conversion then wanted single turbos.

 

hey i have a ? if you have to pick a clutch for your rx-7 which one will you pick for it A #1 solid hub clutch or A # 2 sprung hub clutch