This is probably a little long, but any ideas would be appreciated. so with the new nasa pt rules being released, there's a good chance most of us rotaries guys noticed the new porting regulations so after counting my points for my build, im at PTB with 11, then adding 8 for weight puts me at PTB points. im building this car for PTA and im leaving 20 points for the old streetport points. the car is a S4 TII, and according to my adjusted power to weight for PTA, i can not have more than 297 at the wheels. i have counted points for modified intake location, aftermarket intercooler, fuel system, modded TB, and exhaust from turbo back, with cat removal. since rtek is now a "no points modification" is there a chance i can get the car around that power with a stock S5 turbo on a streetport? im worried that if i port it and show Greg (pt cheif) the dyno numbers, he might put me in sts2, and again any idea's would be aprreciated, and if anybody has any other ideas, please post them too haha, thanks

Justin
Evil Genius Racing

 

297rwhp is going to put you right at the 8.7:1 lbs:hp for ST2, isn't it? That's 2538#. I'm surprised the PT/TT rules don't require a dyno sheet for all forced induction cars, as well as the ported rotaries.

Anyway, I ran a stock S4 turbo at around 21psi on the street for a bunch of miles with a Microtech MT8 controlling the fuel (2x850+2x1050 injectors) and ignition. I didn't dyno the car in that configuration, and pushing 21psi with the little turbo had me a bit worried but it held together for over a year before I took it off the road and started the still on-going build. It ran side-by-side with the old Mustang Cobras of the day, so I assume it was putting down somewhere north of 225.

I've pretty much resigned myself to ST1 or ST2 when the build is complete. Not so much due to huge power, you don't have to make much to hit the 8.7:1 when you're weighing 2500# or less (as you've noted). :-/

 

8.7 :1 is the minimum for PTA as of the new rules, and i am looking at a race weight of 26XX because of nasa's "adjusted" p.t.w ratio, unless i get more points free after the dyno sheet check.(?) Also on the forced induction front, im trying to get clarity on that new +5 points for boosted cars, its not clear if it is all boosted, or add on cars, soo that might be a little bad on which way it turns out. thanks for the response btw

 

Thanks for calling out the new 8.7:1 PTA rule. I hadn't seen that in the "Changes for 2009" posts I had seen. Weird that PTA and ST2 are allowed the same minimum power:weight.

Pretty sure I'm in STx, anyway, the 60-1 HiFi turbo I have on the car has always been intended to push about 400hp @ 14psi. I suspect I'll have to play with weight reduction and/or more boost since that puts me in a bad place in ST1. I suspect an FC Turbo is not the car to have in ST...