STx Notes, February Fastrack

[Chip42]

I think that STU will be OK for multi-marque. at least as good as WC ever was - so 6+ makes competitive. I can live with that. but I still want out of market stuff to be allowe dbecause it makes sense, and because it might raise that number by 2. I have a personal motivation, but it's surmountable with extra $$$.

STL really would benefit because the USDM offerings <2.0L is pretty slim (read: honda) but the class allows so much less that you DO run the risk of an Uber moter there. thus the banning of the B18-C5 and the F20. Toyota 2ZZ-GE should be added to that list to be honest. leaves the class with very few real options. but that's

 

[Mrsideways]

Correct me if I'm wrong but does this mean that a Turbo WC car can run it's VTS sheet + 5% but without the STU sized restrictor? And I'm sorry if this has been discussed before but the VTS sheet does not mean they have to run Toyo's does it?

 

[Chip42]

as I understand it, if you run "to the VTS sheet" you run EXACTLY what's on that list (no more, who cares if you run less) and run the greater of VTS indicated weight +5% OR the STU weight +5%. this is NOT well explained for turbos because without an TIR, there's no "STU" weight.

what's your turbo's inlet ID? you could use that I guess. I'd write to the STAC for turbo VTS weight clarification.

 

[Greg Amy]

Chip's right: it means if you're running on a VTS sheet (including any required restrictors/boost limits), you run that weight +5%. And it's intended that tire make/model is free, not required to be Toyos (VTS does not specify tires, that's part of the appropriate Appendix A).

I'd have to look into the VTS of specific cars, but generally speaking turbo cars in 2009 Touring were classified pretty heavy (the 1.8L A4 was 2900, for example)...add 5% to those and they should not be a factor. But, if we find an outlier, you can be assured it will be restricted in some fashion back into place...

GA

 

[Mrsideways]

as I understand it, if you run "to the VTS sheet" you run EXACTLY what's on that list (no more, who cares if you run less) and run the greater of VTS indicated weight +5% OR the STU weight +5%. this is NOT well explained for turbos because without an TIR, there's no "STU" weight.

what's your turbo's inlet ID? you could use that I guess. I'd write to the STAC for turbo VTS weight clarification.

No turbo. I was just wondering.

 

[Chip42]

I've seen you in so many cars I just don't try to assume I know what car you might be taling about.

 

[Mrsideways]

I've seen you in so many cars I just don't try to assume I know what car you might be taling about.

Nope, I drive whatever is offered but no turbo cars are offered.

Turbo cars worry me. I've got a solution but it basically involves making them uncompetitive and sending them to STO.

 

[Matt93SE]

Turbo cars worry me. I've got a solution but it basically involves making them uncompetitive and sending them to STO.

I think you're trying to overcomplicate things. given the inlet restrictors required, there's a definite limit on available power, which is pretty close to the same max power as you could build with an NA engine running the equivalent displacement.

i.e. my 2.4L KA24DE engine *could* be built to 300whp with about $15,000 in work. That would go in my 2640lb car. An SR20DET with 36mm inlet restrictor in the stock turbo (Garrett T28) could theoretically flow enough air to make about 300hp max according to a tech that works at Garrett.

So I wouldn't be too worried about being killed by the turbo engines. You're still limited by the same damn inlet restrictors that the GT guys despise.

 

[Mrsideways]

I think you're trying to overcomplicate things. given the inlet restrictors required, there's a definite limit on available power, which is pretty close to the same max power as you could build with an NA engine running the equivalent displacement.

i.e. my 2.4L KA24DE engine *could* be built to 300whp with about $15,000 in work. That would go in my 2640lb car. An SR20DET with 36mm inlet restrictor in the stock turbo (Garrett T28) could theoretically flow enough air to make about 300hp max according to a tech that works at Garrett.

So I wouldn't be too worried about being killed by the turbo engines. You're still limited by the same damn inlet restrictors that the GT guys despise.

See the issue is it doesn't limit the tq. And Tq can be darn near as potent as HP. If you limit boost people figure out a way to hide the amount of boost shown. My personal opinion is we should put a restrictor on the Oil feed line to the turbo it can have all the air it wants... for a few seconds.... Kidding!

Now here is an interesting Idea. Can you take a Turbo Motor and remove the Turbo and run it under N/A rules. Specific idea I had was a Volvo S80 Turbo motor it's a 2.8L 6 cylinder. The N/A's S80's are 2.9's. Ditch the turbo and put high compression pistons in it and put it in a earlier volvo. Say a 142. Be a TON of work but it's an idea.

 

[Chip42]

Ian,

I think you'll find that an inlet restricted turbo is pretty much a lesser turbo. the TIRs listed inthe STCS and feb 11 fastrack are small. and the weights are large. NA guys should be OK.

 

[Mrsideways]

Ian,

I think you'll find that an inlet restricted turbo is pretty much a lesser turbo. the TIRs listed inthe STCS and feb 11 fastrack are small. and the weights are large. NA guys should be OK.

I think the solution is relatively simple. (and I know this opens a can of worms). Allow people to Add turbo's then it's a fair game. Everyone gets turbo's if they want em and everyone plays to the TIR game. Would be a heck of alot cheaper to toss a turbo kit and some low compression pistons on the S2000 and run the restrictor to the current weight then to build a $10-15,000 engine at an attempt to hit the astronomic hp # needed for a 2700lbs race weight vehicle + buying another $10k in dry carbon items to get a measly 20-40lbs out of the car. Or doing a K24 swap into it to hit the same hp as the World Challenge cars. And if these TIR's really work it won't matter what size turbo you put on so no need to police that. Put a huge turbo and just deal with lag + no air flow when it coughs on the restrictor.

I really fail to see the difference between allowing an SR20DET swap into a 240sx and allowing another company car with the same size motor to hang the same size turbo on the side of it.

 

[Chip42]

there's a huge can of expensive worms that'd be opened that way.

stock turbos are not optimized for racing. turbos, and their optimization, are an added cost. add to that the full ST(U) engine build allowance and you have a seriously costly playground - and for what purpose? if the sequential gearbox cat weren't already out of the bag, I would think that should be illegal, too, and for the same reason.

I can see you issue with the S2000 - you don't think it will shed enough weight to make the 2.0L min (2200#). out of curiosity - how much power do you think it can make, full build? becasue I figure that to be one of the best 2.0L motors available, period. yeah, it's a shame the car is heavy, but you could change the lump or the car to make it work. eventually, if you go 10/10ths, Id ask for that combo to get some sort of help. not sure how that would work (can't loose weight) but it's a possible option.

 

[Mrsideways]

there's a huge can of expensive worms that'd be opened that way.

stock turbos are not optimized for racing. turbos, and their optimization, are an added cost. add to that the full ST(U) engine build allowance and you have a seriously costly playground - and for what purpose? if the sequential gearbox cat weren't already out of the bag, I would think that should be illegal, too, and for the same reason.

I can see you issue with the S2000 - you don't think it will shed enough weight to make the 2.0L min (2200#). out of curiosity - how much power do you think it can make, full build? becasue I figure that to be one of the best 2.0L motors available, period. yeah, it's a shame the car is heavy, but you could change the lump or the car to make it work. eventually, if you go 10/10ths, Id ask for that combo to get some sort of help. not sure how that would work (can't loose weight) but it's a possible option.

The K motors are much better then the F(S2000). The K's get Varible cam timing (via Ivtec) among other things. There have been a lot of people trying to make real hp out of them. The fact is you see fancy engine builds over and over with little results. Without adding stroke or Bore or A LOT of compression just nothing yields you any real net hp. It depends on a Dyno but I'm yet to see one that would be close to STU legal make more then about 240whp on a realistic dyno. The .5pt in compression you can do in STU and the cams will yeild little to nothing. I've seen some extremely high compression cars pop the 300 mark but they were stroker drag motors with 13 and 14:1 compression.
I'm pretty well gutted but haven't done lexan or Carbon Fiber and the car is right at 2600lbs before driver. From what I see the hood is pretty light and you can only get about 10lbs, the trunk can get 15lbs but the dry carbon trunk is $2000. A regular carbon trunk only gets you about 8lbs weight out. The lexan rear window is 8lbs. I figure if I really went nuts and bought all the carbon bits I could see 2500lbs, maybe less if I started over and put a different cage in it. But that's 2500 before driver. Add 180lbs and realistically it'll never get under 2650lbs. The lightest caged S2000 I've seen was 2460lbs + driver and the C-west full carbon fiber car was 2200+driver. So a Full Dry carbon car with EVERYTHING removed would just barely be under weight for the 2.2L motor.