2020 STU Discussion
Mar 22, 2020, 08:26 AM
#16
As someone who just had a fresh OE clutch and just got tuned with the OE boost pill, gah. I know, it's still a proposal. But this seems to me like something that is going to get people excited, lots of shiny new allowances people want.
Is there enough benefit to an FMIC at STU power levels to justify it? I'm guessing it can't be lighter than OE. Also.. new tune with the pill removed.
The nice thing about 285s is that they're shorter though. I need to do some digging but I thought someone in the archives had gotten 285s under their car when we were talking about a previous rules proposal, Rick J maybe?
(Whether it's worth it on a 10 or 10.5 wheel is a separate question)
Does the ACD count as an electronic differential?
For tires, you'll want to be on 265 A052s and 18x10.5 wheels. 285 A052s arent going to fit under stock fenders and the 265s may be tough also. Dont necessarily think about the number on the tires tho, its a dang big tire. The 295 is definitely 305 in size on my pinched 10.5" wheels .
(Whether it's worth it on a 10 or 10.5 wheel is a separate question)
Originally Posted by FasTrack
Tuning for automatic/dual-clutch transmissions and electronic differentials
Mar 22, 2020, 08:54 AM
#17
Currently just a proposal. Open for feedback. If you have any thoughts on it, now is your time to write a letter. They really do read and consider the letters.
I understand the argument, but I don't see this holding up under protest. Wavetrac doesn't market their diff as an OEM equivalent, they market it as a performance upgrade over the OEM diff. Regardless of how true that is, we can't swap it for the same reason we couldn't swap clutches.
Front diff strength shouldn't matter for normal, non-Pro Solo autocross though.
I see where we differ. We're already running 265 tires and 10" wide wheels in STU, so I didn't include those in my estimate. Also, I didn't count the front diff swap because it's a no-go. And I'm not in a rush to replace my clutch until the day it starts slipping, which is something I budget for. Being able to upgrade the clutch should save money over time.
I'm not convinced 10.5" wheels are going to fit under the fenders within the STU rules. It could work if we could get the rules expanded to allow some fender pulling and/or trailing arm replacements, but I don't know if I see that happening.
I understand the argument, but I don't see this holding up under protest. Wavetrac doesn't market their diff as an OEM equivalent, they market it as a performance upgrade over the OEM diff. Regardless of how true that is, we can't swap it for the same reason we couldn't swap clutches.
Front diff strength shouldn't matter for normal, non-Pro Solo autocross though.
I see where we differ. We're already running 265 tires and 10" wide wheels in STU, so I didn't include those in my estimate. Also, I didn't count the front diff swap because it's a no-go. And I'm not in a rush to replace my clutch until the day it starts slipping, which is something I budget for. Being able to upgrade the clutch should save money over time.
I'm not convinced 10.5" wheels are going to fit under the fenders within the STU rules. It could work if we could get the rules expanded to allow some fender pulling and/or trailing arm replacements, but I don't know if I see that happening.
. We know it has no performance benefit and sometimes you have to follow Smokey's logic. But if you aren't doing pro's, you'll be totally fine on the stock diff at STU power for a long time. But if it does fail, know it takes out the whole T-case. Power wise, I'm not sure how much extra power you'd get with the open boost rule being limited by 93 octane. But I'm guessing 350-360 hp with conservative timing will be realistic. That's enough the stock clutch isn't going to be happy long. So its just a matter of time before that needs changing. And if you're already on 10" wheels then that's solid enough. But if people are on 9" wheels I'd be going bigger.
Mar 22, 2020, 10:08 AM
#18
I'm not sure how much tire they can fit, though.
That's how I read it.
Mar 22, 2020, 10:53 AM
#20
Evolved Member
This is a big change to the current state of the STU!! I see some good things in there, but still not sure about some others.
To start here is they are saying they want to "Decrease average age of competitive STU cars", yet at the same time proposing to add old cars like C5 Z06 or old NSX!
I am also wondering if STU was in fact struggling and in need of such drastic change...
Allowing bigger wheels/tires will only help some of the cars (also some more then others) and I am ok with with (just OK though). Not allowing some additional tweaks to make sure those larger items fit properly inside the fender doesn't make lots of sense.
Allowing bigger IC is strange - nobody would say just because I can't upgrade my IC I am not going to race in STU...maybe it is just me though.
New boost allowance is going to help more cars too, and after partial implementation for the old new boost rule, this should be good.
Clutch thing I do like, since I was always under impression this was needed for all the car that increased power levels with previously allowed mods. It is hard to swallow that after you destroy your inadequate clutch due to too much power your car now makes, you would go and put the same one in there again.
Electronic diffs/transmissions is a tricky one, but just like the electronic boost control before this, almost impossible to enforce. It will open lots of cans here, and some definitely could have worms in there...
One diff allowance for AWD is a welcome one for sure! When do we start asking for another one?
All of the new cars are another tricky one! They are opening all those cans for the existing cars and as it that mess is not good enough, they want to add more oil to already big fire! I wouldn't go there at least right away, but...
To start here is they are saying they want to "Decrease average age of competitive STU cars", yet at the same time proposing to add old cars like C5 Z06 or old NSX!
I am also wondering if STU was in fact struggling and in need of such drastic change...
Allowing bigger wheels/tires will only help some of the cars (also some more then others) and I am ok with with (just OK though). Not allowing some additional tweaks to make sure those larger items fit properly inside the fender doesn't make lots of sense.
Allowing bigger IC is strange - nobody would say just because I can't upgrade my IC I am not going to race in STU...maybe it is just me though.
New boost allowance is going to help more cars too, and after partial implementation for the old new boost rule, this should be good.
Clutch thing I do like, since I was always under impression this was needed for all the car that increased power levels with previously allowed mods. It is hard to swallow that after you destroy your inadequate clutch due to too much power your car now makes, you would go and put the same one in there again.
Electronic diffs/transmissions is a tricky one, but just like the electronic boost control before this, almost impossible to enforce. It will open lots of cans here, and some definitely could have worms in there...
One diff allowance for AWD is a welcome one for sure! When do we start asking for another one?
All of the new cars are another tricky one! They are opening all those cans for the existing cars and as it that mess is not good enough, they want to add more oil to already big fire! I wouldn't go there at least right away, but...
Mar 22, 2020, 12:15 PM
#22
STH only: As utilized only on engines originally equipped with forced induction, induction charge heat exchangers (also known as “intercoolers” or“charge air coolers” [CACs]) are unrestricted in size and shape. Air-to-air CACs and radiators for air-to-liquid CACs must be cooled only by the atmosphere except for standard parts. Body panels, fascias, or structural members may not be cut or altered to facilitate CAC installation. Removal of vehicle components to facilitate installation is not allowed. Holes may be drilled for mounting. Factory boost piping may not be modified or replaced.
Mar 22, 2020, 02:25 PM
#23
What tire size and wheel width are the current Evo 8/9 running? This will be tricky for me to demod the car back from a half-prep ASP car as my fenders are slightly pulled in the rear to fit 285 A7. I suppose running the same wheels/tires as everyone else, nobody is going to bother to give me a hard time, but who knows.
Is restacking the OEM rear diff considered a diff change in this case? I am really intrigued by this new rule as I would not hesitate to run in the new STU class.
Is restacking the OEM rear diff considered a diff change in this case? I am really intrigued by this new rule as I would not hesitate to run in the new STU class.
Mar 22, 2020, 02:59 PM
#24
What tire size and wheel width are the current Evo 8/9 running? This will be tricky for me to demod the car back from a half-prep ASP car as my fenders are slightly pulled in the rear to fit 285 A7. I suppose running the same wheels/tires as everyone else, nobody is going to bother to give me a hard time, but who knows.
Is restacking the OEM rear diff considered a diff change in this case? I am really intrigued by this new rule as I would not hesitate to run in the new STU class.
Is restacking the OEM rear diff considered a diff change in this case? I am really intrigued by this new rule as I would not hesitate to run in the new STU class.
Restacking OEM diff is not considered a diff change. It's allowed under current STU rules because the service manual shows the restacked configuration as the correct configuration. We're interpreting it as being installed wrong from the factory.
Mar 22, 2020, 04:46 PM
#25
Cool. I forgot the restack is a OE allowance. That's even better in my case. But with the new rules though, I think the Supra/M2 can both handle 285 easily and open boost will just be a wash, it certainly doesn't bold well for the Evo. The newer cars are generally heavier these days, so hope that will keep the Evo somewhat in the game still and will likely be course dependent too.
Mar 22, 2020, 04:51 PM
#26
Cool. I forgot the restack is a OE allowance. That's even better in my case. But with the new rules though, I think the Supra/M2 can both handle 285 easily and open boost will just be a wash, it certainly doesn't bold well for the Evo. The newer cars are generally heavier these days, so hope that will keep the Evo somewhat in the game still and will likely be course dependent too.
We can't fit more tire. A little extra boost will help a small amount, but 93 Octane still limits it.
The wildcard would be if someone can find a magic combination of rear differential upgrade and ACD tune that transforms the handling.
Evo X with open boost and huge tires might become more attractive now, though.
Mar 22, 2020, 05:52 PM
#27
Evolved Member
Mar 22, 2020, 06:09 PM
#28
I still think this platform is capable of taking 1st at nationals with the right tires/driver the way the rules stand...
Mar 23, 2020, 06:42 AM
#30
Major changes proposed to STU in the latest Fastrack: https://www.scca.com/downloads/49412...ition/download
Proposal would increase tire limit to 315 for all cars, actual open boost, clutch allowance, single differential allowance, and adds a few cars.
Would be a significant change to the class. Any thoughts on how the Evo would compete with 285s, open boost, and a single upgraded diff? Seems like some of the proposed additions to the class would be tough to compete with.
Proposal would increase tire limit to 315 for all cars, actual open boost, clutch allowance, single differential allowance, and adds a few cars.
Would be a significant change to the class. Any thoughts on how the Evo would compete with 285s, open boost, and a single upgraded diff? Seems like some of the proposed additions to the class would be tough to compete with.