Modifications for STU
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Evolving Member
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Modifications for STU
I am considering prepping my car for STU. I just want to know what mods are allowed since this is a new class. I am not going to be making a run a nationals anytime soon, so It is just a regional thing. Any help would be great . Thanks
Take a look here:
http://www.moutons.org/sccasolo/Rule...t_touring.html
All of the allowances there apply, including the STX rules at the end.
STU additionally has no wheel width limit, and 245 tread width limit for AWD cars.
Those online rules are slightly out-of-date, so you may want to double check specific modifications before buying/installing them.
To be competitive in STU, an adjustable coilover suspension setup will be highly recommended. A lightweight catback exhaust and an STU-legal reflash (one which doesn't change boost control parameters) will also be very helpful. I would guess that those changes will get you 80-90% of the performance of a "fully built" STU car.
http://www.moutons.org/sccasolo/Rule...t_touring.html
All of the allowances there apply, including the STX rules at the end.
STU additionally has no wheel width limit, and 245 tread width limit for AWD cars.
Those online rules are slightly out-of-date, so you may want to double check specific modifications before buying/installing them.
To be competitive in STU, an adjustable coilover suspension setup will be highly recommended. A lightweight catback exhaust and an STU-legal reflash (one which doesn't change boost control parameters) will also be very helpful. I would guess that those changes will get you 80-90% of the performance of a "fully built" STU car.
The rules will be very similar to other ST classes. Go nuts with suspension, but for power you are kinda limited to a reflash, some sort of air/fuel control such as a SAFC, intake and exhaust. You can upgrade brake pads and rotors as long as they are the same size as stock. Honestly, you're not gonna have to do much, STU isnt taking off like it was supposed to, so competition is kinda limited. If you really want to be competing with other people I'd consider SM or ESP
I can't find my 04 rulebook, but I don't think IC pipes are legal -- that's one of the differences from SP. I believe you are permitted to change the MAF pipe, but nothing from the turbo outlet to the intake manifold.
Originally Posted by EVO8LTW
I can't find my 04 rulebook, but I don't think IC pipes are legal -- that's one of the differences from SP. I believe you are permitted to change the MAF pipe, but nothing from the turbo outlet to the intake manifold.
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...SCCA rules are easy, if it dosen't say you can to do it then you can't, no grey area there. 
Also, you can't build up the engine in SP, no cams, rods, pistons, etc. allowed (and theres already a clarification on cams stating that). 
Also, you can't build up the engine in SP, no cams, rods, pistons, etc. allowed (and theres already a clarification on cams stating that).
Last edited by RT; Aug 27, 2004 at 06:48 AM.
Originally Posted by RT
...SCCA rules are easy, if it dosen't say you can to do it then you can't, no grey area there. Also, you can't build up the engine in SP, no cams, rods, pistons, etc. allowed (and theres already a clarification on cams stating that).
Also, you can't build up the engine in SP, no cams, rods, pistons, etc. allowed (and theres already a clarification on cams stating that). 
Don't tell the long-time SP guys that you can't "build" an engine. You absolutely can, but there are restrictions. It is an often repeated "myth" that SP doesn't permit internal engine changes. Here are some of the things you can do:
15.10.P. Cylinders may be rebored to no more than .0472 in. over standard bore and the appropriate standard oversize piston may be substituted. This overbore dimension is an absolute limit; no additional tolerance is permitted to accommodate wear. Cast or forged, non-stock pistons of the same dimensions and configuration as original equipment pistons may be used. Additionally the replacement pistons must be of the same weight or greater as the original equipment pistons. This does not permit alternative ring configurations.
15.10.Q. Rotating and reciprocating parts may be balanced but not lightened.
15.10.R. Intake and exhaust ports and manifold openings may be matched provided no change is made more than one inch from the port/manifold interface. Material may be removed to facilitate port matching, but no material may be added.
15.10.T. The engine cylinder head(s) may be milled only to that amount specified in the manufacturer’s workshop manual. If no amount is specified then a maximum of 0.010 in. may be milled.
15.10.Q. Rotating and reciprocating parts may be balanced but not lightened.
15.10.R. Intake and exhaust ports and manifold openings may be matched provided no change is made more than one inch from the port/manifold interface. Material may be removed to facilitate port matching, but no material may be added.
15.10.T. The engine cylinder head(s) may be milled only to that amount specified in the manufacturer’s workshop manual. If no amount is specified then a maximum of 0.010 in. may be milled.
Originally Posted by TheGVR4kid
JB can you clarify the IC pipes issue?
That's easy. you can't change a thing.. the intercooler piping is part of the intercooler unless the service manual says otherwise. Even then you would still have a hard time.
You are not allowed to touch anything past the turbo. you can install any parts before the turbo, but need to retain the stock factory parts (the MAF sensor) in the same relative position.
IC pipes are off limits in ST. They must be in an OEM configuration.
Those are your ST rules for the intake side of the engine. You can go wild with everything prior to the turbo compressor inlet; just make sure that the MAF sensor remains in its approximate original location. Between the turbo compressor inlet and the cylinders, you can't do much -- putting in a boost gauge is probably about all that you can get away with.
14.10.B. The air intake system up to, but not including, the engine inlet may be modified or replaced. For naturally aspirated engines, the engine inlet is the inlet to the throttle body or carburetor. For turbocharged or supercharged engines, the engine inlet is the compressor inlet.
14.10.D.6. The mass airflow sensor must remain in its approximate original location.
14.10.D.6. The mass airflow sensor must remain in its approximate original location.
Last edited by jbrennen; Aug 27, 2004 at 08:17 AM.
I know those rules JB, I don't call that a "built" engine, I'm talkin' purpose built race engines, not touch up work
....like I said nothing more than clean up son, the rebore rule for example is only there so engines can be refurbished, only a standard sized piston can be used. And so what if you can use a forged non-stock piston, it must be the same dimensions and weight (or greater) than the OEM piston. Alternative ring configurations are not allowed, advantage, little or none.
The point being (which was the correct original point) "built" engines are not allowed in street prepared, cams are not an allowance. No new lifters, no new cranks, no new rods, no replacement heads, in short, no purpose built race engines in SP.
The point being (which was the correct original point) "built" engines are not allowed in street prepared, cams are not an allowance. No new lifters, no new cranks, no new rods, no replacement heads, in short, no purpose built race engines in SP.
