SCCA STX Legal tune

[Cligedy]

I'd like to get a tune for this autox season and I really like what I hear about your tunes, especially that you are able to improve throttle response. For the STX class, pretty much any ECU tuning is OK, except "boost controls" must remain untouched. Would it be possible to get the standard tune with the boost controls returned to the OEM settings? Is this a terrible idea?

Alternatively, would it be difficult to use an OEM map and remove the 2nd gear torque limit and raise the redline to 7k?

As shitty as it sounds, I'd like to minimize the cost and hassle of custom tunes since it looks like next year boost can be modified and I would have to start over. Thanks for your feedback.

 

[awwwww_shift]

following....

 

[Quisp]

How do they check for tunes? Why 7k rev limit? The partys over at 5500 on stock turbo. Maybe for a little over rev to avoid extra shift?

 

[Cligedy]

How do they check for tunes? Why 7k rev limit? The partys over at 5500 on stock turbo. Maybe for a little over rev to avoid extra shift?

Typically autocross courses are designed so that the top speed is in the low 60's. The FiST bangs the limiter at ~58mph /6500rpm. Most autocrosses I run will have sections where I am banging the limiter but are short enough that I would lose time shifting up to 3rd and then back down again. Bumping the redline give me a few extra mph in those sections.

 

[OffTheWall503]

I'm pretty sure almost any and all tunes modify boost controls, so maybe you would be better suited with a TurboTransformer or something.

 

[jeffreylyon]

Stratified offers an option for a boost-limit in 2nd, but I'm not sure that it's to the stock pressure. If you do a custom tune you can ask for whatever you want, but most gains are being found by increasing boost. Having said that, you could get a rev-limit update to give a little extra speed in 2nd, launch control and FFS, and a bump in timing and improved F/A ratio, all of which will help a bit. I've got a slot optimized for the street/HDPE and a slot optimized for the stock boost limit. I've made the mistake of doing a pass in the HDPE slot and just fought wheel spin more (no LSD, yet).

(a little OT) I think that the formula for the FiST in STX is to remove weight, add wheel width, add tire width and compound (I'm really looking forward to the 234/40x17 Direzza ZIII!), suspension goodies (esp. add roll stiffness in the rear), LSD, and (maybe) a lightened flywheel. We're usually rolling onto the throttle right in the middle of the torque band and the turbo doesn't need much throttle to spin right up. I think that we can tinker with the BPV in STX so I may be using a stiffer BPV actuator but, like I said, I'm already over powering my inside front so my next steps are wider, stickier tires and a LSD.

Edit: The 1st and 2nd gear torque limits are boost limits - you can't "remove" the torque limit without breaking 14F.

 

[Cligedy]

I'm pretty sure almost any and all tunes modify boost controls, so maybe you would be better suited with a TurboTransformer or something.

Looks like a TurboTransformer only adjusts boost pressure. No bueno.

 

[Cligedy]

Stratified offers an option for a boost-limit in 2nd, but I'm not sure that it's to the stock pressure. If you do a custom tune you can ask for whatever you want, but most gains are being found by increasing boost. Having said that, you could get a rev-limit update to give a little extra speed in 2nd, launch control and FFS, and a bump in timing and improved F/A ratio, all of which will help a bit. I've got a slot optimized for the street/HDPE and a slot optimized for the stock boost limit. I've made the mistake of doing a pass in the HDPE slot and just fought wheel spin more (no LSD, yet).

(a little OT) I think that the formula for the FiST in STX is to remove weight, add wheel width, add tire width and compound (I'm really looking forward to the 234/40x17 Direzza ZIII!), suspension goodies (esp. add roll stiffness in the rear), LSD, and (maybe) a lightened flywheel. We're usually rolling onto the throttle right in the middle of the torque band and the turbo doesn't need much throttle to spin right up. I think that we can tinker with the BPV in STX so I may be using a stiffer BPV actuator but, like I said, I'm already over powering my inside front so my next steps are wider, stickier tires and a LSD.

Edit: The 1st and 2nd gear torque limits are boost limits - you can't "remove" the torque limit without breaking 14F.

The 2nd gear limit is what I mentioned in my 1st post. It's already a part of the system, and most tunes get rid of it.

I think you're on the right track with what makes a good STX car. My build thread is about to get some big updates soon. I've got a bunch of parts waiting already.

Just saw your edit. Is the 2nd gear thing a boost limit, or is it a torque/ engine load command? If it's the latter then that is controlled by throttle independent of pedal position, which should be legal to change.

 

[jeffreylyon]

The 2nd gear limit is what I mentioned in my 1st post. It's already a part of the system, and most tunes get rid of it.

I think you're on the right track with what makes a good STX car. My build thread is about to get some big updates soon. I've got a bunch of parts waiting already.

Just saw your edit. Is the 2nd gear thing a boost limit, or is it a torque/ engine load command? If it's the latter then that is controlled by throttle independent of pedal position, which should be legal to change.

I'm almost positive that the 1st/2nd gear torque limit is a boost limit.

I'm looking forward to hearing your review of the MFactory LSD.

 

[awwwww_shift]

Stratified offers an option for a boost-limit in 2nd, but I'm not sure that it's to the stock pressure. If you do a custom tune you can ask for whatever you want, but most gains are being found by increasing boost. Having said that, you could get a rev-limit update to give a little extra speed in 2nd, launch control and FFS, and a bump in timing and improved F/A ratio, all of which will help a bit. I've got a slot optimized for the street/HDPE and a slot optimized for the stock boost limit. I've made the mistake of doing a pass in the HDPE slot and just fought wheel spin more (no LSD, yet).

(a little OT) I think that the formula for the FiST in STX is to remove weight, add wheel width, add tire width and compound (I'm really looking forward to the 234/40x17 Direzza ZIII!), suspension goodies (esp. add roll stiffness in the rear), LSD, and (maybe) a lightened flywheel. We're usually rolling onto the throttle right in the middle of the torque band and the turbo doesn't need much throttle to spin right up. I think that we can tinker with the BPV in STX so I may be using a stiffer BPV actuator but, like I said, I'm already over powering my inside front so my next steps are wider, stickier tires and a LSD.

No lightened flywheel in ST, and no touching anything in the path of boost either for that matter. so no hard pipes, bpv, and the like. that may change over the next few seasons, but for now in scca, thats what we have to work around...

 

[dL_ST]

can't you just run a taller tire to achieve the goal of getting a couple more MPH in 2nd?

 

[Cligedy]

can't you just run a taller tire to achieve the goal of getting a couple more MPH in 2nd?

I did that in HS, but there aren't many tire choices that work and as soon as the car gets any lower, rubbing becomes a big problem.

 

[jeffreylyon]

I did that in HS, but there aren't many tire choices that work and as soon as the car gets any lower, rubbing becomes a big problem.

Yep - 215/45x17 is about as tall as you can go.

 

[jeffreylyon]

No lightened flywheel in ST, and no touching anything in the path of boost either for that matter. so no hard pipes, bpv, and the like. that may change over the next few seasons, but for now in scca, thats what we have to work around...

Yep - wishful forgetfulness! After re-reading the rules I've realized that the DHM crash bar that I ordered last night is illegal in ST, too. Sorry, Russ!

Looks like we can do the BPV in SP but a BOV will put us into SM.

 

[Cligedy]

Looks like next season OTS tunes will be legal, which makes my search for a legal tune especially frustrating. That may mean a big shakeup in STX too, because there are good tunes for the Gti, FoST, and WRX. Hopefully stock clutches and intercoolers will keep things from getting too bent out of shape.

 

[jeffreylyon]

Looks like next season OTS tunes will be legal

OTS but not custom? That's a little arbitrary, even for the SCCA.

 

[M-Sport fan]

I'm really looking forward to the 235/40x17 Direzza ZIII!)

WHERE did you hear about these, when are they supposed to be released, and are you putting them on your 8s, or getting something wider yet for them?

 

[jeffreylyon]

WHERE did you hear about these, when are they supposed to be released, and are you putting them on your 8s, or getting something wider yet for them?

Google it - they already exists in the JDM and there are a couple of mentions about them coming to the US soon. I'm doubtful that I can fit 9" wheels on the front without pulling the fenders and running less than optimal camber. 235 on a 8" will work. Dunlop even specs. a 8" minimum wheel for their 245/40x17 and I think that I can just fit that in, especially since the ZIII are supposed to have a more rounded corner like the RE-71Rs. I'll give up turn-in but that's a ton of sticky rubber for a little car.

 

[awwwww_shift]

WHERE did you hear about these, when are they supposed to be released, and are you putting them on your 8s, or getting something wider yet for them?

z3's have been rumored for a few months. looks like they will be released this spring/summer in Japan, which means(since we're typically a year or more behind their releases) we should see them 2018 spring or later.... also, don't get your hopes up, as they have never been a leading tire in any street tire class. they're good at a lot of things, but they tend to get greezy when overworked. I'll stick with my re-71's or rs-4's...

 

[jeffreylyon]

I'll stick with my re-71's or rs-4's...

Are you running the 215/45x17? I wish that the RE-71R's were available in shorter sizes...