Hi, everybody.
I'm posting my questions in the "Motor Sports" forum to avoid dumb ricer answers like, "Of course you want more boost".

I figure anyone reading here probably knows racing has rules. I'm rusty, but I know enough about SCCA Street Touring rules to know you're supposed to keep the stock boost map. Other than that, you can mess with everything else, right?

From reading here and there in the forum, and talking to other autocrossers, it looks like the Evo X would have faster throttle response if it didn't run pig-rich and didn't have an emission-control throttle lag. Fixing these things with software will put me in STU, where I might as well get the downpipe and rear swaybar I've been thinking about.

My current experience with software on cars is watching dealer technicians plug in their diagnostic tools to read and reset codes. Having never done that myself, I'm pretty paranoid about accidentally turning my ECU into a brick, or ending up with a tune that's illegal or doesn't run right on the local pump gas.

Seems to me like the AccessPort programmer is a very common item for STU autocrossers. Is it that much better than getting the Works Brain Flash? It looked like the Works product was a pretty simple way to get an STU-legal tune.

If I get the AccessPort, does the device come with a bunch of tunes programmed in? Does that include a legal STU tune? Or do I have to download the software from the internet, and use the device to install it on my car?

Having installed the tune I want, will the car still be able to adapt to changes in altitude and octane? How long does the ECU take to adapt? A day? A week? Hours? I'll be doing some work while visiting a friend in New Mexico, 4300 to 9500 feet above sea level, with 91 octane fuel. By the end of October, I'll return to Florida, at sea level with 93 octane available. Once I get back to FL, I don't want to be running on 91-octane power any more. I'd be the only sucker with that little power.

 

I'm a little closer to making a decision now:
Yesterday a friend told me about the differences between the AccessPort and "open source tuning".

The Tactrix Openport tool looks like a good idea, assuming I can download an STU-legal reflash from the internet.

Is that what most STU drivers are doing?

 

Most people go to a tuner and get tuned on a dyno or tune themselves (you need to know what you're doing)

 

Safest is to take your car to a tuner in your area. I like to see the numbers on the fly and how its responding changes. This helps eliminate some of variables that can't be controlled with a mail in tune. Find a tuner in the area people give good reviews and form a relationship as you will most certainly be back a few times when you start changing other stuff about your car!

 

^ As far as I can tell, the nearest 4-wheel dyno is about 6 hours away. It's a tossup between Atlanta and Jacksonville.

So, you're saying the car shouldn't be tuned without a dyno?
That makes sense, but then if something needs adjustment, it's a 6-hour drive back to the tuner. :-(

 

What do you think will need adjusting?

See if maybe they'll do a ridealong road tune after the dyno tune? Just so that they see the car in its natural habitat and catch any real world drivability issues. Maybe get a hotel and put a couple hundred miles on the car and come back the next day to have them make sure everything looks good? You can get a Tactrix cable and log a lot of stuff by yourself, maybe a wideband too depending on your level of paranoia.

 

I got my ECU tuned on my Evo last night, by an open source tuner who will remain nameless for now. It's in the state where my family lives, and I'm here for the holidays, so I can go back to these guys any time for the next week.

It's a Street Touring tune, and the tuner complained a lot about not being able to mess with the boost. He kept asking questions like he doubted that I knew the rules. I took the rule to mean you can adjust anything in the computer but the boost map. The electronic boost limit couldn't change for a given RPM, throttle setting, etc.

I found the rules at this address: http://cms.scca.com/documents/2011%2...lo%20Rules.pdf

Now that I'm reading the rule again, it's rule 14.10 F.1 (page 89), and it says this:
"1. Reprogrammed ECU (via hardware and/or software) may be used in the standard housing. Traction control parameters may not be altered. Altered engine controllers may not alter boost levels in forced induction engines. Alternate software maps which violate these restrictions may not be present during competition, regardless of activation."

In a stock Evo X, maximum boost is about 22psi, right? I can see where ANY tuner ANYWHERE could take this rule to mean they can't raise the maximum boost level, but the engine can have a 22psi party for the whole RPM range.

I'm thinking this rule hasn't changed for several years, so the SCCA must have had to clarify it. Which interpretation is correct?

I have to keep the stock boost map?
Or just that I'm limited to 22psi?

 

I've heard of people being really up tight about this rule at the Nationals. Having gotten a tune, how do people typically prove that their tune is legal? Does anyone ever whip out their boost map at the local level?

I only plan on racing at the local level, and my fastest competitor (a Subaru owner) is suspect.

 

See 14.10.F:
"no changes to standard boost levels, intercoolers, or boost controls are permitted. Boost changes indirectly resulting from allowed modifications are permissible, but directly altering or modifying the boost or turbo controls, either mechanically or electronically, is strictly prohibited."

You can't change the boost tables at all. It's not just limited to peak boost.

I haven't heard of anyone protesting an ecu tune. I'm not sure how they would enforce it, other than pulling the ROM with a tactrix cable and comparing it to a stock ROM. I don't think many regions have the means to even do that. It's all based on the honor system.

 

I see it now...and that's what I thought. Thanks!

 

Here's why the shop is remaining nameless for now:

It's great that they made the Air/Fuel Ratio leaner for most of the RPM range. Turbo starts to spool about 300rpm earlier, and peak torque occurs 1000rpm earlier. The car feels more responsive now, but if I'm reading the dyno graphs right, I gained 6 hp and lost 2 lb-ft of torque. Now, between the first and last dyno runs, the guy said the dyno wasn't loading the engine right. The dyno was programmed to load the engine as if the car weighed 3625lbs. With a half tank of gas and my 190lbs in the car, the car will weigh more like 3700lbs. Partway through the tuning session the guy input a vehicle weight of 3700lbs, and he said the dyno was doing better with the loading. That might skew the comparison between the first and last runs, but...

I still expected more of a power gain. I could swear I saw an article in Grassroots Motorsports or SportsCar where they tuned the ECU on a Spec Miata and gained 6 or 7hp. I'm starting to think a 6hp gain on an STU Evo is some weak sauce. If you're allowed to tune the Air/Fuel Ratio, ignition timing, and MIVEC, shouldn't you get more of a power gain? And not lose 2 lb-ft?

Am I being too picky, or should I go back and get them to try again?

 

Are there any other shops in your area you trust?

Are there shops that are a decent drive away that you trust?

6 hp sounds low, IMHO.

 

Earlier spool is good.

Don't worry so much about peak numbers. What you're really concerned about is area under the curve. Do you have a before and after dynograph with both charts on the same scale? Still, you shouldn't have lost torque. And those gains seem low to me too.

That's a 2% difference. Might as well be lost in the noise. I really doubt this changed anything, despite what the dyne operator told you.

You're definitely right to be suspicious here. After the poor results, the way they doubted your rules interpretation, the dyno loading 2% change hand-waving, and the poor results I would never return to this shop again.

Tuning isn't easy, but a lot of people are convinced they're experts. See if you can't find a reputable tuner in your area with some recommendations on the forum.

 

Is 6 hp so bad that I should start from scratch elsewhere, rather than revisit the original tuner?

I live near Eglin Air Force Base, and there aren't any 4-wheel dynos in the area. I keep hearing that there used to be one in Mobile, AL, but the shop is closed now. So, the closest AWD dynos are Atlanta and Jacksonville, all about 6hrs from me. I don't know anything about any of those shops.

I figured I'd be better off going to this shop in NC, where it's 2hrs away from my friends and family. I'll be here another week on this trip.

Also, after the tune the owner of the shop e-mailed me asking for feedback, so I think I can say, "Maybe you can do better. When can we schedule a follow-up?"

If I go to another shop, I'm starting from scratch, and paying full price all over again, right? I don't know any tuners, so wherever I go I'm taking a chance.

Edit: I think I was reading it wrong, and I had a gain of 2 lb-ft, not a loss.

 

Unfortunately, I don't have access to a scanner just now. But, it looks to me like I gained area under the curves, especially below 4000rpm. I got them to tune down at 2000rpm, which I think most people don't bother with. I drive at 2000rpm, so we darn well tune there.

The printout is only comparing the 1st and last runs, and since the first run started at 2500rpm, I think that throws off the comparisons of min, max, and avg. At 2500rpm, the boost, torque, and hp are all way higher in the last run.

Perhaps someone could tell me what power to expect from an Evolution X tuned for the STU class. The Mustang dyno printout says I now have 285hp at the wheels. I was hoping for something like 300.