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Old 11-27-2007, 07:29 PM   #1
Blue5spdWRXWgn
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Default STX Power

I probably should start with an explanation of what I already have (engine wise):
  1. Cobb downpipe with hi-flo cat
  2. Borla Hush catback
  3. Cusco heatshield
  4. Cobb AP v1 w/93 oct. Stage II base map
  5. K&N panel filter
Car runs nice, but would like to get all I can within the STX rules. I plan to get two pro tunes:
  1. a street tune with increased boost and CELs disabled
  2. an STX tune with stock boost and CELs enabled
In preparation for the tuning session, I'm also considering:
  1. Grimmspeed ported exhaust manifold and hi-flow crosspipe
  2. Perrin dual cat downpipe
  3. Cat-less up-pipe
That should give me clean emissions and good power/spool. It looks like IC hose mods are not allowed in STX and they don't make much difference anyway. Intake mods are allowed, but they don't make much difference either as I understand. I welcome your thoughts.
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Old 11-27-2007, 09:24 PM   #2
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get a catless uppipe asap. technically, the stock heatshield has to stay (but only if your a stickler). The rest looks good.

Suspension probably should be looked at first for stx.
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Old 11-27-2007, 09:45 PM   #3
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With a good tune (or none at all IMO) you'll gain a LOT from some of the mods that common NABISCO "wisdom" says don't make a difference or is a bad idea. Intake makes power across the power band if your tuner has a clue. Turbo inlet pipe makes a noticeable difference. Do your research, there are about a million threads with total crap in them on NASIOC and about three threads with worthwhile actual truth information. Take a look at the setup of the top fully built cars and while you'll find differences between us you'll not find any of us using a stock intake.

As mentioned your heat shield is not STX legal. If you still drive the car on the street I'd skip the cross-pipe since mild steel doesn't look pretty after one winter in the salt and will likely be see-through after a single winter if you do a lot of driving on MI salted roads. I'd do the PnP myself since you can do a much better job yourself if you've got time and patience. The uppipe is a given and I'm not positive that the Perrin setup will actually stay O2 CEL free on every car.

Or you could just buy one of the three National event winning STX WRXs that are currently for sale for WAY less than they cost to build (including ours) and not have to do all the testing and research yourself.
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Old 11-28-2007, 02:17 AM   #4
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Quote:
Originally Posted by xcdhridr View Post
Suspension probably should be looked at first for stx.
+1...
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Old 11-28-2007, 09:53 AM   #5
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I'm pretty sure the catless uppipe will have to have a bung for the egt sensor (it's part of the OBDII emissions system)- not all catless uppipes have this provision (my STi uppipe does not )

I'd also consider doing the P&P yourself on the maniflods/cross over- I had mine coated- probably not overly necessay, but it looks pretty

Here's a thread I started on exhaust setups that will (or in some cases won't) work for the new "clarification"

http://forums.nasioc.com/forums/show....php?t=1364415

Tandem high flow cats w/ the O2 sensor rearward should work- Chris (FTD) used a setup like that (not Perrin) worked well- he also ended actually making more power w/ this setup vs a single catted 2.5" setup- not sure if it was an improved tune or going to 3" or a combination of the two.

Phil- interesting on the intake, I've also always "heard" not much, if any, difference in power. What intake were you running?

Mike
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Old 11-28-2007, 11:00 AM   #6
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Quote:
Originally Posted by PhilC View Post
With a good tune (or none at all IMO) you'll gain a LOT from some of the mods that common NABISCO "wisdom" says don't make a difference or is a bad idea. Intake makes power across the power band if your tuner has a clue. Turbo inlet pipe makes a noticeable difference. Do your research, there are about a million threads with total crap in them on NASIOC and about three threads with worthwhile actual truth information. Take a look at the setup of the top fully built cars and while you'll find differences between us you'll not find any of us using a stock intake.

As mentioned your heat shield is not STX legal. If you still drive the car on the street I'd skip the cross-pipe since mild steel doesn't look pretty after one winter in the salt and will likely be see-through after a single winter if you do a lot of driving on MI salted roads. I'd do the PnP myself since you can do a much better job yourself if you've got time and patience. The uppipe is a given and I'm not positive that the Perrin setup will actually stay O2 CEL free on every car.

Or you could just buy one of the three National event winning STX WRXs that are currently for sale for WAY less than they cost to build (including ours) and not have to do all the testing and research yourself.
Phil, you forgot to mention that the proposed tuning setup is "technically" illegal as well since the base map will not be a stock boost map.

To the OP...where are you in MI? I apparently have one of the few National event winning WRX's that isn't for sale. If you're near me you are welcome to take it for a drive sometime. You really don't need two engine maps. I make more power on an STX tune than I did on an old stage 2 tune. Its more than enough fun for a daily driver.
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Old 11-28-2007, 11:55 AM   #7
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I would second that money is better spent on suspension. The best you can afford, weight reduction, then power.


With that said, I am going to see if I can get some people interested in getting Doug from Topspeed to come back to Toledo for tuning next spring. If you think you're interested PM me. Many people are happy with his results, and I think he's one of the few who gets STX.

There are very few tuners in the Mid-west I would go to, most I wouldn't let tune my lawnmower.

If you're truly interested in STX, a SM map will gain you basically nothing, the little snail's huffing all it can huff.

It's true that it's technically illegal to run a boost base map and switch to a STX real time.

If it were me:

Get someone else's exhaust manifolds cross over pipe and port them, with the money you saved have them coated at a place like this www.swaintech.com . Most of the time these can be had for free from someone who has went to headers, which I consider not the right choice for STX. Unless some one actually did the research and made smaller diameter headers.

You will lose around 18lbs by porting and removing heatshields.

I ran a gutted factory upipe for a long time and really think there's no performance advantage to an aftermarket one, in STX. Again cheap.

You would be better off starting with a dual cat system, but my Cobb DP has been in ready state for awhile now.

Mufflers? I don't like them, my turbo's my muffler.

I would echo that prior to tune look at intake and turbo inlet. I think Phil/Jason both have Blitz intakes. I have an APS long intake, moto gp inlet.

Greg
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Old 11-28-2007, 02:44 PM   #8
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^ maybe I'll just gut my stock uppipe- would be nice to save a little $ somewhere w/ this "clarification"

does Doug do Ecutek as well as AP?
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Old 11-28-2007, 02:50 PM   #9
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Originally Posted by BIGSKYWRX View Post
^ maybe I'll just gut my stock uppipe- would be nice to save a little $ somewhere w/ this "clarification"

does Doug do Ecutek as well as AP?
I would assume, it's listed on the home page.

http://www.topspeedsales.com/(ypfifi...)/default.aspx

As a side note I've done nothing yet to add to your other exhaust thread.
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Old 11-28-2007, 03:35 PM   #10
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^ looks like a yes

what are you waiting for
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Old 11-28-2007, 04:16 PM   #11
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Our tune was done by Doug and is an ECUTek tune. Our intake is a Blitz and we use the GP Moto inlet tube. Jason uses a Blitz but with a custom aluminum center piece and I'm not sure which inlet tube. Tom\Biggly used a K&N Typhoon on the car that Biggly now owns, it replaced the APC piece after some dyno testing was done if I remember right.
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Old 11-28-2007, 05:03 PM   #12
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Quote:
Originally Posted by PhilC View Post
Take a look at the setup of the top fully built cars and while you'll find differences between us you'll not find any of us using a stock intake.

Jeff Barco's 2006 Nationals winning (and 2nd place) car used the stock intake and inlet. This caused me a lot of indecision when I was trying to finish my mods. I went halfway and got a cheap Samco inlet before my tune.
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Old 11-28-2007, 09:05 PM   #13
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Quote:
Originally Posted by PossumK View Post
Jeff Barco's 2006 Nationals winning (and 2nd place) car
Thats cause I wasn't there

-Tom
who recommends a K&N Typhoon, good for 2hp across the board
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Old 11-29-2007, 07:08 AM   #14
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Thanks for the replies guys. Some great points there.

I wasn't aware of the heatshield rule. If an aftermarket heatshield is not allowed, then what is? Are people cutting up a stock heatshield to fit over an aftermarket downpipe and does this then meet the rules? Can you buy one from the dealer separate from the pipe? I like to keep all the original parts to my car.

The egt sensor in the up-pipe is obviously not needed functionally if the cat is removed, so what are people doing to meet the rules? Run the sensor anyway? Does it need to actually enter the flowstream or is it okay to add a closed stand-off fitting?

As for the intake and inlet pipe, the cost seems pretty high for ~2 hp. What about increased inlet temperature of using a shorty inlet? Some are available with an airbox that draws from the wheelhouse. Is that preferred? How about just a better flowing panel filter and a resonator bypass, would that not be just as good?

As for the downpipe, I'm not sure if I should try it out with my current catted Cobb. Is there a test I could run to see if I will get CELs? It's alot easier and less expensive to keep it rather than changing over to a Perrin or Random Tech. dual cat setup.
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Old 11-29-2007, 09:34 AM   #15
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Tom means 2HP over the other intakes he tried not 2HP over stock.

You'd have to keep the EGT sensor in the exhaust stream. If you daily drive the car use the resistor and a plug for daily driving and then just put the sensor in for events to make it last longer.

As for the downpipe you'll never really know until you try it. Each car behaves a bit differently so what works for one person without a CEL may not necessarily work for someone else.
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Old 11-29-2007, 09:35 AM   #16
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you can modify the oe, yes it's available at the dealer

egt has to be installed (during the event anyways) neds to be in the stream from my understanding- some are just putting it in for the event, then removing

that's my current intake setup- slincer elbow w/ a STi (non-oiled) panel- guess I'll have to do some homework on intakes

if you currently don't have a tune and are not getting the cet inefficiency cel- sounds like it might be working, if you have a tune you'll need to get a new map that doesn't disable the cels for the cats. If you look at my thread linked above I believe someone commented on the Cobb that they were getting the cel (better double check though)
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Old 11-29-2007, 09:44 AM   #17
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Phil beat me to the punch

I didn't realize Tom was talking 2hp over other intakes though- ballpark idea on hp/tq over a stock setup?
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Old 11-29-2007, 10:50 AM   #18
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Quote:
Originally Posted by Blue5spdWRXWgn View Post
Thanks for the replies guys. Some great points there.

I wasn't aware of the heatshield rule. If an aftermarket heatshield is not allowed, then what is? Are people cutting up a stock heatshield to fit over an aftermarket downpipe and does this then meet the rules? Can you buy one from the dealer separate from the pipe? I like to keep all the original parts to my car.

If you still have the stock heat shield, simply use a dremel or some tin snips to cut part of it off and make it fit back over the aftermarket DP.

The egt sensor in the up-pipe is obviously not needed functionally if the cat is removed, so what are people doing to meet the rules? Run the sensor anyway? Does it need to actually enter the flowstream or is it okay to add a closed stand-off fitting?

Seem like everyone is slowly switching back to running an EGT and simply carrying extra ones around for when they go bad. Not sure on modifying this sensor location. To be safe I'd avoid it.

As for the intake and inlet pipe, the cost seems pretty high for ~2 hp. What about increased inlet temperature of using a shorty inlet? Some are available with an airbox that draws from the wheelhouse. Is that preferred? How about just a better flowing panel filter and a resonator bypass, would that not be just as good?

In a class that is limited to stock boost, 2hp is more than you think. Yes the price is high. If you're on a tight budget the money is better spent on suspension. Minimum would be a higher flowing filter.

As for the downpipe, I'm not sure if I should try it out with my current catted Cobb. Is there a test I could run to see if I will get CELs? It's alot easier and less expensive to keep it rather than changing over to a Perrin or Random Tech. dual cat setup.

Easiest thing to do is have a base map flashed with no CEL defeats and then drive around for a couple days. You have an AP V1...setup an appointment with Speed Industry. At the least, you could have them take your current base map and simply enable the CEL's again.
See above in red
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Old 07-07-2008, 03:58 PM   #19
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AHHH are you serious - EGT sensor must be installed in uppipe??!?!?

of course my uppipe has no EGT bung, I'm only running local events but still, what is the point of this, it seems like such meaningless beuracratic nonsense (seriously though, can someone tell me what this being illegal accomplishes?)....

I also never knew that a stg2 basemap/stx real-time was not allowed; again, what is this violating? I admit that I don't know enough to know if this makes a difference...

someone please tell me this is an old thread and these rules no longer apply, or at least that they don't give me any real advantage; at the events I run I'll probably never be protested (until someone finds this post) but I'd still like to know (if) I'm legit.

Last edited by thereplacement; 07-07-2008 at 04:13 PM.
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Old 07-07-2008, 04:12 PM   #20
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AHHH are you serious - EGT sensor must be installed in uppipe??!?!? Yep.

of course my uppipe has no EGT bung, I'm only running local events but still, what is the point of this, it seems like such meaningless beuracratic nonsense (seriously though, can someone tell me what this being illegal accomplishes?).... Couldn't agree more, but some people feel those rules meet the desires of the majority of members to keep the class federally street legal.

I also never knew that a stg2 basemap/stx real-time was not allowed; again, what is this violating? I admit that I don't know enough to know if this makes a difference...If your car was checked for a legal map, you could just pull the battery to reset to an illegal map. An STX base map prevents this.

someone please tell me this is an old thread and these rules no longer apply, or at least that they don't give me any real advantage; at the events I run I'll probably never be protested (until someone finds this post) but I'd still like to know (if) I'm legit. These "clarifications" were just added to the rule book last year......Cheat if you must(in the sense that not following the rules is cheating).
I'm in a "street-tire" ESP class myself because of this crap. Maybe in another year I'll spend $1K+ on my exhaust and tuning to have a legal car for STX.
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Old 07-07-2008, 04:40 PM   #21
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We have a pretty long thread about this FWIW

Sticky: AUTOX Super Thread 2008
http://forums.nasioc.com/forums/show....php?t=1202277

-->

STX Setup / Discussion thread
http://forums.nasioc.com/forums/show....php?t=1431201

-->

"Power mods" section

There is also a lot about the new exhaust rules in there, including the link Bigsky posted earlier.

Sadly - the new rules are not going away any time soon, despite the inconsistencies, enforceability problems, etc etc. Yes it sucks. Locally I doubt anyone would care though. I know I wouldn't. But you should still tell your local STXers to see if they care.
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Old 07-07-2008, 08:32 PM   #22
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I'm in a "street-tire" ESP class myself because of this crap. Maybe in another year I'll spend $1K+ on my exhaust and tuning to have a legal car for STX.
I take it the consensus is you need at least a dual catted dp, i.e. my helix high-flow catted dp wouldn't cut it.

Since I'm not fully prepped for STX w/ suspension or tires I'm now thinking about selling off and going back to stock... I def don't want to put more $$$ into it

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Old 07-07-2008, 08:36 PM   #23
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Check out Bigsky's link. There are a few folks on single cat setups that aren't throwing CELs. I went the dual route so I wouldn't need to worry about it. The real test will come when I get ProTuned and find out how many hp that extra cat costs me.
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Old 01-07-2014, 05:02 PM   #24
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Anyone interested in my ap with stx protunes??
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