CorkSport To Market 3" Stainless Steel Exhaust System!

[rexercx7]

Hi all...

There have been several of us writing to CorkSport, an aftermarket Mazda specialty parts supplier, and developer, up in Vancouver, WA., and I have some exciting news to report from the Sales/Tech Team there regarding a new exhaust system/downpipe for the CX-7. Rather than have this buried in another thread, I thought it was important enough to give it its own thread. To wit, I received this email from CorkSport Tech today:

Hello rexercx7 (my real name omitted),

Thank you for your comments and enthusiasm. Indeed, we have already
completed development of an T304 stainless steel 3" exhaust system
and downpipe. We expect to complete final pre-production fitment and
testing within the next few weeks and should have systems for sale in
mid-to-late summer.

Our downpipe and exhaust were designed to give a nice sound that most
family minded owners will not mind. We'll post clips and more
information in a few weeks.

We will also likely have a FMIC kit near the end of the year as well.
We are currently taking a close look at other products for this model as well.

Regards,
Rich

So there you go! There is hope for the CX-7 in the exhaust department, finally.:D This is the best news I've heard in a long, long time, as I'm already having the new ETS 3" TMIC and the CPE XCel CAI installed asap (on order at this point...ETA 10 days to 2 weeks), and it's pretty obvious that those mods are going to add some serious breathing ability/power to the CX-7 2.3L DISI Turbo motor...now it appears there will soon be an efficient, horsepower-adding way to get the exhaust out of the system too!:)

Anyway, thought I'd share the email with all of you. It made my day.

Kindest regards,
rexercx7:cool:

[shadow1]

Sign me up!

[KatDiesel]

Hopefully they will offer a group buy on the first run? Wish they would have given a general idea on price.

[rexercx7]

More news on the Corksport exhaust system from my source there, Richard Harris, who seems to be one of the principals in operations & development ...he writes:

"We are shooting for a retail price of about $600. I think the upper
limit is $700 on the exhaust. We can definitely work with you to
arrange a group buy. A few more details:

Full 80mm (3") piping with dual stainless packed straight through
mufflers. Our mufflers give a deep tone than is quite enjoyable on
turbocharged cars. With the factory downpipe and catalytic the Cx7
without exhaust system is not actually very loud compared to most
cars we deal with.

You can check out our downpipe for the MS6. The Cx7 pipe is similarly
designed. The downpipe tested very well on the MS6. The price will be
similar to the MS6.

As is the case with all our products now, the parts will include
complete installation instructions for the Do-It-Yourself owners."

That's some pretty good news to my finances!:) I'll be posting more news regarding this exhaust system/downpipe situation as it develops. The fact that Corksport is so much into Mazda performance development parts tells me this is going to be an efficient, good sounding, horsepower-increasing exhaust system that's strong, easy to install, and will enhance any CX-7's overall performance.

Kindest regards,
rexercx7:cool:

[BlackCX7]

Sign Me Up. $600 sounds great!:)

[rexercx7]

Sign Me Up. $600 sounds great!:)

So that makes 3 of us already, in the 1st days of this campaign, who will be buying into the Corksport.com exhaust system/downpipe: myself, Black CX7, and shadow1. RaiderMS3 has also voiced a strong interest, though not a commitment yet, so there would be a 4th. I'd like to see at least 10 firm orders before I'd even begin talking to Rich about a "group buy", and any type of substantial discount on the systems, so there's plenty of time and there's potentially a lot of members who could/would benefit from having a nice sounding, efficient catback exhaust system, if not the whole shebang: the exhaust system AND the downpipe setup, which is what I'll be getting.

An excellent downpipe and exhaust system for a CX-7 like mine that will have a modified intake system/TMIC/BOV should be good for another 20HP at full tilt boogie, my wildest guess at this moment in time.

I can hardly wait for all of the above to happen, because I feel like I'm sitting on a cherry bomb without a lighter right now. :D

This is a fantastic OEM engine package that the CX-7 has, and it's up to us, as owners, to improve upon the beautiful things that are already there in place for us to let go, to let them unwind and give up some of their potential. I expect my CX-7 will be pushing right at 300WHP/300+ft. lbs of torque, with the mods I have planned, and I don't think that's being unrealistic at all.

Kindest regards,
rexercx7:cool:

[KatDiesel]

I'm 99.9% sure I'll be buying one.

[shadow1]

My only reservations: emissions compliance. Corksports MS3 and 6 DP's both eliminate the 1st cat. The OBDII rear O2 sensor is after that 1st cat. So there will be a check engine light. In Maryland, I would fail emissions with a CEL. My other concern is that the CX7's 2nd cat is welded onto the midpipe. So there is no real bolt on "catback." It would be a bolt on "downpipe-back" exhaust. I would hope that Corksport offers a high flow cat option. I cannot stand the exhaust smell w/o a cat. Also it is not environmentally friendly. Personally I would prefer to have a high flow cat in the downpipe to maintain OBDII compliance and lose the 2nd cat to inprove performance.

[rexercx7]

My only reservations: emissions compliance. Corksports MS3 and 6 DP's both eliminate the 1st cat. The OBDII rear O2 sensor is after that 1st cat. So there will be a check engine light. In Maryland, I would fail emissions with a CEL. My other concern is that the CX7's 2nd cat is welded onto the midpipe. So there is no real bolt on "catback." It would be a bolt on "downpipe-back" exhaust. I would hope that Corksport offers a high flow cat option. I cannot stand the exhaust smell w/o a cat. Also it is not environmentally friendly. Personally I would prefer to have a high flow cat in the downpipe to maintain OBDII compliance and lose the 2nd cat to inprove performance.

Why don't you email Rich Harris@ Corksport.com, and ask him about those two concerns of yours (and mine of course), because after all they're in Washington State, admittedly a pretty lax state on environmental issues and vehicle compliance with emission standards. Hence, their "outlook" may be different than ours here in California, and other states with tough compliance, and testing rules and laws.

Richard Harris' email is: rich@corksport.com

You have some good questions to ask him, and could help us all out by getting some answers to those tough questions. I've already established the "good guy" relationship with Corksport.com, so maybe it would be best if you asked the questions you posted today.

Kindest regards,
rexercx7:cool:

[KatDiesel]

More questions that should be asked.....any problems with boost creep? Is the ECU able to change enough to make use of the exhaust and or intake/TMIC? Has anyone with a wideband actually checked Air/Fuel ratio after throwing on intake/TMIC?

[shadow1]

When you start changing cats or changing downpipes, you definitely need a boost gauge to see where the boost goes. On Evo's, installing a larger DP results in boost spikes. You need a boost controller to prevent this. I own an Innovate LM-1 wideband but I have no O2 sensor bung to install it into to check the CX7. On my Evo I had a bung welded into my Espelir downpipe for this purpose. Makes tuning a breeze. Install the O2 sensor, plug in the LM-1 and my laptop. Drive to redline and log the data. Make adjustments on the SAFC. Not only makes power but gives me peace of mind that my car is running safe. Run too lean=detonation=need a new motor.
Tuning on the CX7 will be intersting though. It has a high compression 9.5:1, high peak boost 15.6 psi, and direct gas injection. Not sure what would be a safe AFR. In the Evo and Subie worlds, AFR's are kept in the low 11's or less. With direct gas injection, I suspect you can go leaner and make more power.

[shadow1]

I emailed Corksport about their downpipe and possible CEL's:

The downpipe will come with an adapter to eliminate the CEL. We have not decided if we will make a mid-pipe to replace the catalytic. The Cx7 may be too loud for most people without that cat. I'll put it down for consideration though.

Thanks for your interest,
Rich

[shadow1]

Got another email. Corksport is considering a high flow cat option in the downpipe. However it will raise the price from 450 catless to 600-700 with a cat. They will offer a mechanical CEL fix for the catless downpipe (I use a mechanical CEL fix on my Evo). Sounds like they are not doing a full downpipe-back exhaust for noise reasons. I tend to agree. Removing the OEM midpipe with the 2nd cat and the inline premuffler will make for a loud exhaust on a family vehicle. So it will be a downpipe and an axleback system.

[rexercx7]

Got another email. Corksport is considering a high flow cat option in the downpipe. However it will raise the price from 450 catless to 600-700 with a cat. They will offer a mechanical CEL fix for the catless downpipe (I use a mechanical CEL fix on my Evo). Sounds like they are not doing a full downpipe-back exhaust for noise reasons. I tend to agree. Removing the OEM midpipe with the 2nd cat and the inline premuffler will make for a loud exhaust on a family vehicle. So it will be a downpipe and an axleback system.

Oh boy, you got the data I wanted, now to just see if I can translate it!:)

1) Install the Corksport downpipe with high flow cat = $600-$700, which eliminates any CEL problem, no computer AF tuning necessary as the OEM O2 sensor will be in place which works with the OEM ECU to maintain proper AF ratio...then combine that with...

2) Install the Corksport 80mm T304 SS exhaust system ("axleback system"), replacing the stock system from the 2nd cat to the tailpipes, this yields a higher flow exhaust system with a great sound, not too loud for our "family vehicles"=$600-$700 for a grand total of about $1400 for Corksport's complete system...that's the downpipe/high flow cat + the "axelback" 80mmT304 SS exhaust system, each component system costing $600-$700

Those two items, combined, should yield a significant HP improvement over the OEM exhaust system and yet, for us Californians the system will *not be CARB approved*, hence illegal, technically, unless it will pass our bi-annual emissions certification testing (every 2 years out here is mandatory testing for every vehicle up to 20 models years old). And what about a "visual" inspection of the vehicle? Would those mods=a failure outright, that way?

So then, should I simply just bolt on the "axelback" portion of Corksport's system and be happy with improved after/cat exhaust flow and a better sound? Or should I say frusk it, and install both pieces and "see what happens" at emissions check time? I don't have access to a laptop-based system for checking AF ratio with a bolt-on O2 sensor like shadow1 apparently is using for his Evo toy, which he runs "on the edge". My mechanic, however, is very much into performance tuning, and could ostensibly do AF ratio checking, given the right tools to work with for the CX-7's system.

The more I know, the fuzzier some of this gets!:confused:

I'll have the new ETS TMIC, and the CPE XCel CAI systems installed, along with a replacement for the OEM BOV valve no matter what gets decided about the exhaust side of this equation, but I'd hate to have to tear it all apart and replace all components with the OEM systems just so the CX-7 can pass our 2-year emissions system check!:mad: That would be rather absurd, and I guess I'd be forced to leave mine stock if that were the case.

Kindest regards,
rexercx7:cool:

[shadow1]

An aftermarket downpipe is gonna fail Calif visual inspection. Although, the CX7 downpipe is hidden by the undertray. I don't know if the inspectors routinely remove undertrays for the smog check (I haven't lived in Calif since I was 23). The only way the cat affects AF tuning is by allowing more exhaust flow and possibly more boost over stock. The CEL is not due to AF issues. It is a CEL from the ECU thinking that the cat has failed and needs service. The ECU uses the 1st O2 sensor (precat) to help manage fuel. There is a 2nd downstream O2 sensor that is a cat check. In the CX7 this downstream sensor is on the DP and after the 1st cat. Also Corksport has not officially decided on a high flow cat option for the DP. If there is not enough interest, I suspect the DP will be catless like their MS 3 and MS 6 DP's.

[rexercx7]

An aftermarket downpipe is gonna fail Calif visual inspection. Although, the CX7 downpipe is hidden by the undertray. I don't know if the inspectors routinely remove undertrays for the smog check (I haven't lived in Calif since I was 23). The only way the cat affects AF tuning is by allowing more exhaust flow and possibly more boost over stock. The CEL is not due to AF issues. It is a CEL from the ECU thinking that the cat has failed and needs service. The ECU uses the 1st O2 sensor (precat) to help manage fuel. There is a 2nd downstream O2 sensor that is a cat check. In the CX7 this downstream sensor is on the DP and after the 1st cat. Also Corksport has not officially decided on a high flow cat option for the DP. If there is not enough interest, I suspect the DP will be catless like their MS 3 and MS 6 DP's.

There is no "visual inspection" at emission's check time in California. We don't have to go through a formal "visual inspection" of any type, as all that happens in our bi-annual (each 2 years) check is the vehicle is put on a machine with a sensor up the exhaust pipe, and if the vehicle "blows clean" and passes the test, you're done. If it blows dirty, then you "get it fixed" and come back for a 2nd test, get it checked again, and if it passes that 2nd test you're good to go. If you *fail* the 2nd test, you can ask for a variance or "exception", especially if your automobile is older than 10 model years old.
There's some language in the "rules" about car value vs. modification costs to bring a vehicle within compliance, and if the cost to repair/fix the emissions system is greater than the value of the vehicle, and there hasn't been any "tampering or modification" of the OEM emissions system (like a straight through exhaust system without a cat, and similar indiscretions like a highly modified motor with lots of aftermarket parts which renders an emission system useless), and if the vehicle's test readout is "close enough to a passing score on the test" (I believe a variance on older cars is up to 40% of CO2 emissions output, something close to that anyway) then you'll be granted a "variance" and the vehicle is passed. If it's impossible to make the vehicle pass or too expensive to fix vs. the vehicle's value, it's failed and you've got to take it off the road.

It's quite another story with new vehicles, as they're expected to blow clean as a whistle, to wit, every manufacturer's emission's system in CA (except for diesels, which are warrantied for 10 years/100,000 miles--if they're being sold, that is...right now there is no diesel car being sold in CA, only trucks...next year's Mercedes-Benz BLUETEC engine will pass CA's diesel particulate matter and CO2 tests, however, and will be sold here) must be warrantied by the manufacturer for 7 years/70,000 miles. So anything, any part that has to do with emissions, and that includes the entire fuel injection system, the ECU, injectors, lines and hoses, catalytic converters and mufflers (during the 3/50k miles factory warranty on the whole vehicle, even the muffler system past the cat is covered...after that it's a "normal wear and tear item"), the exhaust system, all the recirculation hoses, turbocharger and associated parts, valves, bypass hoses, and fittings...the whole dang fuel and ignition delivery system of any CA vehicle, it's all covered for 7/70 on any new vehicle sold in this state.

A CARB-legal exhaust system would be what I should be looking for with my CX-7, but as yet one doesn't exist, and the Corksport system will not be certified for sale here, according to Rich at Corksport. I don't think that adding an aftermarket exhaust system would necessarily VOID the emission's test that I'm going to have to take in about 21 more months, but it's a big "Maybe" for me, contemplating it now. The exhaust system past the 2nd catalytic converter is a "wear item" after the Mazda 3/50K miles warranty anyway, but the factory downpipe and everything up to the 2nd cat is covered by the 7/70k CA emissions warranty. So it's Catch-22 for me and modifying my OEM exhaust system with non CARB parts. I feel safe in replacing the exhaust system past the cats, but as far as replacing the downpipe I think I'll pass on that idea.

Kindest regards,
rexercx7:cool:

[shadow1]

You can be pretty certain that Mazda put 2 cats in their for a reason. To pass Calif tailpipe test. Fortunately, in MD, I just need to pass a computer OBDII check. So you will fail a tailpipe test w/o both factory cats I bet. If the CX7 was clean enough with one cat, they wouldn't have installed 2. So for Calif owners, the best bet is just the axleback system +/- installing and removing the downpipe every 2 years.

[shadow1]

I got another email from Corksport. I asked about boost spikes with the downpipe. They didn't divulge any specifics but said they used "due diligence" and assured me that their products would not blow up the engine. :p

[rexercx7]

I got another email from Corksport. I asked about boost spikes with the downpipe. They didn't divulge any specifics but said they used "due diligence" and assured me that their products would not blow up the engine. :p

Of course Rich is going to assure you that his products won't "blow up the engine"! But as far as installing/removing/re-installing the downpipe system for CA CX-7's, I'm going to Pasadena on that whole scenario unless Corksport makes the downpipe with a high-flow cat...THEN I'd be very interested in fitting that system into my mods, but only if that's in their plans. I am not the least interested in running a straight-through downpipe that's going to most likely generate a CEL that I'll have to deal with. If the downpipe has the high-flow cat and a provision for the OEM O2 sensor, so that the ECU system will function normally, I'm all for it and will go through the trouble of putting it on, and removing it every 2 years when it's green-slip time.

Kindest regards,
rexercx7:cool:

[shadow1]

You can email corksport and express your concerns to Rich.

However, I am familiar with the mechanical CEL fix that they are proposing for their catless downpipe. I use a similar mod on my Evo since my high flow cat is a barely legal metallic substrate cat that set off a CEL. The fix involves using an extended O2 sensor bung on the 2nd post cat sensor. It takes the sensor out of the exhaust stream so that it sees less air and O2. Thereby it tricks the ECU into thinking that there is a functioning cat that is catalyzing O2.

[Raider]

Shadow1 hit on what Iw as going to post about. The o2/sensor spark plug non-fouler fix. this is widely, and I mean just about everyone, with a protege or protege5 that installed a header used. In fact, I used the method a month ago installing an OBX header on a P5. Simply got to Auto Zone. go tot he HELP! rack, pick out the spark plug non-foulers. 2 come in a kit.

Drill 1 out with a 1/2 inch bit, put around the O2 sensor, then screw on the other non fouler. Then install them to the header, downpipe, midpipe, etc. It is a great thing, never ever fails.

Here is an example of it being used.
http://forums.audiworld.com/a4/msgs/2511177.phtml

[shadow1]

I bought a Helix CEL fix for my Evo that is already premade and doesn't require drilling out a spark plug anti-fouler. $13 from an Evo vendor.

[Raider]

Is that the resistor capacitor fix? That never really worked well on the protegs, and required wire splicing.

[shadow1]

nope - mechanical. Just like the antifouler trick.

http://www.gruppe-s.com/Evo/evoex.htm

Scroll down the page to the Helix CEL fix.

[Raider]

that is nice, one big non-fouler. For those who do not have the tools, this is the easier method. Cheaper than getting a drill, bit, non-foulders and something to hold em while drilling.