Finally, custom exhaust complete, nervous to debut...

[Ecoboost_xsport]

I pretty much went straight pipe all the way back. No cats, no mufflers, no resonators, only an x-pipe. Results are interesting and I'll be running it through its paces to see how it does, power-wise. I am finally able to get away from the last bit of LMS parts I had on this car (full turboback system), or should I say re-branded Corsa system, LOL.

A guy named Alex Gutierrez who has a shop named Big Head Motorsports. Super talented welder. Only online presence he has is IG, check him out at Big Head Cars. He does a lot of high end drag race stuff. And his shop is 3 minutes from my house...that was sweet! I'm going to tag him to do a lot of my future work, i.e., turbo manifolds, IC end tanks (since no one makes any IC for my platform), and maybe something trick with the intake system.

It's 3" all the way to a set of 3" bellows, then transitions to 2.5". There's an x-pipe right after the bellows and then out to the back and ends up with a 4" tip. Used 321 stainless on the test pipes as it retains heat better than 304 stainless, thus making the need for ceramic coating unnecessary. The system is 304SS for everything past the bellows.

But make no mistake, this thing is pretty loud. However, drone is non-existent at cruising speeds, it isn't raspy at all and has a good bass and tone to it. It's just LOUD when you step on it, lol. Which I don't mind so much.

Anyway, the quality of workmanship is out of this world. It's built for performance and maintenance will be easy with all the v-band clamps used instead of slip-fits and ****** joints.

 

[Ecoboost_xsport]

Some sound comparison videos:

Corsa exhaust note, cold start idle:

Corsa exhaust note, driving:

BHC exhaust note, cold start idle:

BHC exhaust note, driving:

I used a GoPro Hero6 Black utilizing the on-board microphone and mounted to the vehicle here:


For the telemetry, I used the Torque Pro app and used a screen recording app on a small tablet. Editing of the videos was done only to get sound from the GoPro to sync with the video of the tablet.

 

[bpd1151]

Impressive workmanship indeed!

Very, VERY nice. Thank you for sharing.

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[tron23]

I agree, the workmanship is out of this world! How’s the back pressure with that setup? Any issues so far?


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[Ecoboost_xsport]

I agree, the workmanship is out of this world! How’s the back pressure with that setup? Any issues so far?


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None yet, but haven't datalogged yet. Nice thing about this setup, I'm having him also do a section with mufflers on it. With the v-bands, it's an easy change out.

 

[tron23]

None yet, but haven't datalogged yet. Nice thing about this setup, I'm having him also do a section with mufflers on it. With the v-bands, it's an easy change out.

Yeah i actually had a similar setup on my SHO a while back with no mufflers and had an issue with the pressure, my god it was horrendous. Got it all worked out with the mufflers and it’s been amazing ever since. You’re definitely on the right track. That setup is beautiful brotha


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[Ecoboost_xsport]

Yeah i actually had a similar setup on my SHO a while back with no mufflers and had an issue with the pressure, my god it was horrendous. Got it all worked out with the mufflers and it’s been amazing ever since. You’re definitely on the right track. That setup is beautiful brotha


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When you say horrendous, in what way? It still feels really strong so not sure what the datalog is going to look like or what will be the thing to look out for in the log...

 

[FiveLeeter918]

Dude, I think I just filled the cup...

 

[SM105K]

Dude, I think I just filled the cup...

 

[SM105K]

Looks good dude.

 

[StealBlueSho]

That is one **** of a job, and it looks great! Sounds nasty!! (Found the link in all the pictures lol)

I think Lee might need a second cup...

 

[Csbbrah]

Super impressive. Love it.

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[Jordan_R]

Looks marvelous. I love how you used some conical diffuser pipes for a super smooth transition. Those fine touches really make it!

 

[Ecoboost_xsport]

That is one **** of a job, and it looks great! Sounds nasty!! (Found the link in all the pictures lol)

I think Lee might need a second cup...

Yeah it has a very "race car" sound to it. If worse comes to worse, I'm wondering if a pair of these would tone it down:

https://www.google.com/url?sa=t&sou...FjAAegQIAxAB&usg=AOvVaw1apL9IJTYRN8kbsYqP1BNA

Might not look the best, but they seem to work pretty well. And take them out for the track.

For the back pressure thing, I'm hearing alot of smart people on both sides of the argument. It's one of the reasons I wanted to try it, it's sort of an experiment.

I know it tends to be unpopular as it's pretty loud and some might consider obnoxious, but I'm interested in hard data as it relates to performance.

So we'll see where this takes me....lol.

 

[6500rpm]

Those welds are a thing of beauty! There's craftsmanship, then there's next level, definitely wow factor stuff.

 

[Iqoniq]

That's flipping cool, man.

 

[Jordan_R]

Yeah it has a very "race car" sound to it. If worse comes to worse, I'm wondering if a pair of these would tone it down:

https://www.google.com/url?sa=t&sou...FjAAegQIAxAB&usg=AOvVaw1apL9IJTYRN8kbsYqP1BNA

Might not look the best, but they seem to work pretty well. And take them out for the track.

For the back pressure thing, I'm hearing alot of smart people on both sides of the argument. It's one of the reasons I wanted to try it, it's sort of an experiment.

I know it tends to be unpopular as it's pretty loud and some might consider obnoxious, but I'm interested in hard data as it relates to performance.

So we'll see where this takes me....lol.

Check out this video from Gale banks at banks performance

He goes into extreme detail on back pressure and turbo optimizations with boost to back pressure ratio and a bunch of other super informative formulas. Yes, it's a diesel but applicable to any turbo application! I learned so much from this singular video. Banks is a fountain of knowledge and always making me drop my jaw to stuff I would had never thought about.

 

[Ecoboost_xsport]

Check out this video from Gale banks at banks performance

He goes into extreme detail on back pressure and turbo optimizations with boost to back pressure ratio and a bunch of other super informative formulas. Yes, it's a diesel but applicable to any turbo application! I learned so much from this singular video. Banks is a fountain of knowledge and always making me drop my jaw to stuff I would had never thought about.

Yeah I've seen that video. It kinda supports my theory and basic knowledge on turbocharged systems. I didn't want to say much, but NA engines are very different than boosted engines. Without doing a dyno run, it is possible I may lose a bit at the low end torque but will likely make it up at the top end in HP. As weak as our trans/PTU arrangement is, I would venture to say, this may help "soften the blow" (for lack of a better phrase) on those components. And I'm ok with that.

The exhaust builder himself (who's got quite a bit of experience in high end racing, as a builder and a driver) said you really want this thing to breath.

I think back-pressure is probably the wrong variable to be concerned about in our application when, rather, thinking about reversion and scavenging (and controlling the pulse waves of the exhaust) should be more important.

My butt dyno says I didnt lose much, if anything. I'm interested to see how things would change if I were to do a datalog and maybe even a new tune.

But I'm still doing my research and learning this as I go.

 

[Jordan_R]

For what it's worth when I was on the dyno I also had a straight pipe true dual, albeit way uglier, I still made so much low end torque that it was concerning. Even on lower timing. These motors are torque monsters even with upgraded turbos. Honestly you may have created a free flowing exhaust to the point where a revision may be necessary!

 

[Ecoboost_xsport]

For what it's worth when I was on the dyno I also had a straight pipe true dual, albeit way uglier, I still made so much low end torque that it was concerning. Even on lower timing. These motors are torque monsters even with upgraded turbos. Honestly you may have created a free flowing exhaust to the point where a revision may be necessary!

Interesting...that was counter to what I was thinking, but I'll definitely be on the lookout. I'll hit up Brad later on this. I know he's got alot going on, so I'm trying not to bug him these days too much. Plus, I am making that transition to full e85 here in a bit, once I finally install that DW300c and those XDI injectors. I was gonna hold off doing any revisions until then, but I may have to rethink that.