Exhaust Pressure Testing

[Proshop]

Yeah I bought a kit with bunch of bends then the chop saw and some flux core stainless. It essentially is in the same location as the stock exhaust.

Do you have a link to the Corsa you purchased? Did it come with the h pipe or did you fabricate your own like Mike?

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[engineermike]

Yeah I bought a kit with bunch of bends then the chop saw and some flux core stainless. It essentially is in the same location as the stock exhaust.

Dude. I did flux core stainless as well. I’m convinced there’s no way to make that garbage look decent. I’ve since bought the appropriate trimix gas and solid 309l wire. The welds look great now and I can assure you my skill level didn’t suddenly get way better.

 

[smokescreens]

Unfortunately very busy. I can get a video done and maybe some pict6if you don't make fun of my welds.

I would like to know what you used for mufflers as well. I liked your review of the exhaust tones.

 

[andrewtac]

I am not worried about the welds, as long as I don't get CO in the car and they hold (which they will). I don't do car shows and if I do, no mirrors.

 

[andrewtac]

I used the axel back corsa, and on here somewhere there was an Amazon link for an h I used to make my h pipe in front of the resonator. I had to chop it and reweld though as it was to wide. I also got a 3" Amazon exhaust kit with a bunch on pipes, just laid under the car and held up the pipes with the prebends and TLARed with a sharpie for everything from the headers to the axle back.

 

[Proshop]

I used the axel back corsa, and on here somewhere there was an Amazon link for an h I used to make my h pipe in front of the resonator. I had to chop it and reweld though as it was to wide. I also got a 3" Amazon exhaust kit with a bunch on pipes, just laid under the car and held up the pipes with the prebends and TLARed with a sharpie for everything from the headers to the axle back.

I’m wondering if I could take something like this (see below) and cut the second h pipe out and add the stainless bros muffler in…

https://www.lethalperformance.com/c...2020-mustang-gt-no-valves-21039blk-14502.html

 

[engineermike]

@Proshop that's pretty close to what I would do if I did it over. I’d probably use the touring axel-back and make the rest with srainlessbrose resonator, custom h pipe, etc.

 

[andrewtac]

That will work probably. I looked at that as well but might have been a little more expensive and figured I could use some fab practice as it had been a while.

 

[Proshop]

@Proshop that's pretty close to what I would do if I did it over. I’d probably use the touring axel-back and make the rest with srainlessbrose resonator, custom h pipe, etc.

That will work probably. I looked at that as well but might have been a little more expensive and figured I could use some fab practice as it had been a while.

Mike and Andrew you two are a lot more handy than I am… I just sell tools for a living not use them anymore ! Definitely appreciate the help thou and ideas. I’m just trying to squeeze every last drop of power out of my little Roush I can. So hopefully free flowing exhaust and maybe a larger TB upfront along with my other mods may do that. This after all is my DD and 800+ to the wheels is more than enough until it has a rebirth as a strip/ weekend street car only!

 

[Proshop]

I know early in this thread some one asked for a picture of the inside of the stainless bros dual 3” muffler so here you go!

 

[Proshop]

My new exhaust project… well I should say my new exhaust and my shops new project. 3” from the collectors back. Should open up the flow just a little bit for my Roush!

 

[Proshop]

So @engineermike you think this upgrade warrants a retune by my tuner?

 

[engineermike]

So @engineermike you think this upgrade warrants a retune by my tuner?

It depends on the situation. I see your car is a Roush blower on E85. Your airflow and knock margin will not change appreciably so I believe you mostly likely wouldn't benefit from a re-tune. If you're using a centrif or na, then airflow will increase so you would need to ensure the fuel system is hanging in there.

If you are knock limited, then you would benefit from additional tuning. I spent some more time tuning my borderline timing tables since getting backpressure down to the target range and I've discovered some pretty significant changes. I'm able to run up to 24 deg timing at 10 psi boost on true 93 octane, which is phenomenal considering I couldn't reach 14 deg before these projects. This improvement is due to both the exhaust work and the XDI pump, plus some more tuning changes I made.

 

[Torinate]

It depends on the situation. I see your car is a Roush blower on E85. Your airflow and knock margin will not change appreciably so I believe you mostly likely wouldn't benefit from a re-tune. If you're using a centrif or na, then airflow will increase so you would need to ensure the fuel system is hanging in there.

If you are knock limited, then you would benefit from additional tuning. I spent some more time tuning my borderline timing tables since getting backpressure down to the target range and I've discovered some pretty significant changes. I'm able to run up to 24 deg timing at 10 psi boost on true 93 octane, which is phenomenal considering I couldn't reach 14 deg before these projects. This improvement is due to both the exhaust work and the XDI pump, plus some more tuning changes I made.

That's a huge change in timing from 14 to 24!!! That alone has to be worth a ton in wheel horsepower!

Interesting that airflow wouldn't change much on a PD blower vs centri blower. Or are you meaning enough to warrant a tune change? What goes in must come out, no? And if allowing more out should mean allowing more in at a lower pressure?

 

[engineermike]

Interesting that airflow wouldn't change much on a PD blower vs centri blower. ...What goes in must come out, no? And if allowing more out should mean allowing more in at a lower pressure?

You have to look at the compressor itself, and the fundamental difference between a positive displacement and a centrifugal unit. A PD supercharger moves the same volume of air every revolution essentially regardless of discharge (boost) pressure. No changing of the exhaust system can affect that. Basically, with a PD supercharger, the only things that can affect mass flow are changing the inlet pressure (throttle), speed (pulley), or recirculation (bypass valve).

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