Turbo Back Downpipe Install
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There's a short section that comes out of the turbo and turns down by the transmission, the "downpipes" couple up after that on a awd.
Not sure if there is a ton to gain, if the motors out just do turbos!
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There's a short section that comes out of the turbo and turns down by the transmission, the "downpipes" couple up after that on a awd.
Not sure if there is a ton to gain, if the motors out just do turbos!




That bolt to the turbos and to the cat pipes.
These pipes have no restriction, dont change sound, and yield no power gains. As much as some of these companies may try to make you believe. .
Removing the cats.. ill leave that for another discussion... psi for psi if you raced a similar car, i think you may be VERY surprised by the results. Cat flow technology of todays cars has gotten extremely good compared to many myths of years ago.
good article:
https://f87.bimmerpost.com/forums/sh...php?p=24603457
Last edited by 5soko; Jun 28, 2019 at 09:24 AM.




That bolt to the turbos and to the cat pipes.
These pipes have no restriction, dont change sound, and yield no power gains. As much as some of these companies may try to make you believe. .
Removing the cats.. ill leave that for another discussion... psi for psi if you raced a similar car, i think you may be VERY surprised by the results. Cat flow technology of todays cars has gotten extremely good compared to many myths of years ago.
good article:
https://f87.bimmerpost.com/forums/sh...php?p=24603457
Srry thought you meant cat less down pipes. Also I’m not into articles. I can find an article that says removing cats shows gains. I’m just speaking from my personal real world experience. And also you can’t compare 2 cars with the exact same mod. They can act entirely different not all cars are identical even the same year make model with matching mod and matching miles. When you remove cats you are creating efficiency , removing heat faster, removing unwanted back pressure. As I agree some back pressure is needed to create a form of exhaust scavenging, but that’s mainly for NA motors where scavenging has a greater affect. I have had many cars. Mod my own vehicles from piston to gearing and diff, except tuning. Also I dyno after every mod on the same dyno same temp within a week from each other . I promise if I lost power removing my cats I would have re installed them without hesitation . Search my post, the last thing I would want to do is miss lead any of my fellow enthusiasts. Maybe Jon doe removed his cats and lost power I’m sure it may happen. But the ratio for gain to loss on much higher then loss to gain on removing cats. Just like everyone who keeps dumping tons of meth with huge nozzles right before the intercooler to show minimal gains. While I mist meth pre turbo with great gain without tuning
And by all means i encourage all members to enjoy their cars and mods, that is what we are all here for right.
but i have seen numerous times a diff outcome in real world runs( cat vs catless, then catless vs catless, same cars) backing many of these claims today how well these new cats flow. Just sharing my experience. You can DM me, maybe we can even meet in person and try it out
and talk more about this.
And by all means i encourage all members to enjoy their cars and mods, that is what we are all here for right.
but i have seen numerous times a diff outcome in real world runs( cat vs catless, then catless vs catless, same cars) backing many of these claims today how well these new cats flow. Just sharing my experience. You can DM me, maybe we can even meet in person and try it out
and talk more about this.
" Some facts- Mclaren catbypass pipes will give you a Check Engine light P420/P430 code on these cars. Often you can use simulators to keep the light off BUT its not guaranteed. The car runs 100% fine but you get a small light on the dash. Simulators give you a 50% chance of eliminating a CEL light.
Fabspeed Motorsport has awesome record setting safe tunes for all these McLaren cars for stock, with highflow cats and also No Cats RACE system with no CEL Lights 100% guaranteed. All of our tunes are set up safely for 92 to 93 octane pump fuel.
Point of interest- in virtually all of our testing super highflow German imported Extra large diameter HJS 200 cell Catalytic converters make more absolute power and torque all across the RPM band than catbypass pipes. The HJS Catalytic converters FLOW 93% of a straight pipe and the cars don't go into overboost/ spike and the ECU doesn't try to trim and pull everything back as what happens when you install a catbypass pipes.
Fabspeed Motorsport has tunes for all catted or no cat Mclaren cars. Whats interesting is that the power increase/ difference in ONLY +5HP by going tuned and catless. In our years of back to back dyno testing since 2010 with these cars catbypass pipes/competition pipes and with a tune you get only an additional +5HP more than a Mclaren with HJS German sport race cats with a tune on "same day same weather". "
First, if you do not tune for catless, I'd agree zero or negative gains. Second, what Mclaren owner would do some dumb *** 02 sims? That is a lame way to "correct" the oxygen sensors, any respectable tuner can fix this in the tune. No simulators necessary. After all that it goes on to say there is in fact a gain... however minimal.




" Some facts- Mclaren catbypass pipes will give you a Check Engine light P420/P430 code on these cars. Often you can use simulators to keep the light off BUT its not guaranteed. The car runs 100% fine but you get a small light on the dash. Simulators give you a 50% chance of eliminating a CEL light.
Fabspeed Motorsport has awesome record setting safe tunes for all these McLaren cars for stock, with highflow cats and also No Cats RACE system with no CEL Lights 100% guaranteed. All of our tunes are set up safely for 92 to 93 octane pump fuel.
Point of interest- in virtually all of our testing super highflow German imported Extra large diameter HJS 200 cell Catalytic converters make more absolute power and torque all across the RPM band than catbypass pipes. The HJS Catalytic converters FLOW 93% of a straight pipe and the cars don't go into overboost/ spike and the ECU doesn't try to trim and pull everything back as what happens when you install a catbypass pipes.
Fabspeed Motorsport has tunes for all catted or no cat Mclaren cars. Whats interesting is that the power increase/ difference in ONLY +5HP by going tuned and catless. In our years of back to back dyno testing since 2010 with these cars catbypass pipes/competition pipes and with a tune you get only an additional +5HP more than a Mclaren with HJS German sport race cats with a tune on "same day same weather". "
First, if you do not tune for catless, I'd agree zero or negative gains. Second, what Mclaren owner would do some dumb *** 02 sims? That is a lame way to "correct" the oxygen sensors, any respectable tuner can fix this in the tune. No simulators necessary. After all that it goes on to say there is in fact a gain... however minimal.
Keep in mind we do not have 200 cell high flow cats as a stock option . Inside our cats there is 2 speperated cells one at the very beginning and small half inch space and another. And that’s per side . So a total of 4 cells. Now I’m assuming we are not talking high flow 200 cell cats because they do flow extremely well. And my statement is based on standard flow cats which is what we have
That bolt to the turbos and to the cat pipes.
These pipes have no restriction, dont change sound, and yield no power gains. As much as some of these companies may try to make you believe. .
Removing the cats.. ill leave that for another discussion... psi for psi if you raced a similar car, i think you may be VERY surprised by the results. Cat flow technology of todays cars has gotten extremely good compared to many myths of years ago.
good article:
https://f87.bimmerpost.com/forums/sh...php?p=24603457
CLS63s: Weistec turbo backs
E63s: kept the factory bridge pipes and had MBH catless down pipes
https://www.youtube.com/watch?v=1s9SrZuwi6s
CLS63s: Weistec turbo backs
E63s: kept the factory bridge pipes and had MBH catless down pipes
Those bus length difference looks like a 100hp gain tbh....
I did not witness this result in person in my experience.
Might wanna check to make sure that one car is actually tuned,
since your saying a catless bridge pipe with a different bend picked up bus lengths when compared to the oem catless bridge pipe. Lol
Those bus length difference looks like a 100hp gain tbh....
I did not witness this result in person in my experience.
Might wanna check to make sure that one car is actually tuned,
since your saying a catless bridge pipe with a different bend picked up bus lengths when compared to the oem catless bridge pipe. Lol
That video is more of a tune vs NON tune video by the huge gap that was put on so quickly. The gap in that race is massive amount of WHP difference.
The oem bridge pipes are actually hydroformed which flow actually very well with no restriction. The oem bridge pipe width is offset by their height, volume is still there in flow because of this. Not sure where this major restriction is coming from to gain so much power, and free so much up you were able to have cooler IAT's? Interesting.
Different experiences i guess. Glad it worked out for you.
Last edited by 5soko; Jul 1, 2019 at 09:20 PM.
That video is more of a tune vs NON tune video by the huge gap that was put on so quickly. The gap in that race is massive amount of WHP difference.
The oem bridge pipes are actually hydroformed which flow actually very well with no restriction. The oem bridge pipe width is offset by their height, volume is still there in flow because of this. Not sure where this major restriction is coming from to gain so much power, and free so much up you were able to have cooler IAT's? Interesting.
Different experiences i guess. Glad it worked out for you.
Now my friend that owns the CLS63s didn’t care what it takes he just wanted the most gains. He started with a stage 1 tune as well. Went to the track and had a similar time as the E63s except he had a better 60ft and got 11.7 at 119mph but the DA was higher at 5000. After that we went with the Weistec turbo backs and the stage 2 tune on 91 pump gas. Both with the same amount of timing and boost. Both are tuned by Anthony Lawshee aka Tony from Race IQ Performance. I saw them both get flashed at our local Race IQ dealer called Silver Arrows Motors in Las Vegas.
This is what we experienced out here with these mods.
Here’s both them in front of the shop.
Oem motor mount on the left Weistec billet engine mounts to fit the turbo backs
Stock vs turbo back
Last edited by Das_it16; Jul 2, 2019 at 01:13 PM.
To be fair, that weistec engine with the red pipe from weistec is the there water methanol injection setup. That on a car is worth a bunch of power.





