Catless Downpipes

[2007 to 2016 M6 Cab]

Damn auto correct ...akrapovic exhaust

Sorry ... Autocorrect Siri sucks!

[bigbrian]

Here is a few clips my car w/ Eisennman Race Mufflers, Eisennman Mid-Pipes, and Motive Concepts Catless DPs.

Revving...
http://scontent.cdninstagram.com/hph...83059751_n.mp4

Downshifting into 1st...
https://scontent.cdninstagram.com/hp...25030718_n.mp4

1st to 2nd to 3rd...
https://scontent.cdninstagram.com/hp...79627241_n.mp4


Brian

[2007 to 2016 M6 Cab]

Originally Posted by bigbrian

Here is a few clips my car w/ Eisennman Race Mufflers, Eisennman Mid-Pipes, and Motive Concepts Catless DPs.

Revving...
http://scontent.cdninstagram.com/hph...83059751_n.mp4

Downshifting into 1st...
https://scontent.cdninstagram.com/hp...25030718_n.mp4

1st to 2nd to 3rd...
https://scontent.cdninstagram.com/hp...79627241_n.mp4


Brian

Brian ... Wow that is crazy amazing dude!!! My computer and iPhone 6 likely do not due justice to just how amazing the sound is!!! I may have wet myself!!!


Ok. 1500 km till I go cat less and then will see about the eisenmann!!! Wow, it sounds crazy dude!!!

[bigbrian]

Originally Posted by 2007 to 2016 M6 Cab

Brian ... Wow that is crazy amazing dude!!! My computer and iPhone 6 likely do not due justice to just how amazing the sound is!!! I may have wet myself!!!


Ok. 1500 km till I go cat less and then will see about the eisenmann!!! Wow, it sounds crazy dude!!!

LMAO... That is probably the best (and funniest) compliment I have gotten!

Brian

[TXAlex]

I have supersprint catless down piles akropovic evolution and MSR intake. Sounds amazing. My CEL didn't come on for a week but now I need software to get rid of the light. I have been using the BMS piggyback and have some awesome gains as far as the seat of your pants dyno. Going to have a few pulls done at Elite this coming week to see where we can go from here. Car sounds amazing and spools insanely fast.

[S800vxr]

All the positive responses are interesting and I say that as when I had my 6 remapped there was a guy there who did all the custom turbo builds for them (separate company) and he was adamant that going catless was a bad idea as the car would overspool top end and cut out/damage the engine, and that low down the lack of back pressure would cause a drop in low down torque..... I'm an engineer by background and that didn't make to much sense to me but he seemed to know his turbos and was quite clear...?

[JOHNBMWM5]

Originally Posted by S800vxr

All the positive responses are interesting and I say that as when I had my 6 remapped there was a guy there who did all the custom turbo builds for them (separate company) and he was adamant that going catless was a bad idea as the car would overspool top end and cut out/damage the engine, and that low down the lack of back pressure would cause a drop in low down torque..... I'm an engineer by background and that didn't make to much sense to me but he seemed to know his turbos and was quite clear...?

I am afraid he was right ( I am a retired Engineer) None turbo-ed engines do get a boost (slight) from straight through none restrictive , however turbo engines do suffer slightly, the extra sound very often "masks it", and very top-end "Could" damage turbos but that's not a given, really depends on cooling and oil supply.
Not knowing BMW tech I can't say for sure, BUT they have introduced a mod to the feeder pipes.
EDIT: I should have added with a re-map + catless additional boost will also cover the bottom end.

I got 10/15 extra Ft/Pounds at the bottom from my B7 RS4 with catless DP and STD Exhaust valves wired open.

[2007 to 2016 M6 Cab]

Originally Posted by S800vxr

All the positive responses are interesting and I say that as when I had my 6 remapped there was a guy there who did all the custom turbo builds for them (separate company) and he was adamant that going catless was a bad idea as the car would overspool top end and cut out/damage the engine, and that low down the lack of back pressure would cause a drop in low down torque..... I'm an engineer by background and that didn't make to much sense to me but he seemed to know his turbos and was quite clear...?

Looking at other Biturbo/twin turbo German engines (S63 AMG for example) I didn't come across the same advice when we removed the cats and did brabus tuning ... i am usually skeptical when someone else may have a financial gain ... ie let me sell you a better turbo for the catless application for the 4.4 L twin turbo from BMW.

I have to ask, did he recommend replacing the turbo's on your M6?

Yes these are very complicated engines ... but I am going with the advice of my BMW Dealer who will also warantee what they do to the car for mods.

The advice my BMW Dealer has, was at 2000 km we are going catless and Dinan tune so Turbo's and Emissions are not an issue

just my thoughts from my talks and mods in the past. I must qualify that I am not an Engineer or Mechanic ... just a Car Guy.

[S800vxr]

The guy who commented about not going Catless had no offerings for the M6 and was not selling anything. We were just chatting over a coffee whilst my car was being worked on as he had picked up some bits and was about to leave. Interesting that someone else has said the same sort of thing now. Most likely go for sport cats although they are very expensive here in the UK.

[2007 to 2016 M6 Cab]

Originally Posted by S800vxr

The guy who commented about not going Catless had no offerings for the M6 and was not selling anything. We were just chatting over a coffee whilst my car was being worked on as he had picked up some bits and was about to leave. Interesting that someone else has said the same sort of thing now. Most likely go for sport cats although they are very expensive here in the UK.

Thanks for the feedback!

Sport Cats ... how much of a difference/less back pressure do we get compared to stock and compared to catless?

Also ... LETS ASK BIGBRIAN RE HIS CAR!

[2007 to 2016 M6 Cab]

Originally Posted by bigbrian

Here is a few clips my car w/ Eisennman Race Mufflers, Eisennman Mid-Pipes, and Motive Concepts Catless DPs.

Revving...
http://scontent.cdninstagram.com/hph...83059751_n.mp4

Downshifting into 1st...
https://scontent.cdninstagram.com/hp...25030718_n.mp4

1st to 2nd to 3rd...
https://scontent.cdninstagram.com/hp...79627241_n.mp4
Brian

BIG BRIAN!!!

WHAT HAVE YOU TO SAY RE GOING CATLESS WITH ALL YOUR MODS AND TUNING?


Advice based on your experience with your car?

1200 km now ... 800 more till catless with super sprint down pipes and DINAN Tuning!

[bigbrian]

Originally Posted by 2007 to 2016 M6 Cab

BIG BRIAN!!!

WHAT HAVE YOU TO SAY RE GOING CATLESS WITH ALL YOUR MODS AND TUNING?


Advice based on your experience with your car?

1200 km now ... 800 more till catless with super sprint down pipes and DINAN Tuning!

The main reason I went with catless is the sound of the exhaust. It sounds absolutely incredible coupled w/ the Eisennman Race mufflers.

As for performance... It's hard to say if it affects performance or not. Without any other mods I doubt catless downpipes will help in the hp/torque department. Catless downpipes could come into play with other mods used in conjunction w/ the catless downpipes. Then again without apples to apples comparison (same dyno, same fuel, same temp, etc) it's going to be hard to say for sure.

Unless these turbos were specifically designed to be used in conjunction with back pressure I don't see how it can cause harm. You have turbo cars pushing 2,000 - 3,000 horsepower and they don't have an exhaust that creates back pressure. So why would it causes these specific turbos harm?

Just my 02 cents though so take it for what it is.

Brian

[2007 to 2016 M6 Cab]

Originally Posted by bigbrian

The main reason I went with catless is the sound of the exhaust. It sounds absolutely incredible coupled w/ the Eisennman Race mufflers.

As for performance... It's hard to say if it affects performance or not. Without any other mods I doubt catless downpipes will help in the hp/torque department. Catless downpipes could come into play with other mods used in conjunction w/ the catless downpipes. Then again without apples to apples comparison (same dyno, same fuel, same temp, etc) it's going to be hard to say for sure.

Unless these turbos were specifically designed to be used in conjunction with back pressure I don't see how it can cause harm. You have turbo cars pushing 2,000 - 3,000 horsepower and they don't have an exhaust that creates back pressure. So why would it causes these specific turbos harm?

Just my 02 cents though so take it for what it is.

Brian

THANKS FOR THE ADVICE AND TAKING THE TIME!

I WILL CARRY ON RE THE CATLESS ... AND THEN PERHAPS THE EISENMAN MUFFLERS!

[Msizzle]

Originally Posted by S800vxr

Cheers for the feedback so far. For clarity my cars already mapped to 730hp (dyno' at 728 to be specific) and I'm not really after more power I just feel the HD cats fitted are either restricting spool or causing a restriction which acts as a heat sink when running hard. Emissions and warrentee are not a real concern as I can remove the tune and DPs if needed.

So just to clarify a stock m6 is rated at 560 and they dyno 480-510whp or so, your car made 728whp with just a tune and drop in filters?So the tuner made 230+ whp?Thats about 870 at the crank!! How much boost is your tuner running? How is he getting all this air in a stock intake and stock dp's and out a stock exhaust? Its not you that I'm questioning its 1 of 2 things, the tuner misled you or the car really did make that power but its on the ragged edge. your car should be 550-600whp max

[S800vxr]

Originally Posted by Msizzle

So just to clarify a stock m6 is rated at 560 and they dyno 480-510whp or so, your car made 728whp with just a tune and drop in filters?So the tuner made 230+ whp?Thats about 870 at the crank!! How much boost is your tuner running? How is he getting all this air in a stock intake and stock dp's and out a stock exhaust? Its not you that I'm questioning its 1 of 2 things, the tuner misled you or the car really did make that power but its on the ragged edge. your car should be 550-600whp max

HP not Bhp so calculated HP at the crank. 560 to 728 is the change so whatever that reduces to at the wheels.
HP is generally taken as engine crank power, Bhp is what you get at the wheels after all the losses.
It's all bollocks anyhow as HP is a calculated figure taken from the torque measured along with peak rpm. I just know it's very fast throught the gears and I've had some heavily modded cars and bikes (last Hayabusa pulled 439bhp!).

[chask]

Originally Posted by S800vxr

HP not Bhp so calculated HP at the crank. 560 to 728 is the change so whatever that reduces to at the wheels.
HP is generally taken as engine crank power, Bhp is what you get at the wheels after all the losses.
It's all bollocks anyhow as HP is a calculated figure taken from the torque measured along with peak rpm. I just know it's very fast throught the gears and I've had some heavily modded cars and bikes (last Hayabusa pulled 439bhp!).

Actually I think bhp or brake horsepower is the power measured at the crank, not at the rear wheels. The term brake comes from the terminology of using an engine brake at the flywheel to measure the torque produced. And I think you are right that the hp is simply calculated from the measured torque. HP = T (ft-lbs) * RPM / 5252. The brake is name of the device that counters the engine torque at the flywheel - hence the term brake horsepower. BHP is not the same as the power or torque measured at the car's rear wheels or brakes.

Also, it is important to note that the Torque and HP are equal at 5252 RPM (5252 RPM / 5252 = 1). If they do not there is something wrong. I suspect it is with the way your car is hooking up to the dyno; a tire to chassis roller contact problem. Most likely I would think something is slipping. Add some weight to the trunk and see if something changes, but it might take a lot of weight - I've heard of instances where several guys got up in the trunk but I would not recommend that - there's a lot of power going on and if something breaks or slips humans don't fair too well in interactions with heavy chunks of metal that have lots of velocity or energy behind them. Anyway, I would question the results of any dyno run that did not have the torque and hp reading the same number at 5252 RPM. It is contrary to the mathematical relationship of hp and torque.

I used to run an engine dyno and did a lot of this for several years. I am not that familiar with chassis dynos. I have used them a couple of times but I was only an observer - they were measuring my car and I was doing some tuning, not running the dyno. I know that there are indeed losses in the drivetrain that make the power measured at the drive wheels lower. A lot of people here talk about wheel horsepower. It is the effective power you end up with but I am not so sure the difference between bhp and whp is such a big deal - after all, the drivetrain losses are going to be there no matter what you do to the engine.

A big reason a lot of people use chassis dynos is the ease of using them, especially relative to an engine dyno. If you've never worked an engine dyno just look at your engine compartment and you'll get an idea how much harder it is to use one. All that stuff in the engine compartment that makes the engine function has to be removed from the compartment, installed and made functional on the dyno too or replicated on the dyno stand. In the case of the S63TU engine, think intercoolers, oil coolers, a lot of those pumps that these systems use, etc. It'd be close to a nightmare building all that gear, not to mention getting sufficient cooling air running through all those heat exchangers - that would take one serious fan. On a chassis dyno you just drive up on the rollers, put a fan in front of the radiator, tie the car down (so that if something bad happens at max RPM and WOT it doesn't take off) and have at it. Much simpler indeed, and it takes a lot less time to make it happen. Plus it's easier to measure changes. Say a few weeks after you do an engine dyno you come up with a new idea or part to try, you have to pull everything out and recreate the engine dyno setup again. This can take days. In the same scenario with a chassis dyno, a few weeks later you just drive up on the rollers, get the fan, strap the car down and have at it. Still much simpler. I think the advantage of the engine dyno is you remove some of the variables that can be introduced by the drivetrain, and especially the contact friction of the tires on the rollers. For our purposes though (we are trying to go fast and don't need extremely accurate numbers) a chassis dyno is great.

What we are after is indeed that seat of the pants feel (I think of that line in the movie Rush where Niki Lauda meets his future wife and tells her why he is such a good F1 driver - "I've got a good ass") and what we can find out from a stopwatch.

[S800vxr]

Were you bored.....

Generally in the UK BHP is the wheel horse power you have and HP is the show off calculated higher crank Horse power you have. On the dynos we use you get a SHP which is shoutout horse power (calculated crank) which is what people here like to throw about as its higher.

[bigbrian]

Originally Posted by S800vxr

Were you bored.....

Generally in the UK BHP is the wheel horse power you have and HP is the show off calculated higher crank Horse power you have. On the dynos we use you get a SHP which is shoutout horse power (calculated crank) which is what people here like to throw about as its higher.

BHP is Brake HP which is calculated at the flywheel/crank (not the wheels after final losses). WHP is term used when calculated at the wheels. HP is a general term and refers to the flywheel/crank HP rating (same as BHP). These acronyms don't mean different things in the US vs the UK or anywhere else for that matter.

All Dyno machines are different and put out different ratings. I've seen a Dyno read 620whp where another Dyno (same car) reads 710hp. You Need to go by the baseline and the final number to understand the actual gain. You can get ~100whp with an aggressive tune with intake/exhaust done on the car. Anything more than ~100whp requires modified turbos. Someone saying they obtained 200whp on a tune alone is full of shit. Just sayin.

Brian

[M6-Coupe]

Originally Posted by chask

Actually I think bhp or brake horsepower is the power measured at the crank, not at the rear wheels. The term brake comes from the terminology of using an engine brake at the flywheel to measure the torque produced. And I think you are right that the hp is simply calculated from the measured torque. HP = T (ft-lbs) * RPM / 5252. The brake is name of the device that counters the engine torque at the flywheel - hence the term brake horsepower. BHP is not the same as the power or torque measured at the car's rear wheels or brakes.

Originally Posted by bigbrian

BHP is Brake HP which is calculated at the flywheel/crank (not the wheels after final losses). WHP is term used when calculated at the wheels. HP is a general term and refers to the flywheel/crank HP rating (same as BHP). These acronyms don't mean different things in the US vs the UK or anywhere else for that matter.

Brian

Correct!

Brake horsepower (bhp)
Horsepower at the output shaft of an engine, turbine, or motor is termed brake horsepower or shaft horsepower, depending on what kind of instrument is used to measure it.
It is the measure of an engine's horsepower before the loss in power caused by the gearbox and drive train etc.

https://en.wikipedia.org/wiki/Horsep...ower_.28bhp.29

[Msizzle]

Originally Posted by S800vxr

Were you bored.....

Generally in the UK BHP is the wheel horse power you have and HP is the show off calculated higher crank Horse power you have. On the dynos we use you get a SHP which is shoutout horse power (calculated crank) which is what people here like to throw about as its higher.

Sir I don't know whats scarier, the fact that you don't know what bhp is or the fact that you or your shop believe that you can make 200+whp with just a tune. Even doing it in a dangerous manner I'm not even sure if it would be physically possible. You can max out the turbos, advance the timing, and risk blowing the motor apart and maybe get close, he would also have to get the ecu to not protect the engine

[2007 to 2016 M6 Cab]

Originally Posted by bigbrian

The main reason I went with catless is the sound of the exhaust. It sounds absolutely incredible coupled w/ the Eisennman Race mufflers.

As for performance... It's hard to say if it affects performance or not. Without any other mods I doubt catless downpipes will help in the hp/torque department. Catless downpipes could come into play with other mods used in conjunction w/ the catless downpipes. Then again without apples to apples comparison (same dyno, same fuel, same temp, etc) it's going to be hard to say for sure.

Unless these turbos were specifically designed to be used in conjunction with back pressure I don't see how it can cause harm. You have turbo cars pushing 2,000 - 3,000 horsepower and they don't have an exhaust that creates back pressure. So why would it causes these specific turbos harm?

Just my 02 cents though so take it for what it is.

Brian

Brian

What tuning did you do after going Catless to eliminate the CEL from going on.

My dealer is planning on doing the Dinan tune

I am at 1500 km ... 500 km more till the supersprints go in and Cats come out!

Can't wait!

Sunny Tatra

[bigbrian]

Originally Posted by 2007 to 2016 M6 Cab

Brian

What tuning did you do after going Catless to eliminate the CEL from going on.

My dealer is planning on doing the Dinan tune

I am at 1500 km ... 500 km more till the supersprints go in and Cats come out!

Can't wait!

Sunny Tatra

I have been driving around with the CEL for some time now. Unfortunately you will need an ECU tune to remove the CEL. I don't believe the DINAN box removes the CEL (correct me if I am wrong guys) because the JB4 box doesn't remove it.

Once my new turbos are built I will be having EuroCharged in Houston do an ECU tune on my car that will remove CEL.

Brian