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Secondary Cat removal

 
  #1  
Old 08-01-2013, 12:39 PM
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Secondary Cat removal

Going to have the secondary cats removed this weekend and replaced with either a 3" X pipe or maybe just straight through 3" pipes.

If its too loud I will have a couple small straight through mufflers installed where the secondary cats were.

However, please chime in if you have done this to your car bentley. How loud will be it ? How does removing the secondary cats effect driveability ? When you brought in for service did the dealer say anything ? ( ie, void warranty ).

Thanks !
 
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Old 08-02-2013, 01:15 AM
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Hello,
What year is yours?. In the ROW/European cars (like my GTC-2010), Bentley itself has OEM-removed the secondary cats . If you want I can look up and give the partnumber for that exhaust-part. Don't know about giving a CELL-ligth if you should switch them. (ECU for EU is different from the US).
Anyway, IMO, the straigth pipes that replaces the cats have not or merely affected the loudness.
 
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Old 08-02-2013, 06:52 AM
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Originally Posted by Daddy C. View Post
Hello,
What year is yours?. In the ROW/European cars (like my GTC-2010), Bentley itself has OEM-removed the secondary cats . If you want I can look up and give the partnumber for that exhaust-part. Don't know about giving a CELL-ligth if you should switch them. (ECU for EU is different from the US).
Anyway, IMO, the straigth pipes that replaces the cats have not or merely affected the loudness.
Thanks Daddy. Its a 2013 Speed. Going to find out tomorrow with a secondary cat removal/3 " X pipe replacement and 3" pipes replacing the stock 2.75 " pipes all the way back to the rear differential.
 
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Old 08-02-2013, 08:40 AM
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Well I can't say for the New 2013 model. I only have documentation for 2010 ( US= my 2011) and earlier.
If it was me, i'd certainly go for the cat removal. Cutting out the cat on my wife's cherished classic Saab convertible gave a very noticible gain in grunt (low end torque).
IMO the slightly bigger and mandrel bent pipes, without changing the exhaustmanifold (spaghetti) and with keeping the stock mufflers, isn't gonna change much backpressurewise. Soundwise i suspect there will be a slightly deeper tone of voice.
Am curious if you will notice any change in drivability.
Have a blast tomorrow !
christian
 
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Old 08-02-2013, 11:09 AM
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im doing mine next week. custom job, im going to weld it myself, drop the centre section. i ordered 2 new gaskets and a nice mandrel bent x pipe.

I am just going to drop it and weld it off the car.
 
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Old 08-03-2013, 07:49 AM
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Originally Posted by REDNOSEGT View Post
im doing mine next week. custom job, im going to weld it myself, drop the centre section. i ordered 2 new gaskets and a nice mandrel bent x pipe.

I am just going to drop it and weld it off the car.
Sounds good.
I was going to get mine done today but going to wait a little while. Replaced the stock air filters yesterday with BMC filters and I cant believe the difference. Going to just enjoy this for a short while.
 
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Old 08-05-2013, 06:43 AM
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I read the last post from [email protected] about the new GT(C) -package.
David claims a 40+hp and 80tq gain from cutting sec. cat's and resonators; with replacement of the mufflers with maxflo's.
I'm happy that, apart from the muffler job, Bentley already did this on my 2010 factory EU-car. Yet they hang on to the 560Hp/650Nm ticket.
So I kind of bought a GTC with close-to-Speed-muscles????? for a bargain price...or are the stock mufflers that restrictive.
Any idea why Bentley would not advert this kind of gain ?
 
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Old 08-05-2013, 08:47 AM
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Originally Posted by Daddy C. View Post
I read the last post from [email protected] about the new GT(C) -package.
David claims a 40+hp and 80tq gain from cutting sec. cat's and resonators; with replacement of the mufflers with maxflo's.
I'm happy that, apart from the muffler job, Bentley already did this on my 2010 factory EU-car. Yet they hang on to the 560Hp/650Nm ticket.
So I kind of bought a GTC with close-to-Speed-muscles????? for a bargain price...or are the stock mufflers that restrictive.
Any idea why Bentley would not advert this kind of gain ?
I do not think the factory rear muffler are very restrictive. You can look straight through them. However, the inside diameter of the rear mufflers appears to reduce down. I think they are SLIGHTLY restrictive due to the apparent reduction at the inside diameter ( ID ). So the aftermarket rear muffler probably that do not reduce down internally would free up a little power. ( More uncorking ).

Also, the factory exhaust is 2.75 " with cheap crimp bends and a less effective H pipe/balance pipe. The after market exhaust is 3" with mandrel bends and a more effective X/crossover pipe. So the aftermarket exhaust will free up a little power. ( More uncorking and this does not take into consideration the removal of the restrictive secondary cats ).
 
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Old 08-05-2013, 11:41 AM
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I doubt you will have to much noise after a straight pipe job. I purchased the Fabspeed H pipe, tune and resonator tail section and the cars sounds like it should have from the factory. These cars are difficult to get sound out of. If there is a negative to the job it might be a little droning round 1300rpm. With the stock system this was the only time the car even sounded decent.
 
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Old 08-05-2013, 12:06 PM
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Originally Posted by Dr.Disaster View Post
I doubt you will have to much noise after a straight pipe job. I purchased the Fabspeed H pipe, tune and resonator tail section and the cars sounds like it should have from the factory. These cars are difficult to get sound out of. If there is a negative to the job it might be a little droning round 1300rpm. With the stock system this was the only time the car even sounded decent.
Thanks for the detailed description.

You have their tune also ? What do you think of the tuning job ? ( Power, driveability, shifting, etc ).

Thanks again.
 
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Old 08-05-2013, 01:00 PM
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Originally Posted by smgco View Post
Thanks for the detailed description.

You have their tune also ? What do you think of the tuning job ? ( Power, driveability, shifting, etc ).

Thanks again.
Yes I bought the ECU tune. The power production is fantastic gaining around 90hp. I have not noticed a great changed in shifting of the transmission. Honestly I have always felt the shift was a tad slow from 1-2-3 under full power but remember I have the older six speed from 07. The drivabilty is fantastic with nothing but gains over the full spectrum of town driving. Other than the outlay of funds there is no downside.

Some might complain of that drone at 1300rpm but it can be solved by downshifting one gear and it's completely gone. I accept this extra "noise" at that rpm to enjoy the better sound at all other times.

I did the changes in two stages getting the tune and the H pipes first and was quite disapointed in the sound which was almost unchanged. My wife said she thought it was quieter. I think she was just trying to bust my nuts, it worked. Since I had to return the down tubes because they would not fit David sent me the new tail pipe section with the little resonators on them and I was finally thrilled. 640hp should sound like something.
 
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Old 08-05-2013, 02:28 PM
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Originally Posted by Dr.Disaster View Post
Yes I bought the ECU tune. The power production is fantastic gaining around 90hp. I have not noticed a great changed in shifting of the transmission. Honestly I have always felt the shift was a tad slow from 1-2-3 under full power but remember I have the older six speed from 07. The drivabilty is fantastic with nothing but gains over the full spectrum of town driving. Other than the outlay of funds there is no downside.

Some might complain of that drone at 1300rpm but it can be solved by downshifting one gear and it's completely gone. I accept this extra "noise" at that rpm to enjoy the better sound at all other times.

I did the changes in two stages getting the tune and the H pipes first and was quite disapointed in the sound which was almost unchanged. My wife said she thought it was quieter. I think she was just trying to bust my nuts, it worked. Since I had to return the down tubes because they would not fit David sent me the new tail pipe section with the little resonators on them and I was finally thrilled. 640hp should sound like something.
Thanks for the very detailed response. I'm probably going to have David tune my car also. ( I'm also considering the good people at Champion ). Your description really gave me better insight into the driveability/streetability of their tune. Thanks again.
 
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Old 08-05-2013, 02:37 PM
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Originally Posted by smgco View Post
Thanks for the very detailed response. I'm probably going to have David tune my car also. ( I'm also considering the good people at Champion ). Your description really gave me better insight into the driveability/streetability of their tune. Thanks again.
It is just as nice and easy to drive as it was before BUT FASTER! If you are loafing around town or down the country road it feels just like it used to but when you step on it ?????? It ain't the lazy fat chick she was. BTW if you can resist using all that seductive power the fuel economy will be roughly the same as pre-mod. The turbo rush in second gear is amazing and it will be auto changing to third before you can reach for the shifter.
 

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Old 08-05-2013, 02:55 PM
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Originally Posted by Dr.Disaster View Post
It is just as nice and easy to drive as it was before BUT FASTER! If you are loafing around town or down the country road it feels just like it used to but when you step on it ?????? It ain't the lazy fat chick she was. BTW if you can resist using all that seductive power the fuel economy will be roughly the same as pre-mod. The turbo rush in second gear is amazing and it will be auto changing to third before you can reach for the shifter.
Fantastic !!
 
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Old 08-18-2013, 04:52 PM
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Originally Posted by Daddy C. View Post
I read the last post from [email protected] about the new GT(C) -package.
David claims a 40+hp and 80tq gain from cutting sec. cat's and resonators; with replacement of the mufflers with maxflo's.
I'm happy that, apart from the muffler job, Bentley already did this on my 2010 factory EU-car. Yet they hang on to the 560Hp/650Nm ticket.
So I kind of bought a GTC with close-to-Speed-muscles????? for a bargain price...or are the stock mufflers that restrictive.
Any idea why Bentley would not advert this kind of gain ?
I had the secondary cats removed yesterday and 3 inch " test " pipes welded in. It sounds great ( same type/style sound as with the cats but slightly louder ) and the increase in power is VERY noticeable. The seat of the pants feel is that David's claim is correct. All it needs now is a tune.

Daddy, I think the difference in Bentleys power rating you referred to has to do with the different factory tune and or different size of the turbos between the GT and a Speed.
 

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