Engine/Transmission (1994 - 1998) Exhaust brake for 12valve

[JHenry]

I have an automatic transmission with a BD valve body and a triple disc torque converter in my '98 12 valve. The engine has a #5 TST plate and is straight piped 3" exhaust. I would like to increase the exhaust size to 4". Is it possible to do this without changing my turbo? Also would appreciate input on what is working for you guys with the automatic. I plan to change to 60# valve springs. What kind of lockup swithch? What kind of exhaust brake? Thanks.

 

[ScottLewis]

On my '98 I installed a MBRP 4" turbo back exhaust behind a BD Brake. I was quite happy with it although it was a bit loud until I also installed a 4" Cat off a '06.

You'll be happy with the brake regardless of what brand you get. I initially had a BD Autoloc on mine, converted it to work like a TorqLoc and then tried a BD TowLoc. I liked the function of the TowLoc best but it kept setting CELs. BD said it was probably because it was a CA truck with the smog stuff. I only ran it a few weeks because of the CELs. New cost was over $400, I'll sell it for $100.



The TowLoc has a lot of functions similar to how my '06 works with the factory approved Jacobs brake. You aready have the valve body and beefed up converter, you need the brake to complete the package. And the 60# valve springs.



Dan

 

[JHenry]

Thanks for the reply. I am still considering your earlier offer to sell the TowLoc. The only obstacle I have is the shop that built my transmission will likely install the BD exhaust brake and TowLoc (if that is what I use), since they are a BD dealer. He's not willling to guarantee anything if I buy a used component.

Did you do anything to the turbo to enlarge the exhaust side of it? I thought I read somewhere that you can convert the Holset turbo from 3" to 4" outlet.

 

[Driftwood Ram]

I would get a 4 inch in-line e-brake and not a turbo mount. That way if you decide to change the turbo you don't have to replace the e-brake.

 

[ScottLewis]

I never modified the turbo in any way. The brake bolted up perfectly in place of the stock elbow.



The 4" in-line brake would be a good option if you think you might want to pump it up more. Suggest you study up on pros and cons.



Dan