Jump to content
mattt

MOT friendly forced induction

Recommended Posts

Hello all

 

I have the TD NA package (uel) + OEM 2nd cat + invidia q300 exhaust. I'm thinking of forced induction in future, but as I understand it from Mike the TD turbo requires the removal of the 2nd cat. As I need my car relatively hassle free and MOT worthy this is unfortunately not an option for me.

 

What options are available to me? If going turbo (or indeed supercharged), would I need a more free flowing sports cat, and would the car likely pass MOT despite catless manifold?

 

Much appreciate any responses to this "have my cake and eat it" question!

 

Sent from my ONEPLUS A5000 using Tapatalk

 

 

Share this post


Link to post
Share on other sites
1 hour ago, mattt said:

 

 but as I understand it from Mike the TD turbo requires the removal of the 2nd cat. 

 

No its not a necessity, you can keep the stock front pipe, the only reason for changing it is to make the most of the turbo kit (in terms of power).

 

So you can have your cake and eat it.

Share this post


Link to post
Share on other sites

Cosworth SC with completely stock exhaust is fine. Having a 'legal' car and avoiding any hassle come MOT was important to me.
Plus, with standard exhaust you can hear the supercharger spin up, which sounds incredible B)

Share this post


Link to post
Share on other sites

A supercharger simplifies the situation as it doesn't mess with the exhaust manifold, but let's not forget that adding boost unfailingly increases the maintenance needs of the car. You'd want to invest in the most mature solution available to avoid issues like the HKS supercharger owners have encountered.

You might also find the cats will wear out sooner if you're increasing the exhaust temperatures significantly, so best to say off high boost.

Thinking about emissions testing, both a turbo and a supercharger will be on boost at testing RPMs, but hopefully the ECU will keep things clean under partial throttle and light load. I think you'd get away with sports cat + second OEM cat, but not the sports cat on its own. One OEM cat is already close to the edge.

Share this post


Link to post
Share on other sites
20 hours ago, Varelco said:

No its not a necessity, you can keep the stock front pipe, the only reason for changing it is to make the most of the turbo kit (in terms of power).

 

So you can have your cake and eat it.

There is more to it than that. I have spoken to mike in the past and his advise was that the cat will get damaged quite quickly if you continue to run with it. The  OE CAT cannot sustain the high flow and was not built for it. So it is not simple to solve that one.

Share this post


Link to post
Share on other sites

Yeah its never going to last as long as staying NA but same could be said with the stock clutch etc etc.

The same can be said for the standard manifold with a supercharger, there has been a few blown out after being used on track.

Share this post


Link to post
Share on other sites

A good secondary cat would work fine - OEM or good quality high flow. The FI will help with the cat getting up to temp. A supercharger is less power restricted by running the OEM cat or exhaust if it helps, a turbo obviously is affected by smaller pipework.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


×