Jump to content
The mkiv Supra Owners Club

Decat


cainhead

Recommended Posts

Hello,

 

Quick question on decats.

 

If I am looking to loose the 2nd cat, I obviously need the decat pipe. What I am unsure of is the diameter of pipe I need. My Exhaust system is an HKS Priest, and I believe it to be a 3" cat back. However when looking around, all decat pipes seem to be 2.5" diameter. Would this fit, and after would I just need to buy an FCD.

 

Cheers for any help given.

Link to comment
Share on other sites

It depends on what you want to do with it mate. But (someone correct me if im wrong) the fuel cut will kick in when both cats are removed.

 

You are right but only if the boost goes above 1bar for 3 seconds.

 

It all depends on what other mods you're going to do but you will more than likely need a RR.

 

Also the 2.5" decat pipe for the Supra will have the same fixings as the stock 2nd cat so it will fit. As for needing a 3" pipe, just adjust the size of the RR until you're holding at 1bar with no boost controller (will need FCD and boost gauge to check).

Link to comment
Share on other sites

Curious logic you have there, whats different about a 3" decat fitment in regards to 2.5".

 

If his cat back exhaust fits on the stock 2nd cat then the 2nd decat pipes that are made for the Supra will fit in place of the 2nd cat. I've no idea if there's a difference with the 2.5" and 3" decat pipe fittings though.

Link to comment
Share on other sites

If his cat back exhaust fits on the stock 2nd cat then the 2nd decat pipes that are made for the Supra will fit in place of the 2nd cat. I've no idea if there's a difference with the 2.5" and 3" decat pipe fittings though.

 

See i read that as if you were saying a 2.5" will fit and a 3" wouldn't which would be completely untrue as its the same pipe with just larger diameter piping but ill give you the benefit of the doubt and you didnt actually mean that ;)

 

Ah yeah, Iv heard you can get boost problems on an N/A :sly:

 

Like when a vac like comes off for example and you get no midrange kick ? :D

Link to comment
Share on other sites

Hello,

 

Quick question on decats.

 

If I am looking to loose the 2nd cat, I obviously need the decat pipe. What I am unsure of is the diameter of pipe I need. My Exhaust system is an HKS Priest, and I believe it to be a 3" cat back. However when looking around, all decat pipes seem to be 2.5" diameter. Would this fit, and after would I just need to buy an FCD.

 

Cheers for any help given.

 

Hi Andrew, You'll be fine with a 2.5" pipe. It'll fit fine as they're all designed to be fit 'n forget direct replacements. You'll see no benefit from a 3" system apart from more noise. No need for an FCD on a non-turbo buddy.

Link to comment
Share on other sites

Hello, just got back to my laptop, thanks for all the reply's. Just to clear up,I have a jspec n/a SZ-R converted to a UKTT. Does this change anything?

 

It means I was right :D

 

Have a good read of this -> BPU

 

:)

Link to comment
Share on other sites

Hello, just got back to my laptop, thanks for all the reply's. Just to clear up,I have a jspec n/a SZ-R converted to a UKTT. Does this change anything?

 

Ah, well the point still stands that you won't need an FCD if you're keeping the first cat, and don't have a boost controller to raise boost further. You _may_ see more benefit from a 3" pipe, but it'll be a trivial difference.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Restore formatting

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. You might also be interested in our Guidelines, Privacy Policy and Terms of Use.