Jump to content
The mkiv Supra Owners Club

Removed the Cats but Boost not risen


Brian Jackett
 Share

Recommended Posts

I removed my Cats last night and fitted Chris Wilsons replacement pipes. Still awaiting HKS dragger rear box so stock rear at the moment.

 

I must say that the pipes Chris supplied fitted perfectly and only took 3 hours to remove old Cats and fit new replacement pipes.

 

I took the car out last night and noticed that it felt a little faster and more willing to boost at low throttle power.

 

However at maximum throttle the boost had not rissen still about 0.8.

 

Any ideas why or will it not rise until I fit replacement rear box

 

regards

Link to comment
Share on other sites

Brian

Worry not.

 

This is purely because you still have the stock exhaust on it.

I had the exact same experience.

I had a totally stock car and fitted CW downpipes to it.   felt a *little* more eager than before but it was just a subtle change.

 

When you ditch the stock exhaust system for an aftermarket one, *then* you will see the big difference.    Is yours J-spec ?

You'll probably need to fit a FCD and a boost guage.    J-specs can boost really quite high with downpipe and new exhaust.

Link to comment
Share on other sites

I think you will find that the exhaust is holding back the available boost.

 

You might find that the problem persists even with the replacement back box as (assuming my memory is correct) there are still silencers lurking in the system that may be restrictive.

Link to comment
Share on other sites

So Brian you're only replacing the back-box and not the entire cat-back exhaust system ?

Then yes Gavin has a good point in that you will still have in the system 1 of the stock silencers which will be a restriction.

To get the full effect of the "de-cat / exhaust" thing, you really need to replace all the exhaust system as the stock system is very restrictive really.

Link to comment
Share on other sites

Quote: from Brian Jackett on 10:12 am on Oct. 19, 2001[br]No, I have replaced both cats up to the back box system. As you know the back box that is replaced by the HKS, replaces 3 boxes in all.

 

That is correct isn't it

 

 

regards

 

 

 

I'm getting confused here?

 

The stock system has two cats (front) and then a silencer on each branch of the exhaust (intermediate)and finally the rear box.

 

Are you saying the the HKS dragger back box also include pipework to remove  the intermediate silencers?

 

 

regards..............

Link to comment
Share on other sites

Quote: from Brian Jackett on 12:24 pm on Oct. 19, 2001[br]Speaking to Chris Wilson he said the dragger connects straight to his pipes. Not using any of the stock exhaust. So the middle two box's are removed.

 

Is that not the case then

 

 

 

The Dragger exhaust does connect to the CW downpipes. The confusion comes from you saying you were fitting a Dragger rear box which suggests that you have bought just the rear box to mount to your stock exhaust, not bought a cat back super dragger exhaust. :)

 

 

regards.....

Link to comment
Share on other sites

Just spoke to Chris and I have got the back box and the pipe from HKS to connect to his exhaust.

 

So you can just buy the back box and connect that to the stock system. That is where the confusion is.

 

So I should get lots more power with no middle box's. Is that not how everyone would do it. Why would you keep the middle box's

 

regards

B1YEE

Link to comment
Share on other sites

You don’t keep the middle boxes you get rid of everything from the exhaust manifold back, if you want the significant power gains.

 

As my MOT tester said you want to rip the lot out mate:biggrin:Very succinctly put. .

 

 

 

The supra is a de tuned 500bhp car. The stock  exhaust system is one of the devises used  by Toyota to reduce the power. MO

 

 

Link to comment
Share on other sites

 

Brian,

 

The Super Dragger you are buying comes in two parts,

the stainless back box and a non stainless pipe which

then joins to the CW de-cat pipe. You will notice a very

nice BHP gain when you fit the SD. You should see boost

rise to 1.1-1.2, CW's de-cat pipe at 2.5"d is designed to

stop too much boost creep.

 

 

BTW, it has to be said, the Blitz Nur-Spec not only has

a fully stainless back box, but a fully stainless middle pipe

and welding that made Ash go all gooey.

 

Blitz Nur-Spec superior ?  looks that way !

 

 

Link to comment
Share on other sites

 

 

Yep, he's right about the welding. It's not often I see a *perfect* weld. But the outlet pipe to rear silencer box was one of the best lines of TIG welding I've ever seen. Whether they are all like that I don't know.

 

As far as exhausts go, the Super Drager is still tops in my book. The Hiper looks a bit cheep and cheerful alongside the Blitz NUR as the latter is fully stainless steel. But it is about £100 more expensive than the Hiper. The sound of the Blitz is much like the Hiper but is a slightly more rounded and deeper sound.

 

But I still prefer the deep, throbbing sound of the Drager. It's a lot more subtle than the other two. Then again, load exhausts are not my thing. My customer was over the moon with the Blitz, though. Which is the important thing.

 

Yours,

J

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.

 Share

×
×
  • 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.