gutted cats today and ground out restrictor washers from exhaust today, (the ones just at the beginning of the mid section, on me jap import.

blimey what a difference this made, noticeable low down power turbo kicks in with more force. i really cannot belive the difference this mod has made.

all that i need now is for me breather kit to arrive for the weekend and i will fit me ECU and boost jets.

this has got to be the cheapest upgrade there is.

 

Sounds like dyno day II is just around the corner.

I have a mongoose exhaust already and I'm going to put de-cat pipes on when they arrive.

 

Will I then still have the restrictors on my jap import, or will they have been removed by one of these mods?

how much were the de-cat pipes?

 

Cheers

 

Vijay

The restrictors are in the mid section of the exhaust, these will be replaced by the Mongoose system. If you are dointg the decat pipes as well then you end up with two totally seperate exhaust systems, which is fine but there is naff all support for them. I found that they vibrated a bit, especially on tickover, the tail pipes were rattling against the body and the pipes were occasionally hitting the fuel tank. What I did was bolt a very short bracing strut between the bolts where the Mongoose meets the cat pipes. This seems to be just enough to prevent the problem and I assume takes some of the load off the downpipe/turbo castings.

Sounds teriffic though, a healthy rumble, but nice and muted. Some of the smoking under hard acceleration has also been eliminated, so Pete's theory that it was soot and crap building up in the cats, then being blown out was almost certainly correct.

I think the de-cat pipes were around £200. I can't remember exactly as I ordered them quite a while ago! Get in touch with Johnny and I'm sure he'll sort you out.

 

Not the best news I've heard Andy, but thanks anyway

Well i have dynoed with cats and without, and it made no difference whatsoever, except that it did come in a bit lower on the power graph.

Having said that it is better with the cats off.

But then i put mine back on lol.

But Waz, you didn't have de-cat pipes, you had gutted cats. This effectively creates an expansion chamber part-way down the pipe. Not sure that would be a good thing.

My de-cat pipes have a straight-thru silencer type jobbie in that position, which I reckon helps to keep the noise down but should have little effect on the gas flow.

I actually did have decat pipes in the sence that i compleetly removed the cats and had some custome pipes madeup.

 

Hnece why i refitted the cats.

thats right warren power comes on earlier for better side ways action. i actually gutted my cats punching through the center and pulling the shit out.

warren did you get those part numbers for me.

dave the answer is yes yours wont have the restrictors if you bought a cat back exhaust.

What, you pulled the shit out of the cat?!!! Poor little moggy!

Originally posted by AndyP:

The restrictors are in the mid section of the exhaust, these will be replaced by the Mongoose system. If you are dointg the decat pipes as well then you end up with two totally seperate exhaust systems, which is fine but there is naff all support for them. I found that they vibrated a bit, especially on tickover, the tail pipes were rattling against the body and the pipes were occasionally hitting the fuel tank.

 

Andy, do your decat pipes have a hanger on them like the original pipes? Mine do and I was hoping that that would be enough to avoid the vibrations you experienced.

 

I'll be fitting mine this weekend...

Erm .... No !