Modify your Pre-CAT

[Monty]

The Stiffy is suppose to fit the stock system too, this will replace the precat right up to the turbo. Stevo is now doing the stiffy with the theaded hole for the o2 sensor and i think he`ll have them jet hotted to

[Elanlover]

Thanks Monty, I've also read that its recommended to port the wastegate at the same time. To be honest, I'm a bit nervous about doing that (just me, nothing to do with the car) and was wondering if its fine to leave it as is. I'm assuming there won't be any adverse affects to leaving it stock but minor imporvments if ported. Is that correct or do I absolutely need to port the wastegate? Thanks!

[Elanlover]

Also, I PM'd Stevo indicating an interest in his "Stiffy" and has yet received no reply. IS he away or am I the only one being ignored because I'm still showing as a "newbie"?????

(Actually, I've been upgraded to "tinkerer" status now )

[Monty]

yes i believe u have to port the wastegate as u get boost creep, i`ve got all this to do I`m sure Stevo will respond, don`t forget to mention u need the stiffy with the O2 sensor hole

[MIKCARUS]

Hi ,
This is a great post and thanks to all for the very good info' but can you tell me if the gaskets and pre cat are standard Isuzu? please as I realy fancy doing this job .

MIKE.

[Enright]

Mike, if I were you I'd be a lot more concerned about how you're going to tackle the 3 pre-cat to exhaust nuts/bolts. They're about THE most solidly rusted on the entire car. If you've recently "gone Peco" or something similar then it's well worth exploring further. But if you're attacking them for the first time, youre probably best off popping down to your local Kwik Fit and slipping one of their monkeys a tenner to get their oxy-acetylene to them. They may be able to dig out the right lower gasket for you at the same, but the upper one is re-useable.

[GeoffSmith]

But if you do, I would recommend replacing them with stainless studs and nuts. Very reasonable prices from the Sultans of Bling.

[MIKCARUS]

Thanks for that guys,
I have stainless from the main : cat rearward but don't know if I should get rid of the lot, from the manifold to the new pipe or just clean out the crap in the pre-cat,
May take all that out and make a complete section in stainless. I do tend to replace all bolts exept high tension with stainless steel, but a good point as they don't cost much and save a lot of time in the future.
Somehow I will make this sound and go like a sports car!

Thank's for advice. Cheers MIKE.

[Enright]

If you could make a straight section to replace the cat, but make it so that the cat could be easily put back in position for the MOT (and then removed again immediately afterwards) you would be near to utopia.

[MIKCARUS]

Yes good point Neil, I may need to put it all back at some point,I need to get it all off at some stage and see what bits I can blag from my s/steel supplier. as pointed out I first need to see if the rusted bits will shift or go to "Quick Fit".
Hope I don't need to put it back for M.O.T. but you never know?

Cheers, MIKE.

[max and andy]

I'm just about to place an order for a Piper 2.25 single box no cat exhaust . £287 inc VAT. Before i do .Is there any other make that i could take a look at .Same sort of money.Are there any other parts i need to order that I'm not thinking of ?Has anybody got an old Pre CAT that they want to get rid of ?I want to pre prepare and remove restriction before removing the one on the car. Thanks for all your help Maxine & Andy

[HJ2]

By the way: You don't need to remove the pre-cat to empty it!

While my car was up in the air for fitment of a PECO / Cybox exhaust, the pre-cat could easily be emptied with a screwdriver and a hammer. make sure all the garbage is out before reconnecting the downpipe.

[nitroman]

By the way: You don't need to remove the pre-cat to empty it!

While my car was up in the air for fitment of a PECO / Cybox exhaust, the pre-cat could easily be emptied with a screwdriver and a hammer. make sure all the garbage is out before reconnecting the downpipe.

For me anyway, it would be very hard to COMPLETELY remove the converter matrix given access only to the bottom 2" opening; a bit like laproscopic surgery I'm afraid. I would imagine you didn't remove the contents yourself, or you would not be saying it was easy. If you BREAK APART the converter matrix, which you would have to do to affect an inferior/caudal "medulla-ectomy", know that the microscopic shards are like tiny razor blades in your eyes and lungs, and will damage those delicate tissues. Goggles and some sort of respiration device must be worn. I would also be concerned that you could leave a considerable amount of residue around the inside pheriphery which will come loose later and partially clog the metallic-mesh packing of mufflers and resonators.

In the end, if you are at the point where you have access to the bottom of the unit, you should seriously consider removing the remaining bracket & six top bolts. If not, pay some sap to have all the detritus fall on them, instead of you.

[HJ2]

I was standing right next to the chap who did it. 10 mins of battering with hammer and screwdriver or chissle did it. All the remains came out. No adhesive at the bottom so the framents don't stick where you can't reach them with a tool. Cleaned flange before fitting... presto!

You are right, ALWAYS use protection, not just when beiing intimite but als when working on your ride. Don't lift the car too high so you have to look in the converter from below saves you an extra shower.

If you're conspicious, go ahead and remove the lot

[nitroman]

There is a metal upside-down u-shaped ring at the bottom of the converter-matrix, press-fit inside the cast-iron shell. Just breaking-up the converter-material will not allow this to be extracted, as it is too big to fit through the lower opening. Left in place, it will interfere somewhat with smooth exhaust flow.

[max and andy]

Is t here another exhaust upgrade .Besides the Piper Rs Same sort of money £300. Max

[GeoffSmith]

The Peco is available from Cybox for £325 or make an offer.

[HJ2]

Yes there is: Cybox (PECO) (whoops, Mini was ahead of me, but see my message a few posts up )

The Ring stays, true, but compared to the 2"restriction it is a restriction beyond measuring capabilities. It is possible that it makes the flow even better. The ring brakes up the flow, causing turbulence. The trubulence makes it easier for the mainflow to pass the 2"orifice restriction.

Complex matter that cannot be answered without FEM analysis, backed up with actual experimental measurements. Luckily even without analysis it is safe to say that you cannot feel if the ring is still in place or not while driving

[max and andy]

Ive read that Peco had stopped making them.Which have the best reviews would you say . Max

[HJ2]

Hi Max,

The Cybox IS the Peco