Hi all, just a question. Do you have to change the ECU if you are going to de-cat. Also is it safe to de-cat.

 

 

Also where can i get de-cat pipes from?

 

Ray

No need to change ECU, yes it is safe, although in some circumstances it may accelerate turbo seal demise !

 

Decat pipes can be bought from GPS, Z Centre, MJP etc

Decatting is a strange one.

 

It is illegal for cars 92+ to be decatted.

 

As for damage, it will speed up any leak on you turbo seals becuse of the increased pressure back up the exhust.

 

It makes the turbos spin up faster so you get more power lower down the rev range and you dont need any ECU change for it, but it is best to reset it after any mod.

 

However for NA I belive the engine will not run as good if its decatted. Something to do with needing pressure.

 

Stuart

Cheers guys for the replies.

Why does removing the cats cause the turbos to wear more quickly? Anyone got a technical answer, I am not looking for old wives tales.

Cats as we know are or can be restrictive and cause a certain amount of back pressure in the system, the rear seal on the turbo is kept nice and tight by this pressure, when you de-cat you change the pressure and over a period of time the seal on older turbos can soon start to wriggle around the piston it surrounds and cause escape of oil into the exhaust, hence they start smoking, once started you cannot stop it really, that's why the infamous Johnny breather kits were used, they put a little pressure back in the system again, but this only bought you more time. This is why all turbo's i sell have the race spec stagger gap total seal on them, they are not effected by the altered pressure.

cheers

smithy :cool:

Thanks, thats just what needed, a reply from someone who knows whats what, thanks.

The reason the seal goes is, with less exhaust back pressure, and the same oil pressure, the pressure difference across the seal is much greater so you stand a far higher chance of the oil getting past. Most turbo smoke problems are actually breather problems NOT rear seals ;) Smithy, where is this piston you speak of in the turbo??? ;)

How do you fix the breather problems? Are there any other symptoms of breather problems

What difference does having de-cat pipes make then? Surely the lack of back pressure is still going to be there whether you have the pipes or the gutted boxes :confused:

Originally posted by shaunmac

What difference does having de-cat pipes make then? Surely the lack of back pressure is still going to be there whether you have the pipes or the gutted boxes :confused:

 

yes!! ;) :D

Originally posted by Posidrive

How do you fix the breather problems? Are there any other symptoms of breather problems

 

Easy! Replace the PCV valves and the breather pipes. Courtesy Nissan in the states do a full kit for doing this - http://www.courtesyparts.com/z32/oe_pcv.html

 

Don't bother with the hose at the back of the block though - I seriously doubt you will be able to replace this with the engine in one piece and still in the car - I could be wrong though. The main parts to replace are the PCV valves and their hoses, and the breather pipes that go onto the turbo inlet pipes.

 

HTH

 

CheerZ,

 

Andy

Other symptoms of brether problems? Possibly oil getting past the cam seals/rear main seal, blowing the dipstick out is another. ALWAYS replace the PCV hoses at the same time as the valves - as you remove the hose it usually cracks into quite a few pieces - makes removal easier though! lol

What happens to the breather pipes on the turbo inlets? Is it clogging or leaks. Mine look in reasonable nick and the PCVs were done about a year ago.

 

How to you get the damn clips that a farthest from the turbo inlet pipes off/back along the hose. I've tries some angles long node pliers and this was just damn frustrating even before I resorted to drink :)