Standard catalyst converters are very restrictive and seriously limits performance.

Many people have blown their turbos due to decatting! I cant see how decatting can be the sole cause of this.

 

I would like to find out how many people have

1. Decatted & blown stock turbos, running standard boost

2. Decatted & blown stock turbos, running between 0.7 bar & 1 bar boost

3. Decatted & blown stock turbos, running over 1 bar boost

4. Decatted & no problems, running standard boost

5. Decatted & no problems, running between 0.7 bar & 1 bar boost

6. Decatted & no problems, running over 1 bar boost

do a search - there is a poll already on this!!

 

its not so much it causes them to go, more shows up a problem if they are worn.

Good poll that man.

hundreds of polls on same subject.

 

One thing to bear in mind is that some have been decatted, then 2,3,4 years later they develop a turbo seal problem - is it down to the decat or not !?

I know there are already polls on this. :) But they are just asking whether to decat or not. There are so many variables to consider and I cant see how decatting alone will cause problems and is more likely due to the boost. I think more research is needed and I hope this poll will help to answer a few questions :bow:

Old turbos + Decat and your in for trouble. Low milage turbos regular oilchanges every 3000 to 4000 miles with a good fully synthetic oil and no problems.

 

The biggest problem with these cars is that most are so called Jspec. 1989 to 1992 cars that would have failed imissions in Japan years ago. So where have they all been?

 

I've seen fresh genuine Jap import cars and they are like new. I've bought a couple. They come with Jspec log book and all auction paperwork and SVA approval sheet etc. I've also seen loads of the so called Jap import car dealers where all the cars are 12 to 15 year old and all done 60K. These cars have been thrashed aroung Indonesia for about 9 years then bough for buttons and sold over here as Jap imports. You only need to look at the interiors of some of these cars. My car is UK spec and has done 130000 miles and the interior is better than any Jspec car I've ever seen unless it's been completely refurbed. Or the genuine Jap imports which I've seen and the interiors are straight and don't look like and entire family have lived in it 24 7.

Standard catalyst converters are very restrictive and seriously limits performance.

Many people have blown their turbos due to decatting! I cant see how decatting can be the sole cause of this.

 

I would like to find out how many people have

1. Decatted & blown stock turbos, running standard boost

2. Decatted & blown stock turbos, running between 0.7 bar & 1 bar boost

3. Decatted & blown stock turbos, running over 1 bar boost

4. Decatted & no problems, running standard boost

5. Decatted & no problems, running between 0.7 bar & 1 bar boost

6. Decatted & no problems, running over 1 bar boost

 

Whilst decatting plays a major part in this theory of blowing turbo seals ( which i endorse IMO) it is not just doing this that is the sole cause.

 

The Zeds system like most turbo cars relies on back pressure, the current exhaust system was designed with this in mind and the Catts are the biggest cause of back pressure.

Now then, this is why also some do blow and some don't.

It is not just a case of who's decatted, but what exhaust system is fitted to the car as well, some exhausts are far more free flowing that others, so please also bear that in mind. But yes, IMO the catts play the biggest part with the exhaust playing a small part.

Mine went shortly after fitting an aftermarket exhaust system to an already decatted car ( 2 years previous) turbos were new as was the engine at the time, a whole new short engine from nissan 22,000 miles earlier :eek:

cheers

smithy

I've now had 7 300zx's 6 of which were TT's,all of them decatted and running a bar of boost with no turbo seal issues.

 

Paul

I'm not sure I can select any of the above options. When I decatted, I was experiencing some smoke but only when the car had been idling for 5 mins or more when hot. Could have been PCVs or rear seals but we'll never know now as everything is being replaced :D

 

Steve :)

I've got a 1995 Z32 (series 2) Twin Turbo with 60k miles on the clock. I believe these are genuine miles as there is a cambelt alloy sticker on the cam cover with a Nissan 94km etched into it, dated November 2005 (Jap Years 17/11).

 

The water pump looks new and I have recently had a knock sensor re-located due to the dreaded error code 34.

 

The mechanic at MJP inspected my car and said its in great condition.

Its the little things that tell you whether the car has been looked after. For example, mine has all four mud flaps, the sun visors on the t-bar roofs look new, dash in great condition with no peeling and the interior is in fanastic condition and it has high class mods i.e. defi guages.

I did pay a lot for the car though - £6200 but I believe you get what you pay for!

 

I have twin Kakimoto exhausts, not sure the diameter. Probably 3" piping.

 

The popular decats on Ebay are:

 

These are only 2 3/8" diameter.

 

1. Am I safe doing a decat considering the above?

2. Surely 3" (not 2 3/8") from turbo all they back is best? Will the 2 3/8" decats fit?

1. Am I safe doing a decat considering the above?

2. Surely 3" (not 2 3/8") from turbo all they back is best? Will the 2 3/8" decats fit?

 

Its a gamble

 

Why do you think 3" as opposed to 2 1/2" would be any better for decatting?

I want to keep all the piping the same size to maximise freeflow. What is the diameter of the cats and the rest of the piping?

Standard is 50mm 2" internal bore. Greg Dupree's super dooper 650 RWHP Z has 2 1/2" exhausts.

 

However if you increase the bore and decat you'll produce not back presure and it will flow better at High rev's, but watch those Turbo seals.

looking at the poll it looks more people have had no problems than the peeps that have

Well do a search and you'll find that this poll has been done many times in the past and I assure I personally only know Two people who have Decated and Tub seals not blown. One if them his car is now showing first signs. The other pulled his engine and sold it to Nend whilst the engine and tubs had only done about 34000 miles.

 

My original tubs lasted 122000 miles with the cats in and failed one week after the cats were removed.

I decatted about a year and a half ago and they lasted about a week before they started smoking. Finally getting round to having them done now but wish I'd got the sound advice I've had since before I did it.

I've now had 7 300zx's 6 of which were TT's,all of them decatted and running a bar of boost with no turbo seal issues.

 

Paul

ive had 3 auto tt,s and drove em like theres no tomorrow with no gearbox issues, lookes like we have loads of luck or its just not our turn yet :(