Decat

Iv'e read that a decat can blow the seals on a standard 20v turbo.

Therefore to have a decat, you have to upgrade the turbo.

Is this true, and if so how does that work?

Is anyone one running a standard 20v turbo with a decat?

Only reason i ask is because mine has a decat, and a standard turbo.

The seals on the standard turbo need some backpressure to work properly. Using a decat reduces back pressure.

Either get a hybrid turbo or put the cat back in - there are plenty of second hand cat's avialiable, so should be easy to do.

I guess technically its a matter of 'when' it'll blow the oil seals. Even when it oes it's not the end of the world, people have driven around on smokey turbos for months just keeping an eye on their oil levels.

By putting on a decat you remove the backpressure created by the exhuast gasses.

Like i say, you can run on a standard turbo fine, it just depends on its condition. Some will last a matter of weeks before they start smoking, others might go for a couple of years.

so if you have hybrid turbo fitted, decatting is the way to go then? and will a hybrid's seals not be affected by the decrease in back pressure ??

Really depends on what you want from the car. A decatted car will also fail it's MOT. Hybrids have uprated bearing and seals so are fine.

Yeah I was worried about that, but my local specialist said that decatting will help things 'breath' easier and increase power a touch, they also do MOT's and said they will just put the cat back for that then take it off after.....

so de-catting the coupe with a hybrid is ok then...

this may sound childish but has any one found there coupe popping flames at all??

i no its not a good thing to do but i was just woundering....

if it was decated it will pop flames.
a decat will help power and reduce lag.
the coop is the first car i have ever herd blowing seals but they do do it.

i'm confused....can someone explain the difference between a hybrid, and a recon unit ? dons't a recon unit have uprated thrust bearings & seals? or can you buy a brand new hybrid ?

You can get a recon unit that is completely standard, or you could ask them to put uprated seals or bearings in it.

A hybrid is a standard turbo with a bigger compressor wheel on it for more power. You can buy a brand new turbo and then get it turned into a hybrid, but usually it will be a refurbed one.

A recon unit could be a standard or a hybrid, depending on the specification of it.

A hybrid will usually be a recon but I suppose you could pay more for brand new components throughout.

A hybrid is simply a turbo that is not 'off the shelf' in it's configuration. You can easily have a standard turbo reconditioned with uprated seals etc. and it will do the job.

well i got mine done and they done some good work to it,
i had a 360 thrust bearing, new seals, and i think they said they had to hone it out abit to fit the slash back blades, in all, the turbo was gleaming when i got it back and drove like a dream and pulled really well!!

yeah you could but whats the point as its would cost near the same money as a hybrid

so if, generally, a hybrid is a re-coned & uprated unit, then is it gona suffer the same shorter life expectancy as has been discussed on here before?

Both standard and hybrid will smoke and can easily blow the seals. It all depends on the condition of these turbos and your driving style. If you decat a brand new standard or hybrid turbo i guess they will last thousands of miles.

For me hybrid is a gimmick by the after mart turbo sellers. You want more power and decat go straight away for the garrett ball bearing GT range. They cost more initially but in the long run it works cheaper.

Eh??, so the hybrid iv just paid alot of money to be supplied & fitted, is only likely to last about 2k ??

No - it will be fine. The roller bearing turbos are more durable, but to say a hybrid with uprated seals and decat will only last 2,000 miles is just daft.

My standard turbo didn't last long after I fitted a de-cat. I think it had done around 65,000 miles on the original and lasted around another 10k with the decat. It went bang and basically fell to bits. I then had a hybrid (GTiR) fitted and it lasted about 10k miles before beginning to smoke. Still not ablt to afford a proper GT, I had it recconed and it is still going strong after 98k miles (another 23k miles) with no signs of smoking.

In my experience a decent hybrid will be fine with a decat, a crap one won't and even the same turbo specialist will produce hybrids of varying quality. You're better off going for a GT nowadays though.

The hybrid should be fine with a decat, if not then it's been badly put together.

i hope not lol

i tell you what im getting a de-cat this week so i will let you know who it goes lol

i dont think it would blow the seals with in 2k
i think hybrid is a good option but roller ball bearing is a safer idea.

but it all comes down to cost at the time!!

Ball Bearing turbo is the industry standard today. No matter what the Hybrid sellers terms are ie cut-back, 360, screw-down, quick release its still a modified journal bearing unit. The ball bearing is 15% increase in performance. This data is from the Garrett site itself... check it out at the end of the page.

Journal v/s Ball Bearing Garrett

so what this thread is saying is with a good turbo, de-catting the coupe is ok yer?

For what iv paid to have this hybrid, considering my driving style & mileage, if I have any probs in the next 3 years i'll be taking it straight back to the garage

Yes, but not as good as de-catting with a GT roller bearing job

The quality of oil you use will also help it live a little longer as well. Although stronger for this application than a standard T28, I think it's fair to say that Hybrids aren't built as well as the factory made items...

I had a standard turbo, GTIR hybrid, and GT28R ballbearing turbos all on my car within the space of a year, the GT28R was the best

i agree to that! nothing is as strong as fatory made!

im going to use a de-cat with a T28 hybrid.

and i guess it the turbo does go...oh well i guess i will have to go bigger!!!

15% increase in performance is a meaningless figure. My old GTIr hybrid would spool faster than my GT28R, and have better throttle response. It really depends on what turbo specification and the application + what you want to get out of the turbo.

De-catting a 20vt isn't the reason for seal failure, lateral movement on the shaft becasue of worn bearings is the main cause.

Turbos have internal piston rings either side of the bearings that have a few thou for clearance, when the bearings start letting the shaft move the recess that these rings sit in is increased and then the seals are effected and thus the car starts to smoke.

A standard turbo will run fine de-catted if everything else is as it should be, boost leaks will make a turbo work harder leading to bearing failure, a blocked crank case breather pipe will cause internal back pressure reducing the free flow of oil from the turbo return, this again will effect the bearings in the end.

The seals aren't oil tight even when new, they do rely on oil pressure and a new turbo will smoke slightly if the car is left to sit an idle for an age.

My advice for anyone who has plans to de-cat their car, first check the lateral movement in the turbine shaft, if it moves don't de-cat it as it's already on it's way out, but that doesn't mean it knackered by any means. Turbos need some back pressure to work efficiently, a sports cat would be a cheaper mod in the long run if your car is fitted with a standard turbo.

I've a coupe here with 105k on the clock which still has it's original factory fitted turbo, there's movement in the shaft and a slight film of oil on the compressor intake, but the car doesn't smoke and it still boosts as it should do.

Now before you all jump on me with flames I've learnt all this from my turbo supplier who's been established for 27 years, there is nothing these guys don't know about turbos and the reasons for why they fail.

One thing not to be forgotten is that you can change the bearing on hybrid turbo with journal bearing. You can´t change the bearing on GT28R with a ball bearing, so you have to buy a new unit.

I was thinking exactly the same thing reading that, but then do garret make a roller bearing unit that is the same size as the GTiR? AFAIK, the GT28R is a bigger turbo that shares the same compressor wheel as the hybrid?

It depends on how you set up your other mods with these turbos. But I dont think Garrett would back a statement that says your Journal Bearing GTIR spools faster than your Ball Bearing GT. GT turbos are used by rally and race cars with lots of boost abuse and last for years. I wonder in competitive conditions how long a hybrid would last?

Joe is spot on. What he said makes sense.

Curious that a cosworth engine can and will run 100,000 miles on a standard T3 turbo when serviced correctly, and they have no cats....

And there's some utter rubbish on this thread!!

And I would place my trust in a properly built/spec'd hybrid. Garrett approved service centres like turbosystems build them and they last for years. Like almost anything car related, its the muppet behind the wheel that kills things.

Garrett's statement is likely true of a turbo with exactly the same spec if you consider journal vs roller bearings, however there is no way a GT30 will ever spool as fast as a t28 journal bearing.

This would be the closest:

http://www.atpturbo.com/Merchant2/mercha...tegory_Code=GRT

In my experience - The GT28R reaches 0 psi more quickly than the GTiR but the GTiR reaches full boost 1.3 bar about 200 rpm sooner. I found that once the GTiR hits positive boost it shot up really fast and gives you a real kick where as the GT28R has a smoother curve. You could say this is all down to the boost control but I've had PRVs, Blitz I-D III, AVCR etc and it always seemed that way to me. The GTiR hits at 3000 and stays solid all the way through the revs and the GT28R keeps getting better and better as the revs rise - 5000-6000rpm is where it's really at

Bang on with that description.

Got you Matt. GTir is kind of for the Wannabe's! GT28R is for the big boys and high boost heroes

this topic is great, it has gone from de-catting coupes to an all out turbo war!!

lmao!!

Well not said Suba

with everything said, and to be on the safe side, I'm on a mission to find a cat!

if i remember correctly the gt serious turbo when new have a plastic caged roller bearing

and if they fail, you can get a new metal caged bearing put in

not cheap though

Back on top,

when i had my coupe years and years ago the standard

turbo was smoking at 77k, which then got replaced
with a brand new GTIR hybrid,which i ran for 3k

before going to a gt28rs which now i have done 2k with a decat

Its all swings and roundabouts

Ben

so what happens to a standard turbo when you use a sports cat..say a 100 or 200 cpi..cos the back pressure aint gonna be as much as a standard cat...or is it..?

Should be fine with a sports cat.

i use to run a 100 cell cat with my hybrid and a little
time on my gt turbo with no problems.

Ben

marco i run a decat with a 360 degree thrust bearing its been fine for 9,000 miles and showing no sign of smoking.

when i 1st took off the cat the std turbo started smoking after a few hundred miles and the turbo was only on 53k scince its been reconned its been fine so far with the 360 degree bearing and 9k of use

nice one Boost me coupe up lol i forgot your name!!

well my de-cat will be fitted this weekend!

your coupe is looking oh so nice, i want the skirts back!

you going to any meets soon?

Yeah tell me when theres a meet and me and ollie will bring our coupes, did the links work for the pic above then?
i put a coupe pics on show us your motors and the new rr thread i just put on

havent looked....

doing it now lol