Advice on turbine size please 0.64 or 0.86.. TD42

[Hof]

Hello again,

Well I have been collecting a fair bit of advice from here and elsewhere, but I have basically decided I am going to go with the GT28RS disco spud..

Next thing, from the info I have read there is a bit of a divide on the turbine A/R, now before anyone jumps down my throat and says "depends on the application" which I FULLY understand now..

I just want oppinions or experience people have had or think about the use of each of these ratios..

Now the application for me will fit somewhere into 10-13psi boost, will be fitting a small TMIC.. From what I have read the 0.64 will spool up quicker, but im worried will choke the engine..

0.86 slower spool up but with more top end..

Hints/tips/advice,suggestions??

Thanks,

Ho

[vn15]

It depends on how the truck is used, pump set-up/std. or bigger plunger??
If offroad only/std. plunger, go for .64ar, otherwise, .86ar, or you will have too much backpressure/high egt.

I have GT2871.86AR on my RD28T, have 12mm plunger, FMIC, 3" zorst, water injection, LPG injection, custom intake, and heaps more.
Truck is used only on the road and works great have 35" and 6" lift on it.

Boost starts at 1300-1400 rpm, 0.6 at 2000 and peaks(1.3bar) at 2700-2800rpm. Truck puts out around 250hp, very good midrange/top end power, all the way to 5500-6000rpm.

[Hof]

Hi thanks for the reply..

Its stock standard and I'm not modifying pump, plunger, etc..

Is used as daily, touring and offroad..

Cheers,

Hof

[TheDato]

Hi Hof,

I have a .86 disco potatoe on my TD42 no intercooler, a bit of a tweak on the fuel screw and only 21/2" dump and exhaust (a 3" system is on the way though). The turbo starts to boost (ie. 2 psi) at 1400rpm and builds to a wategate limited 10 at 2400rpm according to the vehicle tacho and boost guage, EGT's under load get to 500c. I've not had it on a dyno.

It has transformed the vehicle as a road car. The turbo is well on song when cruising at 90 - 100 Kph so it no longer dies in the bum at the sight of a hill. The biggest difference is that it goes about the same even when it's loaded up for a few days away. It used to $hit me when it was loaded up because it was a total slug. In the bush, in low range I don't notice a huge difference but it does pull better for sure especially in the 1600 to 2400 range. Going by the seat of the pants I think there's less engine braking though (is that possible or just my imagination?).

I have been told that the .64 will require more boost (I think in the region of 20+ psi) to keep enough air going in (more air = leaner mixture = cooler EGT's in a diesel) to stop EGT rising to buggery and probably an IC as well. The down side is that the extra boost will effect engine life. I have no first hand experiece with this though so I'm merely passing on what I was told when researching which turbo to fit to my vehicle.

I hope that helps.

Cheers
Muz

[badger]

I have been wondering the same thing.
i have a modded pump and injectors. but dont wish to run over 20psi (i currently run 15).
i just want boost to come on low and hard and for it to be able to hold max boost unil redline.

wich one is more suited to me?

[oondy]

I'm about to get a 0.64 Disco Spud. I've been told to go the 0.64 as the 0.86 will be a bit laggy with the stock pump.

My mate in his GU Ute runs a turbo with same Turbine housing as the 0.64 GT28RS but different compressor, he's got a 4" inlet, and hits full boost of 20PSI @ 2000RPM, pump mods and has 186RWkW. He says that his isn't choked at all at higher RPMs with the 0.64 housing. When cruising at 100-110 it only sits on about 4PSI boost, BUT when he sinks his boot in its crazy - hold on.

He says he gets lower egts now than with his tweaked stock setup, he says that the 0.64 housing is a lot bigger than the factory turbo on the TD42T.

I'm still undecided really but i'm leaning toward the 0.64 housing, but "The Dattos" results speak for themselves too, and Turboglide use the 0.86 housing in the GT28RS Kits also.

tell you what Hof, you buy a 0.64 and then tell me what its like, then I can decide.....LOL.....

cheers

OONDY

[Hof]

Yeah, I dont rev much past 3000rpm, so I am still thinking the disco potato might not be what Im looking for.. I dont really care about the boost value I just want something that is reliable and boosts up quite quick..

O well I guess ill just have to keep reading and asking

Cheers,

Hof

[nikka]

Ive used both housings on my GU ute which runs 35's and standard ratios.
Im also using a front mount intercooler.

The .64 housing boosted instantly and peaked around 3200 rpm, very fun and easy to drive. I had 130kw at the treads with a stock pump (20psi).

I then modded the pump which caused the EGT's to go a bit nuts.
So went to the bigger housing. It brought the temps down and made more room for fuel. Now have 146 kw running 15 psi, a bit laggy but more happy to rev, more gear changing to keep on Boost in the bush though.

The .64 is probably the way to go with what your after...........

[badger]

with the .82 by lag how much do you mean?
when do you start to see boost etc?

i have my pump and injectors modded i intend to run about 15psi (with a lil head room incase i want more later:P) and would like the motor to hold boost up to redline. that said i dont want a lag monstor.
my current turbo is getting very tired but boosts 10psi before 2000rpm and holds 15psi till redline.

wich would be best suited to my application?

P.S. im also considering a turbo cam at some stage wich would prob make the .86 the choice

[nikka]

With the .86 housing the turbo spools a bit off idle but doesn't kick you in the arse until around 2000 and is pretty happy to 4000. When I say laggier I mean its not instant power off idle like the .64, Its more progressive I guess, with more potential power higher in the range.

Pulling through the gears down the road there really is no lag.

Of course if I ran 33,s or less it would be a different story as I run stock ratios.

Overall I think the turbo suits the engine really well, Some guys are using the GT28 in 71 trim which I believe is 'laggier' again but allows for more Horse Power......

[Hof]

Well my very first thought when I was deciding on turbo's was the disco with the 0.64 trim..

My only concern was choking the engine at higher rpm, but since I dont rev the guts out of my car I don't think this will be a problem..

I will be running stock pump, and most likely TMIC, though this will be small (but if not really neccesary I prob wont bother)

Also 33's for tyres and standard ratio's..

One thing I would like to ask is do you have to run 20psi or can the wastegate be set lower??

I just wonder how detrimental this kind of boost is to the engine.. I was thinking more around 11-15 something like that..

The other thing is you said some people run gt28 in 71 trim, do you mean compressor or turbine, because disco potato is 76 trim, and on their website there are no 71 trims in gt28 range..

Thanks heaps for the info, it is much appreciated!

Hof

[Hof]

My bad, there is a gt28, same size turbine, bigger compressor 71trim..

[Rampage]

With the .86 housing the turbo spools a bit off idle but doesn't kick you in the arse until around 2000 and is pretty happy to 4000. When I say laggier I mean its not instant power off idle like the .64, Its more progressive I guess, with more potential power higher in the range.

Pulling through the gears down the road there really is no lag.

Of course if I ran 33,s or less it would be a different story as I run stock ratios.

Overall I think the turbo suits the engine really well, Some guys are using the GT28 in 71 trim which I believe is 'laggier' again but allows for more Horse Power......

hey mate, you say it lags a bit compared to the 0.64 but what about compared to standard setup on the turbo on the TD42T?? Im looking at upgrading my turbo and think that the 0.86 is better as i want reliability and ;lower egts so you reckon this is the way to go?? BTW my old girl has 280,000km on clock, thats nothing to worry about if changing turbo??

cheere

[nzdarin]

I ran 20psi on my old TD42 for 3 years including comps etc with no issues. As long as you keep egt under control then 15psi to 20psi isn't an issue with a TD42. When doing your research were you talking to people about this specific engine as it can handle a lot more than say a Tomota.
We are currently building a motor for one of my support crew. It has a Safari kit (with standard T3 turbo). The head has been ported and gained 28% more flow with vey little work. Valve seat cut and cam ground. The pump has had plunger mod etc. Also wil have water to air IC. This is in a DD and will be running 16 to 18psi. At that level of boost it should last a long long time!