Gt3582R/gt3788R/gt4088R .

[discopotato03]

Searched under GT3788R in case people were wondering what they are about . This is a link to a Supra site and what some think of some of these units . http://www.supramania.com/forums/showthread.php?117662-Garrett-GT3788R...the-middle-ground-between-a-GT35R-and-GT4088R .

Just remember that BB GT37 and GT40 turbos are big frame twin scroll turbos and of all of them only the GT4088R is a purpose built petrol performance turbocharger . The three GT37BB variants are diesel spec units with lower temp spec turbines and turbine housings .

For 500 horsepower it may be worth looking at a GTX3076R or a std GT3582R .

A .

[The Dan]

I was driving down the road the other day and saw a bag in the middle of the lane. It was green in colour

[Lithium]

I assume there was a conversation happening somewhere that you felt your input was important enough to warrant its own thread?

I feel that GT4088Rs are more or less redundant these days anyway, so many other turbos around that do everything that they can do or better.

[BMYHOE]

the was a topic that was closed yesterday.. good to know disco..

[discopotato03]

Some people really like them , said to be a broad ranging thing for their intended power potential . Going to be a better dialed in thing than say a GTX35R . Actually a GT3582R is really a GT40 based turbo but in a small center section and with alien housings .

A .

[The Dan]

That is good information disco but none of it really will make any sense to the end user. They simply don't need to know that so it's not really important.

I have already spoken to this person about the various options for the power goal he has.

For a turbo to spool up the same response as a GT35R with a 0.82 rear and make the same or more power than a T04Z, I don't know why anyone would ever consider a GT35R ever again. They are also the same price

We have done nearly a dozen of these GT3788's now on all different setups inc 1JZ, RB26, 26/30, 25/30, RB25 and XR6 4.0L and they just hammer everything else out of the water.

They are a bit of a fall over in power in the top end when pushed but if you use the 0.99 housing they will go further, especially on a 3.0L bottom end like this guy has

[sky30]

I find it really hard to beleive that a gt3788 can spool exactly same as a gt35 on same motor with no other changes and similar a/r turbine housings ( both would need to be single or both twinscroll).

Any one seen results like this?

[GTScotT]

I find it really hard to beleive that a gt3788 can spool exactly same as a gt35 on same motor with no other changes and similar a/r turbine housings ( both would need to be single or both twinscroll).

Any one seen results like this?

Single scroll 35R

Twin scroll 3788R

Im sure that will help you. Results are there, its a nice unit.

[urtwhistle]

that and a GT37 is actually smaller on the turbine side than a GT35

[The Dan]

that and a GT37 is actually smaller on the turbine side than a GT35

Smaller trim, not smaller turbine

The GT35R has a 68mm turbine wheel

The GT3788 has a 72.5mm turbine

trim size on different turbines is not comparable

[sky30]

Yeah my point was it couldnt be exactly the same spool when using similar housing (eg both turbos with 1.06 twinscroll) as the wheels are larger in the gt37.

[R31Nismoid]

Trim also plays a part, not just wheel size alone.

It's possible to go UP in wheel size, but have better response if the trim is different.

[urtwhistle]

my apologies, I was under the impression that they were an odd ball size that was physically smaller also. I should have measured my Scania spec 3782 rather than making statements lol.

[discopotato03]

As has been said a lot over the years the small frame GT3582R has alien housings for its wheels both sides , I believe its because the original or HKS spec "GT3240R" used a T04S housing on the cold side and a HKS bored out GT30 turbine housing on the hot side . Garrett obviously thought we can do that too and used their own spec GT30 turbine housings . The result is their turbine maps for GT3076R and GT3582R units , bigger turbine in the same housing will flow more but ...

The larger frame units are diesel based ones and the ball bearing cartridge is an evolution of the big frame "GT" center section . The first of these AFAIK was the HKS spec T51R which like the T04Z and T04R 60-1 is modified bearing housing wise to take T series exhaust housings .

A few years back I looked into these GT37Rs and they all seem to be upgrades for Americal diesel "pick ups" ie Dodge Cummins Ram/GMCs/F111s etc . At home I had pics I downloaded and they all used Garrett lower temp spec materials in the turbine and its housing . This was a cost saving exercise because the higher spec materials for performance petrol spec turbos is expensive and in housings more difficult to cast . ATM I can't remember but the diesel spec turbines may have used an extra blade but I'll have to check later .

Comp wise these GT37R turbos used (largest to smallest) the 88mm C spec wheel or the 82mm GT40 56T wheel or I think an 82mm 50T version of the C spec wheel . Look in turbobygarrett under diesel upgrade turbos .

I believe Garrett has a problem with turbines and trims but they make them that way for a reason . They got it right with the 76 trim size on the GT28 NS111 and let us down by not giving use the larger 60mm 76T NS111 turbine (TR30R turbine) . From GT30 on to GT42 most of their turbines are 84 trim inc the cropped GT30 and GT35 turbines , the exceptions are the diesel spec GT37 and petrol spec GT40 turbines which are 78 trim .

The only reason to run big turbine trims is to get more flow through marginally sized turbines and turbine housings . The want to have a lot of gas flow capacity through a reasonably compact turbocharger is the reason we have units like GT30R and GT35R in the smaller BB frame size .

Medium turbine trims work well but when you market turbos on maximum power potential they don't "look" as good . When people want to have high mid range torque and acceptable boost thresholds suddenly big trim turbines don't look so good .

Anyhow most aren't after the sort of performance potential a GT37R or GT40R can give but to the few that are anything that can give a better boost threshold is a godsend and in these cases reducing the turbine trim from 84 to 78 was the way Garrett did it .

Big trim turbines tend to be narrow ranging things which is perfect in big diesel engines that run on full load for long periods of time . Not so good for a performance petrol engine where the wider the power range the better it works .

Note that HKS used T series turbines in the T51R and T04Z , the reason I reckon was those old Ts are 76 trim even though the GT42 etc turbines are more efficient things - not necessarily more responsive things .

ATM Garrett is more concerned with compressors and that is a cheaper way to go , eventually they will have to do something with turbines if they want a bit better response . It wouldn't be that hard for them to make GT30 and GT35 turbines in 78 trim but it would increase the parts inventory having to stock another complete range of turbine housings to suit .

Gotta go , freight train to chase cheers A .

[GTScotT]

Thanks for the above, I needed more insight into trims and sizes

[T04GTR]

dont all garret gt series turbos use inconel turbines? and "cast steel" turbine hosings are simply that? cast steel?

[discopotato03]

Nope , for more "extreme" conditions they use Ni Resist which is a high nickle content iron alloy and Inconel for the turbine wheel .

There is a large range of bush bearing GT series turbos for diesels and even a few ball bearing ones like those GT37Rs and the big framed GT3576R .

Garrett can't justify using expensive materials when cheaper ones do the job in lower temp environments .

Actually even some OE petrol engine turbos get the more mundane materials at times . An example many know is the SR20DETs , I think it was very late S14s and most/all S15s that got ball bearings and the better turbine and housing materials .

A .

[SilverECR33]

good read, thanks disco. however i think im in a gray area here between both of these setups. I sent ya a pm

[FineLine]

good read, thanks disco. however i think im in a gray area here between both of these setups. I sent ya a pm

Stop it Dale, you already know the answer.

I dont give a tinkers toss if garret originally made the 37/88 for a briggs and stratton lawnmower, It owns the 35r in every department. Most importantly in longegivity,

Stop thinking man, It weakens the team.

[Cowboy1600]

It wouldn't be that hard for them to make GT30 and GT35 turbines in 78 trim but it would increase the parts inventory having to stock another complete range of turbine housings to suit .

I'm still a turbo newb, so excuse my questions, if they seem a little silly.

By 78 trim do you mean the size of the exhaust housing? ie, 63 and 82 that we hear about.

So you're saying there needs to be a third option, a 78, which sits between the 63 and 82?

If so, like I said, I'm only a newb to the whole turbo thing so am still learning but this is something which became apparent to me very early on in the piece. It seems there is a void between the 63 and 82, at least for "our" motors. But then I suppose the 4 banger boys probably do well with the 63 and the 3L/4L boys fill an 82 or even 1.06 well. So perhaps the mid capacity motors, such as RB25/26s, are the only ones who would do well with something between a 63 and 82?

That is, of course, assuming we're talking about the same thing....