RB30DET turbo choices

[Steve]

Skyrine-Dave, I was also under the impression that the designation R was used for a hybrid turbo with different spec compressor and turbine.

Garrett dont use naming conventions like GT3040 as such - perhaps this is something started by the local turbo manufacturers to cash in on HKS's popularity? From what I was told the GT series just use the first two numbers ie, GT30.

This is what I was told by a turbo shop anyhow.

[Skyrine-Dave]

Garrett dont use naming conventions like GT3040 as such - perhaps this is something started by the local turbo manufacturers to cash in on HKS's popularity?  From what I was told the GT series just use the first two numbers ie, GT30.

Bingo! exactly what i reckon. As for the 'R' just download the Garrett pdf and it states all.. If my acrobat would let me select the text i'd copy it word for word

[Steve]

do you have a URL?

[Skyrine-Dave]

Here is an image from the pdf... will edit post when i find pdf online

EDIT: here's the link to the latest pdf... I advise you right click - save target as... it is pretty big and takes a while to load if you just click the link

http://www.turbobygarrett.com/turbobygarre...7%2017%2013.pdf

[drunkenmaster]

Ok, another question:

How does desired boost pressure affect turbo selection?

i.e. is there a rule of thumb in turbo sizing for low and high boost applications?

[Sydneykid]

Hi drunkenmaster, I have a few questions;

The RB30DET, is that with an RB25DET top end, RB25DE top end or RB26DETT top end?

If you used an RB25DET top end, do you still have the standard turbo?

What are you going to use the Zed car for?

Is your power target really only 250 rwkw?

The compression ratio of 8.3 to 1 and 1 bar target boost, are they correct?

What engine management are you using?

What boost controller?

With these answers I can give my opinion.

[drunkenmaster]

The RB30DET, is that with an RB25DET top end, RB25DE top end or RB26DETT top end?

RB25DE

If you used an RB25DET top end, do you still have the standard turbo?

No

What are you going to use the Zed car for?

Road car with light recreational track.

Is your power target really only 250 rwkw?

I beleive so, in a 1000kg car I think it should do fine.

The compression ratio of 8.3 to 1 and 1 bar target boost, are they correct?

Yes

What engine management are you using?

Undecided, most likely autronic SM2

What boost controller?

Like wise.

Background:

I am building the car from the ground up, over the last 6 monthes I have stripped the car to a shell, had it sandblasted on a rotisserie, now it is at home with the engine bay and interior painted only and the RB30DET has just arrived home from the engine builders. I have to finish off work on completing my garage/workshop so this gives me some time to do some research/shopping etc.

I could have bought a GTR with the projected cost of the project, so understandably funds are starting to slow down now and hence the interest in running an internal gate and saving $2k of manifold and gate.

Thanks for your help.

[Sydneykid]

Thanks for the answers to my questions, my 20 cents worth follows;

Don't be concerned with the weight versus power, we have an 1180 kg R32 GTST with a bit over 400 rwkw. So 1,000 kgs with 250 rwkw is a no brainer.

I understand your reasons for going internally gated. The compression ratio and boost target don't really suite a HKS turbo, so I would go with a Garrett. My new turbo choice would be a GT25R, they are good for 450 bhp (270 rwkw) and cost around a $2,500.

In the used area, Japanese Motorpsort had T04E kit (turbo, manifold, wastegates) for $2,600 a few days ago. So it might pay to check around, as even if the T04E is totally stuffed they are a cheap ($600) full rebuild. GCG had a used (fully reco'ed) T04E (internal wastegate) for $1600 (turbo only) when I was there yesterday, so that may be an alternative as well.

With the SM2 you can adjust the boost rise, so I would not be concerned with violent power increases. You can soften it up with a few keyboard strokes.

Hope that is of some help

[drunkenmaster]

Thanks for the input.

Does the GT25R flange suit the RB manifold? I had thought (with no evidence) that the GT25's were matched to the SR series.

The decision i have to make is that the GT3540 i have in mind is new and around the $2k mark.

I also had a look around and both horsepowerinabox and UAS offer bolt on upgrades which look like standard turbos with GT cartridges, also UAS have the internally gated GT3040.

There seems to be too many choices to do the same thing.

[Sydneykid]

Does the GT25R flange suit the RB manifold? I had thought (with no evidence) that the GT25's were matched to the SR series.

The decision i have to make is that the GT3540 i have in mind is new and around the $2k mark.

I also had a look around and both horsepowerinabox and UAS offer bolt on upgrades which look like standard turbos with GT cartridges, also UAS have the internally gated GT3040.

There seems to be too many choices to do the same thing.

Hi, you can get GT25R with T3 flange. I am sorry, but I am now confused, I asked......

Is your power target really only 250 rwkw?

You replied....

I beleive so, in a 1000kg car I think it should do fine.

If you had said that your target was really 300 rwkw then I would have recommended the internally gated GT3040. If you had said your target was 350 rwkw then I would have recommended the externally gated GT3040. The reason for externally gated is that I have a rule of thumb, I don't use internally gated single turbos over 300 rwkw. Their response and boost control becomes questionable.

So I don't think there are too many choices, if you want 250 rwkw then GT25R, if you want 300 rwkw then internally gated GT3040, if you want 350 rwkw then externally gated GT3040 is the go.

Or have I missed something?

[drunkenmaster]

Thanks,

very definitive answer there!

What is the GT3040 made using or do garrett actually supply this combination?

So the GT3540 is sliding out of the question?

[Jaws]

Out of all the turbo's mentioned above what ones will bolt straight onto a rb25det standard manifold?.

I would like a custom manifold but I'm not seeing many available, the ones that are, are way too expensive.

[drunkenmaster]

All of them will, whether there sheer size will foul up against anything is another matter and whether you want/need and external gate will also dictate whether you need a new manifold.

Half my dilema above is the fact I cant really stretch the budget another $2k for a new manifold and external gate when my project is already running $10k over budget.

[discopotato03]

Always lots of confusion here . Most Garrett Ball Bearing Turbos (GT)'s have a two or four digit number , eg GT30R . The 30 denotes GT30 series exhaust turbine . It could also be called GT3037 because it has a GT30 turbine and a GT37 compressor wheel . There are exceptions to this eg HKS GT2540 has a GT25/28 series turbine with a TO4E compressor wheel . Some firms such as ATP Turbo in the US have come up with numbers like GT2871 and GT3071 to be difficult . With the last two the second two digits means 71 actually 71.1mm diameter compressor wheels which are GT35 wheels . So a GT3071R could be called a GT3035 by some .

Be very careful with GCG and Ray Hall as they are selling turbos they call GT30's and GT3037's which use old outdated TO4S compressor wheels (1976 vintage) which are the same family as the old 60-1 or 409535-1 as the part number goes . These wheels are seven full and splitter blades and were designed to pump large volumes of air at medium pressure ratios ie one bar or 14.7 psi . They take more shaft torque to drive than the later 97 era six bladed BCI-18 compressor wheels and impart more heat into the inlet air . This shows up as lag (caused by slip losses at the turbine) and increased charge temperatures .

The latest theorys suggest that sizing the turbine and comperssor wheels nearly the same makes for similar tip speeds . If properly sized (both) this increases the engines volumetric efficiency and allows it to produce more torque per pound of boost than the current crop of mis-matched turbos .

Always remember that aftermarket turbos are only a very small part of Garretts business and OEM are where the volume sales are at . Turbo development is an on going process and there are good things in the pipe line . Look at Australia as a backwater for these things and look to the US for the latest stuff . ATP Turbo.com shows details of most of the latest GT-R (not Skyline) series Turbos and the GT28RS and GT3071R seem to be along the most modern lines .

Chow A .

[drunkenmaster]

Very interesting.

So which suppliers are actually supplying complete up to date turbo assemblies?

[Skyrine-Dave]

MTQ Engine Systems pty ltd.

National Garrett Distributor... why go anywhere else. one in each state i think. I got my GT35 for alot cheaper than most places are selling them

[Jaws]

The price difference between a tO4E and a gt3040 is quite significant.

-What differences would be noticeable while driving on the street between the 2?.

-Would the boost come on at the same rpm with both turbos.

PS: For a rb30det:

*power fc and boost controller

*1200 kg car

*300 rwkw

*external wastegate

*factory rb25det exh manifold.

[MonstaS4]

Sydneykid, i'm confused.....

My new turbo choice would be a GT25R, they are good for 450 bhp (270 rwkw) and cost around a $2,500.

According to the Garrett catalgoue, a GT25R is only good for 250 bhp. It has a max air flow of about 26 lbs/min at 1 bar. I thought an RB30DET would peak at about 35-40 lbs/min, but i'm tippin' i've overlooked something

[discopotato03]

There is a GT28 turbo that depending on who you talk to is rated at either 290 0r 320 hp . This item is a common upgrade for CA18's and SR20's and I think is the one in the catalogue .

The one you are after has a 71.1mm TO4S wheel in it and depending on the trim is rated at 350 , 400 , 450 hp . None of these has stellar performance , mainly because of the mis-match between the turbine and compressor major diameters ie 53.8mm (turbine) and 71.1mm (compressor) . When you look at the GT3071R it uses a GT30 84 trim turbine (60mm x 55mm) and a GT35 56 trim (71.1mm x 53.1mm) compressor wheel . Its turbine has very high flow capabilities for it s size , and its compressor wheel is three generations more modern than the TO4S . The compressor is rated at 44lbs/min flow which equates to about 450hp . The turbine is a late high tip width UHP (ultra high pressure ratio) and in a suitable GT30 housing has supported 500 plus hp . The GT3071R is being sold by ATP Turbo.com in the US and if enough people start to demand later technology it will turn up here too . Don't even bother with Garrett in Sydney because they've probably never heard of it and are not interested . Obviously it's easier to sell outdated technology to the un enlightened .

Hope this helps A .

[discopotato03]

The price difference between a tO4E and a gt3040 is quite significant.

-What differences would be noticeable while driving on the street between the 2?.

-Would the boost come on at the same rpm with both turbos.

PS: For a rb30det:

    *power fc and boost controller

    *1200 kg car

    *300 rwkw

    *external wastegate

    *factory rb25det exh manifold.

The TO4E is not really the equal of a GT3040 . Most TO4E wheels have a major diameter of 76.2mm (3") while the GT40 wheel is I think 84mm , higher flowing and more efficient (generates less heat through better design) . To match the GT30 turbine you would have to use an old heavy TO4 O or P trim turbine . So more innertia to over come and less efficient air pump plus the legacy of bush bearings and thrust plates to lunch .

If you seriously want 300rwkw I would look for a GT3240 , or if boost response is a priority use a GT30R with the larger 1.06 exhaust housing and a large external gate . These things don't come cheaply , but offer you a better chance of achieving your goals reliably and less chance of anihilating your engine .

Have fun A .