The Garrett Gt30r Thread - Lots Of Info And Q's

[juggernaut1]

No problems Dane.

[cheegar]

Would there be any real noticeable disadvantages in running the 2.75' inlet as opposed to the 4"?

I have had a good read through and unless ive missed it theres not much mentioned about it.

Btw this is for a gt3071r IW .82rear on an rb25det looking for 270ishkw

Cheers, Chris

Edited February 5, 2010 by cheegar

[JonnoHR31]

2.75 will be fine, easier to install and wont cause any restrictions

[aleks]

Pity these weren't released late last year Ian!

haha just when i get my car running if I found out they started making 1.06 and 0.82 split housings

I wonder how far away untill they release the full series of GTX-R turbos

[Don Dada]

LOL good thinking I will have to anyway, as I have been holding off doing a proper dyno tune on the car until I am content with the boost control. I'll have to take it for a blat and see if I can stabilise the boost curve, and if so it will be on to the dyno to get the tune refined - would quite like to knock that 300kw mark.

So what's the word Lith?

Any results with the big can yet?

[gotRICE?]

I think Lith and I are both waiting for the same tuner.. hehe. Unless he snuck in under my nose

[chrisR34GTT]

Hi guys, I've read through the thread after deciding that I want to do an GT3071R upgrade to my R34, with the aim of achieving 250rwkw of street responsive power. Current mods:

3inch exhaust

fmic

boost controller

550cc injectors

z32 afm

nistune

From my research this is the turbo I have spec'd up. Please let me know if I am on the right track as this is all new to me.

Turbine : GT30 84 trim (60.1mm inducer diametre by 55mm exducer) .

Compressor : 71.1mm 56 trim .

Compressor Cover: Not too what I should do here??.. Inlet 2.75" 0.5AR, Inlet 4" 0.5AR, Inlet 4" 0.6AR port shrouded (what does each do? Is 0.6AR available?)

Cartridge number : 700177-23 .

Exhaust Housing: 0.63 IW (also mentioned by cubes that Garrett also provide a larger internal gate off the shelf??), 0.78 extude honed or 0.78 twin scroll v-band. What are the last two exactly?

Edited February 26, 2010 by chrisR34GTT

[GTScotT]

I dont know where you will get the .78 housing from, but you will run into boost control issues with the .63 IW housing.

Front covers, realistically the options are .50 2.75" and .50 4" and either choice is up to you, i do not see there being a benefit in the 4" considering the actual inlet to the turbo is smaller than both. as for the .6 cover, having done the maths i dont see the need for the surge slotted cover or the extra size in AR.

there are a couple of other threads with GT30 information going around right now.. you may want to check them out.

If you are sure on your plans for 250rwkw, and are not aiming for more, you may want to reconsider your turbo choice. A HKS GTRS will set you back roughly the same amount as setting up a 3071 will and be a total bolt-on. The GTRS will net 250rwkw with ease, the dyno thread shows just about everyone running one is hitting 250. The amount of area under the curve is enormous on that turbo, and its designed to work.. so no mixing and matching and chasing down big boost spike issues. If you havent already check out nengun. also, if you decide you want over 250rwkw you can get the HKS GT2835 pro S. Do the maths on how much your proposed GT30 setup will cost, then check out the prices of the HKS kits... its not that far apart for something that is engineered to work well.

[discopotato03]

Probably take a little while but someone may sell you a GT2835 Pro S turbine housing if you search around .

At times people have bought them and then opted for the larger 0.87 A/R turbine housing , if they don't want to keep their original 0.68 Pro s housing you may be able to buy it from them .

It's probably not a bad idea to use a port shrouded compressor housing and I reckon it'd be possible to mill the big boss version of the T04E housing to achieve it . A bit of milling can make the jelly bean shaped grooves and the slot turned in afterwards . Make sure that slot is positioned properly near the splitter blades or it won't work .

A .

[chrisR34GTT]

Scott, I opted for a 0.63 IW as from what I read the 0.82 IW would be slightly laggier and more suited to a setup that would have more headroom for power later on. But seeing as I'm comfortable (at least for the interim) with 250rwkw I thought 0.62 would be ideal? Is there any other way to get around boost control issues without sacrificing response?

In regards the choice of kits I had thought HKS kits would be right out of my limit budget wise and checking Nengun like you said shows that a GTRS kit will set me back $3K and a quote for a GT3071r kit (without intake and boost pipe) was $2K. So I would definitely like to stick with the GT30.

Now another option that I could take again would be the GCG high flow option. I have heard that these should see 250rwkw with great response but no one has been able to tell me the specs of the turbine or compressor wheel, other than one is steel and the other is larger respectively. Now one of these is $2K, is this a better option? Disco?

[DiscardTheWeak]

will a gt30r fit low mounted on an hks manifold in an s14

[discopotato03]

If better means easier to fit with no non std parts then I guess so .

You could shop around for a 2nd hand GTRS , cartridges for them shouldn't be hard to get . The HKS housings are the important parts .

A .

[tridentt150v]

The cost in the 3071 is in the dump pipe, I think the HKS units bolt up to off the shelf split dumps, but the Garrett item needs a custom job?

[wolverine]

Now another option that I could take again would be the GCG high flow option.

I have back to back tested a GT-RS and GCG Hi-flow on a neo engine and it was pretty line ball. The GT-RS had a very slight edge over the GCG unit by making power a whisker earlier.

Considering the price differential the GCG unit is hard to beat and I reckon impossible to pick seat of the pants.

My money would be on buying a GCG hiflow for 250rwkw (+/-10kw) if you are determined to get more power then this is you are getting into GT3076 territory.

[GTScotT]

Im not sure about the GCG vs GTRS, there are alot of mixed results with the GCG while the GTRS seems quite consistent.

As for easier to fit, its more so buying the random bits equating to a relatively similar cost to the kit. I am personally one always fond of a clear outcome, a HKS kit bolts on in 1 way and has a predictable result within a certain range. Not to say that one is not able to get the same results from a similar package built from garrett and custom bits yet the results to base my expectations on are far and few.

As for 2k for a GT30 vs a 3K GTRS kit; dont forget, the GT30 itself costs 2k.. You then need to fabricate a line kit to the tune of roughly $200, a suction pipe which for a pro to make may want a few hundred on his own.. I have seen people use a 90 deg bend and some silicon but dont forget you will also need to add fittings for the blow off and breather to the motor. Personally I am a major fan of the stock blowoff so I couldnt not add one in, the cost of the 90 deg elbow and 2 silicon joiners will set you back roughly 100 plus perhaps another 100 in having someone add some fittings to it and some extra pipe here and there to connect it all back up (seeing as nothing is stock anymore). You then have the problem of spacing the manifold which has been said to cost as little as $5 but it all adds up, and making a new dump which IMO would be to the tune of $400 Minimum. I dont think running a stock based bolton housing on a GT30 is advisable at all, considering the .63 IW has a hard enough time controlling boost as it is.

Realistically when chasing the results a couple of hundred extra is hardly worth squabbling over.. Considering the HKS kit also comes with gaskets which I have not mentioned above. There is always more to the story than seems, and not everyone can fabricate their own parts.

If wanting above 250rwkw, and do not want to outlay the 3k in one hit, perhaps a 3071 .82 IW or 3076 52T .82 IW would be the way to go.. I am more fore the 3071, while others are heavily more in favor of the 3076 (but in 56T form). One option I am keen to see results on would be the 3076 52T .63 IW although i suspect the outcome would be much like the 3071 .63 IW in terms of boost spike, and I am just not confident in the .82 setup. I like to feel the car give you a sense of urgency that only bad take away curry can give you, like you are more than compelled to keep your ass glued to the seat for you fear the aftermath of standing up at the wrong time.

Yet the answer to all lies in the balance of an external gate and manifold to suit.. And there goes 5k on what will probably match the 3.7k GT2835 pro S... along with all the lead time and obvious cop bait attraction.

Sigh, yet again I find myself revisiting the prospects of a one off garrett build up.. And I was so sure a GTRS would be solve all

[wolverine]

There are mixed results for the GT-RS too, like the difficult to reproduce >300rwkw claims.

There have been a number of variables from R32, R33, R34 turbine and compressor housing variants plus whatever GCG are doing to them internally from the early days of the "500hp" version that surged to the latest version that seems to be well sorted.

Having back to back tested them I am convinced the GT-RS will come on ever so slightly (very slightly) earlier but the price differential makes the GCG turbo the best value in the 450hp range. If you want more power I think this makes an orphan of the GT3071 on an RB25 as it makes more sense to jump to a GT3076 if you want more power.

DaleFZ1 has back to back tested (on the road) a HKS2835ProS and a GT3076 56 trim comp with 0.82 internal gate he might be able share his experience.

Any of these turbos will be absolutely fine.

[GTScotT]

Noone ever said pushing a t28 to 300rwkw, but GTRS making a solid 250rwkw is plentiful in the results thread.

I myself am a major skeptic of the 3076, and would be much quicker to jump on the 3071.. Yet ofcoarse this is my own opinion, and Im well accustomed to being hated for it

A good thing to see would be a 3071 with .82 garrett IW... back to back on a 3076 on road rather than on dyno, and ofcoarse against a gated .63 of the above 2 types.

My brother runs a .63 ex gated on a 2.6 astron in an old sigma, with the first cam spec he ran with a max RPM of about 6000 (alot for an astron) it would come on VERY early and hard, which gave me alot of faith in the setup, although, with a bigger cam to allow revs up to 7000, it became an all out dog... with a 2500 stall on a C4 also.. I am tempted to salvage this setup off his car (currently in storage) but not sure I want to at this stage.

[wolverine]

I hope you mean salvage the turbo and not the Astron.

[GTScotT]

one would hope so, fecken clunker lol

[discopotato03]

You would expect a 650cc per cylinder four banger to get one of these turbos going reasonably early , Stateside they find the Nissan KA24DE (DOHC 16v) four makes good torqe and boost in the mid range .

To put this into perspective if an RB could have 650cc pots it would be 3.9 liters .

Cheers A .