Looks Like Garrett Slipped Another Gtx30 Variant In .

[discopotato03]

Yep waiting for this result because it's the first line in the sand with an RB25 . It will give an idea how this turbo runs with an 82 turbine housing and I'm curious to know if it gives high enough gas speed to make meaningful boost in the lower mid range . Like Lithium I'm wondering about wheel speed on slightly smaller diameter compressors .

I could wish for a slightly larger GTX compressor and just a smidge larger compressor housing like say a T04B 0.70 AR . These housings you generally don't see in performance petrol turbos though I suspect Hypergear is using a version of them in some of their larger Hi Flows . They have the large diameter inlet boss so it should be possible to machine the port shrouding into them like Garrett does on the 60-67mm GTX T04B 0.60 AR housings .

I know I'm using the force here but I reckon there's more to the 10 odd pounds airflow difference between a GTX3067 and a GTX3071 than meets the eye . Using the same turbine housing ie 0.82 AR IW evens the hot side but I wonder if one of Tao's comp housings would help close up the cold side potential .

Just as a heads up Garrett generally uses the large inlet boss and 2.5 inch comp housing outlets on their larger 0.70 AR housings , they do on the T04B T04E and T04S ones mostly anyway . You can buy the Garrett T04B 0.70 AR comp housing but it comes machined for a larger inducer wheel than a GTX 67 so not a bolt for the wheel anyway . AFAIK it uses the same T04 backplate adapter ring for the Garrett GT BB cartridge .

I'm sure Tao has it worked out , cheers A .

[M@&k]

So you're saying a slightly larger A/R comp housing would be of benefit? Never quite got my head around compressor A/R, but thought main effect of going larger was increasing efficiency at lower pressure ratios. Or in other words moving efficiency island downwards on the map.

Edited June 28, 2014 by M@&k

[AngryRB]

I have a 0.63 Garrett housing if your interested in a swap..

[M@&k]

Nah, thanks. I'm just keen to get it back on the road now.

[Lithium]

I bet. So have they not even given an idea of how it is going so far? I'd expect that if they have started trying to tune it that despite boost control issues (whether over or under shooting their targets) they'd have a reasonable picture of if things looked like they were going to be on target or not when kinks are ironed out.

Regardless, hope it all gets sorted out soon!

PS.

In regards to the compressor a/r conversation - I have seen and considered the compressor maps for the GTX3067R compressor wheel and housing combination, and while hypothetically speaking there may (or may not) be gains to be had from a better housing match to the comp wheel etc - I feel that with the information given from Garrett in regards to the comp and turbine sides that a 0.63 a/r and the off-the-shell wheel/housing cold side would give the results you appear to be searching for... at least with suitable boost control. Not sure what to expect from the 0.82a/r setup.

PPS. If I had an ethanol content sensor plumbed into my bloodstream - there would be some amusing logging to be looked at. I look forward to reading this post tomorrow, and seeing if I managed to come across as coherant as I am trying to. Apologies in advance if I failed at that, or my pleasure - depending on how entertaining - or useful this post is

[AngryRB]

Not sure what actuator you have, this is the one from my garrett housing, I think its supposed to be 14psi

doesn't look hard to adjust it.

Edited June 29, 2014 by AngryRB

[M@&k]

Not sure what actuator is being used. I know they tried adjusting already, and now my understanding is that they're looking at getting a different (maybe higher rated pressure) actuator.

Lith, where did you see the compressor map for the GTX3067? The only one I saw from Garrett was identical to the GTX2867. I had to compare the GT2871 and GT3071 to get an idea of what difference the bigger turbine would make.

I've been told the tuning is mostly complete, just that they're trying to sort out the issue of the wastegate opening prematurely. Only indication of performance is that it's making "good hp". I hope that means it's meeting expectations.

[GTScotT]

Lith: can confirm inebriation levels were insufficient for impacted coherency. Must try harder next time. As for ethanol blends, as a wog friend as their parents probably have something pretty close to e100.

M@&k: when looking at compressor maps you are literally only looking at data for the compressor, so looking at the comp map for the 2867 is fine as long as the two units use the same compressor wheel and housing. As for turbine flow you can pull that chart from whichever other GT30 base unit is available. There are no maps which represent a turbo as a 'whole'.

Update on my own car (for those who are aware): I am currently cruising around in it untuned and am loving life. The GTX3071 leaves nothing to be desired over any smaller turbo setup I have driven (on an SR). Trying to keep the gate closed is a challenge and the car is super fast pre-4k. I will upload a video of partial throttle spool shortly.

[scotty nm35]

Update on my own car (for those who are aware): I am currently cruising around in it untuned and am loving life. The GTX3071 leaves nothing to be desired over any smaller turbo setup I have driven (on an SR). Trying to keep the gate closed is a challenge and the car is super fast pre-4k. I will upload a video of partial throttle spool shortly.

My 71 spools up nicely, I agree. I ended up making similar power as the 76 was cranking out, must be a brick wall somewhere in the system. (probably my stock cams and 220mm cooler)

I feel the 71 is perfect on my 2.5L, the 67 should be very interesting on 2L. I am interested in results mainly as I think it would make a good turbo for my 2.3L evo, still undecided as to how far to go with it, stock transfer case and all.

[GTScotT]

As noted:

Edited June 29, 2014 by GTScotT

[M@&k]

M@&k: when looking at compressor maps you are literally only looking at data for the compressor, so looking at the comp map for the 2867 is fine as long as the two units use the same compressor wheel and housing. As for turbine flow you can pull that chart from whichever other GT30 base unit is available. There are no maps which represent a turbo as a 'whole'.

I see. I always thought the turbine would effect the map as well. I've read elsewhere that the compressor to turbine wheel ratio is much better on the 3067 vs the 2867 which would lead to higher efficiency. I assumed this would show up in the comp map as well as perhaps a slight shift to the right given the larger turbine.

Thinking about it now though, I guess the compressor should flow what it flows, and turbine only has an effect on the shaft power coming in at a given rpm.

Attached is comparison of 2871 vs 3071 both in 56 trim which I was referring to. They do use different A/R comp housings though. Would that alone explain the difference between these two maps?

[scotty nm35]

The 71 map just looks better everywhere to me.

[Lithium]

I would say the difference there is the smaller frame housing they used on the GT28, definitely nothing to do with the turbine and I am pretty sure it us the same wheel.

In terms of the GTX2867R versus the 3067 I believe they have the same housing and wheel so comp map should be the same... I haven't checked back to back but I have checked the GTX3067R maps in context of a stock Bolton RB25 setup and I am content that it should be a nice fit for what it seems like you are after.

I am on my phone so won't get too long winded or animated but the simplest and most to the point part of where the attraction of this on an RB25 versus a GT28 based unit comes down to a mixture between driving the compressor, as you mentioned ... but a big issue with GT28s or trimmed GT30S is the outright turbine flow versus what is got out of it.

Overly simplified, imagine for a given amount of airflow into an engine two different turbines will create different amounts of back pressure between the engine the the wheel...all other things being comparable. Imagine that amount of pressure is more or less comparable regardless of the engine setup and boost level, it's just how hard it is to force that amount a mass through that kind of restriction.

Now imagine two different engines with exactly the same turbo and making the same power but different boost levels required to make that power...whether that be due to engine size, head flow, or any combination of things. Let's say one engine needs 14psi and the other needs 20psi to make that same power figure, and we are sticking to the assumption that they both generate the same pressure at the turbine due to moving the same mass (ie, whatever lb/min of air and the relevant amount of fuel to attain target AFR)...and say that magic pressure amount is 22psi.

What will be seen by the tuner when tuning these two setups is on 20 psi this are pretty happy...the fuel curve should look pretty kosher and it's not hugely knock limited or anything for that boost level, however on the same note the 14psi setup could be starting to show signs of being past it's best. That all comes down to the relative pressure across the engine, the whole idea of increasing performance especially from a VE stand point is making it as easy as possible for stuff to flow through the engine. Gases like to equalise pressure so the bigger the pressure difference one way or another, the higher the want for the flow to change direction to the lower pressure .

Reducing the exhaust side pressure relative to intake pressure has a positive affect on both VE (ie kw per psi) and also helps avoid onset of knock due to hot gases flowing slowly out of or back into the cylinder and making it too easy to burn when it's not quite time to. RB25s can be pretty efficient engines when not choked, so putting GT28 turbines in tight a/r housings on them is just cruel and unusual. I think the GTX3067R has the potential, especially with the 0.63 housing, to manage the relative flow on a boltona RB25 to make the most of that compressor while being a responsive wee beast and not choking the motor...at least in an unbalanced way.

Looking forward like everyone to see how the theory matches up, hope they can suss out the boost control to do I some justice

[M@&k]

Thanks for taking the time to edumecate me gents.

Update from me. Heard back this morning. Apparently the issue was that the actuator was faulty. They were swapping that out and then put it back on the dyno to confirm. I know I've said this many times already, but should be finished this afternoon. Provided there's no more issues, I hope to be picking it up tomorrow.

[discopotato03]

Just on the GT2871R 56T vs GT3071R 56T , the compressor housing families are different . T04B 0.60 AR on the 28 series and T04E 0.50AR on the 30 (cropped and full) .

The HKS GTRS and GT2835 Pro (cropped GT3071R 56T) pretty much same but port shrouded comp covers in most cases .

My take on GT30 hot sides on RB25s is more flow , the engine makes more torque down low off boost because it's a more efficient piston pump . You get back most of anything you lost from early boost by advancing the timing . The GTRS by comparison made usable boost earlier but the engine was never as free spinning as with the 30 series .

I think the hard thing to explain to someone that hasn't tried a decent spec GT30 is that you get real good drivability and part throttle torque but real shove in the back comes at higher revs than with a 28 series , it's mainly the full bore (throttle) performance that moves up the rev range . I've only had a 0.82 AR turbine housing so I don't know how the 0.63AR directly compares back to back .

I'm going to assume that Garrett's standard spec GTX3067R had the 0.63AR turbine housing because they though the smaller diameter 67mm compressor needed a few more revs to make boost in the lower mid range . I also think they may have aimed these turbos at people with 1800-2400cc four cylinders and sized the turbine housing to make them come alive in the 2500-3000 rev area . Some of the builds with GTX2867Rs make good numbers but somewhere between having a marginal turbine for a 500 Hp compressor and pushing things exhaust flow wise make a bigger turbine a better match overall . 28 series are logical bolt on upgrades for CAs and SRs but RB25s need larger flow paths than GT28 turbine housings have - even the HKS T3 flanged GT28 ones . I suppose once you get more serious with a CA or SR you'd go for a T3 flanged exhaust manifold and this IW turbo would be a good all rounder on the street . Said to be a better package than a GT3071R and more compact too . Win Win .

The 3067R should be a very streetable unit on an RB25 and the 82 housing will give you low exhaust side restriction , it should allow fairly advanced light to moderate load timing and on boost it should be good in this area if the exhaust and intercooling is effective .

The thing it may not do is give high dyno numbers compared to larger GT30s but at the end of the day if it's free spinning (engine not car) and struggles to gain traction with the boot in who cares .

A .

[wolverine]

Has the 0.63 ever been a restriction under 280rwkw?

I would want as much twist on a GTX compressor as early as possible. Sure we know we can tune an RB and make them go ok with appropriate fueling and more timing down low but surely the point of going for a highflow sized turbo is to get some action happening early.

[Lithium]

Update from me. Heard back this morning. Apparently the issue was that the actuator was faulty. They were swapping that out and then put it back on the dyno to confirm. I know I've said this many times already, but should be finished this afternoon. Provided there's no more issues, I hope to be picking it up tomorrow.

Cool - fingers crossed that sorts it and you get to reap some rewards soon!

[Dale FZ1]

Adrian I've driven both 0.63 and 0.82 and 0.87 Pro S equipped GT30 setups. And I've provided comment about relative performances.

Characteristics aren't radically different. Basically the smaller housing provides higher gas speeds earlier, and at least with Mafia's setup also became restrictive earlier so it stopped making torque in the higher rpm range (ie power peaked sooner than the 0.8 sized housing).

The on boost torque curve effectively shifts to the left by 500-750rpm dependent on pipework, attention to smooth transitions, and whether it's on alcohol or water injection. Your 52T 3076 if/when tuned should be on full song from somewhere between 3800-4200 so that should tell you when Mafia's became lively.

Andrew's comments are hitting the point. He's got the experience of having owned/tuned a few GT30 variations and this smallest unit is going to need some shaft speed to start pumping. And it's not likely to have enough compressor to seriously tax the flow capacity of a 0.63 and choke it. I'd think that you blokes were reasonably accurate in saying the 0.63 "should" be the best match for this 3067 spec on a RB25. The 0.82 is likely to just make it take longer to come on.

Mark has indicated several times he was hoping for an outcome similar to the 2835 Pro S, and with the smaller housing I think it will. Plenty of ignition advance will help the 0.82 spec unit drive into boost and feel as lively as a 2.5 can, but I'd certainly want this baby making noises sooner to justify/accept the lower peak flow it provides. I'm still thinking the projections for anything much over 250rwkW on petrol only (ie no E85 or water injection) as wishful thinking.

I do think it offers good streetable potential and hits the targets Mark is chasing. Watching with interest but it's not going to be the magic solution that the hype has been suggesting here.

[M@&k]

Agreed on all comments on 0.63 v 0.82 housing. For whatever reason MTQ and Galvsport decided on 0.82, and when I queried, they said boost response was good. Won't know for sure until we see results. Also agree I shouldn't inflate expectations, but honestly I'll be disappointed if it only manages 250.

[wolverine]

It will be a good drive IMO either way...261.6rwkw is my guess.