New Garrett Gtx2860R / 2863R / 2867R

[The Mafia]

I emailed them and got this:

 

Thanks for the enquiry. We can supply these with an 0.64a/r, which would definitely bring them on earlier, although our testing did show the test vehicle surging under light throttle. However, we haven’t tested these with the new surge slotting on the compressor housings, so it’s something that could possibly work, as long as the engine is capable of handling the airflow that the turbochargers provide.

The issue we had originally is the GTX turbochargers push a HEAP of air into the cylinders, but the engine just could not handle the excessive flow, and this is where surge occurred. If the cylinder head is modified is the right way, and you have a nice big volume plenum, the issue shouldn’t present itself. Keep in mind we cannot guarantee they will not surge.

You also need a big BOV if you’re planning on running these (Turbosmart Race Port 50mm should do the job)

[burn4005]

no, its the lack of surge port in the original -5 housings pushing the surge line too far to the right when using the GTX wheels

the only place a 2860-5 compressor will surge before the GTX2863 in the correct housing is between 14-18psi, and there is only maybe 2lb/min in it.

as already established, the lack of surge ports is the problem.

whether they've designed these retrofit antisurge covers correctly is anyone's guess, and if they haven't tried them on an RB26 why are they selling them as a bolt on kit as it would appear they have done no testing. even the  A/R of the comp housings match.

Edited November 28, 2017 by burn4005

[r32-25t]

From my conversations with gcg they have been tested on at least one car and that car was built by a very well known workshop, gcg also recommended they be fitted to a larger capacity engine due to the extra lag they have

[Piggaz]

On 27/11/2017 at 4:18 PM, The Mafia said:

Okay I missed those posts. I thought they would have performed better.

 

Those ones above look interesting. I wonder if you can put smaller rear housings on them, like a 0.63

Why would you put 0.64 rear housings on them?

Lets take a big step back and go through this. First things first, standard intake piping. It's tight, small with horrible bends... how much air do you think those pipes can flow? Put a MAP sensor on them somewhere and I bet you will be seeing a vacuum that Dyson would be proud of! That's issue 1.

Issue 2. Jamming wheels into housings that they don't belong in. The GTX 67 mm wheels in the proper housings flow 46 lb/min flat stick. What will they flow in A) GTR compact housings and B) dealing with the nugget OEM pipework? I bet it won't be 46 lb/min!

Issue 3. Turbine wheel. It's the same turbine wheel as what is used on the 2860 -5 which flows 36/min. Somehow it seems to be a thing to just keep throwing larger compressors at a turbo charger with no thought given to the other side. It's just retarded. Air in AND out. How can you get more new air in when the hot side is choked up like a mofo? If it worked then we would all be running pro mod 88 compressor wheels with stock rear wheels and housings. Somehow I don't think that would work. ?

Issue 4. Turbine housing. THEN you take off the 0.85 housings which would have allowed it to relieve itself a little (seeing that the turbine wheel hasn't grown) and tighten it back up. 

2540's - big front, small rear... nuggets

GT RS's - big front, small rear... nuggets.

This really is not a hard concept to grasp. 

Why is it that any of these GTX low mounts don't seem to go much further north than 500 kw (on an RB) irrespective or what size compressor wheel is it it? The cars that use the genuine GTX housings always seem to give a better result. Why? Because it FORCES you to redo the intake piping and go to a 3 inch pipe. However, that doesn't fix the poor little hot side. If you get blinded by the compressor map (which seems ALL too common around here) the 67 mm should make some bloody big numbers... never quite get there though. I wonder why? ?

Would love to see the EMAP of a GTX 2867 0.64 AR. It would be absolutely horrendous. 

Its no different to say a GTX 3582 and jamming a 0.63 rear housing on it. You're A) not going to make the power the compressor can give

B) Everything is choked up. More heat, more pressure. It's all bad. 

Dont want the power that a 3582 can give? Go back a turbo size and keep the larger ass end. It will be a much healthier way of doing it.

[BakemonoRicer]

im with captain Piggaz....GT-R owners need to f**k off the twins and f**king man up....

go a big single with a big ass end.... or go fking home. twins are like f**king with a condom, its not the real deal!!!!

[sneakey pete]

Still maintain i would like to see tomei ARMS with a GTX3071 grafted in somehow.

But then again just get a bigger single

[Dose Pipe Sutututu]

On 11/28/2017 at 8:40 PM, BakemonoRicer said:

im with captain Piggaz....GT-R owners need to f**k off the twins and f**king man up....

go a big single with a big ass end.... or go fking home. twins are like f**king with a condom, its not the real deal!!!!

I've told *cough* someone this 10 years ago, he only listened this year.

[Mick_o]

Oh its been longer than that brah! ?

[reaper]

He listened about 2 years ago its just taken this long to actually drive

[GTRsean]

Tuned today at 101 motorsport, hot and humid day too. Being the baby gtx2860's I think they did well considering.

e75 in the tank                                               nitto 2.8 with otomoto v cam          walbro 460 fuel pumps x 2                          1300cc bosch injectors                              100 cell cat, 3.5 inch exhaust

[burn4005]

what's your redline? trying to work out when these are coming on rpm wise

[GTRsean]

I added some rpm numbers. Roughly that. Rev limit is 9200. Noses over due to either timing backing off approaching revlimit or valve float?

[GTSBoy]

It's not valve float.  Either exhaust flow or timing.

[The Mafia]

2 hours ago, GTSBoy said:

It's not valve float.  Either exhaust flow or timing.

I was thinking the same thing. I would love to see the timing map / AFRs.

GTRSean, can you post a screen shot of your timing map / AFR?

[NissanForLife]

It will be the turbos losing their efficiency and engine pumping losses through small housings.  If you could get external gates onto these twins, I think it would be a different story.  
My engine would not rev much past 7000rpm for this same reason, but man, the response was phenomenal.
I had to run 33psi to get 648hpatw out of my GTX2863 hybrids, when trying to get LPM out of small turbos, sadly the pressure has to go up which hurts intake temps and efficiency. 

[NissanForLife]

The bigger the overlap in the cams, the longer (time) there is a straight passage through to the exhaust housing from the intake manifold.
As the pressure builds in the small exhaust housings, you need more and more boost pressure to push against the exhaust pressure to scavenge the cylinder.   
This is why you don't need as much PSI on larger single turbos, the exhaust flows much better and the lower pressures of boost inlet is enough to achieve the same LPM of air into the cylinder. 
This why I laugh when people gauge an engines "stress or strain" based on PSI figures, it really tells very little, other than how much load the turbo is under, not the engine.
Heat is the killer for twin setups, one because of increased PSI inlet temps and 2 because you can't evacuate the cylinder as well as you can a large single setup, the flow is not there and keeps heat from exiting effricently.   
Yes the increased pipework surface area etc is a factor, but is one of the smallest contributors IMO.
Inlet temps are very important, especially when you do the maths for the compounding effect of inlet temps and then compress it in the cylinder, the cylinder temps skyrocket. 
Just my 2 cents worth and hope my experience helps others 

[NissanForLife]

Throw an EFR 8374 on there Sean and watch your rev limit go way higher 

[GTRsean]

Was told even a gtx3582r gen2 with a 1.01 rear would be nice if I went single.

Pretty happy with the result and how these little lowmounts went.  There is always going to be limitations with these setups but the way it performs, considering people keep asking me if it's a single turbo, I ain't complaining

[fatz]

15 minutes ago, GTRsean said:

Was told even a gtx3582r gen2 with a 1.01 rear would be nice if I went single.

Pretty happy with the result and how these little lowmounts went.  There is always going to be limitations with these setups but the way it performs, considering people keep asking me if it's a single turbo, I ain't complaining

Are you trying to say there are alternatives that are pretty good

 

but the Gtr Jesus (motive DVD) tells otherwise... #stockbottemendworldrecord

 

f**k now I will have to sell the  auto gearbox

[SimonR32]

15 hours ago, fatz said:

Are you trying to say there are alternatives that are pretty good

 

but the Gtr Jesus (motive DVD) tells otherwise... #stockbottemendworldrecord

 

f**k now I will have to sell the  auto gearbox

#notanymore

I did a 9.609 @ 146.10mph on Wednesday