RB26 Single Turbo Advice - Not your normal question

[Up_Troys_Bucket]

Hi,

Have a new R32 GTR in the stable. It's a long story but suffice it to say I have very very little information on this car and it will, in the near future be heading to a mechanic to see exactly what has already been done. 

It already has a big single turbo conversion that is super laggy, full boost at like 5100rpm.

Straight to the very weird question:

I only want to make 400hp at wheels, I want the absolute best street response up to that power level. 

Putting twins back on is cost prohibitive. 

Best single for my purpose?

 

Thankyou 

[WantGTR]

Gen ii 3582r. More responsive than any twin setup and will make more power everywhere. Plus lots more than 400hp

[Up_Troys_Bucket]

10 hours ago, WantGTR said:

Gen ii 3582r. More responsive than any twin setup and will make more power everywhere. Plus lots more than 400hp

Thankyou for the suggestion. Just had a quick look, with a power range of 450 to 800hp it seems way out of my needs, especially coming in at $3,200. 

Does anything else offer good spool up time, more of a 450 top range and come in a bit cheaper? 

I do realise that a 450 to 800 HP window is a great investment at $3200 if you think you might upgrade later but I'm 100% confident I'm happy with 400-450hp

[Piggaz]

7670/1.05

e85

supporting mods

go.

[GTSBoy]

Next size down is GTX3076.  GTX turbos work best at high pressure ratios, so you might even be better off with a non-GTX (ie, GT).

Or, you could go to Borg Warner's matchbot and play with selecting from their offerings.  Likely cost more.

[r32-25t]

I would have said a gtx3076 or if you really want to be a tight ass grab a gt3576 off a fg xr6 turbo but 400hp will be pretty much it’s limit 

[WantGTR]

53 minutes ago, Up_Troys_Bucket said:

Thankyou for the suggestion. Just had a quick look, with a power range of 450 to 800hp it seems way out of my needs, especially coming in at $3,200. 

Does anything else offer good spool up time, more of a 450 top range and come in a bit cheaper? 

I do realise that a 450 to 800 HP window is a great investment at $3200 if you think you might upgrade later but I'm 100% confident I'm happy with 400-450hp

How much are you expecting to spend? What is the current setup? You can take a punt and buy a china version of the turbo if you want to save money. Its a waste but its cheaper.

[Griffin]

Borg Warner s256 or similar. Unbeatable for value and reliability.

Don't get caught in the crowd like all the other sheep on the forum. Do what suits your needs. 

Plenty of cheque book racers on here will tell you otherwise.

[Up_Troys_Bucket]

2 hours ago, WantGTR said:

How much are you expecting to spend? What is the current setup? You can take a punt and buy a china version of the turbo if you want to save money. Its a waste but its cheaper.

I'm not adverse to spending money, I just think if GCG are for example selling the GTX3076R for sub $2000 (admittedly for the RB25) with a 350-550hp range then there must be something in that price range to suit my needs for the rb26. 

I have also emailed gcg to see what they can come up with. 

[Up_Troys_Bucket]

3 hours ago, Piggaz said:

7670/1.05

e85

supporting mods

go.

Not keen on running E85 to be honest. Has to be achievable on pump gas

 

22 minutes ago, Griffin said:

Borg Warner s256 or similar. Unbeatable for value and reliability.

Don't get caught in the crowd like all the other sheep on the forum. Do what suits your needs. 

Plenty of cheque book racers on here will tell you otherwise.

Thanks mate, I will check it out now 

[GTSBoy]

17 minutes ago, Up_Troys_Bucket said:

I'm not adverse to spending money, I just think if GCG are for example selling the GTX3076R for sub $2000 (admittedly for the RB25) with a 350-550hp range then there must be something in that price range to suit my needs for the rb26. 

I have also emailed gcg to see what they can come up with. 

There's no difference in the application.  For all intents and purposes, once you take the twins off a 26, the turbo to make any given power level is essentially the same thing on either engine.

[Dose Pipe Sutututu]

7 hours ago, GTSBoy said:

Next size down is GTX3076.  GTX turbos work best at high pressure ratios, so you might even be better off with a non-GTX (ie, GT).

Or, you could go to Borg Warner's matchbot and play with selecting from their offerings.  Likely cost more.

I would go GTX3576R and a nice 1.xx rear divided housing.

Twins are not responsive, nor are they great for transient response. You need a good twin scroll setup, from what you may have there - it "could" be a dinosaur single scroll setup with a turbo from the 1990s.

[Griffin]

I'm using modified factory twin turbo manifolds with a single twin scroll housing, single 40mm waste gate.

Starts making usable boost from 2000 rpm. Power holds til 8000 rpm without dropping off.

Total cost of $300 for turbo, $4 for 2 x gaskets, $13 for marmon flange . Plus bits I had laying around and a tune.

 

[WantGTR]

5 hours ago, Griffin said:

I'm using modified factory twin turbo manifolds with a single twin scroll housing, single 40mm waste gate.

Starts making usable boost from 2000 rpm. Power holds til 8000 rpm without dropping off.

Total cost of $300 for turbo, $4 for 2 x gaskets, $13 for marmon flange . Plus bits I had laying around and a tune.

 

What turbo and how much power does it make?

[Griffin]

A borgwarner s256 ish off a diesel tractor. Touch under 400wkw. Left the 305 semis on. Not sure if the number would be different with smaller tyres.

[Dose Pipe Sutututu]

1 hour ago, Griffin said:

A borgwarner s256 ish off a diesel tractor. Touch under 400wkw. Left the 305 semis on. Not sure if the number would be different with smaller tyres.

If you ran it on the dyno with smaller street tyres it will read higher

 

[Dale FZ1]

1 hour ago, Griffin said:

A borgwarner s256 ish off a diesel tractor. Touch under 400wkw.

What fuel for that result?  I'm thinking E85.

Post up dyno sheet with torque curve if you've got one!

S256 is still a very good unit, given its age.  Application is on a John Deere harvester.  There's an updated/higher flowing unit too, called S257SXE.  Both built to deliver/handle high pressure ratios, so the thrust bearing is good.  I nearly got one but BW Matchbot and a bit of consultation with Full Race indicated they were a touch small for a 30DET.

Very good match on a 25/26 capacity and a comfortable 450rwhp on petrol.  If I still ran the short stroke bottom end, I'd go for one and spend on a twin gate/split pulse setup.

The new price vs performance for these things makes them a no brainer up against "budget" and "entry level" units.
 

[Griffin]

1 hour ago, Dose Pipe Sutututu said:

If you ran it on the dyno with smaller street tyres it will read higher

 

Ok thought that might be the case.

 

[Griffin]

That's without ecb connected. Single 40mm wastegate, twins aren't needed  imo. Turbo is extended tip compressor. The one I took off is from a CAT engine. Same size wheels with a different size/ shape rear housing. That's going on a 2630 now. Aiming fora responsive 300kw on p98.

That one has been on the rb26 for about 3 years trouble free. Not a drop of oil anywhere and zero wear.

 

Edited May 7, 2018 by Griffin
Typo

[Dale FZ1]

 

Pics show how tidy this one went onto a 25 Neo.  I believe some setup/tuning issues were being sorted at the time but the bones of the job are right IMO.