Jump to content
SAU Community

Recommended Posts

Did a fair bit of searching and couldn't come up with anything about running two SR20 turbos on an RB26.

I know that the GTR uses a compact 5bolt pattern that is not compatible with the regular 5bolt pattern.

I'm assuming there would be clearance issues between the front dump and the rear inlet trying to use regular SR20 dumps?

I'm hoping that with all the aftermarket twin turbo kits getting around that there are GTR dumps designed to suit the regular 5 bolt pattern?

Anyone have any ideas? Otherwise I'll just get some GTR dumps and having the flanges changed over.

Link to comment
https://www.sau.com.au/forums/topic/284159-two-sr20-turbos-on-rb26/
Share on other sites

Send in your stock GTR turbos we can high flow GTRS CHRA into them and every thing bolts back. Lot better then SR20turbos. Also stock SR20 turbos are running off .64 rear and 270 degrees thrust. Plus nothing fits. But if you really want to run SR20 CHRAs we can machine your housings to suit it so every thing bolt on no fibrications required.

Not really keen on spending that much money for highflowed turbos.

What is wrong with .64 rear housings? I thought SR20 turbos were ball bearing (eliminating the need for thrust bearings). What else is there that will not fit?

Machining housings to suit sounds like a bit more work than perhaps 1 custom dump pipe?

only S15 Jap Spec SR20 enignes has Ball bearing T28 turbo. By the time you get the turbos, with customized dump and intake pipes made you probably be spending the same amount as highflowing. plus most of them are 10 years old and will be very laggy to run on standard Twin GTR setup.

Did a fair bit of searching and couldn't come up with anything about running two SR20 turbos on an RB26.

I know that the GTR uses a compact 5bolt pattern that is not compatible with the regular 5bolt pattern.

I'm assuming there would be clearance issues between the front dump and the rear inlet trying to use regular SR20 dumps?

I'm hoping that with all the aftermarket twin turbo kits getting around that there are GTR dumps designed to suit the regular 5 bolt pattern?

Anyone have any ideas? Otherwise I'll just get some GTR dumps and having the flanges changed over.

lot of other issues to contend with other than the dump flange. dont know why you would want to run such crap turbos to begin with (they are good for scrap metal only), gtr turbos second hand are the same price anyways.

Edited by URAS

Your call but not as easy as it first appears . Like people have said nothing fits - except the turbine housings mounting flange and even then I thought GTR GT28 turbine housings were threaded for either studs or through bolts .

The bottom line is that even the factory twin turbos and associated plumbing is all up close and cuddly - and that's with factory engineering .

SR20 GT28 turbos or rather their housings are not even close to what RB26 spec GT25 or GT28 turbos use , they won't position the turbos or their plumbing where everything needs to be - note the "eye" holes on the bottom of GTR spec turbos compressor housings , SR spec or generic comp housings don't have them .

As I said your call but the best minimalist approach (IMO) would be to fit fresh cartridges between the std housings even if that means machining them to suit .

No offense but I wouldn't go near a "budget" RB26 with GTRS/GT2871R cartridges , I would NOT machine the std 26's small comp covers to suit 71mm compressors - too small and defeats the whole purpose IMO .

May seem expensive but really bolt on turbos like the GT2859R's are good things , unfortunately I don't think their cartridges are available separately which is a shame .

You can't really cut corners with bastard twin turbos - way too much time and money involved proving that it doesn't work . Nissan didn't just throw a couple of generic dryers on RB26's , it's not as easy as designing a single system but does have advantages .

Over to you , cheers A .

Your call but not as easy as it first appears . Like people have said nothing fits - except the turbine housings mounting flange and even then I thought GTR GT28 turbine housings were threaded for either studs or through bolts .

The bottom line is that even the factory twin turbos and associated plumbing is all up close and cuddly - and that's with factory engineering .

SR20 GT28 turbos or rather their housings are not even close to what RB26 spec GT25 or GT28 turbos use , they won't position the turbos or their plumbing where everything needs to be - note the "eye" holes on the bottom of GTR spec turbos compressor housings , SR spec or generic comp housings don't have them .

As I said your call but the best minimalist approach (IMO) would be to fit fresh cartridges between the std housings even if that means machining them to suit .

No offense but I wouldn't go near a "budget" RB26 with GTRS/GT2871R cartridges , I would NOT machine the std 26's small comp covers to suit 71mm compressors - too small and defeats the whole purpose IMO .

May seem expensive but really bolt on turbos like the GT2859R's are good things , unfortunately I don't think their cartridges are available separately which is a shame .

You can't really cut corners with bastard twin turbos - way too much time and money involved proving that it doesn't work . Nissan didn't just throw a couple of generic dryers on RB26's , it's not as easy as designing a single system but does have advantages .

Over to you , cheers A .

Off topic but since you mentioned the whole twin v single thing... In your opinion is it worth going twin scroll single or twins...?

I was contemplating getting stock 26 turbos and getting them highflowed, really want about 330-350kw... (Want the maximum response for that power goal) other option i was considering was the gt3076?

PS: This is a 3ltr bottom end.

sorry to drag off topic a bit.

Put the .64 turbos on and see >_<

It's similar to runnning a 1.06 rear or larger - ie fken laggy.

If you are not chasing 450rwkw+ with twins, you do not put .64 rears on.

Wat u on about man? ALL of the aftermarket twins from GT-SS to GT2835 ALL have .64 housings and i think stock turbos do also.

Well originally I was going to go with R34 N1 turbos. Checked the specs on turbobygarrett.com and they come pretty close to the GT2560 (OEM SR20 turbo). Should've specified that they're going on a 25/30 engine but wasn't expecting this to turn into a turbo selection thread.

Stock GTR turbos have .48 rear housings which i think would be a bit restrictive on an RB30

I'd prefer a twinscroll single over the twins but you also have to factor in a twin scroll manifold.

"You can't really cut corners with bastard twin turbos - way too much time and money involved proving that it doesn't work . Nissan didn't just throw a couple of generic dryers on RB26's , it's not as easy as designing a single system but does have advantages" .

In a nut shell the big advantage of the twins is low exhaust manifold pressure and the pulse division of the engines front and rear three cylinders . It can be done with a larger single turbocharger but very few are available that achieve the same thing with integral waste gating .

Anyway the original poster seems to want to get his power ask from a quite low budget and I don't think that's possible with a GTR/RB26 .

The trouble with those engine , so I'm told , is that they don't have enough capacity to drag a GTR's bulk around especially if your trying to use boost for torque early in the engines rev range . Same basics apply , smallish turbos come on early for lets get going torque then run out of gas flow capacity and lose out up high .

You can have the power ask 300-350 (actually TORQUE ask) but don't cry if it won't be pulling at 8000 revs . You just can't have it both ways .

Maybe in a perfect world the GTR's would have come with 4WD RB30 bottom ends , you very probably could have got away with a far simpler single scroll single turbo and used the capacity to cover the lack of low down torque in the 2558cc RB"26" . But Nissan didn't , something to do with turbo multiplication effective capacity and the weight class they could run in with Grp A . Fine for a race car but race cars don't tool around at lowish revs like road cars do , history shows that they blitzed the field - on the race track . In this case the homologation factors bit the roadies on the bum .

There is nothing cheap and simple about GTR's , I think simplest and cheapest with them is to use good bolt on twin turbos because you keep 95% of the parts around them and look standard . The thing is to have a set goal and not change that part way through the build . Built something PRACTICLE that is USABLE and let the heroes live with the laggy intractable pig . Do it once do everything at the same time ie head /cams / manifold matching etc and live with the result .

A .

Well originally I was going to go with R34 N1 turbos. Checked the specs on turbobygarrett.com and they come pretty close to the GT2560 (OEM SR20 turbo). Should've specified that they're going on a 25/30 engine but wasn't expecting this to turn into a turbo selection thread.

Stock GTR turbos have .48 rear housings which i think would be a bit restrictive on an RB30

I'd prefer a twinscroll single over the twins but you also have to factor in a twin scroll manifold.

I'm looking at the same path as you. only difference being the head which is a 26. This car is primarily for drift so i'm not after too much top end. Origionally looked at highflow the stockers, twin r32 gtst highflows (as i have one and another one available for cheapo) and then started looking in to maybe just biting the bullet and going single; GT3076, 35r, t04z... quite a difference in power bands and after reading some conflicting things over the last two i was almost set.

What car is your motor going in? my whole car with the 2630 should weigh in around <1200kg (silvia) so i was inclined to go for a slightly larger turbo with maybe some diff gears off around 4.11 or 4.36 which is another ball park...

I'v never even had the chance to drive in a 26/30 which is why other peoples experiences are a big help!!! I think you should ditch the idea of sr20 twins and look for a proven combo (when i work out what that is....)

until then, suggestions people?

Edited by GT-RZ

If you are going to use twin R32 gtst highflows you'll need either to change the housing or the manifolds (or an adaptor) because they use different flanges.

I know that the easiest path would be use a standard RB25 manifold and a single turbo, but I've got my heart set on this idea. I figure worse case scenario I get it all together and it's a pile of crap I can always pull it off and change it to something else.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Similar Content

  • Latest Posts

    • Hi, is the HKS  Tower Bar still available ? negotiable ? 🤔
    • From there, it is really just test and assemble. Plug the adapter cables from the unit into the back of the screen, then the other side to the car harness. Don't forget all the other plugs too! Run the cables behind the unit and screw it back into place (4 screws) and you should now have 3 cables to run from the top screen to the android unit. I ran them along the DS of the other AV units in the gap between their backets and the console, and used some corrugated tubing on the sharp edges of the bracket so the wires were safe. Plug the centre console and lower screen in temporarily and turn the car to ACC, the AV should fire up as normal. Hold the back button for 3 sec and Android should appear on the top screen. You need to set the input to Aux for audio (more on that later). I put the unit under the AC duct in the centre console, with the wifi antenna on top of the AC duct near the shifter, the bluetooth antenna on the AC duct under the centre console The GPS unit on top of the DS to AC duct; they all seem to work OK there are are out of the way. Neat cable routing is a pain. For the drive recorder I mounted it near the rear view mirror and run the cable in the headlining, across the a pillar and then down the inside of the a pillar seal to the DS lower dash. From there it goes across and to one USB input for the unit. The second USB input is attached to the ECUtec OBD dongle and the 3rd goes to the USB bulkhead connected I added in the centre console. This is how the centre console looks "tidied" up Note I didn't install the provided speaker, didn't use the 2.5mm IPod in line or the piggyback loom for the Ipod or change any DIP switches; they seem to only be required if you need to use the Ipod input rather than the AUX input. That's it, install done, I'll follow up with a separate post on how the unit works, but in summary it retains all factory functions and inputs (so I still use my phone to the car for calls), reverse still works like factory etc.
    • Place the new daughterboard in the case and mount it using the 3 small black rivets provided, and reconnect the 3 factory ribbon cables to the new board Then, use the 3 piggyback cables from the daughterboard into the factory board on top (there are stand offs in the case to keep them apart. and remember to reconnect the antenna and rear cover fan wires. 1 screw to hold the motherboard in place. Before closing the case, make a hole in the sticker covering a hole in the case and run the cable for the android unit into the plug there. The video forgot this step, so did I, so will you probably. Then redo the 4 screws on back, 2 each top and bottom, 3 each side and put the 2 brackets back on.....all ready to go and not that tricky really.      
    • Onto the android unit. You need to remove the top screen because there is a daughterboard to put inside the case. Each side vent pops out from clips; start at the bottom and carefully remove upwards (use a trim remover tool to avoid breaking anything). Then the lower screen and controls come out, 4 screws, a couple of clips (including 3 flimsy ones at the top) and 3 plugs on the rear. Then the upper screen, 4 screws and a bunch of plugs and she is out. From there, remove the mounting brackets (2 screws each), 4 screws on the rear, 2 screws top and bottom and 3 screws holding in the small plates on each side. When you remove the back cover (tight fit), watch out for the power cable for the fan, I removed it so I could put the back aside. The mainboard is held in by 1 screw in the middle, 1 aerial at the top and 3 ribbon cables. If you've ever done any laptop stuff the ribbon cables are OK to work with, just pop up the retainer and they slide out. If you are not familiar just grab a 12 year old from an iphone factory, they will know how it works The case should now look like this:
    • Switching the console was tricky. First there were 6 screws to remove, and also the little adapter loom and its screws had to come out. Also don't forget to remove the 2 screws holding the central locking receiver. Then there are 4 clips on either side....these were very tight in this case and needed careful persuading with a long flat screw driver....some force required but not enough to break them...this was probably the fiddliest part of the whole job. In my case I needed both the wiring loom and the central locking receiver module to swap across to the new one. That was it for the console, so "assembly is the reverse of disassembly"
×
×
  • Create New...