Single or twins

[Andrew Le]

Hey fam :))

Just brought my r32 v spec 6months ago, done compression test it was all good n healthy.

test drive it seems like a nugget boost gauge only showing the needle just under 7+psi

and stock gtr are a nugget lol slow n boring so didn’t think anything of it. Coz before I brought this drove another v spec and it was same thing slow  

so I thought the boost was just turn down so I took it to my mechanic for a tune so turn it up  getting bad news it’s not making boost over 8psi

so his stripping and see what’s the problems  

i wanna go single but I don’t want crazy power so don’t seems no point  and I want the car to still have the factory look 

so gonna go with twins but not sure what I want was having dash 5s in mind I’ll b happy with 300kw 

so wanna see what u guys have out with twins n what power it’s making  

 

thanks a lot in advance 

 

[Steve85]

I'd do a search on the forum before you get flammed here.

Basically, from the other times I've seen this question. Keeping the twins is convenient and cheap, but you'll run out of ability to make power past a certain point.

Converting to single is expensive and time consuming in comparision now, but will yield greater results down the track when you are trying to crack big power.

I think...

[l0ckym]

Check the nipple isn’t still in the boost line

[BK]

Go -10 low mounts, It's fully sick ! ?

8-10psi, Isn't that about stock R32 boost ? Have you removed boost restrictor olive ? Should get around 14psi.

 

[joshuaho96]

Stock the R32 GT-R made 10 PSI of boost with the restrictor, 14 psi without. If you aren't making 10 psi definitely start asking why.

While we're on the subject of turbo selection, is there anything out there that replicates the response of the stock ceramic turbos but with an inconel exhaust wheel? -7s and -9s seem to be about on par or slightly better than ceramic turbos rebuilt with inconel exhaust turbines which means boost comes in a little later. I'm shooting for high 200 to low 300 kW.

[GTSBoy]

1 hour ago, joshuaho96 said:

While we're on the subject of turbo selection, is there anything out there that replicates the response of the stock ceramic turbos but with an inconel exhaust wheel? -7s and -9s seem to be about on par or slightly better than ceramic turbos rebuilt with inconel exhaust turbines which means boost comes in a little later. I'm shooting for high 200 to low 300 kW.

Not sure why you want to specify inconel. If I were spending money on a GTR's turbos, I'd be going EFR, 100%.

[KiwiRS4T]

The answer to the first question is single is better but as above it will cost a bit. Are you sure you will be happy with 200 - 300awkw? If in doubt go the single now.

[joshuaho96]

1 hour ago, GTSBoy said:

Not sure why you want to specify inconel. If I were spending money on a GTR's turbos, I'd be going EFR, 100%.

I guess they're normally referred to as steel turbines, but regardless the point is my power goals are basically maxing out stock turbos rebuilt with steel. Another option would be -7s or -9s but whatever the case this is primarily a street car, it needs to be well mannered and pass California's emissions testing every 2 years. Good turbo response in that high 2000 to low 3000 RPM range is important to me.

[KiwiRS4T]

BTW since you posed the question at the beginning have a look at this:

http://www.goodezilla.com/rb26dett-skyline-gtr-single-turbo-vs-twin-turbo

[Dose Pipe Sutututu]

A modern single twin scroll, with a proper divided manifold.

Won't mention names but some have bullshit divisions.

[Andrew Le]

Only reason I don’t want to go single is want the car to have the factory look. 

And just incase in the future I want to sell it don’t want it to lose value since it’s a v spec. 

 

Andrew from motive DVD got 383kw with the -7 turbos. 

 

So so I’ll be going with them 383kw is plenty for a weekend car. 

[joshuaho96]

7 hours ago, Andrew Le said:

Only reason I don’t want to go single is want the car to have the factory look. 

And just incase in the future I want to sell it don’t want it to lose value since it’s a v spec. 

 

Andrew from motive DVD got 383kw with the -7 turbos. 

 

So so I’ll be going with them 383kw is plenty for a weekend car. 

-7s are going to just barely break 300kw at the wheels, probably high 200s if you have exhaust restriction/wastegate control isn't ideal. They're a good street turbo though. If you want more power -9s will get you there without too much difference in turbo lag, mostly at that 3000-4000 rpm region where you'll notice the difference back to back. 

[Torque Curve]

Once the car is modified its modified, regardless of singles or twins. Andrew made the high figures with high flowed -7's, e85 and cams not just standard -7's.

If you are worried about value then I would rebuild the stock turbos or just add regular -7's and remove the boost restrictor.

modding a GTR is a deep rabbit hole to dive down so decide early if want to "eventually" go big it is way more affordable to go big from the start. 

Up-Garage in the states look like they do some great work so maybe connect with them to get some ideas or if you are looking for big numbers then there is about 5,000,000 post on this site and an entire internet with options for that.

 

[Dose Pipe Sutututu]

If you are going down that "stock" look, just take out your ticking time bombs aka your stock turbos and get them high flowed by Tao at @hypergear turbo.

Get a Nistune board (I can supply and have it fitted/sent back to you), bump up the fuel pressure (if you don't want to install new injectors) a little and just tune it.

The car will look incredibly stock.

[hypergear]

Get a PWR 600x300x81mm cooler or Aero flow to save few coins, General pod filters, Tomei dump pipes, 3 inches front pipe,  3.5 inches 100 cell cat with 3.5 inches cat back exhaust. Turbos I would high flow them to -9 specs with 14psi actuators. I'm not sure about stock R32 ECU, but R33 ECU supported just under 300awkws on that setup on 98 fuel.       

[joshuaho96]

Are your high flow G1 profile dyno comparisons between stock ceramic vs inconel high flow? I would be very surprised if you've managed to maintain stock response.

[BK]

Look if want to retain twins, but upgrade, and have as close to factory response -9 / hks gt-ss is the only option. I have that on the 33 and makes between 310 -330kw in 98 with around 22psi stock cams. 360 - 380kw might be achievable on E85 upped cams but that would be it. Max.

[joshuaho96]

The GT-SS might be the best balance, I've noticed the compressor efficiency seems to be better in the expected regime of operation vs R34 N1, but it definitely gives something up in response compared to stock turbos. I waffle regularly on what is the best turbo for a 2.6 street car with driveability as a primary concern.

[GTSBoy]

1 minute ago, joshuaho96 said:

I waffle regularly on what is the best turbo for a 2.6 street car with driveability as a primary concern.

And the answer is never twins.

[joshuaho96]

1 minute ago, GTSBoy said:

And the answer is never twins.

I think the problem there is more like I've never seen a single turbo build where they targeted a power goal of something like 290-300 kW at the wheels. I believe Hypergear tried with the sst thread but I wasn't too impressed with the results. High mount manifolds that I usually see on single turbo RB26s also greatly increases the amount of heat radiating into the engine bay instead of out the exhaust. Not a fan of the extra volume from exhaust valve to turbine inlet either.

It's all relative to though, to me -9s are as big as I'd go. Street manners are a very big deal to me, it's definitely never going to be a V8 but I want the powerband to start as close to 3000 RPM as possible and hold out until ~7000-7500 RPM if I can help it.