-7/9s Or -5s Garretts

[discopotato03]

I really don't think this choice is a biggie - it can go one of two ways . Simple really .

Do you want responsive turbos that will come in early enough torque wise to make a GTR weight car a nice drive 80% of the time .

OR do you want a car that has another 1000 revs of gee this feels like 1500 Kg being dragged around by a low compression ratio 2570cc engine . More up top but lazy at round town revs .

Take your pick .

Garrett don't make a magic turbo that will give a road weight GTR wings down low and afterburners up top .

No doubt they could increase the turbines trim size and the comp wheels trim and housing size but doing that raises the engine speed at which the things start to DO something .

To me the GTSS/707160-9 turbos would be the go because they are designed to make a fairly std engined car torquey and responsive - to boldly go where a factory std GTR can't torque/response wise .

Sorry people , they are a heavy car that got short sheeted engine capacity wise and you can't have it at both ends of the rev range - not with an RB2568 anyway .

Maybe people should look at the -9's as a light cost way of having more torque - more usable torque anyway - when you don't want to go inside the engine . Sure rip the head off and port it/add higher performance cams/raise the static CR to 9.4 like GMS did and run the car on high octane juice/E85 and make a squillion expensive horsepower .

Also have a car that's a slug to drive normally and has to be booted everywhere to make it go .

AWD cars are animals when you lay the boot in and they go from sane revs , when you have to balance power with your right foot it works so much better when you're not at the top end off your rev range and fighting a gearbox that doesn't like changing at 7500-8000 revs . In the twisty windies it would be a bastard to drive with biggish turbos cams etc .

When torque over a useful rev range means something use the GTSS/-9 , when it doesn't and you own an oil well go larger .

A .

[usmair]

ok thought I might add my results... only just picked the car up yesterday

2860 - 9s from GCG

Stock motor... only mods are the turbos, cat back exhaust and PFC

270rwkw @ 15 psi... not a bad result I thought

standard AFMs were maxing out + injectors are almost at their limits

tuner said the shitty complaince cat is also holding back 15-20kw

now the goal is to get all the supporting mods, wind up the boost and go for 350rwkw

[Nee-san]

I really don't think this choice is a biggie - it can go one of two ways . Simple really .

Do you want responsive turbos that will come in early enough torque wise to make a GTR weight car a nice drive 80% of the time .

OR do you want a car that has another 1000 revs of gee this feels like 1500 Kg being dragged around by a low compression ratio 2570cc engine . More up top but lazy at round town revs .

Take your pick .

Garrett don't make a magic turbo that will give a road weight GTR wings down low and afterburners up top .

No doubt they could increase the turbines trim size and the comp wheels trim and housing size but doing that raises the engine speed at which the things start to DO something .

To me the GTSS/707160-9 turbos would be the go because they are designed to make a fairly std engined car torquey and responsive - to boldly go where a factory std GTR can't torque/response wise .

Sorry people , they are a heavy car that got short sheeted engine capacity wise and you can't have it at both ends of the rev range - not with an RB2568 anyway .

Maybe people should look at the -9's as a light cost way of having more torque - more usable torque anyway - when you don't want to go inside the engine . Sure rip the head off and port it/add higher performance cams/raise the static CR to 9.4 like GMS did and run the car on high octane juice/E85 and make a squillion expensive horsepower .

Also have a car that's a slug to drive normally and has to be booted everywhere to make it go .

AWD cars are animals when you lay the boot in and they go from sane revs , when you have to balance power with your right foot it works so much better when you're not at the top end off your rev range and fighting a gearbox that doesn't like changing at 7500-8000 revs . In the twisty windies it would be a bastard to drive with biggish turbos cams etc .

When torque over a useful rev range means something use the GTSS/-9 , when it doesn't and you own an oil well go larger .

A .

If you look at Displacement versus vehicle mass, the picture isn't really that bleak, I just think the 26 suffers from its status where people no longer consider 400-500Hp alot from a 2.6 Litre engine.

[discopotato03]

I am talking about torque at around town revs , for the state of tune of a std RB26 it isn't sprightly enough in an almost tonne and a half car to feel nice .

The original design concept was an RB30 , 2568cc was all about running in a weight class for tarmac motor sport .

A .

[usmair]

a RB30DETT from factory... perfection

[BoostedBarge]

Haha. Try lugging around a 1700kg Stagea with an RB26. Certainly lack of down low torque is a bit painful for around town driving, but up in the revs it is a different story (as well all know). I'm still running stock turbos and I think they are a bit laggy for the Stagea. I'd love to see a comparison dyno chart between a stock turbos and -7s or -9s. Do they have as much down low as the stock turbos?

[Harey]

Haha. Try lugging around a 1700kg Stagea with an RB26. Certainly lack of down low torque is a bit painful for around town driving, but up in the revs it is a different story (as well all know). I'm still running stock turbos and I think they are a bit laggy for the Stagea. I'd love to see a comparison dyno chart between a stock turbos and -7s or -9s. Do they have as much down low as the stock turbos?

I know its a different engine, but I plotted a few dynos together for the RB25 (see below).

You can see that no aftermarket turbo compares with the low down response of the stock turbo (2-3000rpm). Not sure if its the same on the RB26 but I would expect so.

[Nee-san]

I am talking about torque at around town revs , for the state of tune of a std RB26 it isn't sprightly enough in an almost tonne and a half car to feel nice .

The original design concept was an RB30 , 2568cc was all about running in a weight class for tarmac motor sport .

A .

Yes, they went that way to fit into a certain displacement class, and I wholeheartedly agree with you about the state of tune of a standard 26 but as we know, the R32 GT-R was always destined for a life above 206kw....

As for the torque issue, at the end of the day I will have to respectfully disagree with you.

I think these cars, with the philosophy behind their design are meant to be really driven hard to get the most out of their powertrains.

No one can deny the RB26's output capabilities, which goes a long long way to making up for any loss of lower end torque.

It is a high revving (relatively) small displacement turbocharged engine, one will never see the sort of lower end torque that makes around town driving feel sedate like a turbo diesel.

In fact, many people find having to really drive the pants off something to go quick or get around to be half the fun, just ask the honda boys

Realistically, if having bucketloads of lazy torque is a big kicker for you, you would obviously be better off with a V8, but no ones that desperate

Failing this, RB32DETT = Win.

Cheers,

Mitch.

[GTRPowa]

Take a look at the difference between these Turbine Outlet flanges:

GT2850R-5 (707160-5)

GT2860R-10 (707160-10)

http://gcg.com.au/AllImage/Products/Garret...ns/gtr-5-10.jpg

GT2860R-7 (707160-7)

GT2860R-9 (707160-9)

http://gcg.com.au/AllImage/Products/Garret...ons/gtr-7-9.jpg

Trying to work out here if the flanges are actually different? I mean all 4 turbos fit the same stock dumps we use right?

I haven't seen people talking about having to change dumps etc, or are the dimensions wrong?

You can check the flange dimensions yourself on the website.

[R31Nismoid]

You can use factory GTR dumps (R34) on -5's and make 380rwkw.

Been done before (Snowman here has).

You wouldn't be trying that with -10's though... You are talking 450rwkw+

In other news, drove a mates R33 GTR with -9s tonight. 19/20psi and around 320rwkw.

Compared to my 280rwkw @ 15psi it's certainly faster but doesnt feel that much when you take into account over 200KG's difference.

Comes on exactly the same as mine around 3300rpm-3500rpm

Much smoother though, R33 chassis is very fken nice over a R32 one.

[usmair]

You can use factory GTR dumps (R34) on -5's and make 380rwkw.

Been done before (Snowman here has).

You wouldn't be trying that with -10's though... You are talking 450rwkw+

In other news, drove a mates R33 GTR with -9s tonight. 19/20psi and around 320rwkw.

Compared to my 280rwkw @ 15psi it's certainly faster but doesnt feel that much when you take into account over 200KG's difference.

Comes on exactly the same as mine around 3300rpm-3500rpm

Much smoother though, R33 chassis is very fken nice over a R32 one.

Good to hear

[Count Grantleyish]

You can use factory GTR dumps (R34) on -5's and make 380rwkw.

Been done before (Snowman here has).

You wouldn't be trying that with -10's though... You are talking 450rwkw+

In other news, drove a mates R33 GTR with -9s tonight. 19/20psi and around 320rwkw.

Compared to my 280rwkw @ 15psi it's certainly faster but doesnt feel that much when you take into account over 200KG's difference.

Comes on exactly the same as mine around 3300rpm-3500rpm

Much smoother though, R33 chassis is very fken nice over a R32 one.

Is it on standard injectors?

I have HKS GT-SS (aka -9s) on mine, I made 302.8rwkw @ 18.6psi - stock injectors, stock afm, boost is controlled by HKS actuators.

Now, I'm tempted to get injectors, nismo afm, nismo fuel pump and decent boost controller and go for broke and see what sort of power I can get out of -9s.

[R31Nismoid]

Nope, would be Nismo or Sard IIRC.

It was dropping a bit of boost in the top end though i reckon as mine pulls to 8000rpm solid where this felt it was slightly running outta legs.

That could also be due to the weight.

When i get mine back i'll do some rolling runs and see as both motors are identical (save for power output)... and my cam gears aren't done yet

[iplen]

Pair of -7s on the way, I have decided to stop reading suggestions etc about which way to go, for me it came down to 7/9, I spoke to GCG, said "I want 300awkw, without to much stress, but, will be used for street, and circuit etc, want a car that is responsive and will not being going chasing more later as it is not ALL about horsepower for me and this car" he said -7 all the way, so that was it. Initially they will go on with only mods being:

exhaust from dumps back

Apexi Pods

HKS Hard piping kit

HKS EBC was previously running upto 20psi (on ceramic turbos ) but will probably wind it down to 17-18...

Fuel pressure reg

When we know how that goes it will have run on the dyno with a Top Secret ECU that I scored, if that behaves it will stay on, eventually PFC as well as maybe some injectors.

Results will be posted.

[UNR33L]

Quick question: I just bought a GTR after being on a Non turbo for 3 years on Ps and by all means they are quick as so no need to upgrade power just yet but if i was going to do full exhaust should i be doing manifold / dump as well? sorry for the probably noob question but just getting into the boost scene.

[paulr33]

probably not the most suitable question in here

there are dozen's of howto threads, tutorials and even the rb26 dyno results threads

[Chris32R]

Quick question: I just bought a GTR after being on a Non turbo for 3 years on Ps and by all means they are quick as so no need to upgrade power just yet but if i was going to do full exhaust should i be doing manifold / dump as well? sorry for the probably noob question but just getting into the boost scene.

To answer your question, stock exhaust manifold is fine, stock dumps are fine but change them only if you upgrade the turbos to see any real worthwile gain for the money. Port match your standard exhaust manifold to the turbos if you decide to upgrade them.

After a lot of research and thinking I have personally chosen the -5 route over the -9s. The final decision for me was that the extra few hundred rpm that the -5s would take longer to come on over the -9s it would more than compensate for it in the top end. Considering I have a fairly fresh built forged bottom end, there was another tick in the box which helped me make my decision. The only thing i'm hoping and have tryed my best to eliminate by choosing the right parts/setup for when the turbos go on is the extra lag. I do understand these will be laggier than the steel wheeled 34r GTR turbos (380rwhp) i've got now but i'm hoping not by much. Hopefully next week or the week after I will have my 32r nistuned with the cams, dumps, front pipes, etc.. and the -5s installed with good results. I will post the dyno chart once it's all done.

Thanks

Edited July 2, 2010 by HecticGTR

[R31Nismoid]

It's not just the "few hundred" RPM fully loaded up.

It's also the response on/off boost inbetween gears/throttle and so on that is a key factor, something a dyno chart will never show you.

Best thing is to go in two sorted cars, one with -5s and one -9s and then decide IMO as everyone wants different things.

[Nee-san]

It's not just the "few hundred" RPM fully loaded up.

It's also the response on/off boost inbetween gears/throttle and so on that is a key factor, something a dyno chart will never show you.

Best thing is to go in two sorted cars, one with -5s and one -9s and then decide IMO as everyone wants different things.

Yeah massive difference, Nismoid is right, you actually have to put your car into a situation like that of a racetrack or a run through the hills before you will notice the change in transient response and be able to gauge whether it is right for you, just measuring the point at which the engine makes full boost or even begins to make boost is ultimately pretty uninteresting as it does not give an indication as to how the system will perform when asked to do more complex things like; driving the car with the throttle ie modulating mid corner or how it behaves and reacts dynamically, rather then just shoved down a gear at WOT.

[discopotato03]

Nee-san that's THE exact point and while its trivial to some its everything to many like I think you and I .

Its the lack of part throttle squirt and the need to go many places at wider or full throttle that makes cars at times irksome to drive .

My personal opinion , and that's all it is , is that people worry far too much about what happens north of 6000 revs .

I really do wish people could datalog how they drive their cars so they could see absolutely how much time they spend up there . I just can't get my head around tuning an engine to make power up there - and seldom use it .

People buy V8 powered cars because they make easy lazy impressive torque without having to buzz the engine - keep the revs up so when they prod it it shifts its arse smartly .

I don't see a car as being tough because its lazy to get going , it moves away from a car being a relaxing easy thing to drive .

To me sporting/sporty cars have to have some low to mid range - or they don't FEEL sporty .

To me having a hyped up homologation special is not justification for constantly hold the revs up .

To be brutally honest cars that make real torque at sensible revs feel fast because acceleration from low/no speed is what gives the impression of power/speed , it requires strong torque to achieve and there is no substitute for it IMO .

Some cars that really are fast don't feel like it , some that won't ever crack 200 feel like they can tear your seat out of the floor .

I'm different , I like different things . My god is massive torque and traction that can harness it . I don't need a long extended rev range and strong torque as the engine reaches death is imminent revs , can't see the point .

When the thing starts to run out of breath pull another gear - that's what they're there for . Actually if the manufacturer was nice enough to give you a closish ratio gearbox you don't need to pull telephone number revs before changing . Stay closer to the engines torque peak - and have good acceleration . I think that was the intention with the R34 GTRs having taller final drives and six closer spaced gear ratios . They don't have big turbos and people don't think they are slow .

I'll never have a GTR because of the expense and complexity of the things . But if I did I'd be doing my level best to drag every foot pound out of the thing under 3500 revs that I could because that's what feels good in the real world .

I'd be thinking about the RB30 before anything else because even if the turbo/s fell off it would still have something to get going with .

Sorry people , GTR was homologated with an engine designed to suit a race car class weight and torque down low is irrelevant in a Grp A tarmac racer . Nissan at the time was is dire financial straits and didn't bother to resolve this situation in the R33s R34s which were not homologation specials . An RB30 and VCT would have solved these problems but for whatever reasons Nissan kept the same basic drive line - and didn't race it .

You have the opportunity with non std turbos on a GTR to make them better than the factory had them everywhere - torque wise . You can enhance the second half of the engines rev range with little though to the first half like Nissan did , or you can pull it up earlier with more mid range and top end than std which is what makes a nice road car . No one drives a road car flat out everywhere and its hard to argue driving flat footed always is good .

There's nothing to stop you doing all the manifold/head/cam upgrades to an RB26 with sensible turbochargers , I think it was WilliamsF1 here years ago that made his GTR really grunty with GTSSs doing just this .

I'll be blunt , make torque and have it usable and accessible .

Numbers people I suppose have to have power at revs to achieve a number for its own sake .

When you get sick and tired of chasing the moon torque becomes everything . How much how soon and does the spread of torque match the gearboxes ratio spread .

Do what you will but don't come back and say I wish my car had some bottom end because you have/had the opportunity to do something about it .

A .