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TURBO! which one to use?


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Hi All,

Trust we had a safe and happy new year.

I have an RB30DET, specs .... standard crank machined 10 thou under (increases fillet radius for stronger crank) shot peened & linished rods with ARP bolts, race balanced, ACL forged pistons with coated crowns and lubricated skirts. Billet Steel VLT flywheel & clutch assy. Also have HKS exhaust manifold, genuine HKS 35mm external wastegate (14lb spring) and Trust inlet plenum. FMIC measures 400L x 280H x 65T.

Will be running on 98 premium as a minimum, but probably VP 103 (107.5 ron) mostly.

Have been considering a Garrett GT35/40, but have been advised to use a GT30/40.

With a 4.1:1 diff ratio and R33 GTS 25t gearbox, at 2800 rpm I should be doing, 81.2 kph in 4th and 106.4 kph in 5th.

It's a toy and not a daily driver, so low spool up rpm doesn't concern me greatly and I'm not looking for massive top end HP, driveability is my main concern.

With 245/45's on the rear, I don't want massive amounts of wheel spin coming out of corners, ZERO wheel spin would be ideal.

Searching for about 300rwkw, give or take, at between 14 - 21 psi, and staying under the 7500 rpm problem threshold, which way do I go.

Which is my best option?

Is the FMIC large enough?

Is the wategate large enough?

Is water or water/methanol injection worth considering?

Looking forward to some useful ideas.

Cheers,

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Ghostrider as you know mine will have a 26 head and inlet plus about 9 to 1 CR . My current plans are to use a GT30R (700382-12) . This turbo may not have a huge amount of head room for 3.1 L but its torque I'm after at lowish boost levels . I think efficient breathing is what it takes to make torque and response , hence the RB26's throttle per cylinder , better cams , higher static CR to give good part throttle torque and fuel economy .

That particular turbo (GT30R) is a good balence of turbine and compressor flow and should easily work up to the max of one bar that I would use . I don't seek a boost or RWKW number just lots of torque for the road and easy progressive power delivery . While there's no doubt a GT3540R will make good power on an RB30 will it be friendly in a road car . For me the first 3/4 of the power curve is more important than the last 3/4 . This is where my prioritys lie . Given that Ford used a GT3540R on the 4L XR6 it would have been interesting to see what Nissan would have used if the RB30DET had gone into production in the late 1990's .

Cheers A .

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discopotato03: pleeeease space out your posts more instead 1 massive paragraph ... please :D

I think the GT30R will give a really solid hit from down low, it really depends on what size exhaust housing you are using. I take it you will probably be using the .82 housing?

If so i reckon you'll be making a truck load of torque right from the beginning

Ghostrider:

- Go for a GT35R with .82 housing

- Cooler seems a little thin to me, my old cooler was roughly the same size but 600L

- 245's + rb30det + a Gt30 or Gt35.... traction wont be your friend at all

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Yes thats the plan , I reckon the GT30R not pushing stratospreric boost should come on reasonably early (and not hit like one of our locomotive hauled superfreighters) but not choke up on the exhaust side .

My jury's still out with exhaust housings , I dont want/need high boost pressures and because GT30 turbines are very high flowing for their size I don't expect to get high turbine inlet pressure . If this is the case I may not need an external waste gate and could possibly get away with using one of the HKS T3 flanged GT30 integral gate housings which come in .67 and .87 ARR's . Going this way would save money and inconvienence , also has that vaguely factory look . Finding a dump pipe may be difficult though .

Some of this will depend on which exhaust manifold I use , there may be a cast iron HKS item availabe down the track .

Anyhow off out to be entertained by Austin/Nickols and act like a the sphincter of the universe - can't type in Swahili ! Cheers Adrian .

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Ghostrider, As i've mentioned in another thead, my RB30DET in a VL has been up and running for a month. I'm using a GT3040 with a 0.82 rear. My aims were very similar to Adrians' in that i wanted a fast streetcar, not some animal that didn't awaken till 4000rpm.

The engine is still being run in on 5psi, but so far it does not appear to have any lag at all, just progressive power, and spins very easily to 6000rpm. It starts spooling at 1800rpm and is on 5psi by 2200rpm

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Water Injection is a must for modified cars.

Get it and get it tuned , get a microtech ltx12s.

You will be able to push easly 25psi with water injection and CD Ignition like Crane Cams HI-6.

Will be more safe then a car with 14psi and no water injection and no CD Ignition.

T04S turbo with .70 front comp cover, .84 rear a/r , P trim is good and 60-1 wheel.

This willl give you atleast 300rwkw on 22psi.

Spool very early and hold till 7500rpm.

Trust me, this is a monster setup.

Petar.

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you guys remember he doesnt mind a bit of "lag" depending on your definition of it.

It's a toy and not a daily driver, so low spool up rpm doesn't concern me greatly and I'm not looking for massive top end HP, driveability is my main concern.

So i'd be saying the choice of a GT35/40 is a perfect one.

I have a 600HP GT30 .82 rear on my RB25 with only a rebuilt bottom end (read: stock head)

And 16psi is on by 4000rpm, and ive got till 7800rpm and thats a good 3500rpm of power well above 230rwkw so id say its not bad.

I'll be getting a set of cams to get me a few hundred rpm more and then i'll have close to 4000rpm of good mumbo.

I wouldnt call that a slow or laggy monster at all.

The GT30 is a wicked combo for the 2.5ltr. The GT35 is the best mix for the 3ltr.

Thats just my opinion. And he will lazy home 300rwkw without running stupid amounts of boost.

yeh ide go something like 3037  

then again, maybe a T51R cos if your gonna do it you should do it right!

:burnout:

t51r lol... but a 3037 you can vitrually make with the garrett turbos if you mix/match wheels and housings... costs you half as much too :(

Was going to do that too mine but it was cheaper to rebuild just as the stock 600HP form.

cheers - ash

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Water injection? Using the old t04S technology as well?

he'll make 300rwkw on 22 psi or less with a GT35 and he'll have more response too boot.

i had an old t04 turbo... never going there again, made virtually the same boost @ the ame RPM, but savage wheelspin and it was a pig to drive

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Water Injection is a must for modified cars..

What happens when you run out of water? I can answer that from experience (someone elses), the engine goes bang.

Get it and get it tuned , get a microtech ltx12s.

No dashboard knock warning, so you don't even know that it is going to go bang.

You will be able to push easly 25psi with water injection and CD Ignition like Crane Cams HI-6.

Yep, you have to use something cause the Microtech has real troubles running the standard ignition. You are not upgrading for performance, the standard coils and ignitor will easily handle 300 rwkw. You are covering up for Microtech's poor capability, not money well spent.

Why run 25 psi when the GT35R will give 50 lbs per minute of airflow (more than enough for 300 rwkw) at 19 psi. Much gentler on the engine.

T04S turbo with .70 front comp cover, .84 rear a/r , P trim is good and 60-1 wheel.  This willl give you atleast 300rwkw on 22psi..

Your kidding, right? As can clearly be seen on the compressor map it is way outside its efficiency at 1.5 bar and 50 lbs per minute. At 18 psi it is much more efficient and using 20,000 rpm lower shaft speed. Using 22 psi puts it too close to the surge line at 185 rwkw, which would be in the meat of the much used rpm range. To put it simply, every time you accelerate though 4,000 to 4,750 rpm it is going to require careful tuning to avoid compressor surge

Fig9.gif

Spool very early and hold till 7500rpm.

Maybe, but much depends on which core you use.

this is a monster setup.

Sorry but not in my opinion, there is much better around, for less cost and complexity with lower risk.

That's my 20 cents worth:cheers:

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SydneyKid: I want to enhance the size of my manhood with an impressive dyno figure >300rwkw from my RB30DET. Running a forged bottom end, stock 25 head, greddy plenum, GT35R, .82 housing... what sort of boost pressures would i need to run to achieve the enhancement i am looking for? :(

you can take this to PM if you wish :D

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Ghostrider , doing 180 on this and looking into GT3540R .

I found out the BA Turbo does run TO4E 50AR comp cover but only pushes 6psi boost . I'm looking into the 60AR E cover to save some space over TSO4 covers .

God knows which turbine housing , either .82 or 1.06 .

It seems the 31 bottom end (87.5 bore) makes so much torque off boost that its not desirable to get much if any boost before 3200rpm . SK was telling me that this is low enough to do something on the expressways but not low enough to launch into boost at round town revs and speeds . I suspect this is why its important to get the static CR up to 9:1 .

He was also saying most of the time the throttles are barely cracked open so with good tuning the consumption is very good .

Cheers A .

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out of a GT35 or GT30?

GT30 i think you are... so it would be 20+ psi. More you go, further over 300 you'll get. But you'll need to look at using something other than pulp by this stage.

If you dont want to run C16 or other race fuel and push big power, then CDI and WI is your only safe STREETABLE thing to do.

WI is safe, water is free.

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On your water injerction systems, where is the nozzle?

I dont see why on a daily driver with a modern effecient compressor with a good effecient front mount you would bother with the complexity of a water injection system.

Anyone thought about using something like a Turbonetics BB T66 for their 3L...Supras in the US use them to great effect:)

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On your water injerction systems, where is the nozzle?

I dont see why on a daily driver with a modern effecient compressor with a good effecient front mount you would bother with the complexity of a water injection system.  

Anyone thought about using something like a Turbonetics BB T66 for their 3L...Supras in the US use them to great effect:)

It is not complex, Just give me a PM please Roy since your the only one who sounds interested and motivated.

Turbonetic's turbo's are excellent, but Garret now have Dual RB Turbo's which would be much better then a GT35R in flow and response.

Petar.

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If you dont want to run C16 or other race fuel and push big power, then CDI and WI is your only safe STREETABLE thing to do.

WI is safe, water is free.

Many cars running GT30's are making 300rwkw extremely safely for street use, and they are running on PULP ... not C16 or other race fuel

Cars using GT35's are making 30-50rwkw more and they also have no issues.

Many of the cars have been running for 1-2-3 years and nothing is broken or in need of fixing, so explain how it isnt safe if they are still running strong day in day out?

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I'm running a HKS 2835R with a 1.12 exhaust housing on my 1.8L 20V Golf GTI. at the moment it's untuned and starts pulling hard at 5300 rpm, it's so funny to drive because it only revs to 6500rpm at the moment.

(the aim is for it to keep up with the GTR)

Anyway the turbo would be tops on a 3.1L! i would rekon it would be going silly at around 3000rpm. speak to douge boy and see if he has any spare turbos for sale. great bloke!

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