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single or twin turbo for RB26

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hi guys

i have just bought my first turbo car at 37 after a long history of being a one eyed v8 guy.

I am looking at replaceing the turbos on my r32 gtr and am unsure what to fit.

It will be between a pair of gt3071"s rated at 450hp each or a single gt35/40 rated at 700hp.

Can any one help with which way to go on this? The car will be driven weekends and see track days and drag strip runs.

apart from hks filters and exhaust the engine is stock and i plan on doing the exhaust manifolds and dumps with the turbo.

thanks brian :)

:D

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[WLDCRD] Mentor

[WLDCRD]

Posted
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A single turbo will almost always spool faster than a set of twins if it is matched correctly.

by single do you mean a much smaller turbo...lets say a suzuki cappucino turbo? cos i cant see how a large single can spool faster than two CORRECTLY MATCHED twins.

R31Nismoid Grand Master

R31Nismoid

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Posted

Its not a quesiton of matching.

One would almost always assume you'd match the correct turbo by talking to people.

Both single and a set of twins can be made to work well. a GT35 - 700hp would be a very nice selection

I feel these are the things you need to look at:

Low-mount twins - PRO's

* Cant be seen, hard to get defected

* They often mount on your stock manifold and join to your stock plumbing/piping which saves somm $$$

CON's

* Harder to work on

* Buying 2nd hand you can risk maybe one dying in the future which to replace would be the cost of that one big single.

Big High Mount - PRO's

* Easier to work on

* Looks awesome if you wanna do a bit of "show" with your GO

* Less plumbing in general

* If something goes sick with the turbo, its not expensive to sort out

CON's

* More chance of a defect if your pulled over

* You will need a manifold, but thats offset by the cost of one less turbo

* You will need a new dump and some intake plumbing done

They are just some things to think about.

Of course there are sure to be others that i have not thought of.

BUt that should get the ball rolling with a bit of luck :)

hope it helps.

Guest

Guest

Posted
Posted
Its not a quesiton of matching.

One would almost always assume you'd match the correct turbo by talking to people.

Both single and a set of twins can be made to work well. a GT35 - 700hp would be a very nice selection

I feel these are the things you need to look at:

Low-mount twins - PRO's

* Cant be seen, hard to get defected

* They often mount on your stock manifold and join to your stock plumbing/piping which saves somm $$$

CON's

* Harder to work on

* Buying 2nd hand you can risk maybe one dying in the future which to replace would be the cost of that one big single.

Big High Mount - PRO's

* Easier to work on

* Looks awesome if you wanna do a bit of "show" with your GO

* Less plumbing in general

* If something goes sick with the turbo, its not expensive to sort out

CON's

* More chance of a defect if your pulled over

* You will need a manifold, but thats offset by the cost of one less turbo

* You will need a new dump and some intake plumbing done

They are just some things to think about.

Of course there are sure to be others that i have not thought of.

BUt that should get the ball rolling with a bit of luck  :)

hope it helps.

hi thanks for the info. think the 35/40 is the way i will go. i am going to put a 3l bottom end in it for sure with in the next six months so that should help with the low rpm power and the turbo spooling up.

By the time i buy the 3540 $1800 the custom manifold $650 and tial waste gate $700 it works out the same as buying the twins and seems to have more power potential. car already has a hks intercooler on it. As far as engine management i was going to go for a apexi fc. has anyone got one of these and used the optional boost controller on it. I read on one post the guy was having a lot of problems getting it to work once he plugged in the optional boost controller?

cheers :)

Shaun Mentor

Shaun

Posted
Posted

Where are you gonna get a custom exhaust manifold for $650! Im doing a single conversion at the moment and ive discovered that around $1200 is the lowest custom price there is. Seriously, if you know of someone doing them cheaper can you let me know?

I understand what everyone is saying about twins probably being more responsive, but i decided to go the single for the following reasons:

- Simplicity. When i pulled the engine out and saw all the spaghetti style water and oil lines going to the two turbos, i thought it looked a bit messy (for someone who anal about a clean engine bay). When you go single, you can get rid of all the shit that goes around the back of the engine to the plenum. Also im using engine management with a MAP sensor, so i didnt have to worry about Air Flow Meters on piping.

- Aesthetics. I dont know about you, but i love the look of a polished big single high mount. Having said this, my car will only be driven about twice a week and at the odd wednesday night Eastern Creek drags; im not that interested in circuit work. Also, i wanted to have an external wastegate; i love the sound.

I think at the end of the day, youve got to figure out what you really want to do with the car. I thought F**K IT! Ive always wanted a big single, so im goin a big single! But ive also had a car with a mismatched single turbo where the boost threshold was way too high and that sucked.

For track work and near standard drivability - 2530s or similar. If youre one of those people who sit in the garage and look at youre engine bay thinking F**K that looks good, id go a single. A GT3040 with a 1.06 turbine housing would be nice on a 3 litre. Im going the GT3040 with the 0.82 rear for the standard capacity. I dont really care about maximum power, i just want low boost threshold and torque. Im trying to get the best of both worlds. Ill let you know how it goes!

Shaun.

Id figure out how much it will cost then double it. Theres always something thats blows your budget.

pnblight Mentor

pnblight

Posted
Posted
Really ?? I think a matched single works quite well.  Jade Fishers r33 gtr single t60-1 ran 11.1 qm at 125mph with only 430rwhp . See you at  Motorplex .

yeah was a nice run on SLICKS but the other two big singles i've seen have battled to say the least to get them off the line(no low down grunt or torque or rapid spool up in these examples) And one of the guys actual said he would have trade the power delivery of his single for what we were getting out of the small garret in and instant and as for see at the plex, yeah right i'll grow old and retirer before you put car where your mouth is?

Gts-t Grand Master

Gts-t

Posted
Posted
yeah was a nice run on SLICKS but the other two big singles i've seen have battled to say the least to get them off the line(no low down grunt or torque or rapid spool up in these examples) And one of the guys actual said he would have trade the power delivery of his single for what we were getting out of the small garret in and instant and as for see at the plex, yeah right i'll grow old and retirer before you put car where your mouth is?

touche

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