T04z 'or' Garrett -10's

[Marko R1]

hi guys,

i am building an rb30dett for my gtr & my original thoughts were to go with low mount Garrett -10's.

im aiming for 400+awkw but i want it to be streetable with nice midrange & torque (minimal lag).

previously i had HKS GTRS setup on an rb26 & the lag drove me mad, the HKS GTSS setup which i had after this was much nicer IMO!

then my tuner threw a spanner in the works!!! he thinks i should go with a T04Z for ease of tuning & turbo surge (i guess it just makes his job easier which i dont really care about)...i can think of pros & cons for the T04Z such as being a cop defect, might effect resale with a big single, etc. but i really just want the best results possible.

ive spoken to a few guys here on the forum about this (u know who you are) i guess i am indecisive so im looking for some past experiences & persuasion on which way to go.

1. which of the T04Z 'or' Garrett -10's will give me more peak power?

2. which of the T04Z 'or' Garrett -10's will give me midrange/driveability?

thanks in advance,

marko.

p.s. im doing my head in with this

[Swiper the Fox]

hi guys,

i am building an rb30dett for my gtr & my original thoughts were to go with low mount Garrett -10's.

im aiming for 400+awkw but i want it to be streetable with nice midrange & torque (minimal lag).

previously i had HKS GTRS setup on an rb26 & the lag drove me mad, the HKS GTSS setup which i had after this was much nicer IMO!

then my tuner threw a spanner in the works!!! he thinks i should go with a T04Z for ease of tuning & turbo surge (i guess it just makes his job easier which i dont really care about)...i can think of pros & cons for the T04Z such as being a cop defect, might effect resale with a big single, etc. but i really just want the best results possible.

ive spoken to a few guys here on the forum about this (u know who you are) i guess i am indecisive so im looking for some past experiences & persuasion on which way to go.

1. which of the T04Z 'or' Garrett -10's will give me more peak power?

2. which of the T04Z 'or' Garrett -10's will give me midrange/driveability?

thanks in advance,

marko.

p.s. im doing my head in with this

Think about it this way T04Z or T51R KAI...the KAI (as much power output as 2 x -10's) will make more power...but later.

If you didn't have the GT-RS's set up properly they are a pain on the street as you found out last time and cost lots of $$ to get them right.

The T04Z is simple and effective...it doesn't require the supporting mods to get it nice and streetable...If you want more top-end you can simply change the rear housing for more gas flow.

T04Z...thats the way id go.

[TiTAN]

N1GTR seems to prefer his GT-RS turbos over his old big single.

[Piggaz]

I have GT - RS's on the side of a Tomei stroker with 9.0:1 comp ratio and to be honest i think they are great. There is a very very slight choof choof but nothing to write home about. Perhaps with the 3.0 litre it would be even better. If you like maybe we could meet somewhere and see what you think?

[Marko R1]

so if the t04z makes more power later, does that mean the -10's will boost earlier and make more midrange?

it would be great to see a graph with t04z vs -10's/gtrs

what single setup did n1gtr have before?

[Roy]

Bugger you for buying JFKs RB30s... That is all

[Marko R1]

i missed out on jfk's rb30 and dont ask me how as it gets under my skin. im building my own as a result

[The Dan]

T04Z will out respond a pair of -10's IMO. With the right head work and the right tune.

Strik3r just came off the dyno about half hour ago and he rang me with a 618hp at the wheels on 26psi.

1 bar at 3800rpm was pre tune, not sure what it does now but I'll post up the dyno charts if I get my hands on them soon.

RB26DETT

PowerFC D Jetro

T04Z - Surge ported

6 Boost manifold

4 inch exhaust

Full Tomei head with 270' 10.25mm lift.

Splitfires and HKS twin power.

Standard plenum

The -10's should see a bar after 4krpm.

T04Z is a winner IMO

[paulr33]

i guess it would depend on the specs, if you are comparing twin GT-Rs to a 0.70 a/r rear T04z then probably the t04z would be better

but if its a large truck style big single 1.0a/r ++ then twins hands down

or perhaps t04z with proper twin scroll setup

[Marko R1]

that is 460kw! i went in a gtr with 447kw about 5yrs ago & that was phenominal!

what got me going about the -10's a post that 'BoostdR' added in the "Rb30 Hybrid Upgrade" sticky, as below (granted its an rb32):

OS RB32/26

OS Rods

CP Custom pistons

Modified Pins

Nisspeed Sleeves

Nisspeed Spec Head

Nisspeed Spec Cams

Garrett -10's

Dry Sump

Motec M800

MSD coils

832hp @ 8290rpm and 22psi (maybe a little more in her)

Also 649ftlb torque at 5000rpm and 300ftlb @ 2900 and 400+ @ 4000

This is actually John Munro's new engine for his track GTR...don't even think he knows the results yet

[06tst]

a T04Z with the 0.84 rear will make an easy 400awkw with the supporting mods and have less lag than a pair of 10s

been a RB30 you might aswell go with the 1.00 rear... i reckon that would still spool quicker if not the same as the 10s and make 450kw at least

Edited March 26, 2009 by 06tst

[Marko R1]

out of interest, what size rear housings are available with the t04z which would be best suited for a 3ltr?

0.7

0.84

1.0

[06tst]

dont even bother with the 0.7 ... will restrict the power the turbo can make

[The Dan]

out of interest, what size rear housings are available with the t04z which would be best suited for a 3ltr?

0.7

0.84

1.0

That GTR that I listed has 0.9 rear. You can get them in:

0.84

0.96

1.00

1.14

1.15

1.32

1.52

1.75

I know that the Turbonetics housings bolt on to them so the ratios can be swapped around even more but pretty sure Garrett don't do a 0.7 rear and it's too late for me to ring and ask them.

You would def want the 0.96, 1.00 or the 1.14 for the engine you have.

If you don't care about the total figure (as you stated you only wanted 400kw) then I would go with the 1.00 to keep response as it'll still pull to 8500 quite nicely.

[Marko R1]

it almost doesnt make sense to me as to how a 0.84 T04Z makes as much power (if not maybe more) than 2 x 0.64 -10's...i thought the of physic's would come into play? take it as it is i guess

then with the boost response rates (comparing the 2 systems) would allow the T04Z to win as spooling a 0.84 would not take as long as 1.28 (i.e. 0.64 x 2)

am i on the right page?

[Marko R1]

i remember seeing a graph of the T04Z v's GTRS & i think 2 other turbo's on a recent thread...has anyone seen this?

[BoostdR]

that is 460kw! i went in a gtr with 447kw about 5yrs ago & that was phenominal!

what got me going about the -10's a post that 'BoostdR' added in the "Rb30 Hybrid Upgrade" sticky, as below (granted its an rb32):

OS RB32/26

OS Rods

CP Custom pistons

Modified Pins

Nisspeed Sleeves

Nisspeed Spec Head

Nisspeed Spec Cams

Garrett -10's

Dry Sump

Motec M800

MSD coils

832hp @ 8290rpm and 22psi (maybe a little more in her)

Also 649ftlb torque at 5000rpm and 300ftlb @ 2900 and 400+ @ 4000

This is actually John Munro's new engine for his track GTR...don't even think he knows the results yet

The engine is in the car now, will soon give us a better idea on how the engine performs in real life. The turbo's were chuffing away from coming on boost so early...hopefully my HKS antisurge housing will help on my own setup. Should be very nice track car as the motor is installed in a 700kg R33 GTR

[TiTAN]

A/R =The Area / Radius ratio

A = Area of throat at intake

R = radius of scroll in the housing of either the compressor or exhaust turbine

[paulr33]

stepping outside the square for a moment. from what we have all seen and what is common logic, twins are usually better

we typically assume or expect twins come on earlier, provide better linear response and overall package is better

typically with a big single we see low power, low power, low power, bang tons of power, tons of power

at least in its simplistic form

now im not saying a t04z is lag lag lag lag lag lag, power, change gears

because we know its not, but its reasonable to expect a big single has a big chuck of lag, then power

whereas twins, in a typical scenario are linear power curve, and progressive, making the car very drivable

sure if you use twin 0.82a/r rear GT2835s then its going to be laggy, but lets compare reasonable scenarios

so anyhoo, moving forward i still think you should go for a twin setup

but think harder about the turbocharger choice, setup and what you actually want

there are more than 1 way to get power/response from the setup at hand

choosing a pair of GT-RS's then saying theyre too laggy is simplistic

have u checked a pair of trust turbos

have u checked a pair of garrett turbos

have u checked a pair of apexi turbos

have u checked a pair of hybrid turbos

and so on.....

look at the rest of the picture

- what gearbox ratios

- what diff gears

- what wheels

- how is it tuned

- what cams

- what exhaust setup

- what fuel

all of these can affect power delivery and if one of these is wrong or not setup, then it could certainly make the car laggy

now im not saying go buy a 5k short ratio box, but im saying, if you want twins you can, but you can do other things

to alter the see-saw to drive power vs response from them

[discopotato03]

I don't have an RB26 or twin turbos but I'd opt for the twins because it suits the configuration of the engine/car .

The second critical part is that most of you won't counter the coin to do a properly designed twin scroll system to make the big single work properly .

People here are finally noticing that parallel twins tend to give more linear power delivery - than a single scroll single turbo . Done properly a single twin scroll turbo can do this as well but you have to recreate what Nissan did with two three branch manifolds , two turbine housings , two waste gates .

I feel like a broken record but the rush you people seek is a TORQUE rush not a boost rush or a Kw rush .

I see big turbos like big camshafts , a way to make upper end power and sluggedly performance in the sort of engine rev range you would expect to use on a daily basis .

By the sounds of things you seek good drivability (ie torque where its actually usefull) so it's reasonably obvious to me that a laggy gutless pig would send you crackers at the first turn of the key .

If you liked SS's on your RB26 you could look into GT2530's or GT2860RS's (x2) because they are more likely to put the shove in the back where you want it engine speed wise . Just in case your not sure both of those can use the same hot side as an RB26 specific GTRS but with big trim 60mm compressors rather than mid trim 71mm compressors .

Cars that make good torque without turning "reach for the sky" revs are the ones that leap out of the blocks without this brain dead hold er at 6000 and dump the clutch lark .

A torquey responsive engine has this thing called a gearbox attached to it so when the pace backs off pull the next gear , not hard .

The rev it to 9 and nothing under 5 bloke is behind the 8 ball convincing his production box/flywheel to change at these sorts of revs and if he misses a gear or it bogs down he's nowhere .

He also has to outlay a LOT more for multi plate clutches , exotic gearboxes , diffs etc etc to handle that sort of deliberate abuse .

And the day that dickless Tracy wants to see under the lid at an RBT ...

Anyway your call .