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 Hks Gt-rs Or Gt2871r - which way to go  

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Ticc
  • Ticc
  • PRN 13
  • Member No.: 174,972
  • Joined: 11-August 09
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  • From: Brisbane QLD
Post #1 post 13th February 2010 - 08:01 PM
hey guys,

thought the best people to ask would be people that taken these steps in front of me.
im looking to up grade and am tossing up between the HKS GT-RS OR GT2871R. the gtrs is more expensive but im sure that for a reason, is it worth it though? also i was thinking of going steam pipe manifold so before i fork out a 1000 bucks am i going to need an external wastegate? also are external wastegates legal and whats the deal with twin scroll manifolds? btw its for a sr20det redtop.

if any one has done this which im sure they have, could you let me know how it went, when boost comes on, how much power it put out on there setup.

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the_random_hero
Post #2

I'd probably run external gate if I was upgrading to one of those, but it's really up to you. It's legal provided the waste gas is plumbed back into the exhaust pre-cat.
Twin scroll manifolds are good if you have the proper turbo, pointless if you don't.

iamhappy46
Post #3

GT2871R 52 trim with a 0.86 housing if after all out power, 0.64 housing if want daily driven mid range torque.

I have never needed an external gate on one IF the wastegate controller is electronic

HKS GT-RS is nearly identical spec turbo BUT has a slightly different compressor wheel which allows it to run more efficient at 22+psi boost

baconson
Post #4

garrets get alot of there price cheapness these days, cause they are fairly mass produced, they are great turbo's most of the small to mid frame ones have internal wastegates etc, and id dare say as far as spares etc if the turbo ever needs them, youll be able to source them in aus easier then hks bits

Ticc
Post #5

so is it worth running the external gate or is the usual internal which most come with suffient? ive heard that the gtrs spools a lil quicker as well is it dramatic?

Paullus
Post #6

How much boost/power are you going to be running? That will decide if you need an external gate or not.

Edit: Just grabbed this from the Turbosmart Site:

Is it true that you need bigger wastegates for bigger/more powerful engines?
This is one of the more popular misconceptions. A wastegate is possibly the only component in your whole engine package that can actually be made smaller as you increase your boost/horsepower output. Use this simple guide before setting out to find the biggest wastegate you can afford.

Big Turbo/Low Boost = Bigger Wastegate
Big Turbo/High Boost = Smaller Wastegate
Small Turbo/High Boost = Smaller Wastegate
Small Turbo/Low Boost = Bigger Wastegate

Ticc
Post #7

hmm well im not going to lie i may have intentions of lower boost but its probably not going to happen its to easy to turn it up so probably a bar n up id say so that would kind of mean that the internal gate fitted would be fine? everyone seems to be saying gt2871r anyone for hks?

Paullus
Post #8

Well I run a GT2871r with an internal gate on the Pulsar. The minimum amount of boost I can run is about 13-14psi. Probably got to do with the spring. I don't know how soft a spring I could go before the gate became ineffective. My high boost setting is 18-19 psi.

I'm no expert but I'd say the internal gate would be fine.

antonio
Post #9

QUOTE (Paullus @ Feb 14 2010, 05:28 PM) *
Big Turbo/Low Boost = Bigger Wastegate
Big Turbo/High Boost = Smaller Wastegate
Small Turbo/High Boost = Smaller Wastegate
Small Turbo/Low Boost = Bigger Wastegate


Wrong, you buy your waste gate to how much boost you will run theres a spring which manges this and your only meant to buy a spring that is a few PSI different to your boost level, So for example if you run 20psi you would try find a 20PSI spring but they only make certain sizes, dont remember the line up.

Ticc
Post #10

so how does this work with a boost controller then if the spring regulates the pressure? how much power does ur pulsar put out at the wheels? when does boost come on?

Paullus
Post #11

QUOTE (antonio @ Feb 14 2010, 07:17 PM) *
Wrong, you buy your waste gate to how much boost you will run theres a spring which manges this and your only meant to buy a spring that is a few PSI different to your boost level, So for example if you run 20psi you would try find a 20PSI spring but they only make certain sizes, dont remember the line up.


Only if you wanted to run the same amount of boost all the time. Or you could install a boost controller to allow you to run more boost without having to change springs. I can see what you're saying but I wouldn't want a 18psi spring in mine all the time.

Pulsar made about 280hp at the fronts on a non atmo corrected dyno in Dec 2008. When does it come on boost? 3.5-4k maybe? By 4.5-5 it's on full boost. Starts pulling from 105-110km/h in 5th put it that way.

Boost controllers really only work with pressures up and beyond that of the wastegate.

iamhappy46
Post #12

QUOTE (antonio @ Feb 14 2010, 08:17 PM) *
Wrong, you buy your waste gate to how much boost you will run theres a spring which manges this and your only meant to buy a spring that is a few PSI different to your boost level, So for example if you run 20psi you would try find a 20PSI spring but they only make certain sizes, dont remember the line up.


Wrong. Dont confuse spring settings with exhaust gas volume dynamics

On big turbo/high boost, all of the exhaust gas is being used to spin the turbine wheel, therefore there is no need for a 50+mm gate since the amount of gas actually exiting through the wastegate is very small

Essentially, the more gas volume through the wastegate the bigger the wastegate required. Setting a correct boost pressure is easy wink.gif

20VGT
Post #13

GT2871R with the original internal wastegate is fine. External gate is a waste of effort and money.

bookie84
Post #14

QUOTE (Paullus @ Feb 14 2010, 09:11 PM) *
When does it come on boost? 3.5-4k maybe? By 4.5-5 it's on full boost.


max boost you are running is 18psi?
thats laggy as. I was expecting fullboost by 3.5 to 4k

benny_sr20
Post #15

if hks build a turbo with an internal wastegate which by the way a gtrs will boult straight on to a sr20 including the standard dump pipe. then why would you challenge people who have been building turbos for longer than you have been alive. point is internal wastgate is fine.

Street Tuned
Post #16

Im going to fuck with you a little more again.

Just to state first though out of the two the GTRS is slightly better than teh 2871r. They are basically the same turbo (Garret make HKS Turbos) but the HKS one has a slightly different compressor (I think this has already been said).

If you want the very best go the HKS, if you want the best value go the 2871r.


However Im going to suggest you dont take either. I just put a TRUST T518z on my Sr20 and I MUCH MUCH prefer it to both the HKS and Garret. It has a slightly smaller rear housing at 8cm (which in Garret terms is about .61) so I get full boost 3750 -3800rpm (20psi) where the garret would get it by 4000rpm. Not only that but with the HKS cams it makes ~265kw where the Garret would make 250-255.
The Trust T518z is about the same price as the GTRS as well. Id take it anyday over both the HKS and Garret.

If you arent running cams id expect about 230kw atw with the Garret and HKS (maybe 1-2kw with the HKS)
and maybe 235-240kw with the TRUST

For a SR20 i would run a .64ar for the Garret (HKS only comes in .64)
and the 8cm version for the TRUST.

baconson
Post #17

the man has spoken
where were you when I blew my turbo, oh wait i wasnt here then

TRY TOO
Post #18

I have not driven an sr20 with a gtrs or a t518z. But have owned one with a 2871, with basic mods (exhaust cooler fuel reg) It went very well for what it was, made 175ish rwkw @12psi and was torquey as!

A good amte of mine has the same turbo but with injecters, pfc and all the normal cooler exhaust etc etc. On 16psi makes 270rwhp. It pulls really strong and overall is a GREAT setup for the street. Nice and responsive yet doesnt fall over up top (.8x rear).

You wont be disapointed with the garret!

baconson
Post #19

when I was looking round for a new turbo for mine, before I built my hybrid turbo, most places said garret garret garret, there not the best not the worst, but a good alround reliable unit at a reasonable cost

Street Tuned
Post #20

Oh yeah like I said the Garret is probably the best value at only $1500 or so (or whatever they go for now)

The HKS and TRUST will perform better though - the HKS marginally and the TRUST a bit better. Obviously these two turbos really start to shine at over 20psi which in Australia can really only be achieved on E85 or C16.

I have a friend with a T518z and BC Cams who on E85 race fuel is making almost 290kw with full boost of 25psi at 4200rpm which is insane the thing pulls sooooo hard Im amazed the standard S15 gear box is still alive.


I could also fuck with you even more and start talking about other options likea Garret 3071r .64 or TRUST TD-06 25G which arent much more expensive and make silly power with awesome response. Infact they are almost the same price.

But Im going off on a tangent. If you have the money = T518z all day everyday and every tuner should say the same. If you are on a budget and want the best value = Garret 2871r .64 52" trim.

baconson
Post #21

well thats a goodle thing about turbo lag etc, its a bit kinder on the driveline. i like my current setup cause i come on full boost at 2500rpm, only running 14psi mind you, but i love the responsiveness (ex v8 boy)

while im here, any one recommend a good turbo for a 400cc engine that revs to 16000rpm?
ive been recommended a garret, but seems theres alot of people in this current topic that know there stuff

Street Tuned
Post #22

one of the garret motor bike turbos would be the way forward I dont know the specs on them but there is a few to choose from.

baconson
Post #23

yeah i think thats the go, looked at a few of them, just gotta work out which one, and yeah seems garret is the only option, capa sells em

ps, sorry for stealing the post for a bit smile.gif

Sharpy
Post #24

QUOTE (TRY TOO @ Feb 15 2010, 01:52 PM) *
I have not driven an sr20 with a gtrs or a t518z. But have owned one with a 2871, with basic mods (exhaust cooler fuel reg) It went very well for what it was, made 175ish rwkw @12psi and was torquey as!

A good amte of mine has the same turbo but with injecters, pfc and all the normal cooler exhaust etc etc. On 16psi makes 270rwhp. It pulls really strong and overall is a GREAT setup for the street. Nice and responsive yet doesnt fall over up top (.8x rear).

You wont be disapointed with the garret!



My Trust T518z with 10cm rear housing makes 257hp on 10 psi, 300hp on 16 psi, and am hoping for 350- 370ish hp on 20-22psi

iamhappy46
Post #25

QUOTE (baconson @ Feb 15 2010, 03:04 PM) *
well thats a goodle thing about turbo lag etc, its a bit kinder on the driveline. i like my current setup cause i come on full boost at 2500rpm, only running 14psi mind you, but i love the responsiveness (ex v8 boy)

while im here, any one recommend a good turbo for a 400cc engine that revs to 16000rpm?
ive been recommended a garret, but seems theres alot of people in this current topic that know there stuff


Turbo lag is not really 'kinder to drivelines', as the sudden rush of torque causes the shafts to seperate allowing only the tips of gear teeth to transfer bulk torque from midrange to hirpm... the result is the lovely S15 gearbox destruction wink.gif I have always found a electronic boost controller to gradually 'bleed' the boost on over a few hundred rpm keeps gearboxes and clutches alive a LOT longer.

For a 400cc engine, I would recommend a turbo from a Suzuki Cappacino 660cc convertible, would be ideal for an engine that size and reving that hard. Best of all, they can be bought cheap(under $180 from importers wink.gif

Street Tuned
Post #26

QUOTE (Sharpy @ Feb 15 2010, 05:19 PM) *
My Trust T518z with 10cm rear housing makes 257hp on 10 psi, 300hp on 16 psi, and am hoping for 350- 370ish hp on 20-22psi

yeah dude bump that shit up you are only just getting into the efficiency range. 20 psi with that rear housing will be wicked although a little laggy. Sadly 98ron fuel wont see much over 20psi with days as hot as these.

I assume you have cams?

TwinCam16
Post #27

Sharpys 180 isnt what id call laggy

Ticc
Post #28

oh well this changes it all lol,i was always under the impression that the trust turbos were bush bearing and didnt have the effectivness of the ball bearing garret/HKS items. i dont seem to hear alot about them usually all i hear is there more reliably.TD 06 25G what kinda power and response lol im listening. also if it helps car already has exhaust, s15, injectors, s15 ecu and i think piggy back of some sort, s15 turbo,fmic, and a turbosmart manual boost controller. but yeh i think the system is up for a large overhall lol also i dont really wanna wait past 3.5 to 4k rpm for full boost as it will hopfully be a STREET/ track car. also where do you go about getting a truct turbo at a decent price?

Sharpy
Post #29

QUOTE (Street Tuned @ Feb 15 2010, 07:08 PM) *
yeah dude bump that shit up you are only just getting into the efficiency range. 20 psi with that rear housing will be wicked although a little laggy. Sadly 98ron fuel wont see much over 20psi with days as hot as these.

I assume you have cams?



Yeah I have 264 degree 12mm lift cams

rocker arm stoppers, springs etc revs to 8000rpm, full boost at 4000 and holds 16 psi all the way to redline


getting a 1 bar actuator soon as my 10 psi one i think is too small (wont hold anything above 16psi past 6200rpm, just drops back to 16) extensive testing has been done, this is one of the last things to test.

Sharpy
Post #30

Trust turbo is Bush Bearing, like i said i start coming on boost about 2600-2800ish, but its gets to 4000 pretty quick and its game on then. which really isnt too late.

good for general driving, and easy to always keep on boost.
baconson
Post #31

turbo lag is friendlier, the car is already rolling when that torque comes on, you dont have to break the inertia of the car being still. and torque increases more steadiy with revs, you dont go from -20hg vacumm at your 800rpm and by 801rpm your at 20psi
its a sloped torque increase, as opposed to say a roots style blower, where your full boost instantly on a stationary car

Ticc
Post #32

ohk fast fours ( the bible ) quote the HKS GT-RS is a great little ball bearing core turbocharger, hand picked from the burgeoning garret catalogue. capable of great power that easily levels the T518z in a straight up fight! down side comes from the engineers being to trciky and making it spool up and build boost TOO QUICK. this resulting in severe copressor surge in some applications, with the GT-R being extremely prone to this phenomena. what about GT3037 420hp?

iamhappy46
Post #33

You wont get compressor surge of a SR20DET, the HKS RB25DET GT-RS conversions used to get it a lot and HKS had the fix of 'buy our erectronic boost controrrer so you can map boost Vs rpm' to fix probrem

Ticc
Post #34

so how come fast fours seems to think that the GT-RS is far in front of the T518z other then the compressor surge and every one on here says the trust im so confused.

iamhappy46
Post #35

The GT-RS is a 0.64 housing... hence it does spool quick and why 8000+rpm GTR's also suffer from problems. So nice of Fast Fours to offer a 'direct' comparison on a SR20 though.

Just buy a GT2871R, the money you save can be spent on tuning which with the right maps, can allow the SR20 to induce a lot of midrange torque and lower range the rpm that boost is generated.

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