GT28RS with .64 a/r housing

Hi guys I've been doing a lot of research into my engine rebuild & turbo upgrade - after reading many threads here & twinturbo.net & nico etc, I still can't get a straight answer to my question regarding the GT28RS turbo with the .64a/r housing.

Basically there's dyno results showing that a RS produces as much torque on pump fuel as a R produces on RACE FUEL!
Obviously the trade off is lag - but Z1 & CZP are claming that with the .64 housing the lag is minimised.

Picture a rebuilt engine with the following mods -
forged 88mm, 9.1 c/r pistons
Balanced internals & ported heads
New/ reground cams to aid in spool
Nismo 555cc's
NISTUNE ECU
GT28RS turbo's with .64 a/r (obviously)
3" dump pipes & test pipes
3" exhaust
3A pods
twin intakes
UDP

My question is will this set up provide same spool as the GT28R?
Considering I'm upgrading/ strengthening the engine & supporting mods, I beleive the RS's would be the only way to go.

OR

Do I do everything above and stick with the 28R's - if so, would this get me closer to the torque that the RS's can produce?


I understand this is a tough one

Thanks guys

 

good so far

add 740's , OS Valves
with 9:1 go with GT28RS , spool torque will be as good as GT28R (slotcar proof)


cam choice is important too no bigger that 264/9.5 (midrange torque,spool)

although GT28R's will be a weapon with this set up

(same choice dilemma I went through)

 

28rs is a physically larger turbo then the 2560r thats known as the 28r. its more efficient then the smaller turbo = less lag..

rs will give u more top end then a tiny 2560r

 

LOL they are physically the same size!!

just different wheels

 

housings are the same size between the 28R & the 28RS (if .64 on both). It's the wheels that are larger in the RS

*EDIT*
Blackbeast beat me to it. lol.

 

2560r and 2860rs use different size CHRA's guys

hehe when u fellas going 2 stop arguing whats best and come 2 the dark side big turbo land..

why not get some sport 900's same spool as a disco more top end and same price as a 28rs kit!!!

 

Forgot to mention - what about with N/A diff or Leader gears on top - would that be overkill - considering traction should be alright whilst using semi slicks
Would the GT28RS's with the 4.10 diff ratio match/ outperform the R's for bottom /mid range?

 

2860rs will always out perform a 2560r dude even on a stock engine

 

leader gears /na diff doesnt make your turbos spool quicker ,it gets you in the powerband quicker at where it spools.

ask yourself what you want to use the car for then choose turbo.

ported heads
os valves
jwt400+ 264/9.5

88mm 9:1 wiseco
eagle rods
good fuel rail 740cc
twin intakes
3"dumps exhaust

this with Gt28r's is what my original set up was going to be, IMO still the best street/track set up for the Z32.
350rwkw all day

With Gt28RS still good spool but over 400rwkw

 

Thanks Rob, I understand what your saying HORSEPOWER WISE, but out of the 2 turbo's with the same engine upgrades as you & I have listed, which will supply more torque?
When people talk about the RS's coming on so strong it's due to the torque they create - so what I need to know is - when the R's come on boost is it just as aggressive or less than the RS's? - regardless of the KW/HP output - I know the R's have more meat in the middle but why have I heard more people describing the RS's as coming on like it's way stronger?

Cheers

 

GT28RS will make more torque (hence more horse power)
GT28R will (as a guess on above engine) come in 200-400rpm sooner but drop off sooner

 

Also forgot to add - AMS manifolds to the list

 

Dude, 3071R's do NOT make boost as fast as 2860RS's, they're a frame larger. 2860RS has perfect Turbine to Compressor wheel ratio and would offer the best boost response, largest power band and top end power out of the lot on a 1.5 litre (or even 1.6 for strokers I'd imagine) bank. Also the 3076R is the original/best GT30 turbo, not the 3071R which has the smaller Comp wheel to minimise Lag. Hybrid's are no good, something becomes a trade-off with them.

 

dyno sheets show otherwise,,, for the price why not go the big boys..

 

one dynosheet from specialty Z promoting their new SP90 KIT VS JWT700 .86a/r.

And tuned by them.. you have a lot to learn

good old TT.net.

 

if you had the same 0.64 exhaust housings on both turbos would the spool be similiarr or still different because of the larger internal wheel ? (obviously taking in the supporting mods are the same)

 

might be a little less lag in that regard due to less volume of air that needs to be compressed in the smaller housings, but wouldn't expect it to be a stack.

Put it this way, i've got *just* slightly less lag than a GT28R turbo with .64 housings. And i'm running GT28RS cores in stock housings.
...so with my bigger wheels than a 28R, i'm still getting slightly less lag (only by a couple of hundred RPM), but potentially more flow still due to the bigger 28RS wheels.
So that's just for that example, so i'd say that same theory would apply for the bigger boys aswell when it comes to wheel size & housing sizes.

That's just from my experience. I'm sure Black Beast can also add his own personal experience to this too...

 

You have journal bearings too don't you Benny?

 

its a bit hard to quote whether you have less lag than GT28R unless comparing on same engine .

I achieved 24psi at 4300rpm with my big high flows .On my set up I believe GT28r would have spooled quicker.
I now realise I had higher comp (with cams)

My old turbos on a stock engine would probably spool 500rpm later

Every setup is different

 

Yes, journals Chrispy.
But as Black Beast said, it's hard to directly compare unless on the same engine. And also the tune comes into play somewhat with minimising lag (particularly timing).

So it's not a good example really, but more of a ball-park so to speak.