4age - most "responsive" turbo options

**YLD-16L** · 21-04-2006, 08:32 AM

Nice work Cameron, while some are struggling to just fit the SC14 you went twin charge and it sounds like it works quite well - thumbs up!

Are these off a specific model GTR or are they the same accross all models (I'm assuming by GTR you mean the nissan type).
How cheap is "cheaply" (ballpark figure)?

Mine was off an R33 but I think the T28 remained basically the same from R32 --> R34. You should be able to pick up a good second hand one for anywhere from $200 to $350. Mine was purchased about 4 years ago from a guy who was upgrading his twins on his GTR and it only had about 8000km on the clock, so the turbo was quite fresh and was $300 (back then turbos were more expensive too).

**gixer** · 21-04-2006, 05:59 PM

I run a GT28RS with the 0.64 turbine housing on a 20V and this spools very quickly and very nice power.

**no_tofu_speed** · 21-04-2006, 06:08 PM

What sizes (sm and lrg) are the standard T28. And how can you tell if it is a ceramic wheel unit? I have heard about ceramics and.... scary...

**gixer** · 21-04-2006, 06:21 PM

T28.....oh mate where do you start, there are so many different configurations it's not funny, and thats just on the nissan cars, then there's the HKS T28 stuff!!!! I have started a database of T28 turbo's I am coming across, I am measuring wheel sizes so I can work out trims, ar's etc etc this will just be a database of physical dimensions and not BHP output. I have just made up a hybrid using a GTR T28 with a larger comp cover 0.64 and a S15 turbine cover(with shrouded wastegate) a friend will be using it on his turbo 4age down the track some time and it will be interesting to see how it performs.

**mullett** · 21-04-2006, 08:14 PM

It depends on the motor too. For turbo'ing, you're better off than me to start with as far as response goes, because the AE92 had a higher compression ratio than the AW11 GZE. If you're really, really keen on a responsive turbo, maybe you should consider different compression ratios, cam selection...etc, all to match the turbo you have in mind. The 'Disco Potato' T28 has some excellent reviews...

RM.

**EldarO** · 21-04-2006, 10:25 PM

oh, for uber response, i just remembered,

4EFTE turbo. - phucked if i know what it is though.

Eldar.O.

**roadsailing** · 21-04-2006, 10:32 PM

bear in mind that a really peppy turbo will hurt the amount of power you can make at high RPM.

if you go too "responsive" they car will just be annoying to drive.

don't go too small!

**EldarO** · 22-04-2006, 12:37 AM

eheheh, he said the most responsive

hell, go for one of those 3 cylinder 900cc turbos!

Eldar.O.

**no_tofu_speed** · 22-04-2006, 12:47 AM

aww leave me alone *hids in corner*

**Ghetto-AW11** · 22-04-2006, 03:10 PM

I have a garret gt25/40 440hp Turbo on mine, and there is bugger all lag.

**nick.parker** · 22-04-2006, 04:19 PM

Hi Cameron,
Your twincharged setup looks sweet. Don't suppose you have any in car video

?

On your website it says SC puts out 13psi, turbo puts out 10psi, 10+13=23.....at what points in the plumbing are you measuring these pressure? The turbos absolute output pressure (i.e. 10psi + 14.7psi) is effectively modified by a pressure ratio of the supercharger, rather than just adding the boosts. With some gross neglect of the real world :-

For 13psi just the SC, pressure ratio is (14.7+13)/14.7 = 1.88
For the turbo 10psi is a pressure ratio of (10+14.7)/14.7 = 1.68
and 1.68 * 1.88 = 3.16 abs pressure ratio or 2.16 atms of boost = 31.7psi

But, if you had a stock sc engine at 8psi.
For 8psi just the SC, pressure ratio is (14.7+8)/14.7 = 1.54
For the turbo 10psi is a pressure ratio of (10+14.7)/14.7 = 1.68
and 1.68 * 1.88 = 2.59 abs pressure ratio or 1.59 atms of boost = 23.4psi (what you say your manifold pressure is)

Cheers, Nick