Rb20 Gurus - Help Me With My Turbo Choice!

[Psymon]

Hi all,

I've been tossing up whether to put an RB25 in my R32 GTST or just to try and squeeze some power out of the RB20. I've decided to stick with the RB20 for the simple reason that I don't want to be pouring too much money into my car right now.

So anyway i'd like a bit of help with turbo choice for the RB20. I already have a HKS cast manifold with T3 flange and external gate. I have 2 heads, one completely standard and another with some work done but not sure what. It's obviously had a bit of port work done, it definitely has larger cams which are supposedly HKS 270 degree items. It also has upgraded valve springs and HKS adjustable cam gears.

From what i've read in various threads, the RB20 isn't really on song until 4000rpm or more, but i'd still like something fairly responsive.

So using the parts I have lying around, what would you guys be suggesting to squeeze some life out of the old RB20?

[wolverine]

With the HKS cast manifold then you have to go a twin scroll housing.

GT/GTX3071 is my two bob's worth.

How much power are you after?

[StealthX]

How long is a piece of string? You havnt listed anything about power targets bro...

Good choice I'd say would be a gt2871r with a t3 flange, what ever the hks alternative is (GT-RS?).

[SimonR32]

TD06-20g L2 seem to work really well on RB20's for decent power...

Wheezy (I think) had really good results a few years ago

Have a look at one of these http://cgi.ebay.com.au/Turbocharger-Kinugawa-TD06SL2-20G-w-T3-V-Band-Housing-/280626811233?pt=AU_Car_Parts_Accessories&hash=item4156a95161#ht_2159wt_1139

[Rolls]

save the money and buy an rb25, or better yet save your money and buy an already modded 32 with a 25 or a gtr.

be the best decision you ever made financially, also you'll get a faster car quicker than if you try and do it yourself.

[SimonR32]

save the money and buy an rb25, or better yet save your money and buy an already modded 32 with a 25 or a gtr.

be the best decision you ever made financially, also you'll get a faster car quicker than if you try and do it yourself.

Did you just describe buying a GTR as "the best decision you ever made financially"?!?

A RB20 with 260+rwkw is nothing to sneeze at, it'll knock more things off than you think... Including most RB25 powered R32's without big turbos

[Psymon]

I'm not really chasing a certain power number, but i'm chasing more power than I can get with a highflow or turbos along those lines. 240-250ish would be nice and i figure should be plenty for a mainly street driven car.

Yes i'm aware the 25 is a better option, but i have these parts lying around so at this point i'd rather just put the parts on and enjoy driving it for a while.

The car currently has the hks manifold and gate fitted with a HKS T300s turbo, but that turbo is just too old/laggy/big for the RB20 so i'm looking for something a bit more suitable. So from where it is now it won't be a great deal of work to change turbo. Maybe some slight piping changes and a re-tune.

[Rolls]

250kw rb20s are a dog to drive, don't waste your money you will just get frustrated and be annoyed if its a street car.

[Psymon]

Yes i understand everyones opinions in the RB20 vs RB25 debate. But all I want to do is put a turbo suited to the application on it and enjoy driving it, which at this point will be cheaper than changing the engine.

[wolverine]

Rolls, if I can find Legend01's dyno of his RB20 you might have a bit of a rethink.

Found the link to the UAS dyno chart making +270rwkw , couldn't find the 300rwkw one which is somewhere in the NSW section (from memory).

http://www.skylinesaustralia.com/forums/topic/58229-top-rb20-club-do-you-have-over-260rwkw/page__view__findpost__p__3129315

Edited February 10, 2011 by wolverine

[Rolls]

Yes i understand everyones opinions in the RB20 vs RB25 debate. But all I want to do is put a turbo suited to the application on it and enjoy driving it, which at this point will be cheaper than changing the engine.

In my opinion there a turbo suited to 250kw street driving on an rb20 does not exist.

Rolls, if I can find Legend01's dyno of his RB20 you might have a bit of a rethink.

Found the link to the UAS dyno chart making +270rwkw , couldn't find the 300rwkw one which is somewhere in the NSW section (from memory).

http://www.skylinesa...ost__p__3129315

Looks pretty good for a 20 but I am still sceptical of the transient response compared to the equivalent on an rb25, plus with a 25 you have VCT with makes low throttle low rev driving very very nice.

Edited February 10, 2011 by Rolls

[ako299]

hks 25/30 best money i spent on my car cant go wrong ull make 230rwkw witht he right mods n boost n isnt laggy like a td06

[toffy]

TD06-20g L2 seem to work really well on RB20's for decent power...

Wheezy (I think) had really good results a few years ago

Have a look at one of these http://cgi.ebay.com.au/Turbocharger-Kinugawa-TD06SL2-20G-w-T3-V-Band-Housing-/280626811233?pt=AU_Car_Parts_Accessories&hash=item4156a95161#ht_2159wt_1139

this would be my choice with the worked head , sell the hks manifold and buy a 6boost with trust flange or something similar .... or buy the china copy with t3

I'm not really chasing a certain power number, but i'm chasing more power than I can get with a highflow or turbos along those lines. 240-250ish would be nice and i figure should be plenty for a mainly street driven car.

Yes i'm aware the 25 is a better option, but i have these parts lying around so at this point i'd rather just put the parts on and enjoy driving it for a while.

The car currently has the hks manifold and gate fitted with a HKS T300s turbo, but that turbo is just too old/laggy/big for the RB20 so i'm looking for something a bit more suitable. So from where it is now it won't be a great deal of work to change turbo. Maybe some slight piping changes and a re-tune.

the problem there is you can get some pretty good high flowed these days that would simply eat your hks t300

hks 25/30 best money i spent on my car cant go wrong ull make 230rwkw witht he right mods n boost n isnt laggy like a td06

i disagree , personally i'm not a fan of hks 2530 after owning one ,the kkr 430 i put in its place is a more responsive turbo , And i have the dyno sheets to prove it! ( i actually sent my 2530 away to be checked/rebuilt if need be but it was given a clean bill of health )

[R31Nismoid]

a KKR 430 more responsive than a 2530?

Something was wrong there... And before you get dyno sheets out - they are not the best indicator of throttle response etc. Very much so on a RB20 given loading up heavily will alter results.

The 2530 is a smaller turbo, and plenty of results in the RB20 thread you can compare against but for 230rwkw/20psi, pretty much 'the' choice by most people.

And you MUST run 18-20psi on the 2530

TD06-20g L2 seem to work really well on RB20's for decent power...

Wheezy (I think) had really good results a few years ago

Have a look at one of these http://cgi.ebay.com.au/Turbocharger-Kinugawa-TD06SL2-20G-w-T3-V-Band-Housing-/280626811233?pt=AU_Car_Parts_Accessories&hash=item4156a95161#ht_2159wt_1139

Yes, Roy has had excellent results with that combined with the Greddy manifold & stock plenum

Recently he changed to the Plazman/6boost combo, lost power and response

Was in his build-up thread for further details.

[toffy]

a KKR 430 more responsive than a 2530?

Something was wrong there... And before you get dyno sheets out - they are not the best indicator of throttle response etc. Very much so on a RB20 given loading up heavily will alter results.

The 2530 is a smaller turbo, and plenty of results in the RB20 thread you can compare against but for 230rwkw/20psi, pretty much 'the' choice by most people.

And you MUST run 18-20psi on the 2530

yeah i know dyno sheets won't show much but you can definately feel the difference. I thought the same thing which is why i sent it [the 2530] to be checked out . to give you an idea : the kkr starts to spool around 2krpm and hits full boost around 3.8k , slow to get to full boost i know but you can definately feel it from 2krpm any way to try to accelerate , the 2530 made boost around 3krpm and full boost around 4krpm in memory , made it feel like a laggy pos in comparison on the road , both are/were running around 20 psi on 98ron (bp) the hks had gtr injectors and pfc , the kkr is using nistune with std injectors is about the only difference in setup

[wolverine]

this would be my choice with the worked head , sell the hks manifold and buy a 6boost with trust flange or something similar .... or buy the china copy with t3

Why??

The HKS cast manifold is divided,it would love one of those 0.78 twin scroll V-banded housings hanging off the side of it plus Psymon already owns it.

I would definitely go for a GT3071 with the aforementioned turbine housing.

[toffy]

Because i like the td06 more than the 3071?

[eightsixboy]

this would be my choice with the worked head , sell the hks manifold and buy a 6boost with trust flange or something similar .... or buy the china copy with t3

the problem there is you can get some pretty good high flowed these days that would simply eat your hks t300

i disagree , personally i'm not a fan of hks 2530 after owning one ,the kkr 430 i put in its place is a more responsive turbo , And i have the dyno sheets to prove it! ( i actually sent my 2530 away to be checked/rebuilt if need be but it was given a clean bill of health )

Really? A KKR better then a HKS?

No offence but i always thought KKR were fairly cheap/crappy turbos?

Also whats the go with the Kando Dynamics turbos? Are they any good?

IMO you wont get a drivable/liveable rb20 with 250rwkw, I hated my rb20 when I had only a vg30 on, was so laggy it wasn't funny, I put the standard turbo back on for now, I either will be going a 2530 or rb20 highflow and power goals around the 220rwkw mark, hopefully will be fairly responsive still.

Either way if your gonna spend this money on the 20 you might aswell keep it in the long run as the money spent now could be most of the money for a 25.

[wolverine]

Because i like the td06 more than the 3071?

But why change the manifold?

[Roy]

Not going to go into the debate of RB25, everyone has different views and I can see the merit in both schools of thoughts.

What I will say is sadly, Russman has just stripped his RB20 with Poncams, HKS 2530 and 230rwkws so we will never get any footage of DECA side by side rolls with my TD06-20G powered RB20 with std cams making about 250-260rwkws etc...

But seat of pants, Russman having driven my car and I have driven his on the street and track ....there really isnt that much differnce in lag between the cars. His car does have more drivability with about 10-15rwkws more at 3,600-3,800rpm, but at 4,200rpm they are making the same power and from 4,500rpm I am making about 30-50rwkws more in the top end as the 2530 really falls over at about 6,500rpm and the TD06-20G keeps pulling to about 7,600-8,000rpm.

So the 20G does make for the quicker car when you are opening up the taps and going through the gears. If you are in the same 3rd and 4th gear sections of blipping up a gear then braking and start stopping the 2530 would probably get the better of it. the 20G is clearly quicker over the qtr mile and on a track, with a clearer advantage once you need to start accelerating over 180km/h. At Winton the merits of each setup probably end up about equal. At places like Winton and Sandown the 20G is probably the better setup.

So , thats as detailed an example as i can really give. For me the take away is that no matter what turbo you throw on an RB20, they will not come on cam and make power until after 4,000rpm so trying to overcome the short stroke rev nature of the engine with a small turbo is counter productive.

I think your car with the std plenum, std head and cams, with the HKS manifold with a 3071 with a twin scroll rear T4 housing would be a good thing. It would make about as much power as the 20G with probably better response or there abouts. Throw 19psi at it and a healthy RB20 will last a long time with a good tune.

Stick with the std head and cams. I have played with a 6boost manifold as Ash has said and its no better then the Greddy manifold it replaced, evidence suggest it could be worse then the Greddy manifold. I have been there and done that with cams and lost power with Apexi 260/9mm cams so back in went the stds. Plenum, i currently have a Plazmaman on and after more tuning and playing around we have now almost got the same power and almost the same response as i had with std. I would have had far more money in my pocket and as good, a tad better performance with the std plenum. I am so far down this road I am going to try a bigger exhaust housing now to see if the 6boost manifold and Plazmaman manifolds are being held back by the restrictive hot side of the 8cm housing on the 20G...so this hasnt been economical but i find the trialling and understanding for myself half the fun...but also a lot of the frustration

So stick with the basics of a well selected turbo setup that is well tuned...3071 gets my vote...will come on nicely just as the short stroke RB20 gets enough air in its lungs. My car will be up in Brisbane in a few weeks so if you havent been for a ride in a 250rwkws Rb20 then you are welcome to get a feel for it. I wont be surprised if you decide to go Rb25, but it will at least serve to help with your expectations