Gt3271 On Rb25 R33?

[Justlikemusic]

GT3271 on RB25 R33?

I got one yesterday... I think it's a bit small for my 4L falcon, but it would probably do. However now I am thinking of just daily'ing the falcon and converting the skyline to a manual and putting some crazy boost into it.

1. Will the GT3271 be too big for the RB25? I think its A/R .69 rear housing.

2. Also what would be a safe amount of boost to feed a good condition 120k RB25?

3. 10/15psi two stage boost controller? And what type of power would I be looking at at these boost levels with this turbo (Other mods only 3" cat back, then FMIC, injectors, fuel pump and Wolf)

4. Also what would I need to change to put this turbo on the car?

5. Same manifold? Custom dump? Custom charge piping

Will pay you back for your wisdom with mad videos of drifts at collie =)

[JKR-32]

Post videos or gtfo!

That turbo does sound like a bit of a mismatched setup though. Don't think it woud be much of a goer on an rb25 as it would be laggy and not deliver much top end...

[Justlikemusic]

One on the left

[simpletool]

A bit too small for the RB25 also. The compressor map shows it runs out of puff at 40 lb/min and the exhaust side would support that. It would be a nice progressive turbo (only mild turbine trim) but prob max around 230rwkw.

So it's a bit lower flow on the compressor side than a GTRS, but a lazier turbine.

Guestimate behavior : Slower response but more progressive than a GTRS with lower exhaust temps and ultimately less power as well.

Definitely too small for a 4L engine!

Crazy boost isn't going to happen with this turbo on a 2.5L, it'll just run out of flow higher in the rev range. You need at least a 3071 (56 trim) to give it much grunt.

[simpletool]

I think you'll find the 4.0L falcon engine flows only slightly more than the 2.5L RB25.

sure it's a bigger engine but stock it doesn't rev anywhere near as hard and the heads aren't as efficient either. Put those 2 factors together and the 4L would require only a slightly bigger turbo.

ie. 3071 for the RB25 vs GT30 (3076) for the 4.0L (would be my pick)

or GT30 for the skyline and GT35 for the falcon (for more power but more lag - you'll need a built 4L engine though equivalent to stock XR6 turbo engine or better)

Edited February 13, 2011 by simpletool

[simpletool]

1. Will the GT3271 be too big for the RB25? I think its A/R .69 rear housing.

No, too small to be worth your while and fulfill my response to Q2 below.

2. Also what would be a safe amount of boost to feed a good condition 120k RB25?

1.1bar is a good start with a good tune on a good decent condition RB25.

3. 10/15psi two stage boost controller? And what type of power would I be looking at at these boost levels with this turbo (Other mods only 3" cat back, then FMIC, injectors, fuel pump and Wolf)

Two stage boost controller not needed. I run 15psi all the time these days, my GF drives it occasionally to work in Sydney traffic (even my mum has driven it) and they drive like your typical but responsible driver. If you don't want all the power then don't use all the accelerator. Power level on a little bit larger turbo at 1.1 bar is around 260rwkw. I doubt this turbo will hold 1.1bar until max power, if it does it won't make much more than it would at 1bar. I'd guess 230rwkw max - depends on tune and dyno.

4. Also what would I need to change to put this turbo on the car?

Water and oil lines - braided or equivalent. Dump pipe and some elbow adapter for inlet (probably all that is needed). Not sure on the flange but it says T3, a proper split pulse manifold would be nice since you have a split pulse housing (is there only one T3 type?) Then again.....you're not going to use that turbo are you?

5. Same manifold? Custom dump? Custom charge piping

see above.

Edited February 14, 2011 by simpletool

[Justlikemusic]

Thanks for your replys.

The GT3271 is a 73 trim 0.78 turbine housing in standard form. There is two types of housings with that turbo, one is a journal bearing other is an oil-cooled free float. Not sure how to work out which I got, but it's from a Perkins diesel motor. The exhaust housing is very big though. 2.5" straight out the back of the turbo so that is why I figured if it is .78 A/R and the falcon is only revving to 5500rpm on the street then I might be able to get away with running 10psi and 5500rpm limiter on the 0.50 A/R compressor.

I found I could get rebuild kits for $250 for this turbo, and I paid $100 for it... the falcon is a bit of a ghetto build and I'm happy to upgrade later if this turbo will work for now. I think I'm only expecting about 250rwkw on the Falcon... but a crazy torque figure. I can see the turbo will run out of puff at 300-350hp.

Im just really unimpressed with the go of the R33... Im sure im getting some form of spark breakdown after 4000rpm and I've siliconed up the coilpacks and cleaned up the plugs (did this on the weekend when I had a flat battery and was siliconing the plugs anyway). I will replace them over the next couple days and see how I go from there. Can't really justify spending $400 on JJR coilpacks on a car I might not even keep for long. It's highly noticeable when I ground the boost solenoid and run 7psi all the time. Maybe it could be something as little as spark blowing out from gap and older spark plugs. Never run a turbo car before so dunno about the spark blowing out business... seems its a common issue. The other option is to run a VN commodore wasted spark setup.

Currently got 3" cat back, R34 SMIC, K&N filter

If I can fix the spark problem and install a 10psi wastegate, split dump, high flow cat and cold air intake maybe that will suffice... there is a big difference between 5/7psi and 7psi, and that is with the constant 7psi turning to crap after 4000rpm. Im sure 10psi is going to be a big jump with the other mods.

[juggernaut1]

I run the twin scroll .78 housing on my sr20 with a 3076 (52 compressor) and run a 3.5 inch dump off the back of the housing. It works well but is a tad too small for an RB25 IMO......and definately too small for a 4 litre Falcon motor when you consider they have a GT35 turbine in a 1.06 open housing in standard form. Whilst the Ford motor might not rev like an RB they still make bulk hp low in the rev range meaning you still need a decent flowing exhaust housing and turbine.......the twin scroll .78 housing will just choke it.

Edited February 14, 2011 by juggernaut1

[Justlikemusic]

Ok so the 3271 would be better suited to a heavily worked 2.xL 4 cylinder motor?

Im sure I seen people use .63 housings on the 4L falcon engines.... most of the turbo builds are .83

Boostedfalcon.net has these builds on it.

Edited February 15, 2011 by Justlikemusic

[juggernaut1]

Ok so the 3271 would be better suited to a heavily worked 2.xL 4 cylinder motor?

Personally I wouldn't waste my time with that turbo, no one uses them for a reason.

Im sure I seen people use .63 housings on the 4L falcon engines.... most of the turbo builds are .83

Boostedfalcon.net has these builds on it.

Sure you can use those housings but when the factory fits a 1.06 open housing with a GT35 turbine and makes around 550nm of torque by 1900rpm. Add boost, fuel, cooler, exhaust and tune in the case of the factory F6 Falcons and your looking at 350rwks - 370rwks without breaking a sweat. So it seems like the factory sized turbo has good low down torque with reasonable potential for top end.

http://forum.rdpbris...ic.php?f=4&t=80

Edited February 15, 2011 by juggernaut1

[Justlikemusic]

Ah that sucks... =(

Didn't know the specs at the time, but it was $100 so just bought it... rebuild kits are $240 so it's a cheap Garrett turbo. I guess I'm better off with a rightly sized ball bearing turbo in the long run.