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Rb25det Gt3582r My Predicament,

Ryanrb25

By Ryanrb25,
in Engines & Forced Induction

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dano4127 Veteran

dano4127

Posted
Posted
Yea but im sure that rb30 was build to handle 30+Psi lol

Can front wheels and covers be swapped over like rear ones?

Yes they can but you will find it is a very expensive exercise! Rear housing from Garret from memory was $600+

And yes +1 to a .63 housing being way to small on a 3L it will choke up for sure IMHO it is a bit of a misfit size in the Garrett range...

The .82 is not too bad on a stock RB25 more suited to a built motor but it will be a good balance between not having to buy a new turbo when you get the 3L cause a .82 on a 3L is a response monstor :domokun: I personally have a 1.06 rear on my 3L and wouldnt have it any other way as it feds on the power so nicely. Also I might add mine is internal gate and am having no problems with boost control 7psi actuator and a Turbosmart T and holds dead on 15psi.

And is it definately internal gate?

hahaha

Ryanrb25 Grand Master

Ryanrb25

Posted
  • Author
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Thanks for the info guys, For now i think im going to wire the Internal Gate shut, Mod my manifold to house an external gate and still use the .63 rear. I like it at the moment how i can cruise around at the moment like everything is normal but flat foot it off the line in first and it doesn't break traction. If the .63 generates too much heat ill put an external gate rear .82 housing on the turbo and keep it that was until i wack it on a 3L.

Thanks for the Info.

chrissso Proficient

chrissso

Posted
Posted

Hey guy,

I think 'the mafia" did a gt30 with a .63 rear end. Search for his threads. I dunno if you're already onto it, but it makes for a good read.

Also, just something I would consider if I was in your shoes... Why don't you use the GT35 with a ext gate setup until you get your 3.0l

from what everyone on hear says, the ext gate spools the turbo quicker, and then you have an upgrade path. You may or may not want a .82 rear house when you 3.0l, but that's then, not now.

bubba Grand Master

bubba

Posted
Posted
Yes they can but you will find it is a very expensive exercise! Rear housing from Garret from memory was $600+

And yes +1 to a .63 housing being way to small on a 3L it will choke up for sure IMHO it is a bit of a misfit size in the Garrett range...

The .82 is not too bad on a stock RB25 more suited to a built motor but it will be a good balance between not having to buy a new turbo when you get the 3L cause a .82 on a 3L is a response monstor :( I personally have a 1.06 rear on my 3L and wouldnt have it any other way as it feds on the power so nicely. Also I might add mine is internal gate and am having no problems with boost control 7psi actuator and a Turbosmart T and holds dead on 15psi.

hahaha

You have the XR6T version yeah? with the 0.50 front cover?

How does that affect compressor flow?

dano4127 Veteran

dano4127

Posted
Posted
You have the XR6T version yeah? with the 0.50 front cover?

How does that affect compressor flow?

I do but also have a .7 cover

There is no noticeable difference between the .5 and .7 without changing the tune, might get some gains when it gets retuned though...

psi Experienced

psi

Posted
Posted

I have found that bigger turbo's with low boost make heaps of wastegate air. So if the gate is too small, and or the waste gate dump is to small, the issue comes where the gate cannot dump enough gas to stop the turbo from spooling up.

Ryanrb25 Grand Master

Ryanrb25

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yea we figured that one out, going external gate so will resolve that...I was talking more of whether the .63 rear can flow enough through it to cope with the gt35 front cover and the volume of air its producing to not create too much heat.

Adriano Grand Master

Adriano

Posted
Posted

If i were in your predicament, i would seriously consider selling it and buying a proper matched turbo. As you seem aware, a 3082 is behind the 8 ball, as teh ex wheel is too small to generate enough torque to accelerate the rotating mass quickly. And by using a .63 exhaust, it is partially alliviating that, but adding high backpressure to the equation. I would be fitting a .82 3076, as IMO it is the ideal turbo for an rb25 after 280-300rwkw. Even if you fit the rb30 (which i dont think you will need to)the same turbo can be used, and fry the tyres up to the legal speed limit with more response than you can poke a stick at. If you feel you must have more than 300rwkw, then bite the bullet and get a real gt35r, with a .82internal or you can get away with an external gate .63, but i believe on pump fuel the exhaust backpressure will limit the power to far less than the comp wheel is capable of making. We need something between a gt30 and gt35!

Ryanrb25 Grand Master

Ryanrb25

Posted
  • Author
Posted

i find this topic interesting....

Just incase anyone cares...

my gt35 with .63 rear isn't as laggy as you'd originally expect.

3000rpm = 0.56bar 8psi

3500rpm = 0.82bar 12psi

4000rpm = 1.04bar 15psi

Once external gate is fitted should be fairly good.

Just hoping the .63 rear doesn't choke up the gt35 housing too much in the top end. For the conservative boost ill be using it shouldn't.

R31Nismoid Grand Master

R31Nismoid

Posted
Posted

^^ thats fairly laggy IMO.

I had my GT30 .82 on by 4200rpm and was over 15psi and make more power than you will be able too :yucky:

500rpm to get that last 3psi once spooling is indicative of the large compressor side

Ryanrb25 Grand Master

Ryanrb25

Posted
  • Author
Posted

after 4k the boost sky rockets but thats when i back off, yet to see what it does after that.

yea but at the end of the day, It's all about experimenting....gimme a break...i just spend 2k on this turbo, gotta stay positive hehe.

I'm not doin it to beat anyone else...doin if for my own thrills.

It's fairly laggy i know but off boost it drives great and doesn't break traction which is what i was after.

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