Dynograph R34 GTT OP6 anyone?

[Torques]

Dynograph R34 GTT OP6 anyone?

Can someone post a dyno for an R34GTT with the standard OP6 turbo?

(Or OP6 on R33GTST if someone fitted one)

I'm primarily interested in the boost curve

 

Cheers

[KiwiRS4T]

(Not my car) Boost curve will depend on what kind of boost control you have. For more results trawl though the RB25 turbo upgrade section at the top of this page. A number of people post with non-upgraded turbos...

[Torques]

Thank you,

The background is that I have an OP6 exhaust housing and I am marvelling if it's worthwhile to use that housing on a

RB25GTST hybrid turbo (I'm concerned about lag)

 

 

[GTSBoy]

"marvelling"?  WTF?

[Torques]

50 minutes ago, GTSBoy said:

"marvelling"?  WTF?

Lag vs top end ... if that helps

[GTSBoy]

I was picking on your weird English.  Marvelling <> wondering.

But to answer the question....What are you trying to do?  If you are just asking about putting an OP6 housing onto an R33 turbo, and doing nothing else, then don't waste your time.  There's no point doing ANYTHING to stock turbos.

If you're talking about using an OP6 housing to build a highflow from.....then given that the only two parts that are kept when highflowing an RB's turbo are the comp and turbine housings, then what you're really asking is "what is the performance difference between an R33 and an R34 highflow?".  In which case there are a million bits of information available on here that already answer that question.  You should look at the Hypergear thread and his website to see what the difference is.

[discopotato03]

I think the most practical way to look at these OP6 Turbos is that the factory used them as part of a system to make better overall performance than the R33 RB25DET spec engine did . They made a completely new cylinder head and valve train , altered cam specs and changed the inlet manifold as well . Bore stroke and static compression ratio are the same . The bigger turbine housing they already had from the four cam single BB turbo VG30DET .

You should look up the standard power outputs for R33 and R34 spec RB25DETs and note the torque peaks but more importantly where they occur in the rev ranges . Don't quote me but I think with the R33 version the torque peak was up near 5000 revs where the R34 version was more like in the low 3000s . To me it looks like Nissan wanted more lowish and part throttle torque in the R34 engine and achieved that without a low turbo boost threshold or onset if you like . Things like higher air speeds through a slightly smaller runner diameter inlet manifold possibly with a smaller volume plenum chamber . Cams with a bit more lift and a bit less duration which would increase the cylinders trapping efficiencies .

When you can make more low end torque you can afford to raise the boost threshold with things like larger turbine housings - which have advantages higher up . You wouldn't achieve the same thing on an otherwise standard R33 spec RB25DET by only substituting the OP6 turbine housing or complete turbo . I imagine you would start to open a dip in the torque curve by having boost start later .

Nissan would have been looking for cleaner exhaust emissions for a late 90s car and I also think the R34 GTt may have been slightly heavier than the R33GTS25T .

Given a choice you would always start with an R34 engine but rebuilding an R33 with the R34 spec rods pistons and head should give the best of both . Staying with the R33 inlet means all the plumbing and most electricals can stay the same . From memory just need to rejig the CAS wiring and change cam solenoid plugs .

This is really only economically viable if your engine needs a rebuild or you can't quite justify an RB30 conversion .

A .  

  

[Torques]

Happy New Year!

Thanks for the input.

Background is that I have a new hybrid turbo with the 21U housing.

It's a prototype and for me to test.

 

Since I have an unused OP6 turbo I was 'marvelling' if there were any merits in changing the 21U for the OP6.

 

Picture one is Hybrid vs OP6

Picture two is OEM vs Hybrid

 

 

[Torques]

17 hours ago, discopotato03 said:

I think the most practical way to look at these OP6 Turbos is that the factory used them as part of a system to make better overall performance than the R33 RB25DET spec engine did . They made a completely new cylinder head and valve train , altered cam specs and changed the inlet manifold as well . Bore stroke and static compression ratio are the same . The bigger turbine housing they already had from the four cam single BB turbo VG30DET .

You should look up the standard power outputs for R33 and R34 spec RB25DETs and note the torque peaks but more importantly where they occur in the rev ranges . Don't quote me but I think with the R33 version the torque peak was up near 5000 revs where the R34 version was more like in the low 3000s . To me it looks like Nissan wanted more lowish and part throttle torque in the R34 engine and achieved that without a low turbo boost threshold or onset if you like . Things like higher air speeds through a slightly smaller runner diameter inlet manifold possibly with a smaller volume plenum chamber . Cams with a bit more lift and a bit less duration which would increase the cylinders trapping efficiencies .

When you can make more low end torque you can afford to raise the boost threshold with things like larger turbine housings - which have advantages higher up . You wouldn't achieve the same thing on an otherwise standard R33 spec RB25DET by only substituting the OP6 turbine housing or complete turbo . I imagine you would start to open a dip in the torque curve by having boost start later .

Nissan would have been looking for cleaner exhaust emissions for a late 90s car and I also think the R34 GTt may have been slightly heavier than the R33GTS25T .

Given a choice you would always start with an R34 engine but rebuilding an R33 with the R34 spec rods pistons and head should give the best of both . Staying with the R33 inlet means all the plumbing and most electricals can stay the same . From memory just need to rejig the CAS wiring and change cam solenoid plugs .

This is really only economically viable if your engine needs a rebuild or you can't quite justify an RB30 conversion .

A .  

  

 

Hello,

I found the first dyno run I ever had with my (back then) standard GTST. Only mod was an installed boost controller to the standard turbo.

HP figure is at the engine. Torque max is at 3700rpm

So from what you're writing I understand that the OP6 exhibits more lag but this is offset by the different design of the head/runner/cams?

The current hybrid I have installed maxes out at 260RKW, I'm not sure but I suspect this is also due to the restrictive 21U housing?

(that's basically why I am looking at the OP6)

 

 

 

 

 

 

 

 

[KiwiRS4T]

If you want a bolt on hybrid turbo Hypergear makes a number of great turbos. Have a read through his thread.

[Torques]

48 minutes ago, KiwiRS4T said:

If you want a bolt on hybrid turbo Hypergear makes a number of great turbos. Have a read through his thread.

Yep, that's still an option ...thing is that I'm in the UK and postage/import duty would make things expensive.

[KiwiRS4T]

17 minutes ago, Torques said:

Yep, that's still an option ...thing is that I'm in the UK and postage/import duty would make things expensive.

At prices half that of some Garrett turbos freight and duties will mean they are still competitively priced and a lot of RB focused research has gone into them...

[GTSBoy]

PLUS....if that "hybrid" turbo is some sort of highflow, then the 21U housing should have been machined out to suit the larger turbine and there is no way you can fit the OP6 onto it without also machining it out.

PLUS, there is no such word as marvelling.

[GTSBoy]

OK, so it is a word.  But goddamn, it's painful to read/hear.

[KiwiRS4T]

marvelling | Definition, meaning & more | Collins Dictionary

https://www.collinsdictionary.com/dictionary/english/marvelling

1.  
2.  

This time when he unbuttoned her dress he did it slowly, marvelling at the velvety finish of her skin. 

 

Personally I've never looked at a turbo that way...

[hypergear]

OP6 is made for a Neo engine, and it has higher CPR, and more VCT cam angle.  Fitting that housing to a normal R33's high flow will result in an average of 500RPM worth of lag and increase HP by roughly 15kws. 

[Torques]

12 hours ago, GTSBoy said:

PLUS....if that "hybrid" turbo is some sort of highflow, then the 21U housing should have been machined out to suit the larger turbine and there is no way you can fit the OP6 onto it without also machining it out.

PLUS, there is no such word as marvelling.

Yes, the housing would get machined to accommodate the larger wheel

marveling -> http://www.dictionary.com/browse/marveling 

[Torques]

1 hour ago, hypergear said:

OP6 is made for a Neo engine, and it has higher CPR, and more VCT cam angle.  Fitting that housing to a normal R33's high flow will result in an average of 500RPM worth of lag and increase HP by roughly 15kws. 

 

Thanks Stao,

500rpm is a figure I can understand, not sure it's worth 15KW

From your experience what is the power limit for the 21U housing due to back pressure?

[Torques]

12 hours ago, KiwiRS4T said:

At prices half that of some Garrett turbos freight and duties will mean they are still competitively priced and a lot of RB focused research has gone into them...

 

You don't have to convince me mate

I've been following Hypergear's developments for long.

 

[GTSBoy]

40 minutes ago, Torques said:

marveling -> http://www.dictionary.com/browse/marveling 

Do you actually use it in that sense in the UK?  Because that's seriously f**ked if you do.  Marvelling (double L, because we can at least agree on the correct English spelling if we're not dealing with retarded Americans) implies that the thing you are looking at is a marvel, something weird, strange or otherwise non-comprehensible.  Like looking at a circus freak.  When you are trying to work out how to do something or how something works......that's wondering.  At least in the English usage that we use.  Is marvelling something that is used in your part of the UK?  Just your subculture?  The whole place?  Note that I'm not unfamiliar with the UK, I've spent a bit of time there.  Never heard it used in that way.