R34 Gtr Build

[TREGTR]

The more interesting people and things I can meet and learn about the better, I am going to be in Sydney for a week leading up to WTAC next month - might have to try and swing past JEM sometime. None of us have all the answers, so always interesting to share experience where willing - I'm certainly always open minded to new ideas... as at this stage I can't see how you can't associate spool with inertia (and other things relating to turbo design), considering turbo shaft rpm comes from a mass being accelerated and that mass is drawing and pumping air - the better it is at moving air versus the amount of energy it has available to move it, the better it is going to perform overall... I would have thought. But yes, if there is an opportunity to discuss it when I am over, I'd love to... one of my favourite topics

So impeller design, turbine design, ceramic roller bearings (cooler air) and other design features play no part in spool? Just the mass of the spinning components? Seems a bit f=ma isolated

[Lithium]

Did you see where I wrote 'and other things....'? I just pointed specifically at inertia because the other things could be more subjective when comparing two turbos.

[MR 33]

lol thanks bob!! Cant wait

[TREGTR]

Did you see where I wrote 'and other things....'? I just pointed specifically at inertia because the other things could be more subjective when comparing two turbos.

As a bracketed caveat perhaps, but the main thesis you were suggesting is that Bobby was unaware of spool being (a small part function) related to the inertia of the rotating assembly.

[Lithium]

Possibly poorly worded on my behalf - sorry! The main reason I was focussing on that is that it's a pretty big part of the picture when you are talking a turbo which has a 6% bigger inducer area and 20% bigger exducer area on the compressor before you even begin to look at how effective the wheels are "pound for pound" as it where. When you are just using exhaust gases to push that mass to >100,000rpm it makes way more difference to how it drives than you may give it credit for. The aerodynamics etc will have a bigger effect on the possible boost thresholds than the inertia will, but I'm talking about real world stuff - not static loading or controlled sweeps on a dyno.

Anyway sorry Bobby, if this is going too far off topic for your discussion here I'll leave it till I catch up in Oz next month

[BOBBYr34]

All good mate add what you need to this thread as discussions are always good to see other people's ideas and I am open to all ideas and open to discuss my ideas or should I say john skola 's ideas

[TREGTR]

Possibly poorly worded on my behalf - sorry! The main reason I was focussing on that is that it's a pretty big part of the picture when you are talking a turbo which has a 6% bigger inducer area and 20% bigger exducer area on the compressor before you even begin to look at how effective the wheels are "pound for pound" as it where. When you are just using exhaust gases to push that mass to >100,000rpm it makes way more difference to how it drives than you may give it credit for. The aerodynamics etc will have a bigger effect on the possible boost thresholds than the inertia will, but I'm talking about real world stuff - not static loading or controlled sweeps on a dyno.

Anyway sorry Bobby, if this is going too far off topic for your discussion here I'll leave it till I catch up in Oz next month

His whole point is that that turbo is properly matched via the Turbonetics turbo graph to the build by John. Meaning it's in its peak efficiency band and not surging. All the info is recorded on the graph.

[Lithium]

His whole point is that that turbo is properly matched via the Turbonetics turbo graph to the build by John. Meaning it's in its peak efficiency band and not surging. All the info is recorded on the graph.

This was discussed a page or so ago, no - all the information is not recorded on one graph. To some degree plotting where the engines expected VE against a compressor map is the easiest part of choosing a suitable turbo, if you are going to try and make the most of the whole setup. It is clearly a very important part, too - but there are plenty of serious variables to consider beyond that map which will play huge parts in terms of how well it will work.

Using the logic that the compressor map has everything you need to be concerned with, and using a turbine housing with a restrictive throat is a good way of making it responsive - a GT2876R with a 0.48a/r turbine housing could be argued to be a perfect bolt on turbo for RB25s yet for some reason that isn't the case

[TREGTR]

Possibly poorly worded on my behalf - sorry! The main reason I was focussing on that is that it's a pretty big part of the picture when you are talking a turbo which has a 6% bigger inducer area and 20% bigger exducer area on the compressor before you even begin to look at how effective the wheels are "pound for pound" as it where. When you are just using exhaust gases to push that mass to >100,000rpm it makes way more difference to how it drives than you may give it credit for. The aerodynamics etc will have a bigger effect on the possible boost thresholds than the inertia will, but I'm talking about real world stuff - not static loading or controlled sweeps on a dyno.

Anyway sorry Bobby, if this is going too far off topic for your discussion here I'll leave it till I catch up in Oz next month

It sounds like Turbonetics highly qualified engineers might benefit from a discussion with you in a new thread.

[Lithium]

Naw chucks, you give me too much credit - as I also suspect you give yourself too much credit in regards to what you can tell about someone you have never met! I was merely suggesting that there maybe slightly better products available designed in the last 5 years than those designed 20 years ago - not that I know anything better than the ones that designed those products.

Anyway, back to this build - I am ultra keen to see how it comes together... what is next?

[TREGTR]

Naw chucks, you give me too much credit - as I also suspect you give yourself too much credit in regards to what you can tell about someone you have never met! I was merely suggesting that there maybe slightly better products available designed in the last 5 years than those designed 20 years ago - not that I know anything better than the ones that designed those products.

Anyway, back to this build - I am ultra keen to see how it comes together... what is next?

No need to get emotional. Yes, 20 years worth of expert product development might suggest it is a perfected product. Most mechanics would never buy the first year of a new model car, after all. Also, how old are RB26s they are still a very good design by today's standards, just saying

[Lithium]

Seems a bit like this thread must be due for an update

[MR 33]

Im pretty sure the car was started up over the weekend... if not it is damn close to being running!!

[MrFijiGold]

It is indeed alive. Saw vid on FB a few mins ago.

[MR 33]

Lol so it is! Looks awesome

[Lithium]

Hah yes - it wasn't a coincidence that I made that post Very keen to finally see how this Turbonetics + a whole pile of innovative ideas stuff works together. Good luck for tuning, when are we likely to hear results?

[BOBBYr34]

From this point onward a new chapter starts.

[MR 33]

Yeeeessss the real story begins now!!

[Al Despo]

Unreal!

[sleptema]

After spending the past 4 hours reading through this thread, I have come to the conclusion on a few things:

1) I should probably get back to work

2) There is a lot of things that I still do not understand

3) I plan on building a 34 GTR myself, but I have much better ways to spend 3 years and god knows how much money on this kind of indepth project. Though, I admire the patience, skill, knowledge and workmanship that has been put into this magnificent machine. This is truly remarkable and will hopefully change the future of modifcation of RB engines, and cars in general - especially if this venturi manifold does spool that turbo in the way and at the engine speed that it should.

Just a couple of questions Bobby. I know you have probably done many more calculations than I have on the following question/comment concerning the air compressor to try make boost on idle.. We had a shop engine we were trying to do the same thing to, and we could only make a measly 5psi after having 3 lines of shop air tapped into the manifold pointing directly at the impeller - obviously we could only get such low compression because the impeller runs off volume rather than pressure. How do you manage to overcome this?

Also - 3 years is a long time to be working on this project, how did you stay motivated up to this point? I certainly would have lost interest and even reading the thread I skipped a few pages at the end haha.

You were involved in building one of my mates' r34, I think you named it goldfinger. I can see now why he chose your company to build his car because you obviously have the willingness to go the extra mile for your customers as shown in his car, and in this thread. +1 to you and to your team. If I ever have the money (haha not in my lifetime) to do something as dramatic as this, it will be a no brainer who to go to. Good luck with the rest of the build.