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Discussion Starter #1
Any idea the benefits of larger throttles on the RB26? I've never really seen too many of these used on tuned cars and even demo cars. I imagine that more air means more power if combined with other variables(ie injectors, mapping...)

Any thoughts?

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Here are my thoughts, DCD.

IMHO, the larger 6 throttle bodies are best used where increased high rpm air flow is required but not at the expense of responsiveness - as you get with a larger single throttle conversion. For example, circuit cars. However, they are not paricularly popular because:

(1) They are quite expensive (same costs as a single throttle conversion);
(2) The overall increase in surface area of the throttles is restricted due to machining constraints - its about 3-4mm increase in diamater for each throttle plate;
(3) The compromise in responsiveness from going to a single throttle body setup is outweighed by the gains in mid to high range torque that a large single throttle conversion provides; and
(4) In a high powered RB engine, there appears to be just as much to gain from a reshaped intake plenum and air charge entry point as increased individual throttle body size (ie. improved air trajectory into the plenum resulting in better air distribution, particularly for cylinders 5 & 6 which seem to suffer from getting more air than the other cylinders).

Cya O!
 

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Discussion Starter #3
Thanks hipogtr. Thought as much after reading the single throttle body thread on SDU. I would have thought this could be a haflfway option between stock throttles and a big 80-100mm single. But as you said the price is far too high...

I was wondering what size of throttle bodies the old Gr.A engines used to run? Any ideas?
 

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Hey DCD... Based on the Group A Calsonic BNR32 specifications (in the GT-R Owner's Book), they use the factory 6 butterfly throttle body. There's no mention of any changes or enlargements. Come to think of it, maybe that is on of the things that the Group A cars are restricted from changing.

Cya O!
 

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Definitely one of the best reference books I've seen around, DCD. I think that type of book will be coming out for a number of other cars as I've already seen the RX-7 one as well.

Cya O!
 

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Discussion Starter #8
Its called "GT-R Owners Book" and its 2500Yen. Contains a look at a few racing GTRs, goes through the RB piece by piece, and a few other things like GTR catalogues. The main section is a very good graphically represented guide of basic maintenance procedures. Gives you all sorts of info on parts that need to be looked at, tells you the tools you will need, the approx time you need, parts number and generally very useful info. Would be twice as good if I could read Japanese properly...but nonetheless a very good buy.
Its been out a month or so...but I would have no idea who would sell this in the UK
 
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