Aftermarket Rb26 Plenums

[wogzilla]

can you boys post up all your pics of inlet manifolds to suite rb26 please.

any pics of high hp gtrs engine bay will do, but would prefer close-ups..

cheers

[R31Nismoid]

what if a good number high HP ones are still using the stock item?

[manage13]

what if a good number high HP ones are still using the stock item?

<{POST_SNAPBACK}>

I'm with you there!!!

Gary (Sydneykid) had a great post awhile back stating that changing to aftermarlet plenums have in most cases no gains and in some cases negative gains.

[ISL33P]

stock one is rated at 1000hp........but i suppose any plenum could do that with enough boost

i know of a rb30 making 600rwhp with a std plenum and only a front mounted tb

[R31Nismoid]

stock one is rated at 1000hp........

Changed your tune since August on that eh?

Thought it was 700hp

http://www.skylinesaustralia.com/forums/in...85012&hl=plenum

:lol: :lol: :lol:

[ISL33P]

and now i change my mind, they are rated at 2000hp like i said depends how much boost you want to put into in it

[Dahtone Racing]

hi octane have an awesome one

www.hioctaneracing.com.au

[R31Nismoid]

and now i change my mind, they are rated at 2000hp like i said depends how much boost you want to put into in it 

hahahahah :lol: :lol: :lol:

[ISL33P]

....... make that 3000hp, two of those thumper turbonetics turbos should do the trick

[djhatton]

i see little point in changing either. there's nothing wrong with the factory one. i still wonder why nismo re-invented the wheel with their aftermarket jobbie.

d

[Mik]

i see little point in changing either. there's nothing wrong with the factory one. i still wonder why nismo re-invented the wheel with their aftermarket jobbie.

d

<{POST_SNAPBACK}>

The standard one may be okay for power, but with the standard plenum, more air is distributed to the rear cylinders which means an unbalanced engine and leaner mixtures on the rear cylinders (if you tune with one O2 sensor).

Hence why RB26's tend to always do ring lands on number 6, rather than one of the front cylinders.

[djhatton]

hmm! interesting. i'm curious to where/who did the testing on this and found those results...

d

[R31Nismoid]

well thats basically why people flow test the injectors before they put them in... with the one flowing the most going to the rear...

[djhatton]

i c. any test results anywhere - flowbench or otherwise?

d

[R31Nismoid]

its just normal injector slow testing, if thats what you mean

[Duncan]

And the flow differences in injectors can be substantial, even after something like an hour of cleaning there was a variation of over 5% in the injector flow rates, which could result in a difference like 12:1 target but one cylinder running at 13:1

[djhatton]

its just normal injector slow testing, if thats what you mean

<{POST_SNAPBACK}>

oh.. no i was referring to the flow figures of the stock 26 manifold runner to runner...

d

[600hp]

i thought the guy was wanting photos not people stating there opinion.

no offence.

[proengines]

It's not a terribly easy thing to flowbench test as it's impossible to accurately reproduce the conditions inside the plenum as they would be with the engine running. Pulsing and reversion will make a difference to the way the air is distributed.

You can test the percentage differences between the head with a bellmouth and the head with a plenum attached for each cylinder and gain some results from that.

The best way to test would be with an exhaust temp gauge on each manifold runner just out of the exhaust port. If you know that all the injectors flow the same and the rear cylinder runs hotter than the rest then you know that that cylinder is getting more air than the others.

Most decent computers let you trim each injector to compensate which can bandaid the problem.

[djhatton]

assuming even injector flowrates and flow between ports/chambers in your head, (say cnc'd or similar) are there any manifolds out there, custom or otherwise, that will distribute air evenly?

d