New Intake System

[nonnac]

hi all,

just thinking of making a twin throttle body intake system for my r33 na,

so far thinking twin 60-65 mm ish TB plenum into 2.5" stailess y piece, through 2.5" stailess to my AFM and appollo filter ( CAI around filter of course ) . just would like some thought on the matter.

so far got bigger injectors, fuel pump, fuel reg and zorst to go with it if i go ahead with it.

cheers

[MBS206]

Personally, if I were going to the trouble of a new plenum for running extra throttle bodies, I'd be going to ITB.

personally though, you will find at your power level (Which for all the mods you have, only the exhaust is a power up) the twin throttle won't aid performance. It'll give a change in throttle sensitivity (Which many people see this as "response" but it's not)

If you plan on doing some extensive head work (Costly) and playing with Camshafts, then I'd be looking to playing with a throttle body setup. Until then, you won't see a power gain, so it would be throwing away good money (Much like changing the fuel regulator). The injectors you should be able to get away with not needing to upgrade them or the pump for a little bit.

The big thing is to work out what you truly want from the car, how long you plan to keep it etc.

If you just want a little bit more, without spending millions for tiny gains. Exhaust, CAI with a good panel filter (Keeping the air box as there's no point making a custom box) and tuning it.

From there, play with some good suspension, tyres and brakes.

[zebra]

As Matt said, no gain in adding an extra throttle plate, your current one is no restriction.

I doubt you will gain anything, infact I would say you will go backwards from where you are now.

Also why bigger injectors?

the NA injectors are 270cc, so good for around 270hp, which is a very serious RB25DE and you wont get anywhere near that with just an exhaust.

to get there think 13-14:1 comp, huge cams and hours upon hours of headwork and race fuel.

[nonnac]

" From there, play with some good suspension, tyres and brakes. "

like my kei office coilover height and damper adjustable and 2 front and 2 rear sway bars, federal super street 245/45/17, r33 gtr full brake set up.

and mat yeah probly right dont have very many go fast bits to need twin TBS lol yeah ive only got 5zeigen 2.5' zorst, hks cam gears,

thaks muchly for the responses so far most helpful.

[TwoCents]

" From there, play with some good suspension, tyres and brakes. "

like my kei office coilover height and damper adjustable and 2 front and 2 rear sway bars, federal super street 245/45/17, r33 gtr full brake set up.

and mat yeah probly right dont have very many go fast bits to need twin TBS lol yeah ive only got 5zeigen 2.5' zorst, hks cam gears,

thaks muchly for the responses so far most helpful.

Is your car in Brisbane? If so keen for a look

[sriver killer]

Bring it to my workshop and we can have R33 night

[nonnac]

atm its in coffs harbour but it will be in brissy prob a month YAY just gota get back from working away in busted ass hill ( brokenhill ), when i get back and drive it up im hell keen.

[blk94r33]

As above, I doubt the single throttle body is a restriction for a standard N/A. I'd still go with the solid free-flowing intake pipe, but other than that...

[mad082]

a mate of mine had a twin TB setup on his 200+rwp rb30e in his old r31. he said it wasn't really much of an improvement over a single TB.

[nonnac]

i thought that would be the case. but all up for the custom plenum and pipes and the likes has only cost a lttle bit so ill throw it all on and test i,t but id say ill be posting back on here that it didnt work well hahahah

but i still think ill be beter off with the adjustable reg and the likes, as we all now what you put in as air you need to compensate with fuel and out the exhaust ( what goes in must come out ).

cheers guys ill post back when its all in and tell you guys that you were right hahah

[Gerg_R31]

i got a standard r33 rb25 tb and upper plenum if your interested, cut flange off the upper plenum, cut and weld onto another upper half done

[MBS206]

i thought that would be the case. but all up for the custom plenum and pipes and the likes has only cost a lttle bit so ill throw it all on and test i,t but id say ill be posting back on here that it didnt work well hahahah

but i still think ill be beter off with the adjustable reg and the likes, as we all now what you put in as air you need to compensate with fuel and out the exhaust ( what goes in must come out ).

cheers guys ill post back when its all in and tell you guys that you were right hahah

The issue is, at idle, the car will still make the same power, so its breathing the same amount of air, and using the same amount of fuel.

Once you're ringing its neck, you'll need more fuel higher up.

Adjusting the base fuel pressure will richen up EVERYWHERE in the fuel map, not just where you need it.

Save your money by NOT buying the reg or injectors, and get a PFC and have the car tuned.

The stock injectors have plenty of head room for what you're going to do and will make the car WAY more driveable, and provide better fuel economy around town.

[nonnac]

i took some of your advice matt, didnt go with reg and pump, you were right was no need, now running twin throttle body plenum, all going good so far, just figuring out some minor glitches.

i ended up making a resonator air box ( still need to make a permanent one maybe a nice looking chrome one or stainless one ).

the car pushes out alot of air out the back, i have got my hands on a one piece jj1 split front pipe and high flow cat to 3" cat back, to coup with the mass air flow ( got it really really cheap as it was damaged but got my boilermaker mate to weld it all back up now ) going to put it on tomorrow to see how it goes.

ive replaced pretty much all the sensors while i had the inspiration to mess around with my car

ill post again when i get it all together with permanent parts and running nice, with pictures

any advice would be welcome, remembering im doing this for fun and a project, to see what will really happen

p.s. ive got consult so it makes setting thins and reading things alot easier, i.e. tps, o2 and what not

Edited October 12, 2011 by nonnac