2 X A.f.m. And 2 X T.b.

[dondesoto]

Dont know if anybody has done this on an rb25de . I now have most of the parts to make up a 2 x tb and 2 x afm setup . just waiting on a s/h manifold to arrive . Am going to cut off the side off the plenum where the single TB is , then weld on a 12 mm plate and mount the 2 x TBs on it . Then install seperate tubes to each of the AFMs . Electrically hooking up thru the apexi safc 2 which has provision for 2 x AFMs then converts signals back to a single feed signal to the ecu . Will keep you posted on progress .

presently i,m running a 68 mm tb , and its on a rb30de .

Edited August 22, 2005 by dondesoto

[Beer Baron]

why would you want to do that?

[NA_R33]

less restriction, rb twin cam heads flow very very standard, what holds them up as with any NA engine is the ability to breath through the exhaust and intake system.

Very interested to see how this goes.. keep us posted

[Eug]

Sounds like a very good idea Don, are you going to do a dyno run before all this (would be keen to see your RB30DE results) as well as the changes the twin throttle bodies would make.

Eug

[dondesoto]

Sounds like a very good idea Don, are you going to do a dyno run before all this (would be keen to see your RB30DE results) as well as the changes the twin throttle bodies would make.

Eug

<{POST_SNAPBACK}>

no wont be doing a dyno before , i use the test and tune nights at the drags to see how its running ( best 14.7 @ 93 mph ) . but i may put it on the dyno to get it fine tuned after i do the mods .

also waiting on an adjustable exhaust cam gear to fit as well , and still got to fit the 4.11 locked diff .

Edited August 22, 2005 by dondesoto

[rob82]

Have seen twin throttle bodies on a VL 3.0L with medium cams made 141rwkws. Thats almost double the power of standard.

[dondesoto]

progress on the manifold , flanges for throttle bodies to be made . using rb25de/t throttle bodies

[dondesoto]

more progress pics on 2 x throttle body manifold

[Eug]

nice progress Don!

you doing all this yourself?

[dondesoto]

nice progress Don!

you doing all this yourself?

<{POST_SNAPBACK}>

yep all my own work , aluminium welded all bits then filled with devcon aluminium putty and smoothed .

[NA_R33]

15 3 phase migs.... 1 tig.... and not one can do alloy..... stupid workshop!! i ennvy you don..

[Nosmo]

What are you doing with your old 68mm throttle body and plenum?

[dondesoto]

What are you doing with your old 68mm throttle body and plenum?

<{POST_SNAPBACK}>

well i will see how this setup will work 1st.

[dondesoto]

seems i cant run 2 x afm s , so am going to make up a Y piece from the 2 x t/b and just use the 1 x afm

Edited October 28, 2005 by dondesoto

[Eug]

any reason for that Don? safc?

[dondesoto]

any reason for that Don? safc?

<{POST_SNAPBACK}>

well this is the way i understand it .

with 2 x afm the output signals of the afms would be 1/2 that of just 1 x afm

the safc can accept 2 x input signals , then sends out 1 signal which is just an average of the 2 x inputs not adds them together .. so i still end up with just half the normal signal . the ecu would send the ammount of fuel to suit that signal , not enough .

[dontfeelcold]

well this is the way i understand it .

with 2 x afm the output signals of the afms would be 1/2 that of just 1 x afm

the safc can accept 2 x input signals , then sends out 1 signal which is just an average of the 2 x inputs not adds them together .. so i still end up with just half the normal signal . the ecu would send the ammount of fuel to suit that signal , not enough .

<{POST_SNAPBACK}>

sounds logical.

Did you paint the the plenum with something?

[dondesoto]

sounds logical.

Did you paint the the plenum with something?

<{POST_SNAPBACK}>

yep painted it silver cold galvanising paint . not too shiny or tackey like chrome paint and lasts longer.

[Eug]

well this is the way i understand it .

with 2 x afm the output signals of the afms would be 1/2 that of just 1 x afm

the safc can accept 2 x input signals , then sends out 1 signal which is just an average of the 2 x inputs not adds them together .. so i still end up with just half the normal signal . the ecu would send the ammount of fuel to suit that signal , not enough .

<{POST_SNAPBACK}>

i see... that changes things a bit. are you opting for a larger diametre single pipe before the Y piece? what type of afm are you intending to use?

is this the case for gtr's? can anyone else shed some light on this.

its great to see you doing something different don, keep us posted!

[BADR33]

hey. for the SAFC cant you tune it to run +or- 50% less/more fuel? so there for you should be able to tune it to run with more fuel to cater for the increased airflow? just hook it up to one afm and run 50% more fuel?

i can see the logical part of the thinkin that you will end up with half the signal of 1 AFM. there must be away around it either using resistors or somthing similar. otherwise just go for a aftermarket computer.

very nice work tho.