Six Throttle Bodies

TheDigitalPimP · Post by **TheDigitalPimP** » Tue Dec 13, 2005 10:07 pm

I'm contemplating a six throttle body set up to go on my 6A12 Mivec. I know RPW do something similar but I have all the gear to make an inlet manifold and can source some TB's so would like to give it a go myself!

Has anybody got the RPW six throttle body set up installed? If so whats it like... what electronics are you using with it eManage, Apexi etc.

Chiangstar · Post by **Chiangstar** » Tue Dec 13, 2005 10:31 pm

are you planning to make this a track/drag car or a street car??

simon

TheDigitalPimP · Post by **TheDigitalPimP** » Tue Dec 13, 2005 10:38 pm

Chiangstar wrote:are you planning to make this a track/drag car or a street car??

It'll probably be used for a bit of everything TBH! I want to get the most from it with out going FI. Increasing the standard TB to 63 or 65mm doesn't seem enough and the RPW dual TB system seems a step in the right direction but still not the best IMO.

I know i'm going to loose some low down torque but hopefully the gains in power should make it worth while.

Post by **Bennoz** » Tue Dec 13, 2005 10:48 pm

If your gonna be spending that kind of coin on your intake, you ought pull the heads off as well - get them ported & decked. All good and well to get the flow right in the manifold, but why not get the flow right into the heads - then get that flow to good use by compressing it harder in the chambers

Or am I thinking with a fuel pump & corporate Amex in my hand

TheDigitalPimP · Post by **TheDigitalPimP** » Tue Dec 13, 2005 10:56 pm

Bennoz wrote:If your gonna be spending that kind of coin on your intake, you ought pull the heads off as well - get them ported & decked. All good and well to get the flow right in the manifold, but why not get the flow right into the heads - then get that flow to good use by compressing it harder in the chambers Or am I thinking with a fuel pump & corporate Amex in my hand

Don't worry the heads will be off as well for porting, polishing and skimming!

I have a full workshop at my disposal with Milling Machine, Lathe, Welders etc so I might as well make some use of it!

p13nox · Post by **p13nox** » Tue Dec 13, 2005 11:49 pm

A friend of mine did this on his teg type R, it cost him a fortune and the results were ok, but not half as good as you would expect. It also drinks fuel now.

Personally I would have thought a turbo conversion would be better value for money, ie more gain for your Â£Â£Â£Â£Â£

TheDigitalPimP · Post by **TheDigitalPimP** » Wed Dec 14, 2005 12:16 am

I reckon I can do it for Â£500!

I will make the manifold myself from Aluminium. I can get the 4 flanges laser cut for Â£50. So its just a case of fabricating the pipe work and welding it up. Been offered 6 throttle bodies for Â£100 and will make an Airbox from GRP... CF if I can afford to. My mate reckons he can do the electronics so it still uses the ECU's cold start sequence along with modifying the signal from the map sensor with fueling adjustment via an Apexi.

I think it sounds feasible and am prepared to give it a go! If it don't work then i'll just whack the old manifold and 63mm TB back on and sell the 6 TB's and Apexi. But at least it will have been tried!

p13nox · Post by **p13nox** » Wed Dec 14, 2005 12:25 am

Would you like the email address of my mate who had TBs fitted to his teg? I think the mapping side of things was a bit more complicated! It does sound like a value for money mod though! Make sure you get some drawing made too so I can get some made

Post by **smorison** » Wed Dec 14, 2005 9:15 am

based on vacuum testing porting the tb to 65mm drops it to almost 0mm mercury, with a well designed intake you can actually generate a bit of positive air pressure.... i wouldn't worry about 2 or 6 tb's i'd concentrate on the intake.

TheDigitalPimP · Post by **TheDigitalPimP** » Wed Dec 14, 2005 9:30 am

smorison wrote:based on vacuum testing porting the tb to 65mm drops it to almost 0mm mercury, with a well designed intake you can actually generate a bit of positive air pressure.... i wouldn't worry about 2 or 6 tb's i'd concentrate on the intake.

Interesting! I take it you have done some inlet manifold work on the FTO?
Care to enlighten me of this positive pressure design? I've got a couple of books one from Weber and one from Cosworth. Both cover intake design and have chapters on choosing a TB to suit the application etc... so i'll take a detailed peruse of them at some point!

I had thought of having a bonnet vent feeding directly into the TB's creating a ram air effect and thats still on the cards....

Post by **smorison** » Wed Dec 14, 2005 12:26 pm

yeah my car has had a little work done to it, the area your interested in has been modified with:

TB enlarged (still oem TB), ported and polished.
intake plenum ported and polished.
runners ported and polished.

i've had a few different intake setups and i'm working on a new one (well its kind of 2 in one, for day to day driving with a quick change for track work - the changes are not legal on australian roads)

at the moment i after about 60km/h i get 0 vacuum on the intake side which means that the air being delivered through the intake is 100% of what is required for "perfect" combustion. NA being a sucking design (not a force fed like turbo / supercharge), getting 0 or positive pressure is a huge win, it leads to the potential to run higher fuel loads without running rich... more fuel, more air = more power. On really cold days the denser air turns it into a positive reading (boost) ...

this leads me to believe that:

a. as much air as is required by my current tune is being supplied

b. larger or more TB's will create slower moving air resulting in:
. b1. laggier on throttle response through slower moving air
. b2. less dense air being delivered into the cylinder
(resulting in low to mid throttle response / power being pathetic, possible high end gain - but not tested)

c. twin / quad / 6pack TB's are purely for HiPo designs and big monster drag setups - or riceability

design improvements:

a. create an intake that has a positive air pressure (boost) to get more in.

b. review airflow on intake using flow bench once positivie pressure has been reached to see if any improvements are required.

anyway that's as far as i'm at right now i do not have the time to build the design i have on paper and do testing, i'm hoping in the new year when my work gets back under control to be able to continue developing my car.

Incase your wondering how i measure vacuum the VAFC (with mivec adapter) display's it for me...

oh btw reading off the dyno for vacuum is a complete waste of time as the results are not real world results, you really have to be in a wind tunnel (or on the road) to get the fluid dynamics of air racing over the car to get a proper reading.

Post by **smorison** » Wed Dec 14, 2005 12:33 pm

on the fuel mileage issue... all mods made to my car to date have not had a negative impact on "normal driving" fuel economy

note: normal driving

most have had a positive impact...

of course as soon as i start more "spirited" driving the ability to burn more fuel every revolution has a negative impact on fuel economy...