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TB or not TB - That is the question
MakeEverything - 6/4/10 at 07:29 PM

Ive got a set of 38mm R6 TB's and am contemplating how difficult it would be to buy another set (though i only need 6, not 8), and put them on BOB. Im wondering what the added advantage would be over a custom inlet plenum.

I am restricted for space, and the TB's wont really help the issue, but its not the end of the world.

Engine is a 2.9 Cosworth (BOB) V6.

Questions are:



  1. What additional power would i see by adding the TB's?
  2. Are there any other advantages over standard inlet and single TB?
  3. How easy / difficult would it be to balance all six? Ive got a colourtune kit, so not impossible its just a time thing.


Im planning to get the car running, ill have the inlet plenum and standard TB to start with and set the Megasquirt up,but then look to change to TB's if there are significant advantages over the single TB.

I await a response from the font of all knowledge that is LCB.....

ETA 38mm, not 28!

[Edited on 6-4-10 by MakeEverything]


clairetoo - 6/4/10 at 08:48 PM

As far as I can work out , I gained close to 30 bhp and moved peak power from 5600 to 7300 on a mechanically standard 1.8 V6 Mazda - that was with 41mm Triumph TB's .
I think I'm getting similar gains on the 2.5 - it pulls like a train right up to 8000 , and still managed 34.6 mpg cruising up from Detling at the weekend .
The stock plenum/manifold on the Mazda V6 is pretty restrictive though - and enormously heavy .

A big plus is you get an engine that looks like this

[img][/img]


MakeEverything - 6/4/10 at 09:02 PM

OK thanks. The more i sit here with the four barrels sitting on the table in front of me, the more im convincing myself that this is the way forward!!

Does anyone know where to get fuel rail material from? I was planning on using six TB's -one for each cylinder - and utilising the existing rails.

Three of the ports on each rail would feed fuel to opposite cylinder banks, so the rail would effectively be on its side. The remaining port on each would be joined, with a Tee off for the fuel, though i would need to figure out a return to the tank this way. Perhaps a PRV which allows fuel back to the tank over a certain pressure....?

Has anyone used braided fuel hose to connect to injectors before?


clairetoo - 6/4/10 at 09:12 PM

That sounds like a bad idea - without a through-flow of fuel any air would only be able to get out via the injectors , and the fuel sitting in the rails would also pick up a lot of heat .
Far better to run the fuel in one end of one rail , and return from the other end of the other rail - like this ?

[img][/img]


MakeEverything - 6/4/10 at 09:19 PM

OK, i see your point. So if i were to modify the existing R6 rails and either make up solid or flexible connections to the injectors, it should look like this;

Fuel Rail Concept
Fuel Rail Concept


MakeEverything - 6/4/10 at 09:25 PM

These are my TB's by the way.

TB's
TB's


clairetoo - 6/4/10 at 09:25 PM

That would probably work - but how would you hold the injectors in place ? They are normally clamped in by the fuel rails .
Another problem is linking the two banks of TB's - it took me a long time to design my linkage......(picture in my photo archive , in throttle bodies)


Andybarbet - 6/4/10 at 09:28 PM

I reckon if its going to look similar to Claires set up then you should do it purely because it'll look fantastic !

Shiny & Carbon, niiiiiice :-)


matt_gsxr - 6/4/10 at 09:30 PM

Wow that looks very nice Claire.

To answer a question from the first posting:

http://www.rossmachineracing.com/


To answer a second. Balancing the TBI's wouldn't normally use a colortune. The normal way of doing it is to balance the flow and hence pressure. This can either be with a carbalancer/Morgan carbtune/ or similar type of device. Some people claim to listen down a pipe for the hissing and balance that way but that is too difficult for me.






Matt


MakeEverything - 6/4/10 at 09:32 PM

If i put solid links between the rail (secured to the head) and the injectors, then this would hold them in place.

The linkage is the fun part, and i have a solution, but itll need some planning and development nearer the time. Ive even thought about joining the butterfly shafts together so that they are one piece all the way through on each side, but again that needs some more thought.


MakeEverything - 6/4/10 at 09:35 PM

quote:
Originally posted by matt_gsxr

To answer a second. Balancing the TBI's wouldn't normally use a colortune. The normal way of doing it is to balance the flow and hence pressure. This can either be with a carbalancer/Morgan carbtune/ or similar type of device. Some people claim to listen down a pipe for the hissing and balance that way but that is too difficult for me.





Yeah, Carbalancer is what i meant, sorry. I have colourtune as well though!!


MakeEverything - 6/4/10 at 09:42 PM

quote:
Originally posted by Andybarbet
I reckon if its going to look similar to Claires set up then you should do it purely because it'll look fantastic !

Shiny & Carbon, niiiiiice :-)




Youll hear it when it starts up for the first time!!!!


clairetoo - 6/4/10 at 09:58 PM

quote:
Originally posted by MakeEverything



Youll hear it when it starts up for the first time!!!!

I wonder if it will sound anything like this


Chippy - 6/4/10 at 10:25 PM

Richard why do you want to cross supply the injectors, your BOB is the same as my BOA in as much as it runs batch fire, giving two or three squirts of fuel to each bank. So 123 and 456 both recieve fuel at the same time respectively. I think the old saying, "If it aint broke, don't fix it" applies here mate. You are just making a load of work for no gain. Cheers Ray


MakeEverything - 6/4/10 at 10:38 PM

quote:
Originally posted by Chippy
Richard why do you want to cross supply the injectors, your BOB is the same as my BOA in as much as it runs batch fire, giving two or three squirts of fuel to each bank. So 123 and 456 both recieve fuel at the same time respectively. I think the old saying, "If it aint broke, don't fix it" applies here mate. You are just making a load of work for no gain. Cheers Ray



I hear you Ray, and the last thing i need is unnecessary work!!

The rails mounted on the opposite side would only be to try and keep the fuel lines / supply as straight as possible, seeing as i was initially looking at keping the fuel rails off of the bike TB's and utilising them rather than making some.

Turns out, that its not as expensive as i thought to have some made up, so ill have some that fit onto the top of the injectors.

Thanks Ray. I might be tapping you up for some help in plumbing the cooling system if thats ok please?

Cheers,

Rich.


MakeEverything - 6/4/10 at 10:44 PM

quote:
Originally posted by clairetoo
quote:
Originally posted by MakeEverything



Youll hear it when it starts up for the first time!!!!

I wonder if it will sound anything like this



I think mine will sound a little different to that, being that the exhaust pipes are less than 6" long with one of these either side!




[Edited on 6-4-10 by MakeEverything]


MakeEverything - 7/4/10 at 05:00 PM

Bought a second set of TB's today. exactly the same from an '04 bike, for £57!

All i need now is the standard manifold and one for the TB's and were good to go!


boggle - 7/4/10 at 08:02 PM

with regards to the fueling....

on a flat four the standard rail setup is in series.....on advanced tuning it is common practice to change to parrellell, via a manifold blockthen to the regulator back to the tank....this stops the last cylinder to be on the line getting lower preasure than the others stopping it from leaning off.....

this may be different on a v6 for some reason???

as to fitting the injectors, i have some alloy injector cups that take a side fed injector, you are welcome to them....you could fit them into a flange adaptor???


MakeEverything - 7/4/10 at 08:25 PM

quote:
Originally posted by boggle
with regards to the fueling....

on a flat four the standard rail setup is in series.....on advanced tuning it is common practice to change to parrellell, via a manifold blockthen to the regulator back to the tank....this stops the last cylinder to be on the line getting lower preasure than the others stopping it from leaning off.....

this may be different on a v6 for some reason???

as to fitting the injectors, i have some alloy injector cups that take a side fed injector, you are welcome to them....you could fit them into a flange adaptor???


Thanks bud, Ill give anything a go and now ive got my TB's, i want to get them sorted ASAP.

In all seriousness, its not far away from starting. Just needs;

Engine Mounts
Engine Adapters (tomorrow hopefuly)
Megasquirting
Exhaust Headers & Stubbys made up (Ill use cast ones to start with)
Fuel Tanks made up
Header Tank & Catch Tank Fitted
Plumbing & Cooling

Not much really, just some messing around.


Chippy - 7/4/10 at 09:56 PM

quote:

I might be tapping you up for some help in plumbing the cooling system if thats ok please?



Hi Richard, any time mate, no problem. Cheers Ray