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EFI experts needed (Relocating TB's on R1)
Tralfaz - 4/3/05 at 11:43 AM

Greeting all,

My build in an R1 powered,Caterham sized seven. I am trying to avoid having any bonnet penetrations for the intake or airfilters. To that end I am looking at the possibility of relocating the TB's into a horizontal orientation by creating a manifold.

See pic....


There are 4 identical runners (like the one closest in the image). The 'box' on top is not connected.

A proper Airbox will be created to feed the TB's

So here is the question.

Will I need (or would I be better seved) to relocate the injectors onto the intake runners closer to their original position relative to the valves?


Regards,

Brian

sebastiaan - 4/3/05 at 11:46 AM

Brian,

Yes, you probably (!) will need to move the injectors closer to the head / intake valves. Else you'll probably end up with a big puddle of fuel in the runners, crappy throttle response and a lousy tickover.

Cheers,
Sebastiaan

tks - 4/3/05 at 01:31 PM

as close to the valve's as possible is my advice..

the petrol on the valve is also for cooling purposes..and then it vapors good...

also you should think in therms of delay...
of petrol delivery...when you give full trottlhe and then you will close it you can imagine that your shot of fuel is not in the cilinder but in the tube..

just weld a piece of aluminium on the boddies and drill the right holes..

TKS

britishtrident - 4/3/05 at 02:38 PM

I suspect if you inject that far away from the head runners would need to smaller dia to raise the air velocity -- in short it will cost power.

Tralfaz - 4/3/05 at 03:30 PM

Thanks all,

As I suspected. Just making sure I wasn't making myself more work. No problems creating some new injector mounts.

Regards,

Brian

Tralfaz - 4/3/05 at 10:43 PM

Actually, I now have a new thought. Rather than moving the injectors, perhaps I can add a Second set and keep the originals. At low rpm's the new injectors would be used at high rpm's, wide open, both, or possibly only the outers could be used.

Hmm....

Regards,
Brian

[Edited on 4/3/05 by Tralfaz]

garage19 - 5/3/05 at 03:33 PM

quote:
Originally posted by britishtrident
I suspect if you inject that far away from the head runners would need to smaller dia to raise the air velocity -- in short it will cost power.


I shouldn't think it will cost power. It might even gain you some. The only problem you might get is at low rpm when the air velocity is low and the fuel might drop out and start to puddle.

Up at the top end where there is plenty of air velocity you will be fine and might even gain through better mixing and the cooling efect of the fuel spray in the charge.

I dont think your runners are way too long. If you look at a car set up with a long 45 style manifold and some Jenveys with the injector in the throttle bodies they might be nearly the same ditance fom the valves.

I would give them a try where they are you can always add the injector bungs later if your idle is struggeling.

I guess the puddling fuel would give problems with idle emisions?