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Would this work

Posted: Wed Nov 28, 2007 6:55 am
by boomer
[IMG=http://img187.imageshack.us/img187/3199/itbne8.th.jpg]

I left a post on HybridZ but it's almost dead, so I try my chances here!

I have a set of 3 delortos on a cannon style manifold. The carbs are not in good shape, corrosion inside, but the barrel are in top cond. They have been ported to the manifold and it would be shame to bin them!

I also have a rebuild engine bloc F54 with a milled and shimmed P90 head, fast road cam, 6/2/1 exhaust.

I would like to convert my DHLA into ITB, the easiest way would be to fabricate a fuel rail with the injectors aiming in the barrel of the carbs!
I could secure the fuel rail to the air box.

How far inside the plenum should I go, witch injectors are slim enough to restrict air to the minimum still giving around 20/25 lbs/h ????

I would like to keep the 3 carbs setup without giving too much clues about the ITB conversion

Posted: Thu Nov 29, 2007 4:50 am
by FridgeFreezer
Short answer - it should work. BMW did this on touring cars as a second bank of injectors, and my cousin is building a similar setup on his BMW. Many TBI setups fire onto the throttle plate.

Posted: Thu Nov 29, 2007 5:00 am
by boomer
life is so simple :lol:

Posted: Thu Nov 29, 2007 5:15 am
by FridgeFreezer
Starter for 10 courtesy of BMIHT Gaydon:
Image
Apologies for bigness of picture!

Posted: Thu Nov 29, 2007 6:00 am
by efahl
I was going to say F1 has been doing it for decades, and Fridge's picture of the Hart motor bears that out. Here's a video (5 meg) of the 2004? Renault V-10 motor on the dyno, where you'll see essentially the same setup.

Crank up the volume!

http://www.not2fast.com/f1/renault_v10.wmv

Posted: Thu Nov 29, 2007 6:51 am
by boomer
Aren't we in business now!
Thanks a lot, I know my options now.
Still: which injectors would be best suited?
No need to go farther into the plenum?
No risk of back-firing?

This is nice!

Posted: Sat Dec 01, 2007 6:40 am
by bionicbelly
That is freakin awesome!

Posted: Sat Dec 01, 2007 8:05 am
by Mk1rocco
I've seen systems like that before but always on all out racing engines. I'm wondering if there's a reason for that, could such a system be made streetable? I'm sure these system are great at or near WOT, but what about at or just off idle, especially during warm-up?

Posted: Sat Dec 01, 2007 5:34 pm
by 78Spit1500Fed
Okay, so air velocity isn't such a concern at 15,000 RPM... how about at a tenth of that, say at idle?

I just wonder how that would work at low RPM's?

-Brian

Posted: Sun Dec 02, 2007 1:15 am
by boomer
This is one of my main concern!
My guess (I have only a PHD in WDYDTF - [why did you do that for] is that it should work like an SU where the fuel come from behind the butterfly all the time.
I do know that the idle on Dual Barrels is a bypass of the main jet IN FRONT of the butterfly, yet it work wonder on the SU.

My second is that vapour of dustirezed (?) fuel could work their way close to the exhaust! I Need a tight airbox, maybe vented to the outside of the car?

If your'e OK to help me on the thinking of this thing I have more questions: One at the time and one on a post

Posted: Sun Dec 02, 2007 1:23 am
by boomer
Question 1:
I plan to gut the aux venturi.

I don't need it as it's only a high tech jet, right?

So I will slice it, I want to keep the ring in the center to use it as a base for the injector nose, inside the barrel. And use turbo ZX barbed inj. on a custom made steel fuel rail.

Posted: Tue Dec 18, 2007 7:55 am
by boomer
I have almost everything figured out now.
Yet I still have other options I need to consider:
Welding some injector bosses on the intake manifold would be the easy way :?
But I don't have enough room to fit injectors at the std 45° angle, is it all wrong to use the injector at a 90° angle at +- 3 inches away from the intake?