Can you convert Webers to FI?

[EricB]

Someone was talking to me about this, that they were going to convert a set of triple webers into individual throttles and use fuel injection???????????? I didn't know what to say...

Is this even possible?

Can someone shed some light?

Or is it easier to point me at a URL or book?

Thanks,

-e

[HS30-H]

Hi Eric,

Don't know about anywhere else in the world, but this has been quite common here in the UK for a number of years.

Essentially they gut the Webers ( or Dell'Ortos / Solexes etc ) and use the bodies and butterflies as the base for injection bodies. You can buy all the parts you need from Weber ( throttle position sensors that fit on the end of the throttle shafts etc etc ) and it can be quite effective.

In fact it was so effective that companies such as Lumenition started to make their own kits that bolt onto side-draught manifolds. That's the big advantage; being able to use the manifolds. Weber are even marketing their own versions now too. I think you can find them on several websites ( try the Lumenition one ).

Cheers,

Alan T.

[Brett240]

i just finished doing this with good results except the injectors are in the manifold itself. check out my gallery.

hey alan, do you have a link to a store in the uk that supplies the throttle position sensor? mine mounts off the throttle shaft behinf the webbers and im not totally happy with it.

[HS30-H]

Hi Brett,

Look for LUMENITION ( Google search might give you a link ). They are ignition parts suppliers / manufacturers - but they make injection kits to replace side-draught carbs too.

I'm off to Japan in a few hours, so if you can't find what you need I'll look into it in more detail for you when I return after 6th Nov.

Cheers,

Alan T.

[EricB]

www.lumenition.com

that was easy...

-e

[Bpaccaud]

interesting!!!!

What is the approximative price for this complete kit throttle, wire, and ecu unit?

And how can you tune the ecu (with a special controler or computer)?

what value can you adjust on the ecu programme?

exemple: inject timing point and fuel injected (open time of the injector)?

[Gav240z]

Great I love the idea of this just gotta work out what i will need and how much it will cost me so I can start saving.

First things first however install new camshaft then go injection

[EricB]

does someone have a pic or pics of either webers or dellortos or mikunis having been converted to FI - just curious to see what that looks like exactly... the throttles lumenition sells just look like individual throttle bodies as you would find in any other modern application.. i am curious to see how a modded carb ends up looking... step by step even perhaps?

i'll keep digging on the net in the meantime...

-e

[Zedrally]

Pardon my ignorance, but would this also be possible on SU's?

[Dtsnlvrs]

TWM Induction toyed with the idea of a su replacement throttle body, but found that most if not all su users when doing a conversion will opt for a dcoe body....the su conversion was aimed mostly at the british car guys but they all go with a single dcoe....prob cause of the siamesed intake ports. Anyway here is a good link.

www.twminduction.com

www.sdsefi.com

[Cuong Nguyen]

Hi All,

I have a set of 45mm throttle bodies that are Webber bolt pattern. I bought these brand new and was going to install it on an L18 in a Datsun P510.

I have since sold the car and will now get one more throttle body so that I can build a nice L28 to go with it all...

[Cuong Nguyen]

2nd picture: 45mm efi throttle bodies

[Cuong Nguyen]

3rd picture: 45mm efi throttle bodies

[Cuong Nguyen]

lucky last...

[EricB]

hey this brings up another question,

last week i think i asked what the science was with the different lengths of velocity stacks, and someone replied saying the shorter they were the more power they produced up top in the rev range, the longer they were the more power they produced at the bottom of the rev range...

cuong's pics, alan's pics, and the pics i have of serious S20 powered race machines all show LOOONNNGGG velocity stacks - the person who said the above got it bakwards, right? longer the stack the higher the peak power...

another thing while i am at it...

if we compare say a 40mm high velocity stack vs a 60mm one,

does changing from one to the other merely MOVE the peak power in the rev range to a higher level without actually changing the HP figure, or does it actually make more power because the air/fuel travels a greater distance inside the stack and is therefore more accelerated when it enters the combustion chamber and therefore maybe also more of it enters the CC when the valve opens meaning a higher HP figure...

in short: does longer make more power, or are they merely for tuning your carbs to be in sync with your aftermarket cam's higher operating range...

-e

[Dtsnlvrs]

Well you see it is like this. On carbureted engines, the longer the intake tract after the butterfly, the more torque, see it allows for higher velocities thru the venturi by creating more vacuum at throttle opening due to the longer tract between the butterfly and the intake valve. Velocity stacks are sort of misleading, they are not really designed to increase velocity rather to straighten the airflow before it reaches the carb jets....its side benifit is that changing the length will create minor increases or decreases in air volume....very minor, but when tuning carbs to perfection these differences can be used to help final tune. This is called "Tract Length Tuning" On fuel injection engines, this is negated due to having a pressurised fuel spray as opposed to "sucking" out of float bowls. This is aloso why throttle body injectors dont have venturii's. The Air horn (velocity stack) on injection bodies is used to straighten the airflow before the butterfly, and for show.

[Dtsnlvrs]

Did I also mention that tract length tuning is almost considered a black art...usually the confines of an engine bay removes the possibility of true tract length tuning. It was lost when fuel injection was first used in formula one....they no longer needed the velocity stack lenght and then covered the engines....art lost.

[EricB]

thanks russell

that's exactly the kind of answer i was looking for...

-e