EFI to Carburetor Conversion

[blaze_away]

To cut a long story short, the electrics that run the EFI on my Chim have been messed with and so I'm looking at removing the EFI, as a solution to all the electrical issues, and fitting Carbs.

Anyone got any thoughts, advice, guidance on this ?

[haircutmike]

Interesting.

Guillotine has on his old grief.

[taylormj4]

Interesting, what sort of carbs are you considering.
I remember a Boxer inlet manifold used to be available several years ago that too four carbs - SUs I think. Others used to use downdraught dellortos, which were apparently awesome but rather thirsty.

Matt

[dbv8]

If i was on a tight budget and had a Weber 500 at hand then I would give it a go to get me running.
I think the 4 barrel could be tuned for good performance and economy and would give that nice carb induction roar that has to be loved.

Otherwise convert to MS and live in the now.

[haircutmike]

I built a kit car about 20 years ago, fitted an Offenhauser manifold and a Holly 4 barrel carb.

That was the Rover 3.5 and ran as smooth as silk right out the box!

[dbv8]

haircutmike said:

I built a kit car about 20 years ago, fitted an Offenhauser manifold and a Holly 4 barrel carb.

That was the Rover 3.5 and ran as smooth as silk right out the box!

I think you must hve been lucky Peter. Once you start messing with those Holleys all they are good for is all out. They were very popular and still are on the hot rods etc for drag racing.
The Weber is easier to fine tune and much more economical day to day.

[taylormj4]

Have a look at this web page - fantastic amount of info and great pics

http://www.mez.co.uk/ms12.html

Matt

[EggsBenedict]

That Weber 500 is also badged as an Edelbrock - worth knowing.

[haircutmike]

dbv8 said:

haircutmike said:

I built a kit car about 20 years ago, fitted an Offenhauser manifold and a Holly 4 barrel carb.

That was the Rover 3.5 and ran as smooth as silk right out the box!

I think you must hve been lucky Peter. Once you start messing with those Holleys all they are good for is all out. They were very popular and still are on the hot rods etc for drag racing.
The Weber is easier to fine tune and much more economical day to day.

It was sooo smooth that I ran a slush box with it, maybe I was lucky.

I also ran the mallory dizzy iirc.

[dbv8]

EggsBenedict said:

That Weber 500 is also badged as an Edelbrock - worth knowing.

It is an Edelbrock. Mine came as a kit with an Offenhauser dual plane manifold.
Worked very well on a mildly tuned 3.9 in an SD1. Was OK on fuel and pushed the old bus into 3 figures on the 1/4.



Or how about twin 2" SUs

Edited by dbv8 on Tuesday 28th February 10:32

[Alexdaredevilz]

Have a google of fast ez efi

[blaze_away]

Loads of info there folks. From those posts it looks like clearance under the Chims bonnet might be tight.

I like the idea of twin SU's but would the clearance at the top of the whole assemblies foul the undeside of the bonnet ?

[blitzracing]

You will never get through any emissions tests if the car is post august 1992, which seems likley as its a Chimaera. Carb's just cant control the fuel acurately enough for catalysts to work. A complete non starter Im afraid.

[carsy]

haircutmike said:

I built a kit car about 20 years ago, fitted an Offenhauser manifold and a Holly 4 barrel carb.

That was the Rover 3.5 and ran as smooth as silk right out the box!

Did exactly the same, it ran superb.

From what i have read the Webber 500 seems a better bet these days than the Holley.
I was under the impression they would get through the mot with a change of jets, specifically for the mot and then change back.

[sparkythecat]

taylormj4 said:

Have a look at this web page - fantastic amount of info and great pics

http://www.mez.co.uk/ms12.html

Matt

Thanks for posting that Matt.
Loads of good stuff on there

[Getragdogleg]

I had an Edelbrock 500 on my Rover V8 engined car and binned it in favour of a FAST EZ-EFi kit, very complete, very simple, less agro than a carb.

[GV]

blaze_away said:

To cut a long story short, the electrics that run the EFI on my Chim have been messed with and so I'm looking at removing the EFI, as a solution to all the electrical issues, and fitting Carbs.

Anyone got any thoughts, advice, guidance on this ?

I converted my Wedge 350i to an Edelbrock Carb with an Offehasuer dual plane manifold. I aslo did away with the crap Lucas Dizzy swapping it for a Mallory Unilite with a Hyfire 6AL CD Box with Promaster coil. Result - blisttering throttle response in any gear easy maintenance and above all - simple fault finding diagnostics. The problem I have is what to badge my Wedge now the 'i' has gone from the 350. The Hyfire is soon to be upgraded to a Petronix as their product provides a stronger spark right up to the rev limit as opposed to 3000 rpm.

To set your car up you will need to throw away your fuel pump, your EFi loom and all the other electronic bits and pieces. You will need a new valley gasket, throttle return spring and a fuel pump pushing out lower pressure for the carb. Your carb may have to be re-jetted depending on your engine cc. If going for the Mallory Unilite you will need the drive gear for the dizzy and an uprated coil (Mallory). Your rev counter may need to be rewired off the Unilite.

Drop me a line and I can talk you through it. My other bit of advice is to shop around for prices in the UK as the usaul outlets are pricey. Better still, if you know someone travelling to the USA give them a shopping list and you will save loads.

In terms of refinement a lumpy tickover is noticeable - but I put that down to not having the setup tuned to get its maximum value. Otherwise it is well worth the investment with no loss to power - if not better performance...

[Simon says]

Get the EFI fixed, so much simpler in the long run, for example what happens when you sell or MOT time? Carbs & Cats mmmmm.

[MPoxon]

I would be tempted to complete the conversion just for the carb induction sound especially downdraft webers

[GV]

MOT's no problem 3 so far with no issues. As for selling the car? Provided your advert says what it is and why it was done - the buyer will have decide over spending an armful if the Efi goes manky or already is, or have the knowledge the Carb is already sorted, settled in and doing its job. Besides, the Efi was primarily brought in to reduce emissions something that modern carbs don't have an issue provided they are in tune....