My brother is on the last leg of a Duratec install and is about to purchase some DC0E 45`s to run it.

I`m told he needs 5 progression holes in them.

Can someone explain why and what effect if he goes for the 3 hole version etc?

On the Zetecs the extra holes prevent it bogging down when going from a light throttle to full throttle. Dont ask me why...

I always thought it was to eliminate a flat spot ?

Anyway i always believed my old zetec had 5 progression hole 40's as it flew no flat spots ect ...
it was only when selling the carb's and found out it was only a 3 hole ....

so you don't need them as such .. But i have never had 5 hole ones so i cant compare im sure someone on here will have tho ...

Ive never looked into it before and have had a few sets before on different cars but never noticed any huge flat spots etc(unless they were all 5 hole...doubtful).

Cant see it making that much difference really?

why not use dhla 45s

The 5 hole version stops the progression issue that tends to affect the 3 hole version
(so they don't suffer with the flat spot/bogging down)

Alot of the Later 45's have already been modded

Webcon used to have a jig for doing this iirc although some brave owners have done it for themselves


Dellortos don't seem to suffer with this issue...

I put webbers on my Duratec and spoke to Webcon and they said it needs 5 holes and the reason is to prevent a flat spot on light/early throttle pick up. They were very helpful but still needed to go on a rolling road to be jetted correctly. Ran much, much to rich. They don't have an off the shelf set up like the blacktop zetec as a lot of zetecs run carbs but most duratecs go injection due to emmission problems. Not a problem for me as I converted from pinto.

I had webbers on my Zetec there was a flat spot if nailed from tick over if floores above 1300rpm all was good they had 3 progression holes

laptoprob - I agree i don't think it will make a massive difference like i said my old zetec had no flat spots and was very responsive ... this is what lead me to believe they where 5 hole until i eventually looked

But saying that Austin man has said he noticed an issue with 3 hole



[Edited on 8/3/12 by monck]

[Edited on 8/3/12 by monck]

It can make quite a big difference. Some rolling roads told me not to waste my money with them until I improved on my original three progression holes. Sent them to webcon. Cost me 100 pounds from memory. If you have 4 you'll get away with it. If you only have three, get them drilled. Carbs will be with webcon for 2 months though. Don't consider DIY. Can't be done with a hand drill!

Appreciate the comment chaps. Reckon best bet is to just buy a set(s/h) and see if we are lucky.

From the look of it its all down to drivability/smoothness so will take the chance i think.

P.S.Anyone got any?(i`ll drop a threadin the wanted later i think)

Honestly mate it will make a difference, if you've spent that amount on the conversion you don't want a hesitant engine when you boot it and for my I would get the right thing.

Sent my 45s of to Webcon to get the fixed (well the RR tuner did) and the post office lost them. Took a month or so before the insurance would pay out...

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Originally posted by Tiger Super Six
Honestly mate it will make a difference, if you've spent that amount on the conversion you don't want a hesitant engine when you boot it and for my I would get the right thing.

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Not on a duratec but in my old Tiger Six I went from a pinto to a zetec and used the old carbs on the new engine. Whilst it ran ok there was a real hesitation when you put your foot down. I never took that to the rolling road so it stayed like that.

When I did the Duratec I wanted it to be right so I spoke to Webcon about the carbs I owned and what I needed to do. They advised what was required and in the end I sold the old ones and put on a new set that had the right number of progression holes. I then took it to the rolling road and was v pleased with the outcome.

I didn't realise how many different versions of 45's there are - I stuppidly thought a 45 was a 45! If nothing else it's worth a call to them to pick their brains and understand it a bit more.

Just what i needed ta

[Edited on 9/3/12 by laptoprob]

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Originally posted by thunderace
why not use dhla 45s

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Originally posted by thunderace

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Originally posted by thunderace
why not use dhla 45s

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you do know that dhla 45 do not have this problem and i have a matching set forsale

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