Carb Jet Settings Etc

[Wurzel 16]

There is a link on EBay that goes to a sellers 'settings' for jets, emulsion tubes etc on Dellorto carbs.

 

The link is here if anyone want to look.

 

Basically, he has given sizes as follows:

 

For up to 135HP

 

Choke 32, Main Jet 135, Emulsion tube 7772.5/7, Air corrector 200, Idle jet 52, Pump jet 33-40 and Needle valve of 150.

 

For up to 145HP

 

Choke 34, Main jet 142, Emulsion tube 7772.5/7, Air corrector 200, Idle jet 55, Pump jet 42 and needle valve 150.

 

The carbs I purchased (not from this guy) have the above except choke 33, Main jet 145, Idle jet 52, Pump jet 33.

 

I was wondering how sellers can say that these settings would be good for your car? Are they approximate settings that will allow your car to run well but not to its optimum?

 

Pugspares do the same, they sell new carbs 'already jetted to suit the 1.9 GTi'. I'm assuming that they can be bolted on from the box and with a bit of tweaking to mixture and throttle, can be made to run straight away. If you were then to take it to a rolling road, would they change things (at more expense) or simply adjust the mixture etc?

 

I'm obviously a bit vague on this and so need some help. I guess I'm basically asking if the carbs I have with their current settings would work on my standard motor. The only thing I can see that will need changing is the choke size from 33 to 34. Is this, however, really necessary?

 

 

Sorry for long post, hope someone can help.

[Guest daz205]

if you do a search on here for a jetting program there is a link which takes into account your peakpower engine size etc etc which would give you a better guide than for up to x bhp use this

[Sam 4]

33 will give more low down grunt but there won't be a HUGE deal in it!

[Wurzel 16]

33 will give more low down grunt but there won't be a HUGE deal in it!

 

That's what I thought. Looking at the figures this guy has got compared to the jets etc on my carbs, It seems mine are set up for between 135-145Bhp. It will probably run a bit rich on my engine (standard) but I would rather that than lean, at least for the journey to the RR.

 

I did a search for that jetting program. Found it alright, as I did last time, but it doesn't want to run properly for some reason. There are a load of squiggly digits following my cursor around plus it doesn't calculate the settings once I have entered the criteria, it just beeps at me (in true BBC Microcomputer fashion )

 

Any one help me?

 

Forgot to mention, it is definately low down/mid range I'm after. The engine is too old to thrash at top end for too long.

Edited December 23, 2003 by Big Nick

[Guest Pete Faulkner]

The only thing I can see that will need changing is the choke size from 33 to 34. Is this, however, really necessary?

incidentally, I changed from 30mm chokes in my 40's to 34mm chokes. Gained 10bhp with a little bit of re-jetting. I can't imagine you'd find much difference going from 33 to 34.

Are 33mm chokes available??? thought they went up in even numbers?????

[Wurzel 16]

Are 33mm chokes available??? thought they went up in even numbers?

 

I think the more common choke sizes go up in even numbers. Mine are definately 33 (stamped on them) and if 10Bhp is made on a 4mm difference, I think I'll stay with the 33's rather than spend £60 to £80 quid for 2.4Bhp

 

As for the 33's still being available, I don't know. The carbs I have (dellorto) have been sat around for a while as all the gaskets have dried out, so probably quite old.

[Sam 4]

yes you can get all numbers, or USED TO BE ABLE TO, you can only get even now i think, all i seen anyway