2.0 type 4 rolling road jetting

Hi all.
I've been told almost all air-cooled vw are jetted lean from factory. When I ask what main jet they used after rolling road they can't remember.
Hopefully if I can get this driving again ok I will use the stainless two exit exhaust (bluebird style/like factory box style). It will definitely need more than 132.5 main jets(pair solex 32/34pdsit). What did you use pls?

 

I was always told that running an engine lean made it run hotter…. not a good thing….so why would they leave the factory like that?
Saying that, I didn’t know that you could alter size of jets on a standard carb.

 

I thought they were jetted on the rich side. the venturis are about 26mm or maybe 27mm. I know on most carbs with 30 vents 135 is about right/a bit rich so I doubt 132.5 is lean with a much smaller venturi.

 

^this, certainly for the type 1 Solexes. Can't believe they'd run them lean - disaster on an aircooler.

 

I think the aircooled engines ran progressively leaner from carburettor Type 1 to FI Type 4 over time as emissions demanded less HC output. The need to run lean defeated the head cooling at some point (e.g. dropped valve seats from softening heads) , and water cooling had to take over.

 

Carbs can only be set correct at WOT and idle . Everything in between is what it is .. thats why FI is superior and tuneable at every throttle increment and load .. hence better mpg .

 

If the carburettor is matched to the engine then you can do quite a good job, but everybody loves sticking carburettors that can feed 3 to 5 litre engines on our little VW engines and then being surprised that they cant be tuned except at idle and one other throttle position...

 

What carbs are those?
Mine are off a 2L(?) Alfa - yours are for a 2.8L Granada so you must be referring to yourself?

 

Yes..

 

Rich, is better.
‘Keep a cool head’, as an old guy told me.

 

If the rolling road place told you Air-Cooled engines run lean and they couldn’t remember what jets they have fitted I’d find a new rolling road.

 

Hi, thanks all.
I measured the main jet with wire measuring 135 (digital cheap calipers).
Went straight thro 132.5 main jet.
I'm in the process of setting up those carbs with stock exhaust. The main centre mixture screw is 8.5 turns out. (Seems a lot...)
Base L/R mixture screws 3 turns out. Snail balancer said 5 and 5.1. Vacuum guage on n/s fluttering everywhere. O/s more stable. No vacuum at idle.
There probably are no baffles left in the exhaust ~all blown out now....
Ps thought some factory jets like dellorto measure bigger than stamped /no idea why.

 

I looked on David vizards YouTube channel.
In some instances F. I. made less power than carbs- will let him explain it.
Generally I'd agree with u IHU.
I don't have enough expertise etc for all that~more concerned about KISS principle. keeping it simple for stupid me.

 

The area in front of the engine hatch over gearbox is hot. Can still just touch it. Never noticed before. This clue might be important (no temp guage or AFR here).

 

Is there any oil in the gearbox?

 

Is this from your heater pods possibly?

 

Yes oil in gearbox. Heater pods will see if jamming open. Cheers.
Spent hours driving and adjusting out main centre mixture screw. Better each turn out. End of day, 95% normal driving experience. 8.5 turns out. Great.
Next day, started fine. Crisp exhaust. Leave 2 min to warm{no chokes}.
Pull too gently away, stalls, immediately back to square one as day before.
Banging, stuttering. Idles fine, roll with no throttle fine. Full throttle OK above 30ish mph. Nothing ok in between~ esp 10-40mph.
What gives?

 

After 10 turns out that adjuster jet is on limit and loose.
It timed up OK at 28>30* max advance all out.

 

The idle jets have 12.2v and click when connected. When disconnected at idle there is no rpm drop either side.
Ive tried loosening the jets which fixed this fault, on another thread. Nothing.
Everything has been cleaned and recleaned.
All the rubber pipes in the engine bay have been replaced.

 

The idle mix is a balance of the mixture screw on top of the left carb and the other 2 at the base of each carb.
The idle speed is a balance of the speed screw on top of the left carb and the throttle stops.
Both circuits should be providing about 50%... so...
It sound like you have some more adjusting to do - maybe you are just adjusting the speed screw and not the mixture on top of the left carb?
By judicious disconnection of solenoids you should be able to get it idling half speed on either the separate carb adjusters (mix and throttle stops) or the 2 screws on top of the left carb.
It sounds like you have this out of whack.
Good luck!