What jets are people running?
What jets are people running?
OK just out of interest I was wondering what size jets/venturi's people are using in their 912's carbs's. Mine has twin weber 40 idf's fitted and I was just wondering if it is jetted correctly for peak performance. What jets/venturi's are other people running and what is performance like?
- Nige
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the only way is to get it setup on a rolling road, they'll all be abit different on what jet sizes they need. It doesn't have to be a Porsche specialist, but somebody use to setting up multiple carbs. I took my 912 to a local guy who races MGs, he fettled it on his rolling road, opened up the jets tweaked the timing and it ran the best it ever had done. All for £50!
I was just trying to get an overview really of what different jets people were using and what power results different setups will give (ie more low down torque or top end power) Only reason I ask is because my webers are running 28mm vents with 52mm idle jets and 115 main jets and in the original guide book I have which refers to the solex setup it states 32mm vents with 55mm idle jets and 120 main jets. I am aware that I can take it to a rolling road and get them to play around with it as I have done this before with my previous car (they didn't actually manage to improve on the setup I already had) but from my experience the people who have experimented with there own cars setup in different ways and have gained good results is as good a way of doing it.
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Try F7 emulsion tubes,130 mains,55 idles,and the air correction jet on top of the F7(Im guessing you have F11's) 170 I think.
And 32mm venturi's,28's are too small.
And 32mm venturi's,28's are too small.
1985 MZ Simson/KH 125 Sprint bike
1302s one family owner
1963 AMC 660 Classic
1957 Peugeot TC4 race bike
Sadly gone:
74' 914/4 2.0
68' SWB 911
1302s one family owner
1963 AMC 660 Classic
1957 Peugeot TC4 race bike
Sadly gone:
74' 914/4 2.0
68' SWB 911
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Looks like you have the older VW type webers,these also have a cam operated accelerator pump,where as later webers have a rod operated one,the cam ones can throw alot of fuel in,causing the car to run rough/rich on pick up,they are a pain to calibrate,I have in the past reprofiled the cams on them to lessen the "squirt"!,though again I think you can also replace the accelerator nozzles.
Doing all those bits should transform your car.
Good luck.
Doing all those bits should transform your car.
Good luck.
1985 MZ Simson/KH 125 Sprint bike
1302s one family owner
1963 AMC 660 Classic
1957 Peugeot TC4 race bike
Sadly gone:
74' 914/4 2.0
68' SWB 911
1302s one family owner
1963 AMC 660 Classic
1957 Peugeot TC4 race bike
Sadly gone:
74' 914/4 2.0
68' SWB 911
I think they have the rod operated pump tbh, I bought them brand new a week ago from vw speedshop in manchester so I would think they should be the latest design. However when I bought them Paul did mention that they stocked 2 differently jetted versions of the 40's one sort with 28mm vents and one sort with 32mm. I thought I needed the ones with 28mm as this is what the old broken italian ones were running that I had removed from my car. It looks as though I should have chosen the 32mm ones with hindsight! However I spoke to Jim Calvert at stateside tuning last night and he recommends a very similar setup to what you have advised so I am now awaiting the arrival of some 32mm vents, 135 mains, and 180 idles, he reckons the 52mm idles and f11 emulsion tubes that I have should be fine with that setup so I will give it a go and let people know the result
cheers for all the advise
cheers for all the advise