TheSamba.com :: View topic - 2110 with 44 idfs should I change vents as seems sluggish

Sun Sep 16, 2018 11:34 am

I have 2110 fk8 cam 9:1 cr twin Weber 44 idfs jetting 36 mm vents 200 airs 55 idles 145 mains
Pertronix 2 flamethrower dizzy 30 deg
Berg exhaust
Valves 42 x 35
1:4 rockers

The engine runs very good and no problem at idle or temps and pressure are good.
I just feel it’s not as quick of the mark as it should be low down, but from 4000 rpm it flies .

I have a set of 32mm vents that I could try would these help low down and what jet sizes would be recommended,
I would rather have low down performance than top end.

Any advice will be much appreciated.

Sun Sep 16, 2018 1:11 pm

Jetting seems on point if you go by math,
Not sure about this but I believe the fk8 likes 10:1 compression,
What is your deck height?

Sun Sep 16, 2018 1:12 pm

You're not running huge tires by any chance?

Sun Sep 16, 2018 2:26 pm

You need to wait for someone to chime on who knows how to picks vent, Redline is a good company to call for an idea.

Thing is there I heard are based on Valve size, I run 34 Vents in my 2180 with DRLA 40's. Yea, some people say there to small a carb for the engine, but this is a street car and still gets around good, just runs out of breath around 5,500 RPMs.. But yes, most like 36 mm vents in a 2180 to get the RPMs, my engine though is a mild build, Engle 120 Cam, 1.1 to 1 ratio rockers, 42x37.5mm valves..

But yea, think vents are based on Valve size to a degree for initial set-up.. This a street car or drag car? RB

Sun Sep 16, 2018 2:56 pm

My car is a super beetle cabrio running Porsche 16” wheels with 55 profile tyres

Sun Sep 16, 2018 2:58 pm

What is your diff? Know?

I run 4.12 Diff, like the torque for the mountains. Works way well and no
issue for speed, not sure why people push the 3.88.. RB

Sun Sep 16, 2018 3:13 pm

whats the quench distance? what is the dist? how is the dist curve?what intakes? the jetting looks right, but may need more main due to low cr, but not a lot and probably wont feel it. what exhaust?head work?you could possiably degree the cam about 4-6 advanced more for the low cr....but remember it's not a 2332 so it aint gonna be a rocket ship. 1.34 rockers may help and should be a bolt on if the geo is right now. if the quench distance is wide that will also contribute to your slugynishy engine. there is a lot of unknowns on our end ,you have all the answers right there... it should run good, a fast dist curve may help if it's a crap oe style curve.

Sun Sep 16, 2018 6:18 pm

Hello Mr. Mark, have you heard the deal before on the vents are a ratio formula on the valve size to get initial, You have seen a lot of engine and tuning..? RB

Mon Sep 17, 2018 4:28 am

I'd try them 32mm venis ,but 43mm maybe the cat's meow? :lol:

Mon Sep 17, 2018 4:41 am

mark tucker wrote: whats the quench distance? what is the dist? how is the dist curve?what intakes? the jetting looks right, but may need more main due to low cr, but not a lot and probably wont feel it. what exhaust?head work?you could possiably degree the cam about 4-6 advanced more for the low cr....but remember it's not a 2332 so it aint gonna be a rocket ship. 1.34 rockers may help and should be a bolt on if the geo is right now. if the quench distance is wide that will also contribute to your slugynishy engine. there is a lot of unknowns on our end ,you have all the answers right there... it should run good, a fast dist curve may help if it's a crap oe style curve.

Maybe im just use to driving my modern 250 bhp car and im comparing it with that !!!!
The distrbutor is a Flamethrower pertronix 11 with silver springs

Heads have had work they are 044 's
As for quench distance havent got a clue never heard of it ??

If i try the 32mm vent what jetting would anyone recommend??

Mon Sep 17, 2018 8:25 am

Kind of hard to help without knowing what exact work was done to your heads. Quench distance is deck height plus any extra space in the head before the flat surface that's parallel to the piston crown.

Vent to valve ratio might be a decent rule-of-thumb, but what if you have stock ports with 42mm intake valves? A large venturi won't help at all. It will depend more on your minimum port cross section.

Mon Sep 17, 2018 10:22 am

also a 2110 can be a 82x90.5 or a 76x94 ??

I'd also lean towards the idea of your trans being a 3.88 based on the car that it is in?? but that is not fact.. just an assumption.

Vent size can add low end torque and take away from top.. the torque is what makes the seat of your pants say if it is snappy or not..

personally - I'd too look at timing and jetting for the "snap" you are looking for

and hopefully there is a good compression for the setup/valve size you are running.

Mon Sep 17, 2018 3:11 pm

tommiebsmith wrote: also a 2110 can be a 82x90.5 or a 76x94 ??

NO

If you want to fuck around and worry about doing the math to 6 or 7 digits past the decimal point maybe they will come out close but the standard in the VW community has always been

76X94 = 2109
82X90.5 = 2110