IDF Flat spot

Bizarre Moderator The artist formerly known as blue74l

12,785 posts · joined Aug 2002 · 8 Jul 2003, 9:42 am

#63814

can only assume i have to play with jetting but here is the story.

Been playing with the IDF's cause i want to get rid of a flat spot.

If you slowy drive up it is smooth, until you hit about 3500 revs. It is about 30-35kms/hr in first or 45-50km/hr in second. At this point if you hold it there it burbles loudly and falls on its face. If u shift before this point it is as smooth as. It is just sooner or later you have to cross this point
You can easily drive through this flat spot but it does make for a bit of on/off of the carbs.
I like it but the wife doesnt
I dont think it is accelerator pump cause it runs smoothly up to that point.

Blocked progression ports?

Jetting at the moment is
40 idles 1 1/2 turns out
120 mains
180 airs
32 vents
F11 E tubes
Stock valved 040 heads

The carbs are IDF 36's and as such dont have access to air bypass screws.

Would different E tubes give a smoother change from mains to air coming in? This is where the problem lies.

If you just floor it it takes off and pulls hard.
If you rev it in neutral (no load) it revs nice and smooth up past 5ooo no worries

Barry

Futue te ipsum!!!

Gracey Wolfsburg Wizard

511 posts · joined Feb 2003 · 8 Jul 2003, 12:48 pm

#63852

It sounds like it's rich on the main circuit. At 3500 rpm the progression circuit should be just about finished. I'd say try a 115 main and see what happens.

Andrew Grace

Menangler Custom Title Time!

1,991 posts · joined Aug 2002 · 8 Jul 2003, 5:25 pm

#63914

I would change those 40 idle jets to 50s and see how it goes,

FAHRVERGNUGEN;
Description of a pleasurable sensation,
Experienced when a car and it's driver are in mutual harmony, A unique driving experience, Pleasure, Satisfaction,
A feeling experienced by Volkswagen Drivers.

vw54 Administrator Always Waiting 4 Friday

16,723 posts · joined Aug 2002 · 8 Jul 2003, 5:30 pm

#63918

BARRY

ive told you this before, put the car on the GAS analyiser and stop all the bloody guesswork n stuffing around.

Then you will get the mixture right and have better fuel economy and more pleasurable to drive to boot.

But i would also do what Beck suggest fora start till you can get in analyised.

[Edited on 8-7-2003 by vw54]

I read it on FACEBOOK so it must be true

http://forums.aussieveedubbers.com/viewtopic.php?tid=91278&page=1#pid848630

http://forums.aussieveedubbers.com/viewtopic.php?tid=63561&page=1#pid624099

http://forums.aussieveedubbers.com/viewtopic.php?tid=4832&page=1#pid452603

http://forums.aussieveedubbers.com/viewtopic.php?tid=60650&page=1#pid574409

Bizarre Moderator The artist formerly known as blue74l

12,785 posts · joined Aug 2002 · 8 Jul 2003, 7:47 pm

#63952

If i didnt fiddle i wouldnt have anything to do 😀

Dave Bich
It was a gas analizer that i reckon caused me my problems.
On dyno day my print out for 3rd gear
@50 - 12.8
@ 65 - 11.5 and flat from there on

That was with the 135's in there. I was under the impression i was rich. So i put some 120's in there and i went harder. Just a bit on/off for the wife.

Anyway i have just gone back to the 135's and yes it is better. Just to prove my gut feel was right in the first place. I might play with some airs for the fun of it.

Dave Beck
Sorry - i am definetly right with the 40's. I reckon it is the fact they are 36's and have soldered up air screws that does it. I had 50's in there and thw revs would pick up when i bottom out. I would back fire as well - badly. I am 1 1/2 turns out. Nope 40's it is.

4.1 x 32 = 131.2

i wonder if the dyno AF meter was out?

Futue te ipsum!!!

rufbug Seriously Crusin Dubber

127 posts · joined May 2003 · 8 Jul 2003, 8:36 pm

#63976

maybe your emulsion tube had your main jets coming in too soon and coming in over your progression circuit and providing you with a too rich a condition. therefore a stumble in your engine ( flatspot), maybe raise your emulsion tube number.
:sandrine

Bizarre Moderator The artist formerly known as blue74l

12,785 posts · joined Aug 2002 · 8 Jul 2003, 9:02 pm

#63988

I will fiddle with that on the week end

I have F57's and F2's to play with

Futue te ipsum!!!