Skip to main content

Closed14 replies

Dual Carb Performance

K ktmitsy
I know this question has probably already been asked; however, I couldn't find it when I looked back at the old files. I just bought a used VS and have noticed that the car sort of drags a bit when the car is running at a steady rate of speed in 3rd or 4th gear. This problem occurred when the car was somewhat cold and then went away after being run a while.

What should I know about dual carbs (when compared to a single carb). How long do these things take to get warmed up? Do they need to be warmed up before they begin to perform properly? Should I have my carbs looked at? Does it take an expert to really get the two carbs working together?

I had a single carb on my old Speedster, so the dual carb thing is new for me.

Thanks.

Dave.


ps - the used '01 Black VS I just got on Tuesday is awesome. I was suprised at how well the car was built. All of the seams look really good, and the paint is an 8 on a 10 point scale. The leather interior is also really nice.

1957 Other/Unknown(Speedster)

Original Post

Replies sorted oldest to newest

K ktmitsy
I know this question has probably already been asked; however, I couldn't find it when I looked back at the old files. I just bought a used VS and have noticed that the car sort of drags a bit when the car is running at a steady rate of speed in 3rd or 4th gear. This problem occurred when the car was somewhat cold and then went away after being run a while.

What should I know about dual carbs (when compared to a single carb). How long do these things take to get warmed up? Do they need to be warmed up before they begin to perform properly? Should I have my carbs looked at? Does it take an expert to really get the two carbs working together?

I had a single carb on my old Speedster, so the dual carb thing is new for me.

Thanks.

Dave.


ps - the used '01 Black VS I just got on Tuesday is awesome. I was suprised at how well the car was built. All of the seams look really good, and the paint is an 8 on a 10 point scale. The leather interior is also really nice.
FM Former Member
Dave,

A warm up is needed anytime for an aircooled, but especially when it's cold and you have duals. My ICTs warmed faster than the IDFs, why? I don't know.

If you have IDFs you may want to get an electric fuel pump that maintains 3-3.5 PSI Fuel Pressure. John Connely at Aircooled Net sells one that is quiet and self-regulates at a constant 3.25 PSI. This may help with any starvation issues.

Jim<
(Message Edited 9/15/2003 1:35:24 PM)
K ktmitsy
George, Bruce, and Jim:

Thanks for the feedback. There is a noticable difference between a single solex and dual carbs (I don't know what kind I have).

My knowledge of this stuff is extremely limited. I am one of those get in and drive guys, although I wish I was more informed. Can you please explain the difference between IDF and ICT?

Thanks guys.

dw

FM Former Member
Most dual carb set ups have no need for chokes simply because the intake manifolds are so short compared to a single carb set up. If you're having problems on warm up, you might want to check inside the fan housing. Whewn Volkswagen designed the original cooling system, they installed internal "flaps" which directed the cold air away from the cylinders. After proper warming, the flaps would change their direction towards the #1 & #3 cylinders due to engine placement.
The "flaps" are attached to the thermostat which expands & contracts depending on the engine temperature. Most cars that have been modified have had these flaps removed, espiecially in hotter climates such as here in California where there usually is no need for them. But in colder climates (North Eastern Winters) theyt are almost mandatory for correct warm up procedures. If you need a pic of these flaps, let me know & I can get you one.
Post Content
Remove This Ad

Membership Required

We're sorry. You must be signed in to continue. Sign In or Register
×
Are you sure you want to remove from your Block List?
×
Loading...
×
When you block a person, they can no longer invite you to a private message or post to your profile wall. Replies and comments they make will be collapsed/hidden by default. Finally, you'll never receive email notifications about content they create or likes they designate for your content.
Note: if you proceed, you will no longer be following .
×
Link copied to your clipboard.
×

Access to this requires a premium membership.

Supporting Member

Please help keep us running!

Supporting members have donated about $4.00 a month ($49.00 US per year) paid annually.

  • Priority support
  • Removal of inter-page (between thread) advertisements.
  • Access to Build Manuals
  • Access to Knowledge Base
  • Access to Supporting Members events.
  • Access to Leveraged Group Buying from site Merchants.

AUTO RENEW: You membership will auto-renew after 12 months. If you prefer not to auto-renew, you can cancel your premium membership at any time and it will remain in effect until the end of the 12 months. To cancel, sign in at SpeedsterOwners.com and navigate to: (Your User Name)  > Premium Membership.

PLEASE NOTE: Your credit card will receive a charge from CROWDSTACK PAY, the payment processor, not SpeedsterOwners.com.

$49.00 per 12 Months (plus tax if applicable)
×