A Question About A Manifold And Some Carbies...

[yakkmeister]

Hey guys!

 

Some know about my plan to graft a 2T-G into a Ke-35 Coupe ...

I have been looking for carbies and manifold to suit.

 

I have discovered a neat little twin carb manifold and twin carbies (they look like side draught with a sliding sleeve device?) off a toyota Corsa.

It would seem to be from a 3E motor. I have not been able to glean any more info than that, except that they came off a 1500cc or 1800cc SOHC motor from a jdm corsa.

I am wondering if;

A) The whole manifold will fit

B ) If not A then will the carbies function for my application? Re-Jetting and other standard-type mods are acceptable.

 

Thanks for your, most precious, time!

[Redwarf]

Don't waste your time reinventing the wheel. Get a 2TG manifold, and a pair of Webers/ Dellortos. Solexs should be used as paper weights.

 

The manifold wont fit, and there's a good chance the carbies wont, either. However without a picture, I can't definitively say.

 

R

Edited April 22, 2007 by Redwarf

[yakkmeister]

  Redwarf said:

Don't waste your time reinventing the wheel. Get a 2TG manifold, and a pair of Webers/ Dellortos. Solexs should be used as paper weights.

 

The manifold wont fit, and there's a good chance the carbies wont, either. However without a picture, I can't definitively say.

 

R

 

I think these are the SU style carbies.

Is that the same as Solex? I have heard that the SU carbies are pretty damn good ... I will try to get some pics next time I'm down the coast.

[Redwarf]

  yakkmeister said:

I think these are the SU style carbies.

Is that the same as Solex? I have heard that the SU carbies are pretty damn good ... I will try to get some pics next time I'm down the coast.

 

Su's are fine, however I don't think there was ever a manifold to suit a 2TG. The factory carbies were Solexs, similar to Webers, but not as good (IMHO).

 

I really don't think SU's suit a 2TG application. You want at least a pair of 40 Webers, and if you're going for big grunt, 45's are even better. SU's only have one throat, therefore the flow divides into two on the way into the engine. Each weber has two throats. Ergo, two Webers, four throats. One for each hole in the head. :).

[Felix]

  Quote

SU's only have one throat, therefore the flow divides into two on the way into the engine. Each weber has two throats. Ergo, two Webers, four throats. One for each hole in the head.

 

Actually this isn't quite true, from the way I read it.

 

The airflow availability of the SU isn't halved. With a four stroke four cylinder engine you have one complete power cycle of all four cylinders every 720 degrees of crank rotation. So each cylinder is drawing air for 180 degrees of the 720 degrees.

 

There is no intake pulse overlap in a four cylinder engine, so even if you have a single carb feeding all cylinders, each cylinder takes turns sucking on the carb. ie. they are NOT drawing off it all at once.

 

As an example, say if you had a set of twin 40 mm dcoe webers on an individual runner manifold, each cylinder only sees the flow potential of one throat of the webers, around 175 cfm. If you had a single DGV weber on a theoretically perfect single carb manifold, each cylinder would see the flow potential of both throats of the DGV, about 225 cfm.

 

It is the manifold efficiency which pretty much has the final say in how much flow is available to each hole in the head. It is not the flow of the carb divided by how many cylinders are sucking off it.

 

Sorry Redwarf if I read what you said wrong, but I just had to point out what seems to be a common misconception when it comes to carbs.

[Redwarf]

Ummmm.... You think far too much. :)

 

I understand what you're saying, but is that a perfect world theory?

 

Thinking about the fluid mechanics of it, the hard bit would be the inlet manifold, and to have a non-terbulent airflow. Hence I personally believe that you do lose a bit having to split the airflow, which realistically is what is happening. I keep thinking back to if air was water, and the turbulence created by alternate movement through runners. I'm also a rock ape who thinks two holes good, four holes better. :P

 

Discuss. :D