<VV> Plug Secondaries (140hp only)?

[James Davis]

All my Cars and FC have 4 carbs the Ultra Van does not.  The reason is 
simple.  Pushing 5,000 pounds into uphill campground parking spot requires 
maximum torque at about 2,000 rpm and, thus, a very mild cam.  Since the 
engine (with the OT-10 cam) runs out of breath at 4,200 rpm, what purpose 
would the other two carbs serve?  If you rev a 167 cuin Corvair above about 
4,500 rpm the two extra carbs make a difference that shows up in the 
G-Tech.  I also run headers, Isky or Crane valve springs, and roller 
rockers on all 4-speed engine. and use a 6,000 rpm red line.  After all 
that is where the tach stops (vbg).
Jim Davis

At 05:30 PM 6/9/2004, N. Joseph Potts wrote:
>OK - that was a nice thread about 140hp vs 150/180hp.
>      Now, I've got a question that is a bit more realistic for a guy who has
>a 140, but no other Corvair. This concerns secondary carburetors Yes/No.
>This does NOT concern changing heads! Assume KEEPING the 140 heads and
>blocking off the bases for the secondaries, perhaps changing the crossshaft
>to a two-carb type.
>      My own limited experience with running in this mode leads me to expect:
>
>* Performance as smooth as with 4 carbs (properly jetted/adjusted)
>* SOME improvement in gas mileage (how much?)
>* Presumably some reduction of performance (how much?)
>* Possibly some impairment of cooling at the ends of the heads where the
>secondaries were (?)
>
>      Anyone who has experience running his 140 on its primaries only is
>requested to chime in with reports of experience, particularly anyone who
>has done so deliberately rather than as a matter of expedience (secondaries
>not working, can't afford ANY reduction of gas mileage, etc.).
>
>Joe Potts
>Miami, Florida USA