I did a little search but nothing really hit on my question. Wacky seemed to be the most knowledgable on the subject. (scary)

Anywho, What are you adjusting when you change the size of the venturies? Other than the amount of air that can go in now. I mean, does it move the peak horse power point higher into the RPM's?

I just bought a brand spanking new 48 IDA with my state tax return. It's now at the machine shop getting some needed mods to keep me from running short on fuel. I called up Jay Cee ent to get some little parts and such also.

 

Finding the right venturi size is a compromise between low rpm response and top end power. Going too big will result in good high rpm power but the engine will experience bogging and flat spots at low revs. This is because there isn't enough air moving through the venturis to create a strong enough vacuum to suck fuel out the fuel bowl. Likewise, going too small will result in good response but may choke the engine at high revs.

 

[QUOTE=seanrot]Wacky seemed to be the most knowledgable on the subject. (scary)
QUOTE]

Wow, Im getting scared too. lol. as he said, the bigger the venturies will result in a lag at lower RPM but hell a fast on top end. About 3 years ago, I've used 45 venturies for occassional freeway racing (imagine being alone in the freeway at 11:30 at night...it was fun). I even suprised a twin-turbo Supra who gave me props for having the ***** for trying to keep up with him (I pegged both stock speedo and tach - so figure it out).

here's my specs (remember , I like to run my carbs rich)
Idle jet - 75 to have a nice lope.
Air/Main/Venturies - 150 /230/43.

 

on boosted applications, you can use a smaller venturi so your bottom end dosnt suffer while the top end still pulls strong with boost feeding the carb!!!
changing to a larger venturi on boosted applications dosnt really increase the top end as it would on a n/a application.....

seanrot... where did you buy your weber?

 

http://www.racetep.com/xmasspecials.html

499.00 had it in two days.

You werent answering the phone this week

 

Spot on!

Any of you guys know where I can find a VE graph for a stockport 12A, and then for a SP 12A?

 

499!!! whoah! i could have definatly saved you a large chunk of cheese!! well you got it in 2 days, i guess thats good, lol

 

yeah i know, but the i want it now bug bit my cheese. I have it at a local machine shop right now. having them knock out that wall and add a 3rd progression hole and opening the main fuel inlet hole. So she is getting her holes ran through.

I will be street porting a engine in the spring when its starts getting warmer and I ordered some 40mm venturies. Was thinking about trying them on the stockport.

 

40mm on a stockport?! wait for the streetport, run the small venturies first , then try the 40's and see what the difference is...

p.s. does the weber hks kit come with a float?

 

nope, havn't seen the float in awhile. but i keep looking. I find another of those i might be able to put my kid hrough college

I did get another shorty intake manifold that I will put the old carb on and put up on ebay. Recoupe my cheese

 

i perfected the brass modded float, took 3 more but i got it to work!!!
15 psi for 4 months and still running strong!
but the plastic ones are still cool

 

awesome, when i go to resell everything I will drop your web site on the auction to get parts