Author Topic: Choke/No choke  (Read 1025 times)

Offline Bills64

  • Garage guy
  • **
  • Posts: 25
Choke/No choke
« on: January 21, 2023, 12:30:00 PM »
If running 98% on the street (daily driving) and 2% at the strip, would having a choke on a 17057274 cost big et's?

Offline Kenth

  • Jet Head
  • ****
  • Posts: 415
Re: Choke/No choke
« Reply #1 on: January 22, 2023, 01:26:51 AM »
Very little if anything, but not adjusting the stop to the air valves for maximum degree of opening does.
1.38" measured from rear edge of open valves to back of chokeblade housing is max, then the valves block fuel flow from the nozzles.

HTH

Offline Bills64

  • Garage guy
  • **
  • Posts: 25
Re: Choke/No choke
« Reply #2 on: January 23, 2023, 10:06:45 AM »
Hopefully 1 last question. On this 17057274 carb is it necessary to hook up the rear choke vacuum canister or can it be bypassed? If it does need to be hooked up, what vacuum source? I'm converting to an electric choke.
This carb is not in the original car.

Offline Kenth

  • Jet Head
  • ****
  • Posts: 415
Re: Choke/No choke
« Reply #3 on: January 23, 2023, 11:28:17 AM »
You can toss the secondary chokebreaker, it´s an emission device for finetuning the choke function and not really needed for performance usage.

Offline Bills64

  • Garage guy
  • **
  • Posts: 25
Re: Choke/No choke
« Reply #4 on: January 23, 2023, 12:33:41 PM »
Thank you!

Offline Cliff Ruggles

  • Administrator
  • Qjet Hero
  • *****
  • Posts: 5401
Re: Choke/No choke
« Reply #5 on: January 26, 2023, 04:46:16 AM »
I'm assuming you are talking about leaving the choke plate and shaft in place?

I've had several customers that drag race in the Stock Classes tell me that it actually hurts power some if you remove those parts.

Here I ran the exact same carb number for decades on the engines powering the Ventura and saw no loss in ET or MPH either way. 

At one point I removed the choke when I was racing the car a lot, but HATED not having one as it was a royal PITA to start the car in cool/cold weather.  The older I get the LESS I enjoyed sitting there "patting" the throttle till the engine warmed up enough to idle on it's own. 

Having fast idle is also a nice feature as you can fire it up, let the engine run about 20-30 seconds, "pat" the throttle so the fast idle cam falls to the next step, then get out and walk around the car and wipe it off, or check things out till it warms up a bit.  At that point pat the throttle one more time and it idles nicely on it's own.

I'll add here that the 17057274 is an EXCELLENT high performance unit.  I used mine for decades and it logged a LOT of track runs and dyno time.  Even back when we did articles for High Performance Pontiac and Popular Hot Rodding (Engine Masters) nothing would outrun it.

It was also absolutely FLAWLESS and never once did I have to take it apart because it developed issues or had any internals fail, etc.  I did take it apart a few times to test some of the parts I'm having made, like the lifetime warranty accl pumps, and high flow needle/seat assemblies........