Carb Tuning

General engine tech -- Drag Racing to Circle Track

Moderator: Team

Post Reply
F-BIRD'88
Guru
Guru
Posts: 6350
Joined: Tue Mar 27, 2007 6:56 pm
Location: Ontario, Canada

Re: Carb Tuning

Post by F-BIRD'88 » Sun Oct 07, 2018 12:53 am

I don't advocate the super quick and floppy all in by 2500 rpm advance curves either.

F-BIRD'88
Guru
Guru
Posts: 6350
Joined: Tue Mar 27, 2007 6:56 pm
Location: Ontario, Canada

Re: Carb Tuning

Post by F-BIRD'88 » Sun Oct 07, 2018 1:01 am

Is the gas in the tank now 100% 93 octane premimun?..... Or.....
A lack of octane (good gas) is a basic here, with agressive 10.4:1 cr.

F-BIRD'88
Guru
Guru
Posts: 6350
Joined: Tue Mar 27, 2007 6:56 pm
Location: Ontario, Canada

Re: Carb Tuning

Post by F-BIRD'88 » Sun Oct 07, 2018 1:05 am

With your afr gauge, what hapoens to the afr as yiu raise up the rpm (raise the throttle from idle , in park. No load...
What happens when you do the same while driving,, low speed light lioad, easy throttle progression, rpm increase, speed increase from idle. Which way does the afr shift too from base idle afr on the gauge?. How much?

All with air cleaner on..

F-BIRD'88
Guru
Guru
Posts: 6350
Joined: Tue Mar 27, 2007 6:56 pm
Location: Ontario, Canada

Re: Carb Tuning

Post by F-BIRD'88 » Sun Oct 07, 2018 1:13 am

I am not a expert on the Ford W motor AFR heads/chamber and what is optimum wot ignition advance, so others with more dyno and track experience on these specific windsir sb heads can jump in.
Some wot time distance blast tests will help
(1/4 mile or .??) This is to rough in the max WOT power timing...( 29-30-32 deg....) With the locked timing curve, as is for now , without getting carried away.

BobbyB
Member
Member
Posts: 134
Joined: Mon Apr 15, 2013 1:35 pm

Re: Carb Tuning

Post by BobbyB » Sun Oct 07, 2018 6:10 am

100 percent 93 octane non ethanol from 2 different gas stations.
I have a good place to do dead stop though first gear WOT. Will that work?
Are there any cell phone apps to helm monitor actual acceleration?

BobbyB
Member
Member
Posts: 134
Joined: Mon Apr 15, 2013 1:35 pm

Re: Carb Tuning

Post by BobbyB » Sun Oct 07, 2018 6:13 am

Are there any cell phone apps that measure speed over time or acceleration?

F-BIRD'88
Guru
Guru
Posts: 6350
Joined: Tue Mar 27, 2007 6:56 pm
Location: Ontario, Canada

Re: Carb Tuning

Post by F-BIRD'88 » Sun Oct 07, 2018 12:20 pm

Not with any real accuracy. A short run in just firstvgear won't tell you much.
A run thru 660 ft testing for mph is good.
Can be a rolling entry start, say 20 mph | →→→.
Getting well into 2 nd gear at least.
A $100 radar gun is great for this.

Tuner
Guru
Guru
Posts: 2145
Joined: Sun Apr 01, 2007 5:26 am

Re: Carb Tuning

Post by Tuner » Sun Oct 07, 2018 12:23 pm

BobbyB wrote:
Sun Oct 07, 2018 6:13 am
Are there any cell phone apps that measure speed over time or acceleration?
https://www.hptuners.com/product/trackaddict-app/

BobbyB
Member
Member
Posts: 134
Joined: Mon Apr 15, 2013 1:35 pm

Re: Carb Tuning

Post by BobbyB » Sun Oct 07, 2018 4:52 pm

In park:
1000 rpm= 12.3 to 1 afr
1500 rpm= 12.7
2000 rpm= 13.9
2500 rpm= 15.7
3000 rpm= 14.5

In gear
650 rpm=12.7
1000 rpm=14
1500 rpm=15
2500 rpm=14.5

This was driving normally on a very slight incline.
Once in a while I see 16 to 16.5 to 1 on level ground & feel a very slight surge.

F-BIRD'88
Guru
Guru
Posts: 6350
Joined: Tue Mar 27, 2007 6:56 pm
Location: Ontario, Canada

Re: Carb Tuning

Post by F-BIRD'88 » Sun Oct 07, 2018 5:34 pm

May just need a slight richen of the 2 idle mix screws.
Or may need +1 on the pri main jet. Or may need a slightly higher float level setting. Or may ne!d a slight bit less pcv valve flow. Is the air cleaner ?

Lastly may need a slightly smaller pri IAB.

BobbyB
Member
Member
Posts: 134
Joined: Mon Apr 15, 2013 1:35 pm

Re: Carb Tuning

Post by BobbyB » Sun Oct 07, 2018 5:50 pm

Using 4x14 K&N filter.
Any reason not to try the 750 Holley with a 4.5 power valve?

F-BIRD'88
Guru
Guru
Posts: 6350
Joined: Tue Mar 27, 2007 6:56 pm
Location: Ontario, Canada

Re: Carb Tuning

Post by F-BIRD'88 » Sun Oct 07, 2018 6:07 pm

Sure, go for it.

BobbyB
Member
Member
Posts: 134
Joined: Mon Apr 15, 2013 1:35 pm

Re: Carb Tuning

Post by BobbyB » Sun Oct 07, 2018 7:19 pm

Tried it with no vac advance. Did not drive nearly as well, as expected. No discernible difference in tiny spark knock when matting it from a dead stop.
I Put the vac advance back on and went for a 50 mile ride. The car is pretty dang good as is, though it is still using oil with about 1000 miles on the new engine. I doubt the raw gas that leaked into the secondaries did it much good.

I guess I will try the 750 with the 4.5 power valve and see how it does. With the 650 quick fuel it pulls hard, at least to me, from about 3000 to 6500 rpm.

F-BIRD'88
Guru
Guru
Posts: 6350
Joined: Tue Mar 27, 2007 6:56 pm
Location: Ontario, Canada

Re: Carb Tuning

Post by F-BIRD'88 » Sun Oct 07, 2018 8:54 pm

Oil getting into the chamber will knock just like you discribe. Change plugs, may be a hair too hot heat range. Keep an eye on oil consumption.

F-BIRD'88
Guru
Guru
Posts: 6350
Joined: Tue Mar 27, 2007 6:56 pm
Location: Ontario, Canada

Re: Carb Tuning

Post by F-BIRD'88 » Sun Oct 07, 2018 9:17 pm

It may just need a accelerator pump shot tweek.
Pump cam or shooter.

Post Reply