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Adjusting throttle pressure??
https://slantsix.org/forum/viewtopic.php?t=18175		 Page 1 of 1
Author:  valiantboy_66 [ Wed Jun 21, 2006 11:30 pm ]
Post subject:  Adjusting throttle pressure??
My little 66 Valiant ran an 18.40 the first time out two years ago. It was purely stock except the wheels and tires witch are 2.45-60-14 and 205 on the front. It had a 2.73 7 1/4 rear end and I manually shifted about 3500 RPM. Last year I built a 8" F@#D rearend with 3.25's and a posie. I ran 18.60's all night, manually shifting, but the car wouldn't shift until 4000 RPM some times 4200. She don't make any power over 3500. How can I adjust the shift points to get them back down to 3500? My bosses are pokin fun at me for spending 500$ to go two tenths of a second slower.
Author:  Doctor Dodge [ Wed Jun 21, 2006 11:44 pm ]
Post subject: 
Dis-connect the throttle pressure linkage from the throttle rod then have someone sit in the car and floor the gas peddle while you look down the carb. Does the butterfly open all the way? If not, adjust the linkage so it does.

Once you have confirmed that you can get WOT, hold the throttle wide while you push the throttle pressure linkage rod all the way down, adjust the threaded link so the trans lever is pushed all the way back at WOT.

Now test drive the car and if it shifts to late for a good et, adjust the TP rod shorter, so it does not push the lever back as far.
DD
Author:  valiantboy_66 [ Thu Jun 22, 2006 12:23 am ]
Post subject: 
Right on, that is good news. Thank you Doc.
Author:  slantzilla [ Thu Jun 22, 2006 12:14 pm ]
Post subject: 
I have 2 questions....

1. Was the weather any different 2nd time out.

2. Why won't it make any power above 3500? Every stock Slant I've seen would pull to at least 4200. :shock:
Author:  valiantboy_66 [ Thu Jun 22, 2006 11:42 pm ]
Post subject: 
Well the reason why I feel it doesen't make any power after about 3500 is the run out. She pulls great and fast right up to about 3500 and then seems to take the same amount of time to pull up to 4000 to shift. I can feel it, its like it flattens out and then its just screaming and your not going any faster and then there is a micro second when I think, she is not going to shift this time, and then (BANG) we're hustling down the track the last 80 feet. Also the conditions were about the same during all of my runs. I consistently run 18.60's with the lower gears. It just feel like I am loosing it on the top end.
Author:  Doctor Dodge [ Fri Jun 23, 2006 11:10 am ]
Post subject: 
Quote:
Well the reason why I feel it doesen't make any power after about 3500 is the run out. She pulls great and fast right up to about 3500 and then seems to take the same amount of time to pull up to 4000 to shift. I can feel it, its like it flattens out and then its just screaming and your not going any faster....
To much mechanical advance - to much total timing will make a car do that. What is your total advance?
DD
Author:  Jeb [ Fri Jun 23, 2006 7:29 pm ]
Post subject: 
While we are on the subject, my car does the same thing as this guys car. How do I determine my total advance?
Author:  Doctor Dodge [ Fri Jun 23, 2006 10:29 pm ]
Post subject: 
Use a timing light, the easy way is to ahe a special timing light that allows you to "dail in" retard so you don't have to add new marks to the dampener
I add the new marks at 25, 30 & 35 BTDC
When you rev the engine (vacuum advance disconnected) you will see the 3 new marks come up to the Zero mark on the timing tab, this will show you how much mechanical advance you are getting.

One tip, if you are running more then 3 or 4 degrees initial timing advance, there is a good chance that the total is more then 30 degrees. (more initial timing with out recurving the distributor = over advancing at high RPMs)
DD
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