|
Author
|
Topic: Race fuel and jetting
|
Strain Gang
Gearhead Posts: 212
From: Thor, Iowa
Registered: Mar 2003
|
posted 08-27-2004 11:38 PM
   
OK guys heres the deal. Last year we ran Unocal 110 race fuel on our iron headed Windsor. Never had to change jets at all. This year we switched to aluminum heads and also to Unocal SuperStock 114. It seems the car is loading up at idle and has a dead spot in it when you whack the throttle off idle. I have tried to spray carb out with carb cleaner (air bleeds, ect) also set the mixture screws to the highest amount of vacuum with a gauge. Is it possible that with the 114, the jetting is too fat then it was with the 110? The plugs always looked clean and nice before with 110, but now they look fairly dark. We started off the year running Autolite 3924 plugs (recommended for the Z 304 head) then switched to Autolite AR 3911. Is it possible that the plug is too cold and not burning the fuel mixture completely? Im kind of lost as this carb always functions flawlessly. BTW, its a Bill Mitchell 750 DP, with a 850 baseplate to bring the carb to 830 cfm. Any ideas ? We just returned from a test and tune session and got a few runs in then got rained out. Im looking for something to try tomorrow at our local track. Thanks, Steve.
IP: Logged |
Tea'sGrabber
Gearhead Posts: 276
From: Seattle, Wash.
Registered: Feb 2003
|
posted 08-28-2004 03:31 PM
I'd first go back to the hotter plugs...see if that cleans up the idle. If so..... weak ignition or not enough voltage to your ignition box.The heads are definately pulling more air into the motor... so you may need to up the squirters.Also check the float bowls.... things get stuck when you start removing varnish... best of luck.... other than the tuning probs.....how do you like the heads?????? Tell me Im thinking about them for me....------------------
Todd 71 Mav Grabber All orig 306 cu.in. Cast Iron heads. Carillo Rods.Best et. 10.71 @ 124 thru the mufflers.
http://mustangsandmore.50megs.com/MembersPics/TeasGrabber.html
IP: Logged |
Strain Gang
Gearhead Posts: 212
From: Thor, Iowa
Registered: Mar 2003
|
posted 08-28-2004 11:46 PM
First off I fixed the problem. I went back to the 110 fuel and Autolite 3924 plugs we were running and it sounded better but still not right. Looked in the carb and thumped the throttle with my hand and the right side squirter on the primaries did not sqirt anything. Took it off and cleaned with carb cleaner and fount a piece of crap in it. Reinstalled and YAHTZEE it worked. The car went from running barely above 7's in the 1/8th to 6.70's. I did have to fatten it up a touch on both sides due to the awesome air flow of the new heads. They are definately competitive with the AFR heads. I am sure impressed with them. Thanks for your accurate online diagnosis Todd. Thanks, Steve.
IP: Logged |
Mustangsandmore Forums
