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Post by mopar redneck on Jul 23, 2011 21:14:49 GMT -5
Been having problems tuning it. It wants to cut out at the launch, and my top end seemed to be lacking a good deal. Minus my r/t, my best was like a 14.96 I think. Heres my last race of the day from yesterday: www.youtube.com/watch?v=h0KKBOSTWno&t=1s
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Post by Jonny tsunami on Jul 23, 2011 23:10:06 GMT -5
Bigger carb for the top end and larger orifices for your accelerator pump would help with the stumble off line
maybe a 750 holly double pump would be good but will hurt gas mileage
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Post by mopar redneck on Jul 23, 2011 23:50:14 GMT -5
Thats where it confuses me. Cause its got a 750 edy one it now. It runs rich, if I leen it out it runs worse. And if I retard the timing it loses top end, but if I advance it, it pre detenates and diesels when I shut it off. Any help would be fantastic! Ive never tried tuning a motor before. Kinda my leafning experience, but its stumped me
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Post by poorboy1 on Jul 24, 2011 9:51:13 GMT -5
I always had issues with dieseling and hard to start when hot when my timing was retarded. Had the ping when it was advanced too far. What compression do you think you are running and what fuel did you run?
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Post by mopar redneck on Jul 24, 2011 11:40:22 GMT -5
We're guessing 9.5-10 to 1. And I was running premium.
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Post by popeye on Jul 24, 2011 12:46:58 GMT -5
Thats where it confuses me. Cause its got a 750 edy one it now. It runs rich, if I leen it out it runs worse. And if I retard the timing it loses top end, but if I advance it, it pre detenates and diesels when I shut it off. Any help would be fantastic! Ive never tried tuning a motor before. Kinda my leafning experience, but its stumped me out of curiosity what are you doing to lean it out? are you changing the jets and metering rods or are you just turning the 2 screws on the front? if you are just turning the screw's on the front you are just effecting how it runs at a idle. you need to change the metering rods and jets. going to a bigger carb might not be the anwser, the "cfm" for a carb is the ammount of air that it flows not how much fuel it dumps. i had a 429 that did not perform very well with a edlebrock 750 i tried my buddies 650 it was like 2 different motors but it was still lacking took the 750 changed the metering rods and went down a size or two for the jets on the primary side and that truck was dang near scary to drive sometimes. here's some very dry reading but it is very helpfull www.edelbrock.com/automotive_new/misc/tech_center/install/1000/1407_manual.pdf
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Post by mopar redneck on Jul 25, 2011 16:01:29 GMT -5
Only reason I have the 750 on it is cause it was $50. I'm Poor.. ha.
The screws on the front. I read up on the carb and I"m going to get the kit that has the diff jets n rods.
Probably wont be able to afford it before sb7 though, so itll be pukin the whole time haha
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Post by mopar redneck on Jul 25, 2011 16:07:32 GMT -5
So for Summer Bash, I got 2 sets of tires I can use: 38.5x14.5x15 tsl/sx's. or 38.5x16x16.5 Baja Claws Iffy about the claws since they are 16.5's
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Post by Rock Dawg on Jul 25, 2011 16:39:19 GMT -5
So for Summer Bash, I got 2 sets of tires I can use: 38.5x14.5x15 tsl/sx's. or 38.5x16x16.5 Baja Claws Iffy about the claws since they are 16.5's Ya, I would stick with the 15's, even though they are a little bit narrower, you can air them down more and that should make them better in the sand for you.
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Post by Rock Dawg on Jul 25, 2011 16:48:04 GMT -5
I use to race a 10 sec camaro (Chev 355 motor) we had a edelbrock 750 carb on it for CFM but the jetting was changed to be way smaller so it would run good. changing the jetting and meetering rods fixed several issues including stubling off the line and dogging on top end. The meetering rod ended up being either at the top notch or one notch down if I remember correctly.
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Post by mopar redneck on Jul 27, 2011 12:46:54 GMT -5
I use to race a 10 sec camaro (Chev 355 motor) we had a edelbrock 750 carb on it for CFM but the jetting was changed to be way smaller so it would run good. changing the jetting and meetering rods fixed several issues including stubling off the line and dogging on top end. The meetering rod ended up being either at the top notch or one notch down if I remember correctly. Just ordered this ;D It's gonna be fun trying to figure out what jets, rods, and springs I need.
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Post by Rock Dawg on Jul 27, 2011 15:30:33 GMT -5
Great! watch this video before taking it apart, it has some good tricks in it. www.youtube.com/watch?v=I0cuIP6FVdcIf I find any specs on what jets/springs/rods to use, I'll post it up. The rods and springs can easily be changed on the truck, but you need to take the carb off for changing the jets, so lets see if we can find a recommended size jetting for your motor to start with :-0. It will save alot of tuning time.
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Post by Rock Dawg on Jul 27, 2011 15:52:05 GMT -5
www.forabodiesonly.com/mopar/showthread.php?t=69255"I found .113 primaries, .101 secondaries and .70x .37 rods worked best at the track - It was a bit "FAT" at cruise but very happy at WOT. " That should get you close. Also reading the I'd start with "move the pump shot arm down to the middle hole". That should be really close for your starting setup. on timing... I'd start with warming the motor up and running it at 3K to set the timing to 32 degrees and then see where it is on idle :-).. It's backwards from what alot of people think, but you are really looking for HP. That is the way most racers start with their timing. If that doesn't work well, then tuning by ear is better then light because of the cam specs. Here is another web site for you. It just shows that you are on the correct path with that carb, cam setup :-).. www.mopar1.us/dyno.htmlHope it helps!
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Post by mopar redneck on Jul 29, 2011 17:14:08 GMT -5
Thanks for the research! Hmm, I didn't know you could adjust the accelerator pump on one. That itself will help my launch a lot, cause its like it's flooding itself out right off the bat, I have to slowly apply the throttle. I'm super excited to get the kit now! lol. Kinda tempting to pull the truck by the house and go ahead n tear into it. See what jets are in it already ect. And yeah I don't have timing marks on the engine. Well I do, but Dodge decided to put the marks BEHIND the power steering pump. Brilliant huh?
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Post by popeye on Jul 29, 2011 20:03:11 GMT -5
in the link i gave to the edlebrock manual there is a graph that helps with what jets and rods to use
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