Another day another lesson learned...

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Another day another lesson learned...

Postby poissant » Tue Mar 18, 2014 10:16 am

Well got back out to the track this past weekend for another local points race. We went a couple of rounds before losing, Jules is having a ball and I am learning a ton of stuff. So all in all a good raceday. But of course I do have a few questions or observations that you guys can help me with. It was an overcast day this past Saturday so it wasn't hot, but muggy as rain was coming our way for later that night. We find that the car is bogging a little when we are getting on the chip at the line, it has even died on us a couple of times. At first we thought because it was cool we weren't getting enough heat in the engine. Jules said on one of this time trials he was only @ 120 degrees at the line. He always turns on the water pump and fan pretty much as soon as he starts the car(always worried about over heating). As it's mostly hot down here building heat in the engine is not normally an issue. In talking with a friend he suggested not turning on the pump or fan until we built some heat in the engine. So we began to try that, but we were stiill experiencing a bog in rpms when getting on the chip. All of this of course is throwing Jules off on his lights..... After we had lost , we were looking at the carb to make sure the float wasn't sticking. Our firend suggested checking the air jets on the carb... WOW ...all of them were either completely clogged or almost completely clogged, blew them out with some carb cleaner and then tested the car at throttle in the pits. It seemed cleaner to us. In my mind, I am thining that when we get on the chip the engine is trying to suck more air to burn more fuel and was inhibited by the clogged jets. Offbase???.. I would imagine it could have been a combination of cold engine and clogged jets causing our problems. ...Just another thing for the crewcheif to check....the list is getting long.. :) We are chompin at the bit to get out there and see if this helps us with this problem, only thing is because of schedling conflicts with my driver, we probbaly won't be able to make a race day(Saturday's) in April. We are gonna try and hit up a Sunday test and tune in a week or so though to get some hits in. Below is a video of our 2nd TT of the day, you may hear a slight hesitation when Jules gets on the chip.

https://www.youtube.com/watch?v=QZrTimwN0zQ&list=UU9PBS1uVp9NhEDosjC9dAbQ
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Re: Another day another lesson learned...

Postby Pool Man » Tue Mar 18, 2014 10:28 am

Gary just like the carbs on the jr dragsters these carbs have a idle circuit. You may be a little of on those adjustments. You should see 4 small screws on the side of the carb. Two on each side, located forward and aft. If those are out of adjustment they can cause a bog at the hit of the throttle just like a jr dragster will,
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Re: Another day another lesson learned...

Postby TS403C » Tue Mar 18, 2014 10:44 am

First thing I would look at is to make sure the accellerator pumps are adjusted correctly and the acc. pump arm springs have enough spring tension in them(add 1 to 3 nylon fuel bowl washers). And if you still have a stumble then I would go up in squirter nozzle size. That should cure that stumble.
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Re: Another day another lesson learned...

Postby poissant » Tue Mar 18, 2014 12:06 pm

Ron we checked that I think we are ok there. Harold we thought jetting also. Gonna check with my engine builder and get his thoughts on it. Need to buy a jet assortment anyway, probably. How bout this one?
We have a pair of 35 quirters on it, gotta look at the jet.


http://www.jegs.com/i/JEGS-Performance-Products/555/15019/10002/-1
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Re: Another day another lesson learned...

Postby TS403C » Tue Mar 18, 2014 4:24 pm

This is the squirter size I probably would go to .045

Like this one http://www.jegs.com/i/Holley/510/121-14 ... ProductId=

And you could always use a good jet kit.

Could you put a new plug in #3 hole, make one pass and shut the motor off at the end of the track, then pull the plug , take a up close pic of it( the electrode and porciline) and post it? Pic like these http://www.dragstuff.com/techarticles/h ... plugs.html
Harold Snyder
Austin, Texas
IHRA Top Sportsman #403C finished #4 in 2008 and
crew chief for my son's 7.90 car #4165
2011 IHRA JR Masters 7.90 Div.4 Champion
2013 SWJDS 12-17 Age Group Champion
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Re: Another day another lesson learned...

Postby poissant » Wed Mar 19, 2014 8:35 am

Thanks for the info Harold, I will try and do that If I can remember, LOL. So right after he gets it off the track, kill it and take the photo.
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Re: Another day another lesson learned...

Postby TS403C » Wed Mar 19, 2014 3:20 pm

Gary the answer is Yes. If you drive it back to the pits it will not give a good reading of the spark plug. Plus I like helping my friends. Just wish that drive to Baton Rouge was just a little shorter, we like the track there and always had a good time there.
Harold Snyder
Austin, Texas
IHRA Top Sportsman #403C finished #4 in 2008 and
crew chief for my son's 7.90 car #4165
2011 IHRA JR Masters 7.90 Div.4 Champion
2013 SWJDS 12-17 Age Group Champion
TS403C
 
Posts: 519
Joined: Mon Sep 11, 2006 6:03 pm
Location: Austin,Texas


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