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 Post subject: Help with Carb
 Post Posted: Mon Mar 12, 2012 11:44 am 
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Looking for some help/opinions on this log. Carb is going way rich at launch, then clears up. Its bad enough to where I though I left in high gear. It did this before when I originally had the tuner metering blocks on there. Then when I put the weber plates on there, I was able to remedy it with my pump cam modification. But now it is doing it with the Jmark spec'd blocks and I am using the white cam up front and a modified brown cam in the rear. On a good note, car ran its fastest ever at the midland track by .03 and 1.5 mph, but in 2500 worst air. I plan on putting a powervalve in there to get the launch to clean up a bit. When this prevously happen with the tuner blocks, I did try the flute, but it didn't help.
Any ideas?

Thanks in advance.

Image

Here is a link to a larger pic.

http://farm8.staticflickr.com/7209/6830353038_71b9bb75aa_o.jpg

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 Post subject: Re: Help with Carb
 Post Posted: Mon Mar 12, 2012 11:50 am 
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Here is the log from the tuner blocks way back when. Looks very similar.

Image

http://farm3.staticflickr.com/2571/3767981039_6dec665934_o.jpg

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 Post subject: Re: Help with Carb
 Post Posted: Mon Mar 12, 2012 1:50 pm 
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Footbrake launch?


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 Post subject: Re: Help with Carb
 Post Posted: Mon Mar 12, 2012 2:08 pm 
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Yes, Plan on putting a powervalve in there to try and clean it up a bit.

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 Post subject: Re: Help with Carb
 Post Posted: Mon Mar 12, 2012 5:56 pm 
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So I was out there looking at the carb. I had tilted it up front and noticed fuel rush out of the boosters. So I fill the front fuel bowl up till it leaks out of the sight hole. Put my handy dandy angle finder on there. I found at 18 degrees, It starts flowing pretty good. Stick my angle finder on the car and find the carb sits 2.5 degrees toward the back. So the angle would only have to change 15.5 degrees before it would start flowing on its own. And this does not take into account g-forces.

So should it do this and secondly, do I have my float levels set too high?

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1/8   6.15@110 NEW BEST 27 Nov 11
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 Post subject: Re: Help with Carb
 Post Posted: Tue Mar 13, 2012 8:23 am 
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I hear crickets,

No opinions huh,

Well the plan is to lower the float level a bit and install a powervalve. We will see what happens on friday.

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1/8   6.15@110 NEW BEST 27 Nov 11
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 Post subject: Re: Help with Carb
 Post Posted: Wed Mar 14, 2012 5:55 am 
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we keep our float levels just below the opening.

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 Post subject: Re: Help with Carb
 Post Posted: Wed Mar 14, 2012 8:06 am 
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Location: Montgomery, Alabama
Are you using the built in RPM channel on your logger?
It has a lag in the RPM scale.


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 Post subject: Re: Help with Carb
 Post Posted: Wed Mar 14, 2012 8:06 am 
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Also see if it does it on a trans brake launch. That would rule out the pump shot.


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 Post subject: Re: Help with Carb
 Post Posted: Wed Mar 14, 2012 8:26 am 
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Mount it sideways! O:) I'm going to consider doing this when I switch to a single carb some time this season. I have seen a few single carbs mounted that way. ;-)

If you search here for the word "sideways" and my username you'll see where this has been discussed before.

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 Post subject: Re: Help with Carb
 Post Posted: Wed Mar 14, 2012 12:08 pm 
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Yes I am, Where are you seeing the lag? I know of the shift, it tends to round it off a bit. I will hit it off the button to seen on friday night. I seem to remember trying that before and it was still there with my previous metering blocks.

I will take a look at that stuff ken. I just know people use these carbs on a lot faster cars and don't have issues. I know this thing will lay down some good numbers once I get it clean the entire run.

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Best 9.87@131 on the rev limitor 1 Feb 2013
1/8   6.15@110 NEW BEST 27 Nov 11
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 Post subject: Re: Help with Carb
 Post Posted: Wed Mar 14, 2012 1:24 pm 
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There is significant delay in the RPM channel compared to the others. Talk to Greg Kelly or Donee. The fix was to move the engine RPM off that channel to another that can be configured for RPM. I'm assuming this is a DL32.


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 Post subject: Re: Help with Carb
 Post Posted: Wed Mar 14, 2012 2:13 pm 
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Yes this is a dl32. Can you point at where you see this? I will contact them.

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Best 9.87@131 on the rev limitor 1 Feb 2013
1/8   6.15@110 NEW BEST 27 Nov 11
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 Post subject: Re: Help with Carb
 Post Posted: Wed Mar 14, 2012 4:40 pm 
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Quote:
Can you point at where you see this?


I found it when my MSD and autometer tach were saying I shifted at 7950 and the DL32 said I shifted at 7600.

My tach showed 6900 flash on the converter and the DL32 showed 6700.

The weirdest part was the log showed the engine never made it to the chip before the transbrake released but it was easy to tell by ear it had been on the chip for a half second.

With no other changes other than switching to a Racepack you can see it is on the chip steady for a half second before the brake releases.

http://bumracing.com/albums/album01/run.jpg

I guess you could call that RPM channel Lazy.


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 Post subject: Re: Help with Carb
 Post Posted: Wed Mar 14, 2012 5:43 pm 
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I see similar stuff, it shows it shifts before the shift chip, Sometimes it rounds off the shift point. Its weird because I can take my msd tester and everything will read exactly the same. But when the car is running, it seems to read 100-200 rpms off.

I am still waiting to hear from greg, donee's problem was different than this, he would lose segments of data through out the run.

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Best 9.87@131 on the rev limitor 1 Feb 2013
1/8   6.15@110 NEW BEST 27 Nov 11
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