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PostPosted: Sat May 12, 2012 10:42 am 
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Took both cars up again last night. Updated the Duster with 2 1/2" exhaust and re-jetted the 2100 with #52 jets. Updated the Dart with .104 jets in the secondaries.

The Duster loved the changes and ran a best of 10.595. It picked up 3 tenths and 2 mph over the last outing. Deb is also running very consistently with her practice runs within 1000ths of each other at 10.69.

The Dart on the other hand didn't like the jet change and was all over the place. The best being 9.33 and the worst at 10.3. I think I have found an underline problem with fuel delivery. When it ran the 10.3 it felt like it ran out of gas. It would rev to 5000rpms and then just die on the shift change.

Deb came in second in her bracket and I eeked out a third in mine.


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PostPosted: Thu May 17, 2012 9:28 pm 
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Tomorrow is another race night, so I went out and did some per-race tuning tonight. Changed the secondary jets back to .101's to try an get some consistence and adjusted the floats. Changed out the fuel filter and installed a fuel pressure gauge.

According to various web sites the formula for determining fueling requirements is a follows: (( hp x .5 ) / 6) = gph. So the Wallace racing calculators indicate that I am putting out around 200 hp.

To support 200 hp you need 18.5 gph of fuel. A few years ago Doug gave a guesstimate that the stock fuel pump put out around 40 to 50 gph so everything should be OK. So back to the fuel gauge. When I started up the car, the gauge registered around 3.75 psi. When it was revved up to 2000 rpms the gauge dropped about 2 psi. Hmmm... I believe that I have found a problem.

So the $20 parts store pump doesn't have what it takes to feed this engine. After browsing the Summit catalog, and considering all possibilities and there costs, the only reasonable fix, is to install a BBM pump.

Accept nobody has really outlined what needs to be done to do that. What brand should be used, Carter, Holley or ???. What \6 pump arm needs to be swapped or grafted on. How do you do this exchange, cut and weld, disassemble and swap. Inquiring minds would like to know...


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PostPosted: Thu May 17, 2012 11:54 pm 
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Why not use an electric pump.

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PostPosted: Sat May 19, 2012 9:05 am 
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Cost, by the time you get done wiring, plumbing and other assorted stuff. It is quiet an investment. I figure that an electric fuel pump installation done right would cost at least $200, and it goes up from there. For that type of money I would rather invest in a fuel system for EFI.

NAPA Online shows a slant pump that is rated at 23 gph with a 4.5 to 5.5 psi for $25. They have a "high performance" pump for the 440 with a 33 gph with 7.5 to 8.5 psi for $10 more. If the slant pump doesn't work, the 440 pump is only $35 more with an unknown modification. One of these would work "good enough".

Last night we ran again. With short shifting the car at 4500 rpm, I was able to keep the bog to a minimum. This produces a 9.3 to 9.4 eight, it also cost me 1st place.

Deb was able to WIN!! She came in first. YEAH... The other guy red lighted, then he floored it. Hmm, he is capable of high 9s in a 10 second bracket. An interesting strategy becomes clear. Get the Duster to run 10.2 or a 10.1 and get the other guy to match or break out. Something that I am trying to employ in my own bracket.


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PostPosted: Sat May 19, 2012 10:50 am 
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EFI Slant 6
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kesteb wrote:
Deb was able to WIN!! She came in first. YEAH... The other guy red lighted, then he floored it. Hmm, he is capable of high 9s in a 10 second bracket. An interesting strategy becomes clear. Get the Duster to run 10.2 or a 10.1 and get the other guy to match or break out. Something that I am trying to employ in my own bracket.


GREAT!!! But I thought ALL bracket racers knew this little tid-bit of info... I figured that out the very first bracket races I participated in. Of course I personally knew some of the participants so I basically knew what their cars were CAPABLE of but no where near the dial in they used... It will bite you from time to time, and I never tried the sandbag routine myself, my car wasnt very consistent, so i just guessed from round to round, and usually did ok for the most part.. if ya run it as hard as ya can every time, and can be consistent thats what wins... not the sandbagging.

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PostPosted: Sat May 19, 2012 12:33 pm 
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This is not NHRA bracket racing. This is "run what you brung" within a specified time slot

Deb runs in the 10.0 second or slower bracket which is defined as bracket 1. The fastest car in the bracket wins. So "sandbagging" does work. The only way to beat the other guy is to go faster or make them break out. Where breaking out is defined as going faster then 10 seconds.

Since the leader of the bracket 1 is actually a slow bracket 2 car, he can pace the other cars and win. We now know how fast he can really go. Thus the above strategy.

I am following this strategy in bracket 2. Bracket 2 is from 9.0 to 9.99 seconds. I am currently the leader. The best that I have done is 9.1, but it is not consistent, because of the fuel delivery problems. I am vulnerable to slow bracket 3 cars that are "sandbagging". Which happened last night. I wasn't fast enough to force a possible break out with a slow bracket 3 car. But he was fast enough to stay ahead by a bumper.

On the fuel delivery problem, I just picked up the NAPA fuel pump for the slant. We will see how this works.


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PostPosted: Mon May 28, 2012 8:26 pm 
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I put in the new pump this weekend. It looks the same as the one from O'Rlieys. Started up the engine and it is reading the same pressure. Hmm, I guess we will find out Friday wither it is any better.

Popping out the pump arm out of the old pump was not hard. The pivot shaft is only swedged in, the hard part will to be getting it to stay in place.


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PostPosted: Fri Jun 01, 2012 6:59 pm 
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Rained out tonight. This is an interesting link to building a quality fuel system.

http://www.centuryperformance.com/fueli ... g-140.html

And it is not a Barry Grant propaganda piece.


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PostPosted: Fri Jun 08, 2012 10:55 pm 
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Rebuilt the 2100 on the Duster. The best 40 bucks that I spent on the car so far, also adjusted the kick down linkage to hold the transmission in gear longer. Higher revs, more power, faster times, or at least that is the idea. We will find out next Friday.


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PostPosted: Sun Jun 17, 2012 5:08 pm 
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Friday night wasn't quite what we expected. We picked up a couple of 10ths with the carb rebuild and lnkage adjustment. But now the Duster is running too rich. I guess the new power valve is working...

I can definitely say that a part store replacement fuel pump can not keep an Edelbrock 500 AVS fuel bowls full. The Dart was all over the place time wise. If I run at 4500 rpms or below there is no problem, but I can't win at the level.

So in the spirit of doing all the wrong things, I pulled the Offenhauser off the Dart for replacement with the Clifford. This should be a big improvement, it should suck gas much faster.

Just a FYI, a Clifford adapter plate will work on an Offenhauser, but not the other way around. The Clifford adapter has slots were the bolts hold the adapter to the manifold so they can align with the slight differences between the bolt patterns.


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 Post subject: Yep...
PostPosted: Sun Jun 17, 2012 7:09 pm 
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Quote:
The Clifford adapter has slots were the bolts hold the adapter to the manifold so they can align with the slight differences between the bolt patterns.


That's due to quality control being not too great in the last 10 years...

Make sure to goop the slots shut before you put the carb gasket on the adaptor plate or you will get some mystery vacc. leaks...

:wink:

Kind of curous how come the stock fuel pump can't keep the eddy happy,
I've never had the stock fuel pump let me down with a 600 Holley and I know that carb likes gulping down the go juice...

-D.Idiot


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PostPosted: Sun Jun 17, 2012 8:02 pm 
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I run Ruster into the 12.20's with a Eddy/ Carter AFB 750 on a stock mechanical slant 6 fuel pump ... no issues.


Greg

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PostPosted: Mon Jun 18, 2012 8:42 pm 
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Then I wonder why it doesn't seem to work for me. The fuel pressure at idle is 4psi. When revved up it drops to 2.5psi. What are you guys getting pressure wise?


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PostPosted: Mon Jun 18, 2012 8:44 pm 
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Kevin,
Have you changed the fuel filter?
Presure drop doesn't mean it's not getting the volume of fuel to the carb.

Richard

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 Post subject:
PostPosted: Mon Jun 18, 2012 9:21 pm 
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I have never checked the pressures on my setup...

Probably never needed to so I haven't.


I would check your fuel filter in the Engine bay and the sock filter in the tank.



Greg

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