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Maxed out Weldon 600A?

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Old Mar 21, 2006 | 02:39 AM
  #1  
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Default Maxed out Weldon 600A?

I doubt that is it but tell me what you guys think

Car is making 675/650 rwhp on our Mustang dyno.

Has a hotwired 600A pump pressure been from 53 to 63 with vac line off. Moto 60s, boost referenced


Car is PIG rich (and I cant get it to lean out much) below 4500 rpm like 9.8 to 10.2:1 at 10 psi setup and 13.5 psi setup. (D1SC car) on the higher boost however it goes wayy lean, duty cycles are high so I didnt want to try to fuel it any more with the injectors, so I figured Id turn the pressure up to get the duty cycle down and the pump should handle that. Upped from 56 psi to 63 and it actually got a little worse.

Upping pressure makes it easier on the injectors but harder on the pump, I would normally take that (how this car responded) as a sign of taxing the pump but I wouldnt think that would happen at this power

What really makes me think is I have a stock returnless setup car here, no boost reference, with a hotwired walbro, right around 11.7:1 a/f seems pretty happy. Its making within 35 hp of the other car, both D1SC cars at very similair boost levels. Injector duty cycles are almost IDENTICAL throughout for both cars, but the one just goes lean up top
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Old Mar 21, 2006 | 09:00 AM
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Originally Posted by GrannySShifting
I doubt that is it but tell me what you guys think

Car is making 675/650 rwhp on our Mustang dyno.

Has a hotwired 600A pump pressure been from 53 to 63 with vac line off. Moto 60s, boost referenced


Car is PIG rich (and I cant get it to lean out much) below 4500 rpm like 9.8 to 10.2:1 at 10 psi setup and 13.5 psi setup. (D1SC car) on the higher boost however it goes wayy lean, duty cycles are high so I didnt want to try to fuel it any more with the injectors, so I figured Id turn the pressure up to get the duty cycle down and the pump should handle that. Upped from 56 psi to 63 and it actually got a little worse.

Upping pressure makes it easier on the injectors but harder on the pump, I would normally take that (how this car responded) as a sign of taxing the pump but I wouldnt think that would happen at this power

What really makes me think is I have a stock returnless setup car here, no boost reference, with a hotwired walbro, right around 11.7:1 a/f seems pretty happy. Its making within 35 hp of the other car, both D1SC cars at very similair boost levels. Injector duty cycles are almost IDENTICAL throughout for both cars, but the one just goes lean up top

My 600A pump (60psi) maxxed out at around 700RWHP on a DynoJet. I had to throw a lot of fuel through the injectors to compensate. I disconnected my boost reference also and I am using 75 lbs injectors. I am running a -8 supply and a -6 return from the regulator. My rails are plumbed in series.

You may also check for boost leaks. My car was going way rich right at 4500 and I found I had two different leaks in my fmic system.

I hope this helps.
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Old Mar 21, 2006 | 09:01 AM
  #3  
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"Upped from 56 psi to 63 and it actually got a little worse." Sounds like you're out of pump. Look at the fuel curve of that pump on the Weldon site for actual lbs/hr.....doesn't flow what you need at that psi.
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Old Mar 21, 2006 | 09:04 AM
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http://www.weldonracing.com/600a_chart.html

Great pumps, but if you boost reference them for big power through 60lb mototrons, you really need two pumps.
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Old Mar 21, 2006 | 09:17 AM
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Originally Posted by onfire
http://www.weldonracing.com/600a_chart.html

Great pumps, but if you boost reference them for big power through 60lb mototrons, you really need two pumps.
Apparently 75lb RC injectors too.
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