Tuning help
Thread Starter
Teching In
Joined: Oct 2012
Posts: 9
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From: Penna
Tuning help I'm running a stock 4.8 with a new 625 cfm street demon carb, looks like a old thermoquad. I can't get this thing to loose the flat/spot, hesitation when I floor it. It doesn't take off right away, a pause then it go's. Also when I go to start it up after being warm it idles at 500 rpm then sits at normal 750 rpm. Fuel pressure? Set at 4.5 psi, bad carb choice? Need help alittle puzzled
I would run 6 psi minimum. Otherwise, you probably need a bigger charge of fuel when you stab it. A 31 squirter is doing great on my 86 TA with a cammed 5.3. On my 94 gmc 4.8, stock, I had hesitation, I did not have a larger squirter but did have a 50cc accelerator pump, it worked as well.
I think it probably was a bad carb choice, unless you can really step up the tip in fuel charge. LS motors love to injest air (thats why they run so hard) and need a big pump shot when you slam it to the floor.
