I just installed a Radix a couple weeks ago and am having some issues getting it to run right. It's on an '03 ECSB Z71, 5.3.

The guys at Magnacharger are being super good though and helping me out...I just wanted to throw some questions out to get even more input.

The first thing that isn't quite right is that this thing is producing about 8.5 pounds of boost when it winds up to 4500+ RPM! It still has the stock 3.4 pulley on it. Needless to say, the truck pings quite a bit when you get on it. This is happening with the stock air box, TOG headers, and a Borla Catback. The truck has 33K miles on it, mostly highway. Magnacharger is sending me a 3.6 pulley to bring the boost down. Just wondered if there were any other ideas out there other than just a freak blower.

Next question, what should the fuel pressure be at an idle? It idles at about 43psi and then runs up to 60psi when your foot is in it.

Next question, is hard starting normal with this kit? I have to turn the key at just the right time after the fuel pump runs to get it to start without it cranking a lot. A little too soon or too late and she has to crank quite a bit. The fuel filter is new, heck, it did this even when we bypassed the fuel filter trouble-shooting something else. Before the kit the truck started consistantly fine.

Anyway, that is about it. Thanks for any input!

 

when i installed my whipple kit, they said the fuel pressure should be around 50 psi at idle with the vaccum hose disconnected. and it should run at 62 psi minimun at full throttle. (vaccum line connected) aslo, radix supergers send a inline fuel pump to keep pressure up. im sorta thinking your inline pump isnt working, so your having a loss of fuel pressure. your stocker is having to push fuel through a non workin pump thus causing hard starting from lack of fuel. Of course, i dont own a radix kit, and this is all just speculation. hope it helps!

 

For your CR, I would think 8.5lbs of boost would be fine. are you hearing ping, or are you monitoring with some type of software?

Your fuel pressure sounds normal.

 

oh yeah,, lack of fuel at higher rpms would hurt performance and the engine maybe. also,, wouldnt lack of fuel also cause pinging too? hope ya find it!

 

Check for a clogged cat, do a backpressure test on it. Sounds like something is corked up on the exhaust side, I only had 7 lbs of boost on mine. Mine ran like *** at first, but after sending it to magnacharger it suddenly fixed itself (they said no problem found)

 

Thanks for the input. No software to monitor yet, but she definitely pings when the RPM's get up there...rattles like a tin can with rocks in it!

Retsell, I've been following you thread really close.

FYI...The guys at Magnacharger said it should only be producing 6.5 - 7 psi.

Thanks guys!!

 

I'm agreeing with the stopped up exhaust. Try running it with the Y-pipe off just for grins and see if the boost is down to 'normal' levels. You should see just over 60psi on the fuel at WOT. Should be around 62 or 63.

Are your headers coated?

 

Yes, the headers are coated.

I guess the is as good an excuse as any to see what she sounds like with open headers!

 

Yup ... be careful though cause if it's knocking .. you won't be able to hear it.

 

When I got my headers they were full of crud - I blew all that out before install, if I hadn't I'm sure the cats would have caught at least some of it and clogged up, espcially stock cats......

but it seems like the fuel pump is working, I mean if it wasn't it wouldn't go up to 60psi right?