Swap fuel plates to help lean out bottom end response?

Hurley

Hurley

BLAKLUNG
SO I acquired what appears to be a gov spring from a 180 pump, installed it in my afc tonight, and Whoa yeah!... However I'm still fairly smokey off the bottom. Here's where I'm at:
- "0" plate full forward
- new AFC spring, factory shim underneath. Modified factory diaphragm washers
- foot has been shaved ~.100"
- dialed in the starwheel to allow afc foot to bottom on housing right before coil bind
- pre-boost screw barely touching afc shaft (any tighter and it's going to make the situation worse)
- full travel right at ~42psi


My Issue: the spring is shorter than the stock spring, so it puts the foot farther forward at rest; in an effort to keep maximum fuel delivery I installed the afc housing full forward on the pump. This makes it soggy off the bottom, but like i said, I absolutely love the response once it gets moving.... Could I swap my #0 plate to something like a #6 and lean out the bottom a bit more? Or would that pull more fuel than I think?
 
Odd, that spring should be a bit longer.....another thing to add is a small washer (think a M8 with a small circle) under the inter AFC washer to allow further travel prior to bottoming out but at the cost of coil bind, back off the star wheel to cure that.

One thing I do it try to get the bottom end fuel so faint that it creates turbo lag, then with the pre-boost screw creep up on it 1/2 turn at a time till desired response. A #6 is a good plate with a soft bottom end but you have to raise the foot all the way to the top for it to be right (insert dropping all that crap...screw, nut, washer, in the pump and fishing it out via magnet) might try a 5 instead but I have no experience with it, shape is shorter than a 6 and should be a little more fuel on the bottom.

A zero is a PITA, hard to tune cause it is all in the AFC, other than that it is on or off!

Jim
 
What about trying a 100 plate? Could you heat the spring and stretch it? Just some thoughts hope you figure something out.
 
^^Jim, I tried the small washer trick (worked well on my previous spring combo), but it puts the foot even farther forward

^wildman, I'm clueless on choosing plate profile at the moment... to be honest I dont want to touch the spring because of its current rate, I'm worried about not doing it just right and ****ering it up. If I had another one just like it I would do it for sure.... but this one was found laying around in a friend's garage and neither of us knows where it came from haha
 
Just back your preboost out some more. Mine doesn't touch the diaphram.

You might just need to slide the housing back some. If its too far forward, nothing you do wil clean up the bottom, at least on my pump that's the case.
 
Shaved foot equals no no. I would try to find an unmolested afc foot if that is an option. You can likely work around it but every fuel setup is different. With the current 7mm comp delivery valves and 5x16 155 injectors even with an afc spring which is at full travel by ~7psi my setup remains ultra clean and responsive unless I come out of my seat pressing the fuel pedal to the floor in less than .02 seconds lol. Light spring is in due to my diaphragm being torn currently and an up coming track visit is approaching and don't want the afc getting in the way of fuel rack at the track. I plan to place back a heavier spring when an intact diaphragm arrives.
 
bsmith said:
Just back your preboost out some more. Mine doesn't touch the diaphram.

You might just need to slide the housing back some. If its too far forward, nothing you do wil clean up the bottom, at least on my pump that's the case.
Click to expand...


I will try that... Iwas concerned that I would be limiting full rack travel if I peel it back even more
 
bsmith said:
You might just need to slide the housing back some. If its too far forward, nothing you do wil clean up the bottom, at least on my pump that's the case.
Click to expand...


I'm pretty sure a 5-6 plate would limit rack travel in this area, regardless (now that I think about your post)
 
Well the 100 has that little ramp at the bottom that keeps the fuel low after the afc is out of the way. That's why I said may try it. On the spring I understand, I wish I had some different springs to try out in mine. I was gonna get a afc spring kit but everybody says they are too short as well. So you still would have smoke down low. I hope you find something, I might need a reference sometime. LOL
 
the springs from the TST kit are actually longer than stock (there's a thread with pics), but depending on starwheel position/ overall boost desires, etc. they dont have enough ass.

none of the springs could get me the fueling 'curve' (boost vs afc foot position) I have been after.

I jsut dont like the looks of the 100 plate... but I assume people are running it with some level of success. The hard part is that every truck's setup is different so your truck might not like my spring and my truck might not like yours
 
Ive got a 10 plate and numerous stock plates I could send you to experiment with. You cut a few of your own profiles and find out what plays best.
 
+1 for CSnyder, I will be testing (i.e. playing) around with a few plate profiles and posting results


(probably over the course of the next month or so)
 
421592_10150838358028662_509218661_12567887_1524075610_n.jpg


heading out UPS to you.
 
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