SLE Issue

March 28, 2021, 09:22 AM

chasracer

SLE Issue

I finally got a go with my SLE but it appears I have some binding or something. It's slow to open the carb. I plan pulling the carb later today and start looking for problems - anything I should be aware of?

K&R Box, K&R Pro Stage unit.

March 28, 2021, 09:37 AM

Cashflow

Make sure you have plenty of air pressure and make sure you lube the cylinder once in awhile. And of course, do what you're fixing to do and make sure nothing is binding. Good luck!

March 28, 2021, 09:47 AM

chasracer

quote:
Originally posted by Cashflow:
Make sure you have plenty of air pressure and make sure you lube the cylinder once in awhile. And of course, do what you're fixing to do and make sure nothing is binding. Good luck!

I was down to about 750-800 pounds yesterday when I tried it - how much is plenty as it has a 100 psi preset Biondo regulator?

March 28, 2021, 10:34 AM

Lenny5160

100 should be good, and I usually look to fill the bottle when it gets down in the 400 range.

My Terminator is sprung so tightly that it’s hard to whomp with any precision, but the SLE is always lightning quick.

Can you verify that the regulator is really giving you 100 psi?

March 28, 2021, 12:19 PM

Goob

quote:
Originally posted by chasracer:
I finally got a go with my SLE but it appears I have some binding or something. It's slow to open the carb. I plan pulling the carb later today and start looking for problems - anything I should be aware of?

K&R Box, K&R Pro Stage unit.

I'll assume you've studied the instructions?

The throttle opening rate is adjustable, and there's a note that you should measure the amount of throttle pull required.

Just sayin'

March 28, 2021, 12:53 PM

chasracer

A couple of times but it says that the rate is already factory set at the fastest speed. And I don't have a pull scale to measure the poundage rate. Just working the carb by itself, the first 3rd seems fine, then it takes a bit more effort, then it finishes over the last bit opening easily.

March 28, 2021, 03:21 PM

chasracer

Update:

Rigged up a poor-man's test rig and was only showing 80 pounds of pressure on the output side. Figured out that the .030 shim in the regulator was worth about 10 psi. Tried a .045 shim and that got my up to 90 psi, so combined the two and ended up at a touch over 105 psi. K&R says 100 psi, max 120 so that should take care of that issue. Now on to the carb and see if that deal is messed up.

March 29, 2021, 07:02 PM

chasracer

Carb proved to be okay, nothing twisted or bent. Put it back on and tested and the carb opens immediately now.

Next I need to increase the RPM slightly when staging. I read instructions a couple of times, guess it'll make more sense when I try it.

March 31, 2021, 06:08 PM

David Friedenberg

Been tweaking on mine. Slowing it down a bit. On SLE my RPM is set ~1300rpm.

Assume you're working with a Biondo kit.

March 31, 2021, 07:14 PM

1320racer

quote:
Originally posted by chasracer:
K&R Pro Stage unit.

April 08, 2021, 07:24 AM

chasracer

Well, thought I had this fixed but it seems that full accelerator pumps put enough load on it that it was still a touch slow. I had tested previously after removing (and draining) the carb and the pumps were not full. I tested it again after raising the pressure - I'm at 117-118 now and it is working okay again. I have put a couple of drops of lube in the cylinder but I wonder if the morse cable needs to be cleaned?

April 08, 2021, 07:51 AM

CURTIS REED

quote:
Originally posted by chasracer:
Well, thought I had this fixed but it seems that full accelerator pumps put enough load on it that it was still a touch slow. I had tested previously after removing (and draining) the carb and the pumps were not full. I tested it again after raising the pressure - I'm at 117-118 now and it is working okay again. I have put a couple of drops of lube in the cylinder but I wonder if the morse cable needs to be cleaned?

If it is the cable causing a problem look at the silver jacket cables that The Chassis Shop sells. They are really smooth and will tolerate a tighter radius bend without as much drag.

April 08, 2021, 08:20 AM

chasracer

Thanks for the info.

My cable runs straight back and then takes a gentle arc over the rear of the trans and up to the carb. I can disconnect it from the carb and move it easily with my fingers - and that's with the pedal still attached.

April 08, 2021, 02:56 PM

JAFR

What kind of angle is there between the SLE cylinder and the throttle linkage on the carburetor? If the angle is too great it will take more pressure to open the linkage on the carb. Where do you have the cylinder mounted on the carburetor linkage, the higher it's mounted on the linkage the easier it will be to pull open.
The cable should not be an issue, when your foot is on the floor the cable is pulled as far as it's going to go. the air cylinder is doing all the work once the SLE is engaged. You might check the pressure at the cylinder itself, maybe you have a kinked line?

April 08, 2021, 05:02 PM

undacuva67

large bore cylinder = fixed

April 08, 2021, 06:25 PM

chasracer

quote:
Originally posted by JAFR:
What kind of angle is there between the SLE cylinder and the throttle linkage on the carburetor? If the angle is too great it will take more pressure to open the linkage on the carb. Where do you have the cylinder mounted on the carburetor linkage, the higher it's mounted on the linkage the easier it will be to pull open.
The cable should not be an issue, when your foot is on the floor the cable is pulled as far as it's going to go. the air cylinder is doing all the work once the SLE is engaged. You might check the pressure at the cylinder itself, maybe you have a kinked line?

Cylinder is dead level with the cable connection. All the lines are smooth and mostly straight or gentle curved.

I have a race next weekend so we'll see how it goes.

April 08, 2021, 08:03 PM

SP 124X

quote:
Originally posted by chasracer:
Well, thought I had this fixed but it seems that full accelerator pumps put enough load on it that it was still a touch slow. I had tested previously after removing (and draining) the carb and the pumps were not full. I tested it again after raising the pressure - I'm at 117-118 now and it is working okay again. I have put a couple of drops of lube in the cylinder but I wonder if the morse cable needs to be cleaned?

You are definitely having an issue. I only run 80psi to my sle but mine is the large cylinder. I have to ask are you saying it's a touch slow because it barely hitting the chip before the car leaves or just cycling it? If on track you maybe be actually having a stumble because the rpm is too low or you're actually snapping it open too fast.

April 09, 2021, 06:04 PM

SP 124X

Just looked at the K&R site if your SLE is actually plumbed with 1/8 line from the solenoid to the cylinder I'd try it with 1/4 line.