Holley Sniper 2300
I was having some issues with getting the Weber Carb and the Supercharger balanced out correctly so I started looking at the Holley Sniper 2300. I had emailed Holley a while ago asking if it would work on a Supercharger and he said it would and I checked with LCE Performace and they said they did it and it worked without any adjustments so I went ahead and ordered it. I double checked one more time with Holley and found out they meant a blow-thru Supercharger (I'm new at this stuff and didn't even know a Blow-thru Superchargers existed, so I'm learning on-the-fly here.) So I kind of freaked out because the Sniper was on it's way and I was really bummed it wouldn't work. I then double checked with LCE Performance and they assured me it would work so I kept my fingers crossed. In the mean time I tried to find out more from Holley why it wasn't suppose to work. They said the only way to make it work properly would be to somehow get the Manifold Air Pressure after the Blower back to the computer in the Sniper. So I started looking at how the Super Sniper worked and noticed all they did (that I could tell :-) ) was add an optional side port to get the MAP from a remote location and block off the bottom port. So worst case (in my head) I thought I could drill a hole and add a barb in the same location as the Super Sniper and block off the bottom port.
I started with the fuel system first. I removed the fuel tank to get a better understanding of how it all worked. I found out I already had a return line so I didn't need to add the supplied equipment to add one (which was great because I wasn't looking forward to drilling a hole in my fuel tank)
Next, Identifying the lines and finding a good location for the new electric Fuel Pump and Filters.
Holley recommends 3/8" fuel lines which I ran to the Sniper but kept the small factory Return line. This worked but made some back pressure so I removed the small but nice metal lines and then ran a 3/8" Return Line and that did the trick, perfect recommended Fuel pressure.
Now I could remove the Mechanical Pump and add the Block-Off Plate.
Next was removing the Weber Carb & Adapter and adding the Holley Carb Adapter to the Supercharger.
Next, Figuring out the Throttle linkage, Fuel line routing and Wire routing. (Don't make fun of my fuel line routing laying on the wheel well lol, I later did it correctly with Earl's 90deg & 45deg connections. :-) )
Next I found a good place for the Touch Screen Controller but I had to remove my beloved Alpine keypad (but it wasn't really working anyways.)
Okay time to add the Air Filter and fire it up! It worked! But it did take months of adjustment and a stop at a local Speed Shop to learn some stuff about tuning and programming it. I also ended up adding a port in the side for remote MAP which I'll describe in a bit.
I was still having some issues with it stalling after letting off a spirited throttle so I thought I would try to Remote the Manifold Air Pressure to the actual manifold behind the Supercharger.
So I removed the Sniper, Drilled a hole in the side and closed off the bottom port with a set screw. I added a small piece of tubing to come out the side so I could attach a hose to it. I later ended up threading the hole and added a barb connection which was more secure.
Then put the set screw in to block off the bottom port, I also took a small punch and peened around the set screw to keep it from backing out like the SuperSniper instructions suggested.
Then added a connection at the manifold. I later changed the barb size to a little bigger one than shown.
Also you can see in this picture I made a little extension arm on the carb for the throttle cable connection because the gas pedal was extremely sensitive (almost like, all on, or all off, type thing)
This almost seemed to do the trick for the stalling but after a few days of driving it starting doing it again, maybe a little less, but still stalling. I took it to Chuck's Speed Shop for some help (They were excellent, very nice and patient with me). They weren't all that familiar with a Sniper on a Draw-thru charger either but hooked me up to their computer and did some adjusting the best they could. They were able to re-calibrate the MAP software to show scaling above 100 kPa so I could set the A/F ratio for Boost. We were going to dyno it too but for some reason there was too much noise in the system so we couldn't get any readings. (I later found out I had a broken Alternator bracket which is also used as a Ground connection so I'm sure that's what the issue was)
I learned a lot about a lot there at Chuck's Speed Shop and had some homework to do in regards to getting the timing under control better but it was still occasionally stalling off a hard throttle (update: the stalling had to do mostly with timing which I was finally able to get control of later (and described in another post below) ,thanks to Eric at Chuck's who kept pushing me to get better control of the timing) . In the mean time I was in contact with Ethan P. Moss at Holley and he has been very patient with me also and has been excellent at suggesting and explaining things to do like "Increase your IAC ramp decay time by a second, and increase your RPM above idle to start ramp to 1100RPM see how that treats it. You’ve added a lot of plenum volume with the blower so idle recovery needs to soften up. & The initial fuel curve is typically a little rich, a little safe that way, and the system tends to lean out as it learns"
I eventually combined what I learned at the speed shop and what Ethan had explained and put the IAC Hold Position way up to 55% and the IAC Ramp Decay way up to 9.0 sec and IAC Ramp Start up at 1300 RPM and then turned the self-learning off. And this finally seemed to do the trick for now :-) It helped alot with the stumble coming off a throttle, but still seemed kind of like a band-aid. I don't think the Sniper likes my Manual-Clutch / Supercharger combination.
Overall I'm really glad I did the Holley Sniper, No more backfiring, Easy perfect starts, No stalling off-road at extreme angles or large bounces and the black soot type stuff that shot out the tail pipe at startups is completely gone now and The amount of available adjustments is incredible (all from a touch screen none the less :-) Oh and some more Power now too!.
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