HighSon

I don't know if an OBD2 scanner will work, but I suspect not. This will, however: Tiny-Scan 301 for Delphi ECU Using Tiny-Scan 301

Better pic of windshield vent...

Haven't posted in a while since solving the excessive cabin noise issue, so I thought I would share a few upgrades to my Sector... Realize that this is driven daily on the street, so some of the mods are to make it more streetworthy. Locking gas door. Rear view mirror. Modified windshield for better airflow in cabin. Lowered and modified headrest bar for improved rear view. Tailgate protector. Folding armrests. Overhead utility rack. Keeps the interior cooler and dryer, too! Folding rear seats. Dust cover and seat protector. If anyone wants links to the rear view mirror, seats, or arrests, let me know and I will post. But know that everything requires some level of fabrication. The utility rack was all custom built. Cheers!

Ok I did finally manage to get some sound deadening installed in my 750. The product I used is a 200-mil peel-and-stick asphaltic/closed cell foam composite from Siless (available on Amazon). I installed it on the panel directly behind your hips (between the seat base and seat back) on the engine side; on the panel behind your legs between the floor and seat base inside the cab; and on the three access panel covers under the seat. I didn’t really feel like disassembling the cab to install the material on the engine side of the panel behind your legs, and I will likely make an aluminum cover panel over it in the cab to protect it from getting damaged, but it worked fine installing on the inside. I have not had a chance to check dB levels yet, but I would say overall the cab levels have been reduced again by a similar reduction realized with the silencer. So I’m pleased with the results and the UTV is much more pleasant to drive.

Nice write up, thanks. For those that cannot fab an exhaust outlet, the Silent Rider silencer includes an adapter similar to the one you made while ditching the spark arrestor. I believe you can order just the adapter as the silencer itself is pretty pricey. [For install see my write-up on addressing high cab noise in this forum.] I have not noticed the level of heat causing damage in my 750 but I had very low hours on it prior to removing the spark arrestor and installing the silencer. I have also considered adding some type of reflective heat shield under the bed, such as aluminum diamond plate, which would also serve to further reduce cab sound levels.

I’m posting this in case someone else has a Hisun in an environment that’s very dusty, muddy or wet and is looking for a method to protect the switch panel. My Sector is street driven daily with lots of dirt roads, dust, rain and mud. Plus I wash out the cab regularly. And while I’m sure that the switches are ok to get wet, over time with the grime I’m equally sure they’ll fail. So I fabbed up a clear plastic switch cover. I’m on an island in Central America, so I didn’t have access to any sheet lexan or acrylic to make the cover itself, but I found one of those clear refrigerator food storage bins of about the right size at the local hardware and cannibalized it. I used a piece of 1/4” aluminum angle and a piece of stainless piano hinge that I had laying around in the shop to make the mount and the hinged attachment. It works well and it’s easy to slip open whenever I need to turn something on or off. Open at the bottom for cord connections should they be needed.

Ok sorry this took me a bit longer to post, but here are sound level results…not terribly rigorous but it gives an idea of the relative difference. Readings are on an iPhone with the NIOSH SLM app. As you may know, decibel scale is logarithmic not linear so the difference in sound level monitored is noticeable. To my ear, still too loud in cab, but you can at least talk loudly and hear with a passenger. Stock 750 exhaust: 76 dB in cab at idle at driver chest level 93-95 dB in cab at 5000 RPM at chest level 85 dB at idle directly behind vehicle at waist level 80 dB at 5’ at idle behind vehicle at waist level 750 exhaust with Silent Rider installed: 72 dB in cab at idle at driver chest level 90-92dB in cab at 5000 RPM at chest level 77 dB at idle directly behind vehicle at waist level 74-75 dB at idle at 5’ behind vehicle at waist level It’s clear to me that in-cab sound levels are at least partly magnified by body panels and layout of the cab. I will post additional pictures and results when I have the sound deadening material installed, probably in a few weeks.

Ok, I received the Silent Rider silencer kit a few days ago and got it installed. My initial impression is that it’s moderately quieter outside the vehicle, but marginally quieter in the cab. I took some “before” dB readings to compare, but I haven’t had a chance to take “after” readings yet; I’ll post the results when I can take those (a day or two). The kit was relatively easy to install, but it did require that I make a bracket in order to mount it to the frame. The kit is intended to allow you to hang the silencer for support, but the Sector has no frame member above the exhaust area — only the tilt bed itself, which can’t be used for that purpose for obvious reasons. So the simplest solution I saw was to invert the hang rods to be prop rods and support them with a bracket on the rear frame member where the A-arm attaches. See pics . This is what comes in the kit. This is the bracket I made to attach to left frame upright where A-arm mounts. It's fabbed from a piece 1/8" plate steel drop I had laying around. Tab on the back is a rotational stop since I used only one screw in the frame member. Silencer with cut down support rods. You'll note that I cut off the threaded bosses on the opposite side of the silencer (used when mounting the silencer to the opposite side) and capped them with stainless allen head screws. The bosses come very close to touching the plastic under the dump bed, so shortening them seemed the right thing to do, plus they look better this way. Bracket mounting location on frame: hole is 5/16" for 8mm flange screw and nut. A couple of non-flanged screws are provided in the kit that could be used, but flanged fasteners are preferred in this application IMO. Bracket installed on frame. Silencer mounted in bracket. This is the adapter provider in the kit, which fits the Hisun muffler perfectly. You have to remove the spark arrestor/exhaust tip to install. Shorter allen screws are provided in the kit, but they aren't stainless so I opted to cut down the factory stainless screws and reuse. They also give you a gasket, but my Hisun is pretty new and the factory gasket was fine. Also, an important note if you attempt this install...I had to cut about 3/8" off the 45 degree adapter pipe so that the silencer would sit a little closer to the muffler in order for it to avoid contacting the bed when opened. As installed, it winds up being very close to the bed when resting in the fully open position, but I didn't see that as a problem since you would never drive it that way where it would see sustained heat. I did notice after installation that it might be possible to loosen the muffler in its mounts and shift it slightly forward toward the front of the vehicle, but I didn't try this. So in summary, my impression is the kit helps, looks good and seems decent quality, but at $180 or so not much bang for my buck, IMO. As I mentioned above, I will post dB levels using my smartphone and an app, but I don't expect massive reductions based on my perception. It is quieter though, no doubt about, just not as silenced as I had hoped. The next phase will be installing sound deadening mat material in the cab, and I will post my experience with that.

This will be a two- pronged attack for me. First is the silencer, because it’s too loud on the street (UTVs are street legal here, but this thing gets plenty of unwanted looks for noise). Second will be to add some sound deadening mat from behind seat all the way to the bottom of the dash in order to get at the “WHAT I CAN’T HEAR YOU” problem… I’ll post my results with both.

Been waiting on delivery to Central America where my ride is located, as I only get packages once per month. I hope to have it by next weekend. As soon as I have it, I will take before and after audio with my phone (fwiw) and report back with photos on installation…

I have a 2022 750 EPS as well, and it’s intolerably loud. I’ve read good things about The Silent Rider exhaust silencer, which installs after the stock muffler. It’s pricey, but the manufacturer claims it has no reduction in power. They don’t make a specific one for our UTV yet, but I contacted them and was told that the BT-98 silencer together with the BT-1A adapter will bolt right on. I’ve ordered and will try to post results once I get it installed.