HMF Utility Series Performance Muffler Product Review

[Cadman]

HMF Utility Series Performance Muffler Product Review
Honda Rancher 420 (07-08)

Let’s face it guys, when you brought your quad home from the dealership you really didn’t think you were going to leave it stock did you? One of the first upgrades most of us do is some kind of performance upgrade. There is one performance upgrade that is easy to install, doesn’t require a mechanic, won’t take a lot of time and best of all, is very inexpensive considering the cost of other performance upgrades. This upgrade I’m talking about is a Utility Series Performance Muffler from HMF Engineering. The HMF Sport/Utility Series features a non-restricted core that's dyno and track tested for maximum flow, torque, and horsepower. Typically, expect a 15%-20% horsepower gain with a deep, "throaty" sound, depending on the model and year of the quad.

We contacted Lance Drew at HMF Engineering and told him about our Project Honda Rancher that we were working on and he immediately expressed interest in the project and sent us a red Utility Series Performance Muffler and since this machine is fuel injected he also sent us a HMF Optimizer to control the amount of fuel being delivered to the engine. You must remember that when adding a performance product you must also modify the jetting or add an Optimizer so you can prevent your machine from running too lean.

First Impression

When we saw the big brown truck arrive at the door we were excited to see the white box stamped with the HMF Logo on the side. The exhaust was packed extremely well with thick brown paper surrounding all the parts protecting each one from damage during shipment. We were extremely impressed with the very durable red powder coat finish and the brushed aluminum pipe. Every HMF performance exhaust is handcrafted and made in the USA at the HMF Brookpark Ohio facility. All exhaust systems utilize 304 stainless steel flanges, head pipes and S-bends. The canisters are fabricated using tough T6061 aluminum or lightweight Carbon Kevlar. The inside of the muffler contains volumized, high performance glass wool packing. All of these components together make a significantly compact and lighter exhaust system when compared to stock systems.

If you plan on riding in a noise restrictive community or trail system with noise limitations, then you might want to consider purchasing the Quiet Core Insert with spark arrestor. You will loose approximately 3-4 db, making this muffler a little louder than stock but a lot quieter than without the Quiet Core. I personally don’t mind the noise it just lets other riders know that something powerful is coming around the corner. And besides, it just sounds good with that deep throaty sound down in the holler.

Installation

Installation is very simple however getting the stock exhaust off could be difficult especially if you are working on an older quad or a quad that hasn’t been cleaned regularly. The first thing you should do is to spray a good dose of WD-40 or similar product onto all bolts that are to be removed. Next, you will need to remove the stock heat shields as instructed by the instructions provided with your new exhaust system. Once all the bolts and heat shields are removed it is time to pull off the stock exhaust. That’s right, pull; pull very hard, my exhaust just did not want to budge but it will come off. Installation of the muffler is simply a matter of slipping the muffler on to the OEM header. Install the bolts connecting the muffler to the head pipe, and then install the bolts connecting the muffler to the muffler bracket on the rear frame rail. Wipe everything down, step back and admire.

I know by this time you are tempted to start the quad up to listen to that new muffler but don’t. Now its time to install the Optimizer. First thing you need to find a dry location to mount the optimizer. Once the optimizer is mounted using the supplied hook and loop fastener, move on to the wiring. Locate the wiring harness for the fuel injector. Once you locate this you can disconnect it and plug in the two harnesses from the Optimizer and be sure and connect the black ground wire to the negative terminal of the battery. Now you need to adjust the optimizer for your ambient temperature and altitude so don’t just crank it up just yet.

The HMF Optimizer is pre-programmed from the factory for the best map that HMF found on their dyno to their pipe at a basic sea level and 60 degrees ambient temperature and with the stock air filter and air box lid off. The recommended settings for the Optimizer for the Rancher 420 are 2.5 / 3.5 / 4.0 The first mode (Green) is the low speed setting, the second mode (Yellow) is the mid speed and the third setting (Red) is the top end setting, modes 4 and 5 are pre-set and do not need to be changed. To adjust the Optimizer you must take the above parameters into consideration but make adjustment to them based on your actual conditions. Tuning an EFI machine is the same as tuning a crab, however you can make extreme adjustments by pushing a button. My suggestion is to find a nice long straight where you can place something on the ground to mark a "start" and "finish" point for reference. Make runs in the low, mid and upper throttle ranges adding fuel (lights to the right) until you feel that the machine performance falls off. Make note of the light # value then subtract 1/2 to 1 light. This should give you the best all around values for your location. What about high elevation? What about hotter or cooler ambient conditions? Higher in elevation means your settings will need to be leaner than a machine at sea level. High elevation means less air which translates into richer running machines. Hotter ambient temps translate into a richer running machine, so if it is 90 degrees it will be a tad rich and 1~3 light positions (Left) leaner may be needed. Colder ambient temps translate into a leaner running machine, so if its 20 degrees it will be a tad lean and 1~3 light positions (Right) richer may be needed.


Generally, the same testing procedure as noted above will dial you in. Keep notes of settings for summer/winter/elevation and making recalibrations will be much easier next time.

Once the Optimizer is properly adjusted you can expect some pretty impressive horsepower gains. For a machine that only makes 16HP all stock a 1 ~1.5HP gain is average. We tested with a stock type air filter, once a free flowing filter is added expect another 1~1.5 more horsepower on top of what we got. So 3HP isn't a bad gain.

Rider Report

We started the Rancher and noticed how docile the muffler sounded. Idle noise was actually surprisingly minimal; however, it is louder than the stock exhaust but it’s not overbearing by any means. While cruising along with a steady consistent throttle, the exhaust was quieter than I had expected but when you open up the gates a little more you could really tell that I was running an aftermarket system. I noticed a snappier throttle response compared to the stock setup. As with other HMF exhaust systems, it has a very distinctive sound. While many associate loud exhausts with horsepower, this isn’t always the case.

Conclusion

The HMF exhaust system for the Rancher 420 has answered the question that few exhaust manufacturers have been able to do and that is to offer a system geared towards total performance. The aluminum construction is paramount to those who demand the best qualities in materials and workmanship. The fit and finish are perfect; we could not find any areas for improvement with this system.

For more information or to purchase the HMF exhaust system for the Rancher 420, you can contact them at:



HMF Engineering
5111 West 164th Street
Brookpark, Ohio 44142
Phone: (216) 631.6980
Fax: (216) 631.6981
HMF Racing / ATV