2009 QUARTER MIDGET CLUTCH TYPE DYNOS

We now have a low cost Quarter Midget Dyno using a simple jackshaft and clutch. It allows you to start your engine with a simple hand held electric starter, walk over to the dyno, engage the data system, go wide open throttle till maximum rpm, shut off system. Do S.A.E. weather correction, download data and graph it or make reports of any data you wish. It’s accurate enough to see .001” jet changes on gas very easy. I worked with a GX120 and made several changes and saw everything I changed on the computer screen. See acceleration data to see exactly were engine acceleration slows or stops, see engine head temp, exhaust temp, air/fuel ratio, oil crankcase temp, etc. with the right data system. This dynos also allows you to dyno any engine up to 25 to 30 hp with a ¾” or 1” output shaft using any clutch. A Premier Titan is recommended with yellow/red springs. With these larger motors you will be able to dyno all clutches, see engagement rpm, slippage ratio and were total lock-up of clutch occurs or were its back to one to one (direct drive). With the “Pro” software you can overlay up to six graphs at a time, including clutch dyno pulls, click on any part of the graph to see increments of torque/hp in 1/100ths of an increment. Or ZOOM in on any part of the graph down to 30 rpm increments. For example, testing top end headers, (6000 to 6400) rpm. See up to 10 columns of data side by side up to 10 columns wide or see “data & difference” which shows you plus/minus data in the third column running vertically down the page. This is a very simple dyno which will last many years. Software can be run on Windows 95’ to Vista. A basic Celeron laptop will work just fine ($500.00). You may need a USB to Serial port Adapter for newer computers without a serial port or purchase a newer system that works thru your USB ports. We will be glad to explain and quote anything your interested in.

THANKS-STAN HEWITT

HEWITT RACING & MFG., PHONE 1-641-775-3395 OR CELL 1-641-512-3395, FAX 1-641-775-3399 OR E-MAIL: HEWITTDYNO@GMAIL.COM

ALSO CHECK OUT MY BLOG: WWW.HEWITTSINERTIADYNOS.WORDPRESS.COM.

Here’s a dyno pull comparasion of a Chinese yellow clone motor on gas. We started with a stock engine with a stock muffler, put in 16 oz. of 10w30 oil and did a couple of dyno pulls. Engine ran very bad, sounded like a bad spark plug. As you can see by the lower dyno pull engine surged very bad due to very lean condition. Made 4.6 hp at maximum at 3000 rpm. First thing we did was remove stock muffler and replace it with a small header we got from ARC.  Really didn’t help much, engine still very lean. Drilled main jet out to .037″ and dyno again. Engine souded very strong and made big jump in horepower. We then tryed Animal springs instead of stock springs. Really didn’t do anything, in fact lost hp on top end. Went back to stock springs and stuck on large RLV header. Made a pretty good jump in hp. Ended up with large RLV header and .036″ jet. I don’t think this header will be legal for the rules that I skimmed thru very quickly but just for your infomation. I think the small header from ARC ran best with a .035″ jet.  I know A.R.C.  & J.C. Specialtys both have parts for these.
About 5400, this motor really fill off. A couple of people have told me spring pressures will make a big difference but they will not be legal!
The dyno sheet show a comparision of a bone stock engine with how we ended up with all stock parts except for jet change. Tightening valve lash settings didn’t make much differance. Ended up gogin back to .003″.  Max torque was at 3600 rpm, peak hp at 4900 after jet change.

Interested in Purchasing a Hewitt Inertia Dyno?

Call me today…

Stan Hewitt
c 641-512-3395
hewittdyno@gmail.com
twitter.com/InertiaDyno

THIS IS THE #1 SELLING DYNO. 2001-2008 “PRO” SERIES DYNO- this dyno comes with new USB Pro data system. This dyno measures 27 ½” x 48” so it will fit thru a 28” door of your dyno room. . It has the new electric start system and the new 35mm belt drive. It comes with a small parts kit to get you started. This dyno has two separate axles and can have a sprag clutch or can be built direct drive. Normally this is bought will a pro type data system and sold with a complete computer system with printer, surge protector, all cables, etc. We would need zip code for freight estimate. We also should talk about what you want for computer system (laptop, desktop, printer, etc.)  – $7816.00 – call me and I can give you all the details or I can make one specifically for your needs. ~ Stan c 641.512.3395

2008 AXLE/FLYWHEEL ASSEMBLIES

From experience in building over 110 assemblies, we make sure these are built correctly to allow no axle keyway wear, loosening or wobbling. The flywheel is built to be used as a brake rotor. We have the outside and inside diameter cut with a CNC torch. Both sides are then ground on a Blanchard grinder so they are parallel. Then we weld on a special female type hub assembly. The axle and male hub are put together and torqued up straight using a dial indicator so that the face run-out is less than .015”. We can use any axle size from 1” to 4” including metric up to 50mm.

Normally we use 1 ¼” stress-proof steel with keyways cut only were they need to be. We never have a keyway where the bearing is going to ride. We stock axles in 1 ¼” and 1 ½” in length to 47”. We can custom make whatever you want. We can also build 40mm at a slightly higher price. We stock one-way sprag clutches and torsion shock systems and can get most sizes overnight. If you want us to ship a flywheel/axle assembly to you, we will need your zip code for a freight estimate. We use R&L Carriers since they have Tommy lift type tailgates to get the assembly to the ground and you can get it into your shop with a pallet jack. Residential deliveries cost an optional $50.00. Its best to ship to someone with a forklift or loading dock. I give a 65% discount off of list price. The flywheel will be banded on a pallet and shrink wrapped. These assemblies include high quality Japanese NTN pillow block bearings with eccentric lock collars. They are computer balanced to less than 5 grams at 500 rpm’s. There is a heavy duty sprocket hub included with a 53 tooth sprocket. If you plan on adding electric start or belt drive it is best to add that before balancing the assembly. If you are using a clutch dyno, use a 24 or 29 hp flywheel with a higher gear ratio so you aren’t so hard on your clutch. I recommend a Premier Titan clutch with yellow springs. Horsepower ratings are for 15 second dyno pulls. I highly recommend installing a flywheel so that electric start and belt drive can be added at a later date. We do sell dynos in kit form so all you do is weld it up and start using it. You will get every part with a basic blueprint. We build dynos up to 125 horsepower with multiple flywheels so you can do 3 hp up to 125 hp. Please note that for flywheels above 30 hp, I recommend 1 ½’’ to 1 ¾’’or 40mm stress-proof axles and those above 40 hp to use 1 ¾’’ or 2’’ stress-proof axles. The following are the three most common flywheels that we sell.

1.25” x 28” rated 24.16 hp. sells for $1681.42

1.50” x 28” rated 29.16 hp. sells for $1761.07

3” x 23” rated 26.5 hp sells for $1759.85

Remember this includes all the labor to do everything including the machine work, assembly, computer balancing, (3) new NTN bearings, key stock, H.D. sprocket hub, #53 sprocket, crating, banding, and put on a pallet for shipping.