Archive for the ‘Ask The Experts’ Category

Where Are My Dynamometers Horsepower Numbers?

Thursday, December 8th, 2011

When viewing your Dyno Sheet from SwedeTech Racing Engines, the first question you might ask yourself, “Where Are My Dynamometers Horsepower Numbers?”

Great question!  We don’t supply dyno numbers.  We do not want to understate the importance of having the proper tools and equipment to build a racing engine and the dynamometer is a huge asset.  However, we want to educate our customers on when the dyno numbers are important.

Like any quality measuring device, Dynamometers provide extremely useful data that can be very difficult to measure in a working environment.  Dynamometers help bring a standard while testing many different components.  There are many variables that will affect the actual numbers that are given by a dynamometer.  Weather, humidity, air temperature, changing dynamometer parts, changing software settings, process used during a power pull, timing of software sampling, load applied by dynamometer, belt or chain tension, and many other variables.

SwedeTech does not try to hide our Horsepower numbers.  We do however want to minimize as much confusion as possible when it comes to the information we provide.  The only accurate way to compare horsepower is to minimize as many variables as possible.

For example, when we compare our dyno numbers, we run multiple test runs in succession, in the shortest time frame possible.  This minimizes many variables.  We have seen horsepower variances from one day to the next, with no changes made to the engine or the dyno.  Many times this is due to atmospheric conditions, but this is an added variable.

When reading your dyno Sheet, we provide you with the essential information.  We provide you with RPM’s and the power curve.  From this information, you can properly assess the best operation range for your engine.  Depending on different tracks and air conditions, you may have to run your engine in different rpm ranges to maximize on track performance.

Some tracks or some sections of a track may require you to use a lower rpm range to maximize the time you spend in the sweet spot or the power band.  Other times, you may have to gear the engine to run at the upper RPM range to take full advantage of the gearing and power band.

Keep in mind that there is never a perfect rpm range for all racing conditions.  Every track will have its own unique characteristic that will affect the engines optimum performance.  An often over looked aspect of the engines rpm range is how it can affect the handling of a chassis, or vice versa.  When you are driving your kart, it is very physical and mental, and at the same time it is a delicate dance between the driver, chassis and engine.

Posted in Ask The Experts, General, Technical Help | No Comments »

SwedeTech Hold Music Contest

Wednesday, November 10th, 2010

We at SwedeTech Racing are looking for ways to minimize to dead sound when customers are on hold. We strive to answer all phone calls when they come in, but there are just some days we can’t keep up. For those days, wouldn’t some good hold music be a nice addition?

The winner of the hold music will receive some of our new 2011 Swag.

When you listen to the file, go back to EKartingnews to cast your vote, or leave a comment on our site here.

Here is a easy link back to EKartingNews

Here are two samples submitted by a very talented SwedeTech Customer. Vote for your favorite

SwedetechTechno30sec

GalanteSwedetechMix30second

The files are about 5mb. May require a bit of download patience. Browser plug in QuickTime

Posted in Ask The Experts, Customer Feedback, General, Video & Multimedia | No Comments »

Why SwedeTech doesn’t provideEGT numbers or ranges

Tuesday, October 26th, 2010

Exhaust Gas Temperature ( EGT ) is a very common and useful tuning aid for 2-stroke engines. SwedeTech Racing Engines is asked many times a week, “ What should I run for EGT? “

Keep in mind that EGT is very sensitive, which is one reason it is a good tuning aid. Many factors affect the reading or recording of your exhaust gas temperature.
Here is a list of variables:
–This distance of the EGT sensor from the face of the piston. Whether you have a fixed EGT sensor position like you would on some exhaust or a variable position if you are tuning with exhaust spacers. We typically recommend placing the sensor approximately 4.5 inches away from the exhaust side of the piston. Before you drill and weld a bung on the pipe, make sure your sensor will not interfere with either an exhaust manifold, exhaust springs, your seat, chassis, seat struts, etc.
–Changing exhaust components such as flex length, silencers, back pressure pills, spacers, and other common tested items will affect the EGT reading. Coatings and treatments will also affect your EGT reading. Always read your rulebook when you want to test certain items. Most associations have specifications for the exhaust system.
–Different fuels and different oil mixture ratios will also affect your EGT. When jetting and establishing your EGT baselines, always use the same fuel and oil that is required for the events you are testing for.

Jetting is a very big factor that will affect your EGT. This is one reason many people use EGT, as proper EGT notes will help you tune your engine for peak performance. The basic idea on jetting vs EGT is, the leaner the jetting ( less fuel to air ), the hotter the EGT. The richer (fatter – more fuel to air) the jetting, the cooler the exhast gas temperature. Keep in mind, this is a very simplistic description. It is not uncommon for the engine to run lean, but have a cooler EGT. This is were your data system comes in.

Once you have your engine tuned to the point that you are happy with the performance, download your data to a computer and review the EGT curves. Heat is created as the fuel ignites, too much fuel (rich condition) in the system and not all the fuel will have time to completely ignite, unable to create enough heat. The resulting left over fuel will cool your EGT. This can cause the piston or spark plug to be wet when you complete a proper plug chop.

You may find that if the engine is running to lean, the EGT will actually decrease as well. Think of your fuel as energy. If you are starving your engine for fuel, it will not have the energy to create heat. Some indication that you are running to lean maybe small oil like droplets that are burned into the top of the piston, or a white or grey exhaust carbon color on the inside of your header or exhaust pipe.

You will want to review your data for the optimum EGT readings that created the most power. Once you have done this a few times, you will see a pattern develop and the range your engine prefers to run. The EGT measurement is very sensitive, so you may find that you have two “identical” setups that run at different EGT.

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How to Check Squish on a Two Stroke Engine

Friday, March 26th, 2010

This guide is a general instruction on how to check squish on a Two Stroke Engine.

First step is to determine what the squish is supposed to be.  If you are using a SwedeTech Engine, we supply this number to our customers.  If you are not using a SwedeTech engine, contact your engine builder for the proper squish measurement.

Squish = The measurement between the piston and combustion chamber with the piston at TDC ( Top Dead Center ).  This measurement is taken at the edge of the piston.

For this example, let’s assume the desired squish measurement is 0.040″.  In this example, you will use 0.050″ solder.  For SwedeTech Engines, we prefer to use solder that is approximately 0.010″ – 0.012″ thicker than  the desired squish measurement.    Note – Some rules such as Rotax call out in the technical specifications the required solder thickness.  Always check your rules to make sure you are in compliance.

Rotate crank so the piston is resting about 1/2″ down from TDC.  This will give you room to insert the solder as well as clearance to run the piston to TDC to squish the solder.

  • Cut two pieces of solder a minimum of 4″ in length – length of solder must be long enough to reach edge of cylinder and maintain control of solder ends from the spark plug hole.
  • When cutting solder, use a sharp razor blade and cut perpendicular to the solder.  This will leave the end of solder square.  Wire cutters will leave the solder edge tapered, and this may affect your measurement.
  • Bend the solder so the you can feed the solder through the spark plug hole, to the edge of the cylinder / piston.  Now insert the second piece of solder in the opposite direction of the first.
  • You will always want to check the squish directly above the wrist pin.
  • With the solder butted up against the cylinder wall, rotate the crank back and forth so the piston “squishes” the solder 4-5 times.  Go past TDC 0.020″ -0.040″ , then rotate opposite back to TDC.
  • Remove solder from cylinder and measure the thinnest part of the solder with a set of calipers that have been zeroed out.  This can be a few 1/1000ths from the end of the solder.
  • Using base gaskets or head gaskets, move the cylinder or head in the direction of desired squish measurement.  Repeat above steps until desired squish is found.
  • Note – If squish measurement from left solder to right solder differ, you may need to move the head around to achieve equal squish on both sides.  Make sure the nuts or bolts for the cylinder and head are torqued evenly to the proper specifications.

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Pump Around Troubleshooting Guide

Tuesday, March 23rd, 2010

If you are reading this guide, you might be having problems with your pump around system.  Please go through each step.  If you think you did it properly, still double check.  SwedeTech has put this guide together to help you troubleshoot your pump around system.

Pump around system pumps MUST BE CLEANED EVERY RACE WEEKEND.  THIS IS NORMAL MAINTENANCE JUST AS ADDING AIR TO TIRES, FUEL TO THE KART OR LUBRICATING THE CHAIN.  DO NOT SKIP THIS STEP.

First things first - Make sure that all of your fuel line fittings have a minimum I.D. of 3/16″ diameter.  This includes fuel tank nipples, vent nipples, fuel filters, and catch can nipples.  This does not include the vents on the carburetor itself.  Make sure all fittings are properly secured and safety wire or clamped at each fitting.  Air can leak into the system at these connections and cause a problem.  For the vent catch tank, make sure the tank is drilled out with at least a 1/4″ diameter vent hole.  If the catch cannot breath, the system will not work.  When checking all the I.D. sizes, make sure the nipples are clear of any obstruction.

Make sure all of your fuel lines are routed properly to each fitting.  Do not assume it is right, Check it.  The pump around system that SwedeTech supplies use the Mikuni Round style pumps.  These pumps have arrows on the cover to indicate fuel flow.  Double check that the fuel is flowing in the right directions.  If the arrow is pointing to the center of the pump, this is the inlet.  If the arrow is pointing away from the center, this is the outlet.  On the pump around pumps, one outlet on each pump is plugged with a set screw.

The pickup line in the fuel tank should reach the bottom of the tank and lay flat on the bottom.  The end of this hose should have a brass nozzle that lies on the bottom of the tank.  Make sure that the fuel line cannot be pinched or pressed between chassis parts, seat parts, weights, etc.  Any restrictions in flow will affect performance.  Make sure when you secure fuel lines to the frame, that you DO NOT over tighten the fuel line.  This will restrict flow.  Note the common theme, DO NOT RESTRICT FLOW.

Start with the routing of the fuel line.  Connect the fuel “supply” line to the tank nipple that has the fuel pick up tube inside the tank.  Between this line, and before the supply pump, add a fuel filter.  The “supply” line will connect to the fuel pump half that you designate as supply.  Both pumps work the same, as long as the fuel follows the arrows.  Connect the line to a pump with an arrow pointing to the center of the pump.  It may help to label one pump “supply” and one pump “return”.   Take another length of hose from this pump half and route to the carburetor inlet.  Typically this is a brass inlet, with some being supplied with an aluminum nipple pressed into the end.  It will also be a barbed fitting.  This arrow should be pointing away from the center.  Leave enough fuel line so you can remove the carburetor easily for jet changes.  Make sure the lines CANNOT get pinched or restricted.  Secure all supply connections.

The carburetors that SwedeTech supplies for the pump around all have the fuel inlet or “supply” on the left side of the carburetor. The return tube is always on the right side of the carburetor. Left side is determined by the view if you are sitting in the kart looking forward.

Now for the fuel “return” line.  The tank will have at least two available nipples.  Designate one for the vent line and one for the return.  (The supply line is complete).  From the tank to the other fuel pump half, connect fuel line to the pump with the arrow pointing away from the center.  This is the return side.  Note the direction of arrows and the fuel flow.  Now connect another line to the other available fuel pump nipple with the arrow pointing to the center.  Connect this piece of fuel line to the carburetor return tube (typically you can tell this was an added tube, and usually it is parallel to the carburetor slide body.  It is also a straight tube with no barb).  Make sure you have enough fuel line to easily remove carburetor for tuning.  Secure all connections.

The final nipple available on the fuel tank should be your vent tube.  Some tanks have 4 nipples, plug the 4th.  Check with your local rules.  Some associations require a catch tank on the vent.  Make sure the catch can is drilled out on the inlet with a minimum of 3/16″ I.D. and the vent hole in the catch can is a minimum of 1/4 I.D.

Pump Around Diagram - PWM or PWK

Diagram compliments of Benn Hur

The above steps are the basics to routing a pump around properly.  If you do not follow the above procedures, you may have problems.   Below is a checklist of common problems.

  • Fuel is spraying out of the vent line of the tank
    • System is pressurizing, fuel is being sucked out of the tank when it tries to achieve equilibrium.
    • Check guide above to make sure your system is plumbed properly
    • Check the fuel pumps for buildup of oil or failed fuel pump half
  • Fuel is spraying out of the vent lines on the carburetor
    • System is not properly returning fuel to the tank
    • Check guide above to make sure your system is plumbed properly
    • Check the fuel pumps for buildup of oil or failed fuel pump half
      • This is typical if the “return” fuel pump is not working properly
    • Make sure all fuel lines are not pinched on the return to the tank
  • Carburetor has a bogging or flooded sound
    • Check pumps for oil build up or failed pump half
    • Double check your plumbing with the above guide

By following the above guidelines, you will eliminate most of your pump around problems.  These systems are sensitive and need to be maintained properly.

I hope this information helps.

To order replacement parts, visit the links below

Fuel pump rebuild kit – requires 2 per system

Fuel pump kit – keep one clean at all times

Fuel Line – typical system uses 10′ – 12′

Fuel Filter – always run a filter

Fuel Pump Mount – rubber isolated

Pulse Line for pump – cloth braided

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SwedeTech Customers – Where Are You Racing in 2010?

Thursday, December 17th, 2009

In an effort to better support all of our customers, we need your input.

Elk Grove, CA – December 16, 2009 – In an effort to better serve all of our customers, SwedeTech is asking for our customers input on where you will be racing in 2010.  This is NOT limited to the big events, but all events including; club level, regional level, national level, and international competition.

With many series and events planned for 2010, SwedeTech needs to know where to focus our resources to offer the best track support possible.  With you helping us focus our track support resources for 2010 and the future, SwedeTech can better support you, our customer.  You can email or visit our press release page listed below with your input.

Please provide your full name, current contact information, series or events you plan on racing in 2010,   email address, phone number, and the SwedeTech engine package(s) that you plan on using.  If you have multiple drivers, please list each driver.

Your information will not be shared with anyone or any organization.  This information is solely for the use of SwedeTech.  With the information, we will be able to put together a schedule for the 2010 season.  Please keep political opinions for the forums.

Thank you for your time and past support.  We look forward to serving our customers in 2010 and beyond.

Please email info@swedetechracing or visit our press release page at www.swedetechracing.com/news-events-blog/swedetech-technical-help/2010-season-poll/

Posted in Ask The Experts, Club News, Customer Feedback, General, International News, National News, Regional News | No Comments »