Elevation ?'s with the MPI Super Charger

[Blueice]

What problems have you encountered when running the Super Chargers at different elevations?

I am looking into the MPI from Mountainperformance Inc. It would be installed on a 2006 Attak that has been extended to a 151 with 2" paddle's. I have primary and secondary clutch setup's for two locations. The two locations that I ride are Sea Level ND/MN and 8,000 to 10,800 in WY.

Is this S/C easily adjustable in regards to boost level's for the different elevations? Does that even need to be done?

Thanks in advance for the information.

 

[mulot30th]

You need to change pulleys.

OR

Have a dump valve at sea level and close you dump valve at elevation.

 

[HAMMER]

Altitude effect on a Stage-I MPI supercharger (max-compressor speed 150,000rpm)

Atmospheric Pressure = 14.7psi +11psi

Absolute Pressure = 25.7 (243.4hp sea-level)

Atmospheric Pressure @ 8000ft feet = 11psi +11psi

Absolute Pressure = 22psi

Approximate Pressure Loss = (25.7-22) = 3.7psi

(3.7/25.7) = 14.3% pressure loss at 8,000 feet

243.4 x .143 = 34.7hp

243.4 - 34.7 = 208.7hp at 8,000 feet

 

[mulot30th]

I am curious to see what Air fuel ratio they are running to get that 243hp at sea level?

this is some good hp level for 11psi

 

[HAMMER]

Look here...($20 annual subscription)
http://www.dynotechresearch.com/techarticles.asp

Yamaha Apex Supercharged MPI supercharger kit on stock Apex
12 psi boost on stock engine with 100 octane gas, Excell stainless muffler
11/28/2006

MPI SC Apex session two Art Andre's sled with fuel upgrades
larger capacity fuel pump, Boondocker boost and RPM referenced EFI controller
12/22/2006

TY thread:
http://www.ty4stroke.com/viewtopic.php?t=34035

TY quote about a different dyno run:

We dynoed John Wheelocks MPI supercharger at 232 at 9lbs. On the same dyno my Powderlites front mount made 259 at 12 lbs. The MPI has sooooo much on the bottom it is very touchy with the throttle. Easy to install, No lag, No heat issues.
Mike Knapp#17

 

[mulot30th]

Look here...($20 annual subscription)
http://www.dynotechresearch.com/techarticles.asp

Yamaha Apex Supercharged MPI supercharger kit on stock Apex
12 psi boost on stock engine with 100 octane gas, Excell stainless muffler
11/28/2006

MPI SC Apex session two Art Andre's sled with fuel upgrades
larger capacity fuel pump, Boondocker boost and RPM referenced EFI controller
12/22/2006

TY thread:
http://www.ty4stroke.com/viewtopic.php?t=34035

TY quote about a different dyno run:

We dynoed John Wheelocks MPI supercharger at 232 at 9lbs. On the same dyno my Powderlites front mount made 259 at 12 lbs. The MPI has sooooo much on the bottom it is very touchy with the throttle. Easy to install, No lag, No heat issues.
Mike Knapp#17

What is weird.... is the MPI vendor here (Gagne Lessard sports) routinely dyno around 200hp on 11 psi apexs... They are using a DYNOMITE dyno, and this is the very same place I dynoed my rx1 and apex... They also dynoed a 20psi mpi stage3 apex mountain at 280hp.

Either their dyno read too low OR dynotech read too high... either way, that is sad because we can't compare numbers from different dynos then unfortunately.

 

[mulot30th]

Was this sled running stock compression? (it will dyno higher with high compression).


My rx1 12 psi dynoed 242hp with stock compression

and 220hp with 9-1 compression je pistons (running richer too and was too lazy to re-jet).

 

[Blueice]

This is all good information. Sounds like there are no issues with running at different elevations as long as it's setup with the correct sized pully and/or a blow off valve is in place.

Are the pully's easy to get at and change? Is there enough adjustment so different belts are not necessary?

Is the super charger good when used bookdocking through deep snow and through the trees or would a turbo be a better choice?

Thank You

 

[KnappAttack]

Of course you can't compare HP#'s from different dynos. You also can't compare the #'s if there is a big change in elevation of the dyno shop. As you go up in elevation, you can tweek the engine to make more corrected HP. Also can not compare summer hot air with cold winter air. It will skew the #'s. You will see more corrected HP if you dyno at a higher altitude, or dyno in hot summer air. Take the same engine down in altitude or into winter air, and the corrected HP will go down if it was tuned to max HP with worse air. Dynos are not the final word in performance. That is why we do not race dynos. They are only a tool, and you have to be smarter than the tools you use.

 

[mulot30th]

This is all good information. Sounds like there are no issues with running at different elevations as long as it's setup with the correct sized pully and/or a blow off valve is in place.

Are the pully's easy to get at and change? Is there enough adjustment so different belts are not necessary?

Is the super charger good when used bookdocking through deep snow and through the trees or would a turbo be a better choice?

Thank You

Supercharger is BETTER than turbo for doondocking because of IMMEDIATE throttle response.

I have both, and apex turbo has nowhere the response of my blower rx1.

 

[mulot30th]

Of course you can't compare HP#'s from different dynos. You also can't compare the #'s if there is a big change in elevation of the dyno shop. As you go up in elevation, you can tweek the engine to make more corrected HP. Also can not compare summer hot air with cold winter air. It will skew the #'s. You will see more corrected HP if you dyno at a higher altitude, or dyno in hot summer air. Take the same engine down in altitude or into winter air, and the corrected HP will go down if it was tuned to max HP with worse air. Dynos are not the final word in performance. That is why we do not race dynos. They are only a tool, and you have to be smarter than the tools you use.

I completely agree.

 

[Blueice]

Do the Stage I kits modify the stock fuel management?

Any difference in buying the MPI from Hartman Inc or Mountain Performance?

Dropping upto 6 large on a sled that is already up to 10k. I hope I make the right decision. This is all good information. Thank you again.

 

[HAMMER]

Blueice -- From your line of questioning I'm guessing you have done zero research. As you mentioned, with the price of sleds and boost these days, don't you think it might be worth your while to do a little reading/homework on members real world experiences in the 4-Stroke Turbo/Supercharger section of this forum (excellent info free of charge). These subjects have been covered several times on both Turbo's and Super's. Maybe even call MPI (free phone call 1-888-649-4609) or read the information about superchargers on their website http://www.mountainperformance.com/superchargers.htm (also free of charge). Just a suggestion.... ;-)

 

[Blueice]

Blueice -- From your line of questioning I'm guessing you have done zero research. As you mentioned, with the price of sleds and boost these days, don't you think it might be worth your while to do a little reading/homework on members real world experiences in the 4-Stroke Turbo/Supercharger section of this forum (excellent info free of charge). These subjects have been covered several times on both Turbo's and Super's. Maybe even call MPI (free phone call 1-888-649-4609) or read the information about superchargers on their website http://www.mountainperformance.com/superchargers.htm (also free of charge). Just a suggestion.... ;-)

New to the turbo-S/C world. I have been doing a lot of reading. I like to ask the questions in my own words. Sinks in better when I do that. I don't do a lot of my own tinkering with the sled. The S/C will most likely be installed by someone else. If I can learn something along the way the more power to me. Thanks for the info.

 

[HAMMER]

Do the Stage-I kits modify the stock fuel management?

Just like a normally aspirated engine (they're all just air pumps) if you increased air flow you will need to increase fuel flow to maintain the proper air fuel ratio. You will need to use a wide band air fuel ratio gauge to determine your air fuel ratio.

The controller for the supercharger is made by Dobeck for MPI.

MPI has many private label customers that use these controllers with different internal parts and programming specified by the company they are built for and it's application (Bender, Simons, Alpine/Powderlites, Pure Logic, etc)

It is essential to able to adjust the air fuel ratio on these machines to achieve optimum performance and rideability. This is especially true when adding a Turbo or Supercharger. The TFi Fuel module is completely adjustable allowing you to maximize horsepower from idle to wide-open-throttle. TFi is different from other systems on the market in its method of adjustability by dealing directly with the fuel injection signal after it leaves the Factory ECU. This eliminates the need for expensive Factory Re-Mapping and it is completely adjustable and tunable. It adjusts your fuel requirements without tricking sensors or modifying the factory settings, which can limit the ECU’s effectiveness at compensating for changing conditions. It plugs directly into your factory harness.

You may encounter the same throttle position at the same rpm in different riding situations. The engine’s fuel requirement will not be the same because the engine is not under the same load in these different riding situations. The TFi is load based for this reason. It reads throttle position, rpm, and it takes into account, boost pressure, and the load the engine is under.

MPI's fuel controller allows you to tune the fuel injection much the same way you would jet a carburetor and has the following adjustable functions.

Pilot (Adds fuel for Idle/Cruise)
Needle (Adds fuel for transition to main jet)
Main (Adds fuel Wide-Open-Throttle)
Boost Fuel Adder (Adds fuel for boost pressure)
Accelerator Pump (Adds fuel under abrupt acceleration)
Altitude Compensation (Adds fuel for altitude changes)

Right now all units are Gen3s or Gen3.5 but look for the Gen4 units in mid-2008 or 2009. The Gen4 units will have a 10-millisecond reaction time vs the current 100-millisecond reaction time. A faster microprocessor = more calculations in less time. It will also be able subtract fuel if needed, unlike the current versions, which can only add fuel.