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MPI 850 Turbo kit, updated specs & photos

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hook

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I don't think this is true because the turbo is compressing the air. There is the same amount of oxygen available in higher elevations, its just not condenced down because of the barometric pressure. It may take a split second longer to compress the air up at say 9000 feet but once it compresses the molecules in the air up to whatever the wastegate is set to you have the same amount of oxygen molecules available at any elevation.
 

hobbes

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That is incorrect. The amount of oxygen molecules per square foot (or whichever area measurement you prefer) is going to be less at higher elevation. This is easily overcome by increasing the boost level as you climb in elevation. The MAP (manifold absolute pressure) sensor incorporated into the system will read the air pressure, which not only changes with altitude change but with temperature and weather changes as well, to the electronic boost control. The EBC will keep the pressure at the manifold the same by increasing or decreasing the boost accordingly. This is why it only takes @3 lbs of boost at sea level to make 200 hp but 6+ lbs of boost at 9000 feet to make the same 200 hp.
 

madmax

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What makes everyone think that a turboed sled can't run at low altitude? My pro rmk with a turbo performance kit runs 7 lbs of boost at my home in Iowa at 1500 ft and it runs 7 lbs of boost at 9000 ft at togwotee. I have the vipec on my sled and I don't change a thing from one place to the other. 7 pounds of boost is 7 pounds of boost!!

Are you sure your running 7lbs at 1500 and 9000ft?

Most kits these days (I would think especially with a vipec ECU) auto compensate for altitude changes.

Running 7lbs at 1,500ft does not give you the same power as 7lbs at 9,000ft.

Considering the barometric pressure at 1,500ft is about 13.9 and at 9,000ft its 10.5 you should be running 3.5 more psi (in your case 10.4psi boost total) at 9,000ft to give you the same power at 1,500 feet.
 
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H

hook

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I am thinking correct. Hobbes, your correct if you are thinking about a naturally aspirated sled, not a turboed sled. With a turbo, you aren't compressing blocks of air with less molecules in them. You are compressing the molecules themselves until you achieve the desired pressure set by your wastegate.

I have a manual wastegate on my sled. Once enough molecules are compressed to overcome the spring in the wastegate, you have compressed enough molecules to achieve the boost pressure and exact amount of oxygen molecules need to make the power you want.

The vipec ECU gives me all the information I need to produce the power I want. The data log option in the vipec allows me to look at what my motor is doing at any given second so I can understand what I need to do to achieve the desired power and adjust accordingly. There is no automatic adjustments. But once I had the settings where I wanted them, I haven't touched them again and my readings are consistant day in and day out.

With piggyback controllers or reflashed ECU, you have no way to know what power you are making. Its just seat of the pants feel and if it isn't running right, you have no way to know what to do to make it run right. Its more of shot in the dark.
 
F
Nov 27, 2007
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medicine hat
Can't wait to see it run, seen a few pictures of the boost-it low boost kit, and heard Impuse is hard at it as well..

More than anything let's hope doo smartened up with the rods, that was the weak spot of the Etec and was hp limiting factor.. What worked perfect one day was chopper out the next..
 

hobbes

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I am thinking correct. Hobbes, your correct if you are thinking about a naturally aspirated sled, not a turboed sled. WRONG, THE SAME BAROMETRIC CHANGES EFFECT BOTH N/A AND FORCED AIR MOTORSWith a turbo, you aren't compressing blocks of air with less molecules in them. You are compressing the molecules themselves until you achieve the desired pressure set by your wastegate. INTERESTING USE OF WORDS, UNTIL YOU ACHIEVE? HOW IS IT EXACTLY YOU ACHIEVE YOUR DESIRED BOOST LEVEL? (THESE ARE RHETORICAL QUESTIONS, I KNOW THE ANSWER)

I have a manual wastegate on my sled.WRONG, ALL WASTEGATES ARE PRESET BY THEIR SPRING RATE. YOU HAVE A MANUAL BOOST CONTROL KNOB THAT WILL ALLOW YOU TO INCREASE THE PRESET SPRING PRESSURE BY ALLOWING THE AIR PRESSURE THAT WOULD NORMALLY FORCE YOUR WASTEGATE SPRING OPEN TO BLEED OFF INSTEAD Once enough molecules are compressed to overcome the spring in the wastegate, you have compressed enough molecules to achieve the boost pressure and exact amount of oxygen molecules need to make the power you want. AGAIN, TO MAKE THE "POWER YOU WANT", SOMETHING IS CHANGING RIGHT? AND YOU ARE MANUALLY CHANGING IT.

The vipec ECU gives me all the information I need to produce the power I want.CURIOUS, WHAT INFORMATION IS THAT EXACTLY? The data log option in the vipec allows me to look at what my motor is doing at any given second so I can understand what I need to do to achieve the desired power and adjust accordingly. There is no automatic adjustments.WITH THE VIPEC, THERE ARE HUNDREDS OF AUTOMATIC ADJUSTMENTS GOING ON EVERY SECOND But once I had the settings where I wanted them, I haven't touched them again and my readings are consistant day in and day out.MORE LIKELY, YOU ARE CHANGING YOUR BOOST BY TWISTING YOUR BOOST CONTROLLER KNOB, AND THE VIPEC IS FUELING YOUR MOTOR ACCORDINGLY BY READING THE CHANGES YOU ARE MAKING... AUTOMATICALLY

With piggyback controllers or reflashed ECU, you have no way to know what power you are making.UM, THE ONLY WAY TO KNOW WHAT POWER YOU ARE MAKING IS BY USING A DYNO Its just seat of the pants feel and if it isn't running right, you have no way to know what to do to make it run right. Its more of shot in the dark.THE VIPEC IS A GREAT FUEL CONTROLLER, BUT IT IS JUST A FUEL CONTROLLER, NOT A POWER CONTROLLER. IF YOUR FUEL CONTROLLER; NO MATTER IF YOU'RE USING A VIPEC, DOBECK, STOCK ECU OR ANY COMBINATION OF THEM; GIVES YOUR MOTOR THE CORRECT AMOUNT OF FUEL AT ANY GIVEN TIME... IT'S GOING TO MAKE THE SAME POWER REGARDLESS OF WHAT THE LABEL ON THE BOX SAYS.

LMAO. Ok buddy. So tell me this. Are you turning your boost knob from 1500ft to 9000ft? I'm not saying you can't make the same horsepower at both of those elevations, but you most certainly are NOT running the same boost pressure if you are. The same drop in barometric pressure that effects naturally aspirated sleds ALSO EFFECTS BOOSTED SLEDS. Just to a much lesser degree. It's just math, hard irrefutable factual math. IE- if you are running the same clutching at 9000 ft that you are at 1500 ft, you've increased your boost pressure by either turning a boost control knob or you're running an electronic boost control that does it for you. Either way, you are NOT MAKING THE SAME HORSEPOWER AT 9000 FT THAT YOU ARE AT 1500 FT unless you are adjusting your boost pressure.

I've been running turbos for 15 years, I don't claim to be an expert but a guy indirectly absorbs a LOT of information when you do something for long enough. This is also why it is getting hard for me and some others, with more knowledge than me, to post on SW anymore. Try to drop some actual factual knowledge and get told that basically I'm an idiot. Don't get me wrong, I've got nothing against hook here. It's good to see so many riders running turbos and gaining knowledge. It only adds to the demand for the latest tech in our arena. What is sad however, is the amount of misinformation that gets flung on public forums like SW, and how often newcomers will pick it up and make bad decisions based on it. My guess is hook has himself a good running kit, for now, and he can twist his knob when he heads west and it runs killer there too. A good VIPEC map that someone with the knowledge and experience to build it will do that for you. So this is my point exactly, somebody with limited turbo experience and knowledge, I won't mention any names, can reap the fruits of someone else's labor and enjoy all that sledding on a great running turbo can offer without having to pour over the details. That's awesome IMHO. Just don't think that because your sled runs well means YOU know what you're talking about... Carry on, I'll just go back to lurking...
 

brycter

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Don't forget air temp, egt temp, and back pressure in the mix if everyone wants to get all on the same page here. There is a ton of math that goes on in the back room that give you guys smiles on you face. Every manufacture works hard on the things you don't see.
 

madmax

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Don't forget air temp, egt temp, and back pressure in the mix if everyone wants to get all on the same page here. There is a ton of math that goes on in the back room that give you guys smiles on you face. Every manufacture works hard on the things you don't see.

So Bryce, this guy has one of your kits with a vipec. Does it auto compensate boost for temp, altitude changes, etc? My guess is yes it does. Can imagine spending that much money on a ECU that doesn't.
 

brycter

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So Bryce, this guy has one of your kits with a vipec. Does it auto compensate boost for temp, altitude changes, etc? My guess is yes it does. Can imagine spending that much money on a ECU that doesn't.

Yes it does. the vipec has has everything i can imagine and some scenario that i have not thought about. but the doos don't run a vipec so it is a bit different scenario.
 
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