harryccc

Advantages of mpfi over Carbuerrator

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Hi, the MPFI (Multi Port Fuel Injection) is a very advanced technology in petrol engines.

The main advantage being cleaner emissions, linear power delivery and hence improved efficiency.

MPFI also helps during cold starts.

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MPFi as Geforce pointed out is now standard and very advancced technology of Carb,

Now even the Maruti 800 Comes in with the MPFi engine which shows that this the End of an era fr the Carb,

But we still dont know what we will see in the coming years may be a still more advanced MPFi engine .

Cheerssmiley20.gif

 

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As a thumb rule you can expect a 20%+ gain in MPFI as compared to carbs. Whether this is in power, or economy or distributed between the two is a matter of detail. You can in general run the engine with more advance, and higher compression than its non-MPFI cousin..

FI permits better control on the air-fuel ration, and provdes better vaporization of fuel. Also, the electronics allows the engine mapping to be optimized based on not just the rpm and air flow but also other parameters (engine temperature, barometric pressure, O2 in exhaust,  etc. Even the throttle position leads to a far better mapping than just the mechanical link to the butterfly.

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hey is the variable valve timing engines VTI newr than the mpfi..???

Definitely. At least FI (not necessarily MP) was there in the 70's if not earlier. VVT requires both mechanical and electronic components, so is a product of the microprocessor age. Also, these being complex designs require extensive Computer Simulation (FEM) for development.

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VVt-i is a better system than MPFi but is costly it gives better response and is the future.

What gives you the idea the VVTI is not MPFI, all VVTIs are either MPFI or DI. Fuel injection takes place in the manifold (some of the later BMWs are using Direct Injection). VVIT VTec etc. are all on the camshaft end.

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Variable Valve timing can be applied to carb or FI, Honda first put it in their carb bikes in 70s, its about engine tractability, burning the right about of fuel at the right time for complete combustion. Of course, with precise metering of fuel aka FUEL INJECTION, Variable Valve Timing works out even better.

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MPFi as Geforce pointed out is now standard and very advancced technology of Carb' date='

Now even the Maruti 800 Comes in with the MPFi engine which shows that this the End of an era fr the Carb,

But we still dont know what we will see in the coming years may be a still more advanced MPFi engine .

Cheerssmiley20.gif

 
[/quote']

All present cars in India - including the M800 - run FI because they need to meet emission regulations by law. I doubt they did it out of purely humanitarian reasons, or to offer the best technology to their customers. :)

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All present cars in India - including the M800 - run FI because they need to meet emission regulations by law. I doubt they did it out of purely humanitarian reasons' date=' or to offer the best technology to their customers. :)

[/quote']

Euro I was the limit of Carb engines, so they are now history. Look at my original post in this section - FI means typically a >20% gain, be in efficiency, or performance or shared.

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ok i understand how Injection improve the performance also like aftermarket products to enhance the performance... not to mention the NOS systems to boost output... i wanna how the headers affect the performance, what are the functions of headers?

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Flow of air, in our out is critical to power. So properly designed intake tract and header with reduced turbulence will lead to maximum intake and exhaust thereby increasing performance. In case of intake its careful polishing as well as design, for exhaust its proper sizing and reducing as much restriction and turbulence as possible.

As for NoS, it temporarily increases the compression ratio, good for dragsters but severely damaging to engine in long run.

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Good explanation Gurkha,

I may just add a little more about Nitrous Oxide (N2O). Normal air has 20% Oxygen, while N2O has 33%. So injecting N2O increases the oxygen content of the fuel-air mixture which in turn leads to a higher amount of fuel being injected into the engine, and this is what leads to the higher power. More fuel and oxygen in the combustion chamber naturally results in a higher pressure  after ignition. Incidentally NOS stands for Nitrous Oxide Systems, arguably the leaders in this technology.

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NoS is typical dragster stuff, not used in race cars of any form. For short term, an engine can survive the NoS onslaught but not viable for long term in any way.

Wanted to add, that competition headers are hours of painstaking work on dyno and race track and are usually hand made job, mandrel bent. The objective here is to have the least bends for exhaust air flow and therefore sharp bends as in OEM headers are avoided.. With mandrel, its gradual bends that are achieved.

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