boost+carb=tuning?

[Anonymous]

ok, so say i added a very low amount of boost, like a (powerful) electric blower that had enough cfm to creat good positive pressure. would i have to retune my carb or what? i know how to do a fuel injected engine, since it senses changes and automatically adjusts, but what do you guys do with a carb? once the pressure is there i know your butterfly still controls how much gets in, so do i just readjust it to get richer or what? if this is stupid i'm sorry. lol just curious.

 

[addo]

I think you're going to get told much less gently, that an electric motor can't meet operating CFM requirements for forced induction, without sucking more power from the motor than it adds. A grunty electric motor needs heaps of juice, and this may require a massive alternator - or even two.

It doesn't stop people spruiking the idea on Evilbay, though.

 

[Anonymous]

An electric leaf blower might add 1 foot pound of torque to your engine from idle to 1500 RPM, and then lose power after that.

There is one electric supercharger out there that is basicly a Vortech run by an electric starter. Only works for a few seconds at a time (less than 15 or 20?), and really needs its own batteries charged through an isolator.

 

[rust collector]

I may be wrong, again, but I think it was a tuning question?

 

[addo]

In a sense, yes. Yet it revolved around an assumption that is almost impossible. That was why I and Linc answered thus.

 

[Anonymous]

Quick answer: Carbs need to be tuned differently for different amounts of boost.

RERALLY quick answer: It depends!! ( I AM serious!!) You don't know how something is going to react until it actually reacts.

 

[Anonymous]

First of all I hope you didn't buy an electric boost device.

"There is a sucker born every minute" P.T. Barnum

Tuning is exactly what you call it. Changing settings and evaluating the results. When you have read a little more and understand the conditions that are discussed, you will probably have some pointed questions.

I would be happy to start a discussion of basic tuning elements if you guy's out there want to find out where to start.

Once again I feel like this is one of the best forums I have followed, and I am very excited about the progress Mike made at SEMA.


If you read this and want more info then just post a "yes"
and we'll all get it started. Might be interesting.

 

[Anonymous]

nah, dont worry i didnt buy one for that purpose. i actually had one that puts out a great deal of air laying around. i was thinking like the difference in stock intake and K&N intake, why wouldnt slight pressure help? after all, a one barrel takes about as much air as i could blow in myself. guess it was a half dumb question, but the carb part i was still curious about. i dont remember how to tell if your running rich or lean (without sensors) and that sort of stuff. also, would it have enough to creat positive pressure in say, a small 1.6l four cylinder which is fuel injected? hmmm

 

[addo]

It's not just the volume of air that something pushes out, but the pressure at which it may do so. There's plenty of stuff that can move serious CFM at no additional pressure to ambient. But the minute you want "boost" in the form of pressure over atmospheric conditions, these devices flake out.

It's why cheap compressors often claim outrageous CFM for small units. Once the screws are tightened, they're gutless.

Rich or lean running may be roughly gauged by exhaust pipe deposits, and plug appearance.

Regards, Adam.

 

[Anonymous]

black smut on your exhaust tips means your running too rich right?
i advanced my engine timing almost all the way (ignitor distributer conversion) before it ran smooth, so possibly its running wayyy to rich and wasting a load of gas in the process. :/ does this sound correct?

 

[addo]

Heavy carbon deposits to the exhaust indicate oil consumption or rich running, yes. So - if you're not burning excess oil, it's running rich.

To an extent it can also reflect driving conditions. City driving uses the accelerator pump a lot, so the motor does run rich many times - even if only briefly.

A friend used to live in Zimbabwe and the neighbours were 60 miles away. He said that the inside of his car's exhaust was a perfect light grey-brown, because the majority of engine operation was at ideal air/fuel ratio for economy.

 

[Anonymous]

I've done a bit of research on axial fan electric superchargers (axials are the only ones that can push the CFM a real engine needs). As mentioned earlier, these fans can push upwards of 1000cfm sometimes, but 1lb psi is the BEST you can hope for, and while it sounds like a good idea... its a wot only device and the risks of having it in your air path are just not worth it.
The design of an axial supercharger has roots in the 60's from jets where like 13+ thin metal fans would be used to compress air step by step to increase performance. A single fan cant do this, and many fans... may, but arent designed to so i wouldnt count on it. And the cost... at about 13 of those things, would rival the cost of a turbo or supercharger.

My theory on these things however is not to use them as a power adder, but as a negative pressure reducer for a boosted system. BIG gains have been found on cars by simply reducing the vaccuum of the intake system pre-compressor, mostly in stock boosted cars since factory air boxes and such leave a lot to be desired. So my idea is to take your K&N intake just like normal, but Y the intake into the axial fan and 2nd filter. This way the fan can never obstruct normal driving airflow, but when the WOT switch is triggered, the fan supplies air with no vaccuum which is easier to compressor and makes power more easily. I may test this when I turbocharger my cougar. At that level, it may be an easy $50 big hp adder, or simply annother $50 wasted, we'll see.

 

[wallaka]

http://www.turbomagazine.com/tech/0406tur_knight/

To summarize, it costs a couple thousand bucks, needs four Optima batteries (or similar quality) and added good power to an admittedly small engine. It does work, however.