Powerband

Mike · Post by **Mike** » Mon Apr 05, 2004 8:56 pm

OK... newbie here. Hello everyone.

I did a search on this and did not find an answer.

I have a 2000 Lanos automatic. Here's my problem/question:

The powerband on this car seems strange. From 0-24MPH it's weak, then from 25-to the end of 1st, it's like someone hit the Nitrous Oxide button. Then it hit's 2nd... up till EXACTLY 49MPH it's weak, then the nitrous again at 49MPH... same for 3rd, but the nitrous comes on at 80MPH. (I know it's not Nitrous Oxide but the difference is drastic not gradual or smooth.)

Any idea why this car does that? It is so weak untill it kicks in. If this is normal this is the stranges powerband I have ever seen.

Any replices appreciated.

-Thanks,

TheGreatAndPowerfulOz · Mon Apr 05, 2004 10:51 pm

My '02 Lanos is just the same way, but it isn't all THAT weak taking off from the light, though when the RPMs are higher, I can really feel the power kick in. It is strange, but my dad's Lanos and my ex's Lanos do not drive like that.
I think you just got one of the cars that is a bit peppier than some of the other Lanos' out there.

Cliff

daewooluvr · Post by **daewooluvr** » Tue Apr 06, 2004 1:26 pm

What you are expericencing is the Etec disengaging and you're Lanos running in non-emisions mode thus creating more power. Of course it's not totally without emissions but it has to do with emissions. This is what the 'E' in Etec stands for.

Mike · Post by **Mike** » Tue Apr 06, 2004 11:23 pm

Thanks for the replies. After doing some digging on this site I figured that's what it probbably is.

Anyone try to tweak this and somehow get more power out of it? There is a screw covered with what looks like a vacuum cap on the intake manifold near back of the device that contols the "E valve" (for lack of some better technical tems), anyone adjust this screw either way?

daewooluvr · Post by **daewooluvr** » Wed Apr 07, 2004 2:06 am

Mike wrote:Thanks for the replies. After doing some digging on this site I figured that's what it probbably is.

Anyone try to tweak this and somehow get more power out of it? There is a screw covered with what looks like a vacuum cap on the intake manifold near back of the device that contols the "E valve" (for lack of some better technical tems), anyone adjust this screw either way?

yes, this has been referred to as the "zip-tie" mod and it's been proven to actually hurt performance.

Mike · Post by **Mike** » Thu Apr 08, 2004 4:12 pm

daewooluvr wrote:
Mike wrote:Thanks for the replies. After doing some digging on this site I figured that's what it probbably is.

Anyone try to tweak this and somehow get more power out of it? There is a screw covered with what looks like a vacuum cap on the intake manifold near back of the device that contols the "E valve" (for lack of some better technical tems), anyone adjust this screw either way?
yes, this has been referred to as the "zip-tie" mod and it's been proven to actually hurt performance.

I am not talking about totally disabling it... I tired that before I even knew what the hell it was (thought it was EGR) and noticed a decrease in performance right away so I put it back to normal immediatley.

I was asking if there was a way of just somehow adjusting it so it releases earlier.

I assume the wires attached to what looks like a solenoid connected to what looks like a vacuum canister comes from the ECU and sends out a signal to release the valve at a caertain RPM. So... I was thinking of putting an on off switch to that solenoid so if I want it to release it a little earlier, I can control it.

Anyone try that?

Post by **PrecisionBoost** » Fri Apr 09, 2004 5:05 am

The controler you are talking about changes the intake runner geometry.

So at low speed the air goes through a longer path which results in more low end torque/horsepower.

At high RPM long path intake runners start to decrease power so the computer hits an electric solinoid to switch to a short intake runner which is most efficent at the higher RPM levels.

If you screw with this you will loose power no matter what you do.....they are engineered around specific RPM ranges to take advanatage of something called intake resonance.

Frankly most people don't understand it's purpose.... it gives better power, better fuel economy and better emissions.

This variable intake runner design is usually only found in much more expensive cars but many companies are starting to adopt it to take advantage of the added gains in power and efficency.

Some cars have as many as three different sized intake runners so that the engine makes maximum power at low,medium and high rpm.

I wish I had the link to the site showing how variable intake geometry works ..... perhaps you can find it on the internet...... it's a technical subject but very interesting.

Mike · Post by **Mike** » Fri Apr 09, 2004 3:22 pm

I did a search on this forum and I saw the information you are talking about, the valve changing the intake length.. and the design used on some Porshe's

Still, as with most modern cars, things like this are adjusted more to improve emissions rather than performnce.

It "feels" as if it is changing too late, also I think the fact that it goes from long to short in the first place gives it a extra little kick, kinda like a garden hose you pinch, and then suddenly release.. for a moment it flows much faster... hard to explain. Just a theory.

When I had it un-plugged and was drving it, off the line it was much, much slower (dreadfull), but I could feel the natural powerband, and the power came on earlier than when the valve normally releases.

I think I might play with it and see what I find. If nothing... then I wasted only a few hours of my time.

Another thing that may or may not have anything to do with it is that I live at high altitude, 5280-5800 feet above sea level.

Post by **PrecisionBoost** » Fri Apr 09, 2004 4:19 pm

I was giving it some more thought.... the tuned resonance point would be changed if you put in an aftermarket intake....so playing with it might make a difference after all.

It's much like a subwoofer port.... it's tuned to a particular resonant frequency (such as 80hz)

An engine.....much like a subwoofer displaces air at a frequency corresponding to the RPM levels.

So 600 RPM = 10 Hz.... 1200 =20Hz.... 1800=30Hz

Most people don't think of an air intake this way... but at various parts of the power band you can get "intake resonance"

Getting back to my point..... by changing to an aftermarket intake pipe you are effectivly changing the resonance points (total length of the tube)

Unfortunatly there are so many variables it would be hard to model what changes it made to the air coming in unless you used a supercomputer (like most automotive manufacturers do)

I guess fooling around with it on a dyno is the only way to really get a good idea of when the best switch point is located.

I also belive that the altitude (air density) does make a difference because this also changes the resonance points.

When doing the research they probably do the calculations at the average height over sea level.....take all the cities in the world..... add up their altitude vs sea level and divide by the number of cities.

If I were to guess it's probably something like 200 ft above sea level.

Mike · Post by **Mike** » Fri Apr 09, 2004 11:51 pm

Erfinder wrote:
I guess fooling around with it on a dyno is the only way to really get a good idea of when the best switch point is located.

That's probbably the best way, however I'm not going to take it to a dyno for that.

The changes can easily be felt in my car in my neck of the woods. So, although I don't go by butt dynos, over the years (I'm 32) I have come to trust mine to a certain point... so that's what I am going to use to test it.

Brian5475E · Post by **Brian5475E** » Fri Jun 18, 2004 5:59 pm

The zip tie does work if you do it right. I did some experimenting. If you zip tie the lever right in the middle you can use both chambers at the same time. Caqr runs good better powerband and still have top end power

Eleven · Post by **Eleven** » Tue Oct 12, 2004 5:07 pm

I have built a little circuit that controls the actuator based soley on RPM, not RPM, engine load, temp, ect like it is stock. This weekend I'll hook it up and play with it (its adjustable) also, I will got he butt dyno route until next season when we dyno the cars before the first of the events. Ill let you know

Eleven · Post by **Eleven** » Wed Oct 13, 2004 5:05 am

Got it hooked up. Still dont have the engine assembled yet tho. So, Ill have to wait to test er out. I also did an ECU hack to engage the EGR valve only when Im not concerned with performance

woo · Post by **woo** » Wed Oct 13, 2004 5:09 am

so etec is variable valve timing??

Eleven · Post by **Eleven** » Wed Oct 13, 2004 2:47 pm

Have you ever noticed how your intake manifold looks more like a mini keg than a manifold?