Max boost, stock tune? Before codes?

[bsn]

What you are saying is the bypass is never closed and acting as a pressure regulator-that's not how it works. The LSA blower is only 1.9 liters and run at a conservative ratio for long life-if you welded the bypass shut its going to run the same boost as a properly adjusted bypass. Boost would come in harder and faster than with a bypass but it would still be the same. The spring you changed is requiring more vacuum before the bypass opens-if it is even opening now but it isn't increasing boost. If its not opening your IAT2 at part throttle is way up there and your killing fuel economy. A roots type blower ratio is always fixed to engine rpm and it can't change without a pulley change.

[Dark Sun]

Originally Posted by FASTFATBOY

I was just telling you that 540 wheel in cool air is about the limit of the stock injectors with a manual trans.

Do I think you're making 540 wheel? No, if that's the only mod you did. It will be around 510 wheel with an auto.


I can tell you this, what you have done has changed the power curve which will inherently effect the transmission as the transmission programming is not made for that power that early if it's an automatic..

Yes it’s an automatic and I’ve also been thinking about that as well. I’m not looking for anything more in power, it’s uncontrollable as it is. But I do think that some trans programming is a definite thing in my near future. HP tuner, and a dyno run hopefully soon as well. The power curve has definitely changed big time, the traction control is useless even in the lowest performance mode “wet”.

[bsn]

You still haven't explained how math and spring rates are getting you more boost. Please state what the spring rate of the factory bypass is and the spring rate or the replacement is and how you get more boost your just bringing it in sooner putting extreme stress on your rod bearings and in the long run not accomplishing anything positive and probably killing drivability and reliability. You can play with the tune or put a pedal commander on and the car will give you the impression it's on steroids. but in reality you have only changed how the car feels and with a tune can do some real damage and destroy a transmission.

P,S, There are plenty of people here making several hundred horsepower more than a stock ZL1 and the cars are 100% controllable and I bet none of them would turn down more power.

[FasNuf]

Originally Posted by Dark Sun

Yes it’s an automatic and I’ve also been thinking about that as well. I’m not looking for anything more in power, it’s uncontrollable as it is. But I do think that some trans programming is a definite thing in my near future. HP tuner, and a dyno run hopefully soon as well. The power curve has definitely changed big time, the traction control is useless even in the lowest performance mode “wet”.

Get better tires. Toyo R888r are excellent for the street as long as it never rains and ambient temps are in the mid 60's or higher. A 40 degree moring and spinning through 3rd gear is usually done unintentionally...usually

[Dark Sun]

Originally Posted by bsn

You still haven't explained how math and spring rates are getting you more boost. Please state what the spring rate of the factory bypass is and the spring rate or the replacement is and how you get more boost your just bringing it in sooner putting extreme stress on your rod bearings and in the long run not accomplishing anything positive and probably killing drivability and reliability. You can play with the tune or put a pedal commander on and the car will give you the impression it's on steroids. but in reality you have only changed how the car feels and with a tune can do some real damage and destroy a transmission.

P,S, There are plenty of people here making several hundred horsepower more than a stock ZL1 and the cars are 100% controllable and I bet none of them would turn down more power.

Your answers are here. You have to also factor in the surface area of the bypass actuator diaphragm for the amount of travel at “x” psi to start to open the bypass. Also your relative altitude to get psia, I’m at sea level so I’m using 14.7. You can get the psia from calling the airport and they’ll probably give it to you in millibars. You will notice in the diagram, that 10.24 hgv is about the same as 9.66 psia, we don’t need the “a” here because we aren’t measuring atmospheric pressure. 10” of vacuum is also about 9.66 psi. So the same spring in the bypass actuator works perfectly on vacuum and pressure. Funny how GM figured that out so that the bypass valve would be full open at 10” vacuum or 10 psi. Now I’ll admit that my bypass is not full open under vacuum, it’s actually about 3/4 open which is more than enough for circulation when not in boost. Now everyone can figure out the exact spring rate for “x” psi.

[FASTFATBOY]

Originally Posted by bsn

You still haven't explained how math and spring rates are getting you more boost. Please state what the spring rate of the factory bypass is and the spring rate or the replacement is and how you get more boost your just bringing it in sooner putting extreme stress on your rod bearings and in the long run not accomplishing anything positive and probably killing drivability and reliability. You can play with the tune or put a pedal commander on and the car will give you the impression it's on steroids. but in reality you have only changed how the car feels and with a tune can do some real damage and destroy a transmission.

P,S, There are plenty of people here making several hundred horsepower more than a stock ZL1 and the cars are 100% controllable and I bet none of them would turn down more power.

It's not getting him more boost, it can't.

When that bypass door shuts it will only make X pounds of boost and that's dictated by the pulley with everything else being stock.

He may be getting boost earlier(I doubt it) but the pulley and blower speed dictates boost level.

The only way to show more boost is make a restriction or spin the blower faster.

[bsn]

OK so you spent all that effort on your post but still didn't answer the simple question of what the factory spring rate was verses the hardware store spring-you can't because especially with a hardware store spring there is no data. What you did was put a spring that felt stiffer between your two fingers. Now the bypass closes at part throttle instead of wide open throttle, your blower is trying to compress air after the rotors and pulling a vacuum before them creating heat. Yes the car feels more responsive but your not making anymore power just bringing it in sooner. As has been stated over and over on a roots type blower you can't make more boost without a pulley change, reduce a restriction before the rotors or add a restriction after the rotors. Boost itself is a measurement of restriction.

[Dark Sun]

Originally Posted by bsn

OK so you spent all that effort on your post but still didn't answer the simple question of what the factory spring rate was verses the hardware store spring-you can't because especially with a hardware store spring there is no data. What you did was put a spring that felt stiffer between your two fingers. Now the bypass closes at part throttle instead of wide open throttle, your blower is trying to compress air after the rotors and pulling a vacuum before them creating heat. Yes the car feels more responsive but your not making anymore power just bringing it in sooner. As has been stated over and over on a roots type blower you can't make more boost without a pulley change, reduce a restriction before the rotors or add a restriction after the rotors. Boost itself is a measurement of restriction.

Yup that’s exactly how I did it, the ol finger squeeze. So my question is, why would I give the information I did to figure this out to anyone? Why tell, when I can teach, I’ll give the equations out and you can do the math. So I’ll give you a hint to help, if the spring in the actuator moves 1” at 10 hgv, and 10 hgv equals 9.66 psi, there’s your first spring rate.
Second, if the blower has a hole in it that’s venting pressure/cfm, that makes it adjustable just like a blow off valve or waste gates. If not, it would have a burst plate or pop off valve for “x” psi. This is how the ECM can maintain an exact psi throughout the rpm range with a mechanically fixed Supercharger. This was figured out in WW2 with supercharged aircraft. They had a lever in the cockpit that when pushed, would increase the spring pressure on the bypass, and raise boost to maximum power for takeoff, and reduce in flight depending on altitude, when power was needed again in fighting for climbing etc, push it forward again. So I’ve done nothing new here.

[gtstorey]

Originally Posted by Dark Sun

So my question is, why would I give the information I did to figure this out to anyone?

So why is anyone supposed to answer you original question?

[Dark Sun]

Originally Posted by FASTFATBOY

It's not getting him more boost, it can't.

When that bypass door shuts it will only make X pounds of boost and that's dictated by the pulley with everything else being stock.

He may be getting boost earlier(I doubt it) but the pulley and blower speed dictates boost level.

The only way to show more boost is make a restriction or spin the blower faster.

So you are saying that the bypass valve is fully closed anytime the supercharger is in boost through out the rpm range? I understand it to work like this, bypass closed to build boost, as the boost increases, the ECM opens the bypass actuator to bleed and maintain “x” psi, as rpm increases, the bypass valve opens further and further, maintaining “x” psi as the rpm goes higher. So if the supercharger is throwing away extra cfm/psi it’s not using through the bypass, I can’t tap into that and use it?

[Dark Sun]

Originally Posted by gtstorey

So why is anyone supposed to answer you original question?

I don’t care if they do, I’ll figure it out anyway just like I did this. I’m just sorry everyone thinks they have a full understanding of how this supercharger works or the bypass valve. All I’ve done is use information I learned from previous boost experience and information from the 1940’s. Everyone thinks all this technology is new, but in fact it’s all from the 1940’s war planes, MAP, MAF, speed density, direct injection. Howard Hughes figured a way to almost triple the range of the P47’s by increasing the boost and leaning the fuel

[bsn]

To answer your question, yes when under boost the bypass closes and stays closed. Using your logic everyone that has changed a pulley wouldn't get any more boost because the computer would be regulating the bypass. The superchargers in airplanes were over boosted with a two stage supercharger to increase high altitude performance, so yes on those there was a way to bypass the second stage to decrease fuel consumption. Maybe as you said in your other post your car is a 1 of 1 and it has a magic supercharger but thats not how it works for every other LSA.

[FASTFATBOY]

Originally Posted by Dark Sun

So you are saying that the bypass valve is fully closed anytime the supercharger is in boost through out the rpm range? I understand it to work like this, bypass closed to build boost, as the boost increases, the ECM opens the bypass actuator to bleed and maintain “x” psi, as rpm increases, the bypass valve opens further and further, maintaining “x” psi as the rpm goes higher. So if the supercharger is throwing away extra cfm/psi it’s not using through the bypass, I can’t tap into that and use it?

It does not work like that, the bypass does not "maintain X pressure" under WOT, it may under part throttle.


When vacuum drops past "X" and the ecm see's the TPS high enough yes the flap closes.

Once again, the blower pulley and or RPM dictates max boost(all else being stock or the same car to car), and nothing else. When that flap closes and you are at 3500 rpm the rpm of the blower speed dictates available boost, not the bypass valve.

Traction control is handled by the throttle plate and timing AKA "Torque Management"

DA also contributes to max boost some.

I have a screen shot of one of my datalogs with a 2.4 upper pulley, I will try and post it.

This car sees 14lbs right before you shift it with a 2.4 upper pulley in cold air, notice the boost PSI, the TPS% and RPM on this log. Pedal is on the floor at 34 mph, pretty sure this is 2nd gear(manual).





This is when I shifted it, notice the same numbers.

[Bigtime53]