6Speeder

Now you're just throwing dust in the air. Your point was a car with stock tune will have a higher top speed at altitude than at sea level. You're wrong. Your point that you can just repulley the stock supercharger and make the same HP as a stock car at sea level is also wrong. The stock supercharger will just be making heat if you spin it that fast. Your point that at equal MAP's the oxygen content is the same is also wrong PRECISELY BECAUSE the IAT's will be vastly different.

Mikec7z

a BMS filter alone can get a car at sea level on a cold night into the p0106 limit.

So... you are telling me.. that that tiny increase in airflow and thus pressure... to hit the map limit at sea level, can't also be done at altitude to hit the same map limit... by adding a smaller pulley, intake, ported TB and x pipe?

... because there are people on this forum throwing the map limit p0106 code above 5000 ft with those mods alone.

Limit is the limit. If the car is at its map limit, its at its map limit. It goes into limp mode. Period. No top speed race will be won in limp mode, not sure if that part of reality is evading you or what.

A second ago you are telling me the car will run lean if you add anymore air... how? First of all the cars are programmed to run rich as they approach the map limit... but lets pretend im wrong and that is a lie for a second... lets do it your way instead...

If your statement is correct that its impossible to get as much oxygen into the engine at altitude and not match the map from sea level by doing upgrades... then how could the car possibly run lean at high altitude (which you say is a fear that they will run lean at high altitude)?

How are people hitting the p0106 limit at high altitude if spinning the blower even 8% faster ONLY creates heat and no more boost (according to you)? Every car at sea level would be running lean and exploding their engines if anything you are saying were reality about a car at altitude needing to worry about running lean... since according to you, sea level cars ALWAYS get more oxygen.. so we would all be running lean always and more so, and no one at altitude would ever hit p0106, it would be impossible (in your world), as spinning the blower faster does not create more pressure according to you, only more heat, so the map limit would never be reached at altitude in your world, nor would running lean at altitude ever be possible in your world.

you are contradicting yourself.

I agree heat is the enemy, but you exaggerate heat levels and how much pulley needs to be used to hit p0106 on a stock tune at altitude... you are acting like it takes a 15% bottom pulley, and doing such a pulley is nothing but heat.... when in reality it does not take that much with the other supporting air flow mods mentioned above ptb, halltech, x pipe, to hit p0106 at altitudes above 5000 ft. So if it does not take that much extra air flow... then how am i going to create all this extra heat?

I'm not.

How would people still hit p0106 at high altitude? They wouldn't

But back over here in reality, they do hit p0106 at high altitude if they put their mind to flowing more air.

Its all over this forum, people asking how to solve/prevent p0106 from happening to their car AGAIN, as it has already happened to them in the past.

According to you, p0106 is impossible at altitude... but running lean is a concern at altitude?

And those of us at sea level just have a magic spell on our cars apparently that the cars at altitude don't have, and that is why we are protected from running lean, but cars at altitude should worry about it?
Nothing you are saying makes an ounce of sense to me. And you claim you have numbers? Show me a stock tune car that is running lean as it approaches p0106. Show me.

You would be a very wealthy man as EVERY person on this forum will pay you for the secret to get their stock cars to stop running rich at 10.8 afr as their cars approach p0106. Let alone one at altitude, where according to you, there is always less o2 in the manifold. Show me this magical car that runs lean, that defies both my logic, AND your logic... since according to you, there is never as much o2 in the manifold at altitude. Show me the magic lean running stock tune c7z

6Speeder

You, my friend, are all over the map, just bouncing around. What you don't seem to get is the difference between how the stock tune responds to mods when in normal operation verses when it goes into COT. Yes, my car runs leaner than stock with my mods. Yes, with the stock tune it does go rich, but only when COT kicks in. I have every mod you listed (except I gutted the rear cats instead of wasting money on an X pipe.) And with all those mods I'm still making less HP than a stock car at sea level. There is no way I can get to stock HP levels with the stock tune and supercharger. Not at this altitude. there is no way my car with all those mods is faster than a stock car at sea level. I just don't have the HP, wish I did.

You seem fixated on this P0106 limit and have it confused with COT. I have never hit this limit of which you speak, but going rich because of the stock tune kicking into COT, of course. I have a gauge and wideband, I monitor my engine's running conditions at all times and my LTFT's are always positive in closed loop. That's running lean. Now it's not soo lean that I'm afraid she'll blow, but concerned enough that I won't add more boost with the stock tune. And when COT does kick in I'm not running in the 10:1 A/F, it's in the mid 11's. My car has never gone into limp mode and probably never will, not with the power the stock tune and stock supercharger are capable of at this altitude.

LuckyC7Z06

Mikec7z

i dont have it confused with COT... and the reason I am fixated on it is because power is created from oxygen which is matched by fuel. Oxygen is our limiting factor... so people attempt to pump more oxygen into their combustion chambers in attempts to make more power. car engine 101. With stock heads, the only way to get more air into the chamber is more map pressure at the manifold, and/or easier flowing exhaust geometry.

If i were in your shoes, and what you are telling me is true about your power levels, i would get the norcalSS catless downpipes. A true x pipe will have much better flow than gutted cats, but i would invest money in the catless downpipes first since youve already addressed the X pipe, and it is somewhat derestricted.

You are not going to run your car lean.

Sure the car gets more rich with COT situations, but the car also gets more rich the closer one gets to the MAP pressure limit of P0106 (it makes corrections and chooses to run more and more rich on its own, gm programmed it to do this to keep the car safe and power levels down)

When the goal is to make more power, and the cars have a limit to how much pressure they are allowed to see in the manifold after the screws, or if exceeded, then those programmed limits put the car into limp mode (p0106).... so you are right, this code will continue to be my focus

The other thing you could do is port your blower/snout, and if i were in your shoes, i would do this as well. Don't waste the money on a 15 or 16 blower if that is what you have currently. Upgrade to a 17+ and have it ported. You will hit the p0106 limit soon enough once you do.

Keep in mind, if you drive down off your mountain to 2000 feet, your car will be hitting p0106 as it currently sits. Your car currently can't exceed 147mph at an altitude below 2500 feet, i would bet money on it. p0106 will throw. And since this is a top speed thread, and your car will have less power than a prius at that moment, maybe you will be fixated on the code at that point as well. Or maybe you will just pretend it does not matter as you drive around at 45mph after you car goes into limp mode, just so you can pretend i have no idea what I'm talking about and you are lightyears ahead of me.

Meanwhile, i will go out on a limb and say the reason your car is making less power is because you have a heat issue due to air in your blower coolant system, and/or the fan at the dyno does not keep your HX cool enough to keep your car from pulling timing on even 1 cold pull where your car had been off prior. Certain shops on this forum are explaining that they are seeing detonation and timing pull, even on the FIRST pull right after cars have been turned on.

So your numbers being below someone elses, does not surprise me... but it does not mean its impossible to get to the stock tune map limit at the altitude that you are at currently.

Nice little play on words you did there

6Speeder

Actually, my numbers are quite good. I dyno'd at 651 SAE RWHP and 690 SAE RWTQ. I don't have an air in the intercooler issue, my IAT2 is right where you would expect. I am running the main cat delete pipes, just haven't dyno'd with them. And as I monitor continuously I know they didn't make my car run any leaner. The only problem (if it is one) is that I am unwilling to add more boost with the stock small supercharger and stock tune. More boost WOULD make it run leaner and that would not be a good thing. Even at this level my car is darn fast. From a 40 roll to 130 I pulled a car length on a friend's car which runs 10.7x's here. I've represented us Vette owners well, showing tail lights to supercharged Vipers, McLarens, Ferraris, Lamborghinis and GTRs.

Now, getting back to your point which made me jump in, no, from experience, you can't just keep adding boost and get to stock HP levels at this altitude with the stock tune and supercharger. You will run too lean and be pumping hot air, not making more power. That means, from actual numbers, not supposition, that my car will not have a higher top speed here, modded, than a stock car at sea level. I don't have the actual, uncorrected HP to do that. Your theory is wrong, a stock tune, stock supercharger won't go faster at altitude than at sea level. Period.

Mikec7z

so before your power was too low, and now it is just right...

and meanwhile, You are still contradicting yourself... you are pretending that it is possible to run lean on your car at high altitude, when you say you have less map pressure than a car at sea level. If the air were less dense of oxygen as your first posts implied it was, then your car should be running richer than a car at sea level. And cars at sea level are not running lean. You are applying old school logic to these cars, and it is completely wrong... since the computers do their own thinking and corrections... but instead of keep arguing with you about it...

Lets approach this another way, what is your AFR that you think is too lean?

I'm going to pound my head against a wall if you say anything under 12.7, since stock they are programmed to run 12.5 at WOT.

And if you don't know your AFR, and you don't have a dyno chart of what it is, and know exactly where the sniffer was plugged in on your exhaust system, ill really pound my head against a wall.

6Speeder

My car does run lean at all times before COT kicks in. My LTFT's are in the +3 to +6 range when in closed loop. My A/F when WOT is a little above 13:1 till COT kicks in and then it goes to about 11.5:1. Again that's leaner than stock with COT. The car will not run rich at altitude because of a lack of oxygen, that's really old school carburetor talk. The MAF samples the intake air and calculates the proper amount of fuel to add. Mine is running lean due to the CAI not positioning the MAF sensor exactly for the stock tune, and due to additional boost. My numbers are what they are, but the fact is even with my mods I am down in power compared to a stock car at sea level. With the stock tune and stock supercharger I will not be able to match stock numbers at this altitude.

Mikec7z

can you please provide the dyno charts for a car that does a 13.1 afr on the stock tune?

Not trying to be sarcastic, being very genuine when i say, there are many of us who would love if we could make our cars run more lean as the engine computer makes corrections and runs a 10.8 afr, and a 12.5 when we are lucky at the lower rpm's.

My guess is, your sniffer is at the back of the exhaust tips, and not at the downpipe, and thus you are not taking into account that readings back at the exhaust tips are always going to be more lean readings.

Personally, i still do not believe your car is running lean, it is virtually impossible.

We at sea level not only have more MAP, we have more oxygen in our air density... we should be running more lean than you, and we are not.

More heat in the manifold after the screws (when you spin the blower faster) means even LESS o2 per unit of pressurized air.

There are 3 reasons all in favor of your car running more rich than ours, not 1 or 2... but all 3.

Your car is not running leaner than a sea level car, it is pretty much impossible.

I'll go out on a limb and predict this again... AS you create more map pressure, your car will run more and more rich, as that is what the cars do. Your is not exempt.

You have nothing to worry about to port your blower snout.

6Speeder

My wideband is right after the exhaust manifold, not in the rear.
"Personally, i still do not believe your car is running lean, it is virtually impossible."
Believe what you want, but you're wrong.
How lean you run is determined by the MAF. Because I am running an aftermarket air intake the MAF reads the incoming airflow slightly wrong.
Yes. I dyno'd stock, then with the CAI, it was slightly leaner. I then added the 9% overdrive pulley and it dyno'd a little more lean.

Mikec7z

so the maf cheat geometry of the tube makes sense, and i had heard about this, but I have not seen where a car will stay lean once it gets past a certain map pressure.

My prediction is that IF you created more map pressure, sooner in the RPM range, your car would drive to 11 AFR sooner in the rpm range.

you may say "well that is impossible, i will run too lean leading up to that point"

but you already know the strategy to make this occur, you could take your afe intake off and put a stock intake back on with a bms air filter... then you could port your blower. See where that puts you.

After that change, you are genuinely flowing more air, making more power, making higher map after the screws and sooner in rpm range, and you will be running rich sooner in the RPM, as well as not running lean in the beginning of the pull since the maf is no longer being cheated.

Once you confirm that the car will dive below 11 afr at lower rpm as the map pressure is built at a sooner moment in the rpm range to cause the car to choose to run richer, then you may gain the confidence to put the afe back on AFTER the blower has been ported, and you have the confidence to see that the cars dive rich sooner and sooner based on map pressure limits being reached.

Frankly, you may hit p0106 with just a ported blower and the bms. If that is the case, then you know there is a limit, you know you have gotten there, and you also know you are no longer lean.

or maybe it takes the ported blower and the afe to get the p0106 to throw... either way, once you are there, i think you will understand my points that the limit of map pressure is what you will eventually hit regardless.

You running lean is a choice currently, you could choose not to, AND still flow MORE air. Its your choice, to stop fooling the maf.

If Afe and var-ram were smart, they would have it where one can clock the maf to different positions... as this would put it more and more into the air-stream. (the way the tubes cheat the maf, if they get the majority of the air to go above and below the maf sensor that goes across the pipe. By being able to clock it, it would allow a person to put it back into the zones of higher flow created by the pipes geometry)

Then a person could tune their car's afr, literally by clocking the maf around and playing with it until they get it in the perfect spot for their setup.

6Speeder

First I'm running the Halltech CAI, not the AFE. The AFE was running WAY, WAY, too lean. I understand they (AFE) fixed that by using a lower airflow filter, which makes no sense to me. As you see, the Halltech runs slightly lean, and the combo of Halltech and 9% overdrive pulley runs maybe 6% leaner, but makes great power. I can live with that. For now. Adding more boost is not the way I'm going to go. Now, without cats, I'm going to tune it, and eliminate the COT, probably aiming for 12.5-12.8 A/F across the rpm range. I seriously doubt that I'll be able to make stock power at this altitude, the stock supercharger is too small for that, but we'll see.

None of the aftermarket CAI's are designed to allow you to reclock the MAF. You get what you get.

Mikec7z

obviously it is your car, so i wont tell you what you have to do, but my point is, the answer to your complaint is the intake tube geometry cheating the maf.

Its not the flow of the air through the tube that is the problem, or even the filter, the car will choose to run the proper afr IF the car gets an accurate reading of the amount of air that is coming down the intake tube.

A person can flow more air by porting their blower with a stock intake and bms filter, vs the afe or haltech alone with a non ported blower.

The ported blower would make you more power and more map pressure after the screws. The blower being non ported in comparison, is a huge restriction.

Ill go so far as to say i would never change the pulley before i port the blower... as porting the blower reduces temps, and pulley increases them.

So if i had a choice which to do first, it would be the port job, no brainer. If I already had the pulley, i would get the port job, and remove the cheated maf tube geometry and see where I am on the dyno.

Then maybe after a couple pulls with the stock intake tube, put the haltech intake tube on, its a quick swap, can happen while strapped on the dyno, no drama to swap intake tubes.

The T-man

so is the factory blower worth messing with $/time wise?
I am thinking just jump to 2650/2900...

Mikec7z

how much more power do you want to make? over 100hp? then yes, i would go to a bigger blower and also reduce temps as the bigger blowers spin slower to accomplish 100+hp and torque numbers.

3 Z06ZR1

Really boils down to goals and how much do you want to spend and then what do you want to with the car.
Then how long down you plan on keeping it? All good questions since you are spend lots of cash.

HessViper

okay MikeC7Z, now you have my attention. First off, I am new here, I have an 03 Viper, and I am thinking about upgrading to something this year. I keep my cars for a long time as you can see. I have had the Viper since it was new.

I want to thank 6speeder and you for having this healthy debate, I believe you are both at the forefront on this topic as I have not read of anyone else with a stock tune with as many mods as 6speeder has, and still has the stock tune. The thread almost got ugly, but you both stuck with it, and I appreciate that, and I am sure others do as well. I believe you are both on a similar page now, seeing as to how 6speeder bought the downpipes that you recommended he buy, and his results were as you predicted.

I want to put up a couple disclaimers before I ask any questions.
1. I am not opinionated on these cars, I am here to learn.
2. I am an inventor of a portable security system and filed patents back in the late 90's, so I am mechanically inclined, an engineer and problem solver by trade, and I love fast cars.
3. If you assume I am countering you, please understand I am only providing my current knowledge, and I hope that you can explain where my current understandings are not accurate on these c7z cars.

I will be modest and honest and admit, when you said that the car would not become more lean with a less restrictive exhaust, I thought you were off your rocker, and I stopped reading your "nonsense".

But now that 6Speeder has created the new thread showing the gains of the Norcal SS Catless Downpipes, I am intrigued. I have re-read this thread over 3 times, with desire to understand your madness, and I believe I am finally beginning to grasp what you are saying. Please be kind to me if I am mistaken, but I want to recap your belief of how this car works with the stock tune. I will continue in my next post...

HessViper

1. There is a limit to how much the map sensor after the screws in the blower can see. If that limit is exceeded, the car will go into limp mode via engine light code p0106, which can be found when the car is plugged into a scan tool or taken to a GM dealership.

2. The car chooses to run rich and/or pulls timing if it detects knock.

3. The car chooses to run rich and/or pull timing if it sees too high of intake air temperature.

4. As the car approaches the p0106 limit, the car has a stair step effect and deliberately chooses to run more rich and/or pull timing.

5. The car determines all of its AFR decisions based on the MAF sensor readings.

6. The car can be fooled to running more lean ONLY by cheating the MAF via the geometry of the intake tube, causing more air to go above or below the MAF sensor or wire (forgive me, I have not seen one of these sensors yet). All other mods that flow more air, will be detected by the MAF and the car will match appropriately via its internal tables, and it keeps the AFR the same at all times (assuming points 1 through 4 are not in effect, as those take higher priority in the programming)

7. Derestricting the exhaust will cause the engine to breath better. If the engine breathes better, it will create more power as more 02 enters the chamber, and will also make less boost pressure at the MAP if the exhaust is derestricted, thus derestricting the exhaust can keep one of these cars away from the p0106 code as the MAP pressure is brought down but power is brought up. The car will make AFR corrections based on the MAF. (and this is why you were confident 6Speeder's car would not become more lean even though it would make more power)

Please let me know if any of the above points are incorrect.

Now for my questions...

This is where I believe I am unsure of things, does the MAF have a limit to how much air flow it can see before the car is put into limp mode? Is this another code, or still the p0106 code?

When you suggested he port his blower, is that suggestion to make more flow and also more pressure after the screws at the MAP, and you were telling him to do this AFTER he did the downpipes as those would bring his MAP pressure down first, and that cancelation in pressure would keep him away from p0106 limits?

If he had done the ported blower first, your belief is he would have started to hit the stair-step sooner, where his AFR becomes more rich due to higher MAP pressure? And that is why you were making the ported blower suggestion since he is already fearful of running lean, and the ported blower would actually make him run more rich since would bring his MAP pressures up?

Thank you all for all of your dedication to these cars, and all of your time helping those of us who are new to all of this, to better understand what you have discovered on these vehicles.

HessViper

Mike, I am in Florida also half the year. I have a place on Singer Island in Palm Beach County, Blue Heron to PGA blvd. I tried to send you a private message, but I can't. I am not sure if it is because I am new, or your privacy is set higher than others.

Please message me back directly if you can, I would like to meet you, and I will buy lunch or dinner to show my appreciation for your time, or I will take you and a friend out on my boat. Thank you for your help in solving the mysteries behind what makes these cars tic

6Speeder

I have never hit this P0106 limit and never gone into limp mode. Maybe it's because I am running at altitude, don't know. I didn't install the Norcal pipes because of his suggestion, I'm the first M7 Z06 on the forum to run these, for well over a year now. I did monitor my engine carefully (I do after nearly every mod) and saw no negative results, well except it's really loud when out of tour sound management.