I have an 02 Z and a stinger, and it is throwing a code, On days with higher humidity and when it's cooler, it doesn't code, usually only get it when it's hot out. I have been driving the car for a while with code comming on and off, it doesn't hurt the car, it's not running that lean, but it's definitly worth getting the tune to get it right.... will be doing soon myself.

 

I installed the Halltech Stinger 2 weeks ago on my 2003 Z06. Also did the ram air mod up on the Halltech web site (took 3 hours start to finish).

I didn't like the rubber coupling connection between the bridge and the MAF. Clamp was too small and a PITA to get on correctly. My MAF had a tab that did not allow the bridge to sit flush when pushed together, I had to notch the bridge around the tab so that this would sit flush. If this step is not done then this sits crooked and could easily slide off (as mine did when I tested by hand) or have leaks.

Have had no problems or codes. I am assuming the codes that everyone talks about would just show up on the DIC, correct? or do you need a scan tool to see if there are any codes?

 

you would need a scan tool, doesn't show on the DIC, it just turns on the check engine light, I took mine to a dealer to have them check the code since I don't have a programmer yet....I def. agree with you Zaino, the coupling was a PITA! I was almost to the point of just buying a different coupling that was just strait hose because it would have been easier.... other than that, it rocks, can def feel an improvment. what was the ram air mod you did? was it the trap system or did you home brew it?

 

Wouldn't the codes show on the DIC if you do the magic button sequence (https://www.corvetteforum.com/techti...D=26&TopicID=1) ?

 

actually yes.... I just read about that right after I posted...doh! oh well, yeah you can check the codes that way.

 

Thanks for the shortcut to the codes:

I had
58-SDM 1 code
60-1PC 1 code
99-hvac 1 code
AO-ldcm 1 code

Didn't write down all the code numbers, couldn't find what 58-sdm stands for?

the AO-ldcm has to do with the left door control module, and I know on occasion when I shut the engine and quickly go to open my door the alarm goes off. I will have to read up on theses codes, I don't think anything is too serius because the car seems to run fine.

 

You need to tune after the Haltech or any header install. The gains are significant.

 

The Z06 MAF is so inaccurate, it is actually a guessometer. The lack of a screen (honeycomb) is responsible for occasional codes. We never see these codes on the LS1 99-2004 or the 2001 Z06, which also had a honeycomb screen.

These screens are commonly used at the entrance of Wind Tunnels to smooth the airflow, thereby approaching fully developed laminar airflow.
Without a honeycomb screen in the latter, it would be impossible to record drag coeficients and airflow dynamics for any airfoil.

GM has now returned to the "flow straightener" as they put it, on the C6. It is the same as on the LS1, size and probably tuning.



Here are some facts:


Here’s the scoop: The Mass Airflow Sensor on the 97-2000 C5, and all 2001 C5s including the Z06 have a factory (Delphi) honeycomb laminar airflow screen in front of the pickup wires. This effectively straightens the airflow and allows accurate metering of the air mass. GM thought they would increase volumetric efficiency by removing the screen the way I did in 1999, and increased the size of the MAF to 85mm appealing to the customers that thought bigger was better. It was not.


The MAF simply registers a voltage value to the PCM which in turns interprets the value to grams/second units to the injectors. Without the honeycomb laminar screen, the value is wrong, or not accurate. The O2 sensors “see” the leftover O2, and adds fuel to each of the 19 fuel cells that appear to be lean. When a 24% correction if entered in any one cell for more than 2 seconds, a 171 or 174 lean code is popped.


In 1999, I invented a venturi ramp MAF utilizing venture ends, which eliminated the need for the laminar screen, by the acceleration of the airflow through the MAF. I sold 100s of our MAFs, and they were tested by GM of Australia (Holden Special Vehicle) along with our TRIC at that time. I met with their marketing rep, and got the dyno results with our TRIC and MAF= 26.1 HP on the engine dyno on the LS1.


That was in 2000. In 2001 GM thought they were smart and ordered MAFs sans the laminar screen on the Z06, and recalibrated it slightly to measure as best it could.

The results was code city for every aftermarket airfilter, including ours.


What happens is the MAF becomes an inaccurate meter without the screen, except on the smaller 76mm unit with our venture style ramping. The 2002-2004 Z06 depends solely on the O2 sensors to correct the Long Term Trims which only allow a 24% correction value in any one of 19 fuel cells.


Generally, the idle cell is the one that trips the codes, since flow is low to the throttle body, and turbulence greater around the MAF.

Our TRAP has eliminated most codes, since I spent a lot of time making a very large plenum and straight section running from the Warhead filter to the MAF entrance.

Bottom line: We never sees codes on the LS1, the 2001 Z06 and now GM has gone back to the 2001 Z06 MAF on the C6, due to too many Z06s throwing codes both with stock and especially aftermarket systems.

“It makes no sense to make a sensor less sensitive” GM now agrees with me, and have gone back to the honeycomb screen in 2005. It will be interesting to see if they pop it out on the 2006 Z06.



Jim Hall

 

given that information, is doing a tune really the right thing to do anyways? since the sensor is incorrect, will a tune push the engine the wrong direction completely? what would be a good solution for some one like me?

 

Thanks for the detail Jim, much apprecitaed.

So, as Jim IS the expert in this area, it seems to me that the solution would be to buy a 2001 MAF sensor. Is this a correct assumption?

Jim, can you post for us a 2001 model # so we can buy it? Can we get this part through you? Is there a part we can add instead of a new maf - a couple or something with a screen in it? Any other options to avoid the check light?

I'd be really happy to avoid spending $500 on a tune-job just to not throw codes. If I did headers or exhaust a tune starts to make sense, but why spend $500 (..and a hotel room cost since I'd have to drive quite a way to get it done.) to tune for a $200 part?!

 

A good tune is your best bet. Besides dialing in the closed loop trims and WOT A/F ratio you can lower the fan temps, eliminate CAGS, eliminate TQ Management, eliminate IAT related spark retard, modify CCOT, and much more.

 

I agree with Russ B. He has quite a bit of experience tuning the C5. The 2001 MAF will solve the codes problem (lean code issue).
The MAF is about $99 bucks from GM. Order the LS1 version, it's the same as the C6 and probably cheaper.

Better yet, get LS1 edit and simply recalibrate the MAF signal that way.

Jim

 

great info on the thread-i have an 01 z-and last yr when i enlarged the airbox-$70 from WCC w/ K & N, large airbridge and connect to MAF-i thought about pulling out the screens-glad i didn't- anyway with that modification, i did notice some seat of pants gain and - a lot more noise under WOT, which i like-never dynoed it-so even if i didn't get much power gains-at least is sounds bad!!
no codes so guess i was lucky-to not have removed the screens

 

I eliminated the lean codes on my '04 Z with the Stinger by fabricating a cheap cold air mod. I agree with RB that a tune is the best way to go. I intend to get my car tuned with the Stinger as soon as I can find the time to get up to LAPD and have it done. Not looking forward to spending the money but what are you going to do. Why do you think we are called car NUTS!


Hi Jim, nice to see you back!

mark

 

As Russ indicated, the LS1 Edit Tuning may be expensive, but it is necessary to maximize the power from the LS1 or LS6.

The factory sets the air fuel ratio for WOT at around 12.3:1. This is rich and can be tuned to around 13.1:1 for max power.

Most folks think that 13:1 is lean. It is not. Lean is anything above 14.7:1, since that ratio will burn all the fuel, with no waste.

The reason 14.7:1 air fuel ratios generally do not work well in WOT, is engine load. The loading causes additional heat, which in turn causes pinging, which results in timing losses due to the knock sensors. 12.3:1 provides some cooling benefits, which reduces spark knock, allowing maximum timing. What would happen if you could run say 13.5:1, without spark knock? More power, less wasted fuel out the tail-pipe.

Remember, the above applies only to WOT or under load (open loop) trims. You cannot reset the other partial throttle settings, called closed loop, since they always return to stoichiometric or 14.7:1 no matter what mods you add to the car. In fact, that is what causes the codes at times.

The PCM attempts to correct the injector pulse width, to either add or delete fuel in the closed loop fuel trims. A record of this called Long Term Fuel Trims, is kept in the PCM for each of the 16 or so fuel trims. If even one fuel cell, sees more than 24% additional fuel or 10% fuel deletion for more than 2 seconds, it pops a lean or rich code accordingly.

This simply means that too much corrrection between the MAF signal, and the O2 sensors have been the case in maybe only one cell. It is usually idle or just off idle cells that cause this. The laminar flow screen in the MAF decreases the errors in the MAF metering, allowing the use of aftermarket systems more readily.

One last thing. Our Halltech 2002 Z06 Twin Turbo, with a stock LS6 motor (except for low compression heads), made 602 RWHP at 8.7 PSI boost, with 21 degrees timing, 91 Octane, and an air fuel ratio of over 13:1. The secret to this remains with me, but can be verified with Andy at A&A Corvette, since he did the dyno and knows the motor. He built it.

Food for thought. Most Supercharged motors at set up fat at around 11:1 to 12:1 air fuel ratio. Mallett told me he sets them up at 10.5:1 eek: . This is truely unnecessary, but that's another story.

Jim Hall :

 

Seems that a screened MAF would cancel any airflow gains.. This is why it was removed in the first place.... might as well leave the stock intake and no MAF screen..

 

We made 602 RWHP on our LS6 Twin Turbo, using the screened MAF. The screen is not restrictive.

Jim