SpinMonster

Before getting into this write-up, I would like to ask each person reading to know a big part of my motivation is the St. Judes fundraising effort on this board. I dont think its much of a reach to understand why this cause is so important but unless you suffer such a painful loss as a result of a childnood destroyed by various illnesses I dont think you could see it from the point of view of it happening to your world. The loss of a child changes you forever and I will never be able to relay the pain associated with it. Take a moment and send 20 bucks to this charity. We have the means to send robots to mars so I believe we can beat cancer, sudden infant death, and form new medications.

I have a dream.....that one day it will say St Jude's Donor under everyone's name.

---------------Make a difference TODAY------------------
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1) Personal checks, cashier checks, or money orders, made out to: St. Jude Children's Hospital and mailed to "pewter99,":

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P.O. Box 17083
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Please put your forum name on the memo line of the check

2) paypal: corvettes4stjude@aol.com

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Follow promts, we get credit for this method.


THE PURPOSE OF THE THREAD:

The standard stock MAF on the LS2 (2005 to 2007) has its limitations. The first is the obvious 85mm drinking straw an asthma patient breaths through to get air into his lungs or in this case, his engine. After 500rwhp the MAF is a restriction. When using an FI application that requires the air to be metered, the unit maxes out with a limit in the 550rwhp range. Those who want the safety of a dry nitrous shot or a greater than 8psi boost from a turbo or supercharger (or a combo of the two) would see that around 5000rpm, the MAF is maxed out and cant be used to provide fueling. The use of a larger MAF unit available from various vendors such as Halltech and Lingenfelter or those who will get a vararam that comes with a 100mm housing like the one I used in this thread extends the range of the MAF because the larger diameter meter has a slower velocity and inputs a lower frequency for a given amount of airflow. On my car, the idle was at 900rpm and input a frequency of 3200HZ with the stock unit and a lower frequency of 2200 for the exact same idle speed. My car would hit 12,800HZ at 5000rpm and now sees 9400 at 5000rpms. The important gain here is that the input freq is lowered for a given airflow amount.

The biggest advantage isn’t that the car can use a dry shot on top of boost now, but rather the car will gain HP from the swap since the airflow restriction of a 85mm unit is worth a 27rwhp gain when you go to the 100mm unit as I did in my case. A friend swapped out the 100mm on his 440ci stroker and went from 510rwhp to 540rwhp. I will post up dyno sheets to show this but I’m not sure what part was the tune and what part was the MAF since they vary so much. I got the fuel back to 11.5:1 and didn’t touch timing for the average gains but didn’t remember to e-mail myself the dyno sheets. I’ll get to it for those who like such things. As far as seat of the pants you cant feel 27hp at this power level.

BEFORE WE CONTINUE- SOME BACKGROUND ON MY CAR’s MODS

I have a 2005 Z51 and I think the only thing original is the crank.
Forged LS2 366ci
228/232 114lsa CAM
LS3 heads
Ported L76 intake manifold
ECS PAXTON 2200 with vortech BOV 15PSI
LG 1 ¾ headers with cats
Z06 exhaust with SONofDREAMS NPP controller
Nitrous Express 50 WET SHOT
Z06 clutch w/fidanza Alum Flywheel (leaving for SPEC Twin in possession)
TractionMonster modded w/305 ET streets
Full oil bypass vented cranckcase (oil in the combustion lowers octane and this is FI)
CARTEK Lev 4 transmission
4.10 gears 2 hardened shafts with a 2004 Z06 diff case installed by CARTEK
Runs a 2 bar operating system utilizing a 2 BAR MAP sensor

SLEEPER:




My car is not stock and I don’t suggest that people will gain anything with a car that doesn’t have the airflow restrictions of higher HP cars.

As seen in this picture, the MAF’s cross sectional area is staggeringly better with the 100mm unit. I used the vararam’s case and a stock Z06 mitsubishi sensor. The housing also served to give me a location for a wet shark nitrous nozzle where the air inlet tube from the valve cover used to go. I dont run a oil return to my intake because octane killing oil in the combustion chamber is a bad thing.

From the top with the 85mm unit having a removed screen to see the differences inside the cases:

The black plug in this picture was removed and the nitrous nozzle fit there perfectly giving a solution that rarely happens to me so readily. Yes its a wet shot.....dont ask.

CarlRX7 has posted proof that using a screen in front of the MAF does in fact smooth out the MAF freq signal in some applications. On my car, I had enough room to the front of the sensor that it didnt make much of a difference but it did clean u some so I credit his proof as true and it doesnt hurt to use one. A search of MAF screen will find a source for a 100mm screen to use. Just epoxy it in the front of your MAF housing.

Here are two pictures of the old sensor on the car and the new sensor.

LOOK AT THE THOTTLE BODY'S HIGH POLISHED MOTOR AND EPOXY PAINTED FRAME.....ignore the wet shot solenoid.


The blank section of the input tube after the MAF is where the Meth injection nozzles will go when I remember to call Doug at ECS to get the kit from him. Maybe he will give me an early B'day present and let me get one at a big discount. Make me feel the love.

Just out of curiosity, do I win the trophy for most number of band clamps on a single intake tube?

I WILL TAKE A MOMENT FOR MYSELF

A plug for the TB that is on my car. It’s a SPINported TB that is also a bling unit on the outside. The TB has the usual porting inside that is comparable to the ones you see. I did the max bling to the outside. The TB frame is epoxy painted and the motor assembly is highly polished. Some pics:




Its $125 including return shipping. My throttle bodies do not trigger any codes nor do they require any codes to be turned off in the tune due to airflow error codes.


BACK TO BUSINESS

The metal case of the MAF concerned me and I was originally thinking it would become heat soaked which was surprisingly not the case. IAT’s never climbed out of control and popping the hood produced a cold to the touch MAF housing. I would still like to have a plastic housing like the one that Halltech produces who has been producing quality air cleaner assemblies that have the unit integrated. The separate one they sell would be the one of choice for an FI car with a S/C or turbo application. The killer bee with ther 100mm would make a great unit for a dry shot nozzle application and would allow a 175 shot on a cammed car with 600rwhp total and still have some resolution to spare. While on the subject of nitrous, anyone who follows my threads knows I am a dry shot lover. You can see here I have a wet shot. The 50 wet shot produces 224rwtq! Wet shots are second best to me because because of fuel puddling/pooling in the intake which can lead to a nitrous backfire. Such a small shot like the one I have here isn’t an issue for this but you can still have a failed fuel solenoid and go lean. I chose a wet shot over my dry shot version because the fuel solenoid takes precidence on the fuel rail even in the event of a pressure drop and inputs fuel no matter what. My dry shot controller doesn’t use the MAF for fueling and you can read about it here:

http://forums.corvetteforum.com/c6-f...wet-shots.html


HOW DO YOU INSTALL THE MAF?

The MAF doesn’t use the same connector as the 2005-2007 unit so you need to buy an adapter from Lingenfelter for the stock LS7 unit (requires a mod to the wiring). Or you can buy the Lingenfelter unit and it comes with the connector. GM sells the LS7 wiring harness with the connector.....please dont ask me for part numbers. I'm a deaf, dumb, and blind kid when I get such PM's. Your search engine and telephone works as good as mine.

For those wanting to use the LS7 unit which is now on my 2005 car, you will need to rewire the stock MAF connector to the LS7 connector and here is the pin out info:
LS2 to Z06/LS7 connector
Pin E to Pin A
Pin A to Pin D
Pin D to Pin C
Pin C to Pin B
Pin B to Pin E

LS2 to LPE style connector
Pin E to Pin A
Pin A to Pin E
Pin D to Pin C
Pin C to Pin B
Pin B to Pin D

The difference with the LS7 and the Lingenfelter MAF pin-outs is simply the reversal of PINs D and E. Lingenfelter’s connector fits the LS7 MAF but the two aforementioned wires must be reversed.

Here is a picture of the connectors. All pins are numbered looking at the bottom of the connector:

These images are from the Lingenfelter site. Contact lingenfelter for info on purchasing their MAF and instructions for downloading the MAF table tuning patch.

TUNING CHANGES

For those who buy a commercial MAF such as the lingenfelter, they give you the new tables/patch but for the guy that uses the LS7 unit the tuning will be more involved. I don’t want to spend 300 bucks on a MAF so I went the route of getting the LS7/LS3 vararam which comes with the MAF case and I bought a LS7 unit for 60 bucks if I recall. Gene Culley was quick as usual with the part which sat on my shelf for a year before I tried to get it to work. I have been told by bolt on kings that their tuner couldn’t get this to idle but it settled in with minor tuning changes so I imagine the issue was in the wiring for those attempts.

For those going to do the swap and it’s the LS7 sensor, the MAF table will need to be nearly doubled to get it to idle. This is good because that’s nearly double the resolution gain. When tweaking the MAF table remember the higher values richen up the fuel. When you first try it, the car will run massively lean to the order of +50 LTFT’s. Double the tables and tweak the idle cells separately to get where you need to be. I suggest you target the same LTFT’s you have at 55mph on the hiway and NOT the LTFT’s you have at idle. When you get the car to run at 55 correct the idle will still be off some so tweak those cells by themselves. When I rewired, I left connectors on the harness so I could disconnect the MAF sensor wires and leave the IAT wires intact for speed density tuning.

I'm sure someone will ask so to get to where my table is adjust all cells so that the 5800hz cell reads around 101 and you will be in the ball park. Simply divide 101 by your current 5800hz value and use that as a multiplier for all cells in the MAF tables and then adjust the idle cells separately.

My car runs a 2 bar MAP sensor from the cobalt GM part number: #12580698
I used HPtuners to install a 2 bar operating system and then tuned boost and PE fueling separately. I am told that this conversion can be done to the 2006 and 2007’s operating system but I don’t see it in my HPtuners OS option menu. Anyone confirm this or have a link to Hptuners’ upgrade for the current version that does the 2 bar OS?

To tune for MAF frequency, you configure the scanner to scan MAF frequency and you drive around sampling the MAF frequency and compare that to long term fuel trends and where you see the LTFT's too high (lean), you raise the corresponding cells on the MAF table up and if the LTFT's are too low (rich), you adjust the MAF cells down. If you vary cell to cell too far, it will manifest itself in a tip in throttle stumble/hesitation. Some tuners adjust only one cell and the one next to it and cant figure out why the idle has a slight jumpy nature to the rpm and its because you have to smooth the cells to either side so as to not have too big a jump during rpm variance.

If you stay within a good LTFT range at various speeds and engines loads you shouldn’t need to vary the linear slope other than the idle cells. In other words dont go adjusting cell for cell but rather the etire table to get a good average. LTFT’s are only an issue as far as getting them to lock near zero. They don’t have to be non-positive all the time while driving. You will have an issue leaning the car out in PE mode if you look for all non-positve LTFT's. Just go by what they lock at.

Keep in mind that when you raise all the cells in the high rpm MAF table, the end cells are maxxed out and wont go over 512g but if you lower them the top end cells that should be maxxed out will lower by your multiplier so try not to lower all of them at the top end if you find you need to lower the rest of the curve. Check periodically on the rate of rise of the shape of the curve. In the end a single hit of the smoothing button s your friend.
Another fact to be aware of is that for some years there is a high and low table. The last cell of the low table must agree with the first cell in the high table or there will be two input values for a single MAF frequency.

NITROUS CONSIDERATIONS:

One of the issues with dry shots would be eliminated with this MAF swap. The C6 with any real power upgrades from H/C or a stroker gets near the max reading of the stock MAF and if you do your fueling with the nitrous pointing toward the MAF, it will max it out. This write-up here will allow you to avoid this along with a mod to the IAT.

The tough thing about dry shots is the tuning. Once that hurdle is overcome, there is no fuel solenoid to fail.

My preference is a dry shot. My dry shot set-up version is different than most. I dont do the fueling by pointing at the MAF for artificial air flow readings to richen up the shot.

For a first point dry shots dont have the intial shock of a wet shot. While its less 'FAST n Furious" effect the result is that it doesnt overwhelm the tires as easy. Once you break traction, you lost.

My system didnt install the way other dry systems do. The usual tuning for a dry shot is to use one dry nozzle pointing toward the MAF to get a concentrated shot of air on the MAF making it think the incomming air is filling the entire volume of the MAF unit and the PCM commands more fuel to be dumped. You also had a hard time adjusting it a little richer or a little leaner. Aiming nozzles can max out the MAF sensor too at one point. You can set up the HPT scanner to log MAF frequency to see where you are at but there is a simple and much more accurate way to tune a dry shot. Another tuning problem is timing; it is adjusted with a timing tricker box and you never know if its working because they intercept the signal from the crank and the scan always shows the commanded timing even if the timing is being pulled.

Harris speed works has an active circiut to adjust fuel and timing curves to suit the fuel and spark retard of any application and it goes inline with the MAF. Its advantage is that it can be adjusted to any amount of fuel or timing. It is an active circuit. Its tuning is another matter. It also maxes out the MAF frequency at some point since it operates by inputting a false MAF frequency to the intercepted singnal in the harness it attaches to. This unit is a great way to tune dry shots....its 150 bucks.

My final methodology for tuning was to make a passive circiut with parts from radio shack and have the dry nozzles far from the MAF on my dry shot. This set-up isnt critical for nozzle location because the IAT circiut adds the fuel not the hit on the MAF. The MAF then gets a more even hit instead of a concentrated hit and its actually near the commanded PE a/f ratio. To get it richer I used an IAT tricker circiut. Its nothing new and wires like this:

I didnt cut the wires since a failure would then potentially alway have my car pulling timing from an open in the resistence. I simply used a resistor to short them when the actual shot fires.

The N2O would mix evenly prior to getting to the MAF and the even flow of air keeps the PE exactly at the commanded PE which is 13:1. The reason for this is that the shot will have the added fuel from a more predictable metered way without relying on the nozzles pointing at the MAF element try and guess method. I will be able to add as much fuel as I want to get the a/f to 11.8:1 where I want it (you can target any a/f ratio you want). To maximize the car's N/A operation, I wanted the circiut to pull timing and dump additional fuel only while my thumb is pushing the trigger button on my T-handle and not always while the system is armed. Off the button my car runs the hottest max effort tune I could do to my car.

Nozzle location: sorry the install isnt stealth which I just dont understand. It not a curse to have a bottle. Its a legit power adder with drag race classes.


I intercepted the signal at the MAF and installed a relay to to change resistence to the MAF's IAT sensor. (this same relay provides the ground for the relay to the nitrous solenoid so if this circiut fails due to the relay, the N2O wont fire). For those not familiar the IAT is a themal resistor and varies its resistance with the temps it is subjected to. The IAT or intake air temp sensor does exactly what it says; it measures the temperature of the incomming stream of air. In the case of my firing the nitrous the resistance is changed to make the car think that the incomming air charge is 199 degrees. Now unless you live and drive on the surface of Venus, the IAT's will never hit 199. The amount of timing is one degree more in the summer. I pull 1.5 degrees per 50HP. Now for the cool part of the tuning.

The IAT not only controls the timing curve from the IAT base spark table but on the fuel tab there is an IAT vs. Injector flow rate table (this is on the general fuel tab for C6's and the PE tab for C5's...in the C5's case its an adder for the commanded PE). In this table IFR is changed according to IAT temps. In the following screen shots of my HPtuners editor, the IAT base spark and IAT vs injector flow rate are pictured. In this first screen shot you can see where I typed in -4 degrees in the high end of the table.



In this next table the IAT vs injector flow rate adjusts the fuel to where I want it. Smaller values richen the shot. The IFR is lowered making the PCM think it has smaller injectors so it makes them dump more fuel. When you first set this up, add a good amount of fuel and pull more timing than you think you will need until you fire it a few times and scan the timing and see the wideband's final a/f ratio:



In my case the 199 degree input instructs my car to dump 8% more fuel than normal. If I want 1% less I type that change in If I want 2% more I type that in. The best part is that it all shows up in the scans. Wet shots need to have constant bottle pressure to maintan a a/f ratio (which it never is) and the only way to richen it up is to change the fuel jet. I just type in what I want and it works flawlessly.

Initially, I scanned the car safely in my driveway (later in use with a 22 shot then 50 then 75 then 100...)and bypassed my WOT switch to allow the IAT circiut to adjust the timing -4 degrees and add 8% fuel while sitting safely in my driveway and simply revving to 3500 where my shot pops in(this was without the bottle open just to see if the fuel gets dumped and timing gets pulled. The scan showed 42 degrees at that load and rpm and without moving up or down on the gas pedal and triggering the circiut, the timing fell to 38 and the long term fuel trends jumped down 8%. I wish I had saved the scans to show some screen shots but the system workd flawlessly and ends the debate in my mind of wet vs. dry.

Now some safety issues. The relay in the IAT tricker needs to be operating to supply the ground for the relay that triggers the solenoid so if the tricker doesnt function, the N2O doesnt fire.
1) The air and nitrous mixes fully to get an even reading and not a concentrated hit in the center of the MAF. This gives predictable fueling. Keep in mind that the MAF isnt used for adding the fuel on this dry system. It finds a baseline for the incoming air and the additional fuel would be added even if there was no MAF. This is the same operation as the harris sped works box. It doesnt need an MAF and it doesnt need the nozzles pointing at the MAF
2) The lack of a concentrated hit keeps the MAF frequency from maxing out and lets you run a bigger shot than you normally would be able to if you used the MAF to add fuel by concentrating the shot on the element.

I dont have to worry about a dry hit heading over the MAF and leaning out or an MAF failure. I have consistency and a degree of control that makes it so versatile. If I want say 1.23% more fuel, I enter the exact value to the decimal (98.77) in the IAT vs. Injector flow rate table. No messing where nozzles point. If the MAF fails, no problem; it isnt what adds the fuel. In the case of my speed density tuned 2005 I dont need the MAF to even be there and the MAP/VE would calculate the fueling and still compensate to the commanded PE. I have a permanantly mounted XD-16 Lc-1 wideband to monitor fuel. The fuel curve never spikes lean on the shot engagment. When you come off the pedal the car isnt under load anymore and doesnt need a sustained rich state. I couldnt get the car to spike lean before or after the shot even staying on the pedal.

I dont like the fuel solenoid and the fuel in the intake manifold idea but so many run it without issue so its up to you. I wanted to just offer an alternative.

If you are going to do this you need to get the MAF patch to extend the frequency limits for the MAF or you can potentially max out the MAF. For those that dont know what it is, on the HP tuner's editor click the operating system button in the upper left corner. A write-entire must be done to enact these changes. If anyone has questions about this system or is close by and needs a hand with its install, shoot me a PM. All my work is shareware and I share secrets. (I guess that means they arent secrets). No charge, just make a ST Judes donation.

Keep in mind that the fuel injectors need to be big enough to supply the needed fuel for the additional requirement. If you have 90% duty cycle with a H/C car and you add a 125 shot you are over the line. Think 40lb'ers for a 500rwhp car which is likely more than 550-600rwtq. Go bigger for silly numbers. Also remember that the fuel pump isnt going to support 600/700 without a boost-a-pump wet or dry. 600HP from a supercharger isnt like the 600rwhp from the bottle. The TQ is 500 for a 600rwhp S/C car and close to 700rwtq for a 475 rwhp H/C car on a 125shot. They call it TQ in a bottle.

Hope this helps.
As always, I hope your interest in this topic was helpful and if not maybe a little amusing.

Please make a donation to St Judes Hospital if you want to show appreciation. Life changes on a dime and I wish that there isn’t a single person out there that has to suffer a loss of a child. You can help save a life here and we can beat these illnesses if we all come together.

I miss you Jay …….one day……

SpinMonster

100 bucks says this is POWERLABS' next mod.

Craigster05

God Bless Jay, and you too for always remembering the children.

Great detailed write up...as usual....now how do we bolt this into my WRX Daily Driver???

SpinMonster

Actually its a common mod for your WRX. It requires the same type of software to tune the MAF.

The Granatelli MAF which people think is a bad peice is actually a great MAF once tuned using the same proceedure on the corvette. Its just not so plug and play.

How is the knee?

fperra

Just an FYI here. I started out using the Haltech MAF housing as I think it is the best design out there. However, I soon discovered that there are problems resulting from the plastic design. The clamps holding the hoses to the housing cause it to permanently distort. I ended up switching to Lingenfelter's housing, which is slightly smaller in diameter.



It did this on both sides. Now that I've seen yours, it's my next purchase.

PowerLabs

You guessed it. I'll send those 100 bucks to St. Jude's after payday this month
Spin, thank you for reminding me once again why I think you are the most valuable member of this forum. I don't see anyone else taking this much time off their day to share hard earned knowledge about how to make our cars better.

danl72

Great mod and a great cause.

oldmansan

Great post as usual Spin. As soon as I get my brakes and suspension installed I'm going to start looking at power mods.

San

dubseven

Nice writeup! Spin will be doing some clutch installs for us, and tuning my APS Vette this coming week! Cannot wait!

carlrx7

Guy,

Im in the process of installing one of A&A's v3 si kits on my car. how much to come and tune it with one of your 100mmMAFmonsters! i just need to find a dyno to rent, right?

or i can postpone the install if you wana help with that too! lol!

-carl

SpinMonster

When I get to NY ED and Sam will have to both be at the table with me for dinner. I think they willl get along just fine.

SpinMonster

An example of a complete kit for 299 that you can get:

Its a bit pricey with all the options and hoses to get it in but for people maxxing out the MAF it gives you an idea of what you can save with the Z06 sensor and a blank 4" tube if you wire things up yourself.

The tune is the hard part but any competent tuner can tackle it.

1bdasvt

,,,let's all send somethng in!!

CMY SIX

90mm will support 1200hp what's the point?

PowerLabs

Will it? My factory MAF maxes out at 5200RPM on my car; I'm making 550whp there, if that. Why do you think it will suport 1200hp?

pmj341

Great write up!!!
I've had a 100mm Maf on the shelf at home for 3 months, maybe now would be the time to install it!!! LPE with tables.!!

SpinMonster

Your statement is not true. The 100mm version I had in this test wouldnt support 1200HP. I saw 11,473hz at redline and the table's resolution is out to 12,200 so we will call it 900HP at the most.....for the 100mm.

I'm not sure where your info from but the stock MAF is maxxed out before 600rwhp.

As far as the point, there are applications that require the MAF to meter air all the time and dry nitrous shots cant be fudging the MAF resolution. Just because it isnt usefull to you doent mean it isnt of value to others. I appreciate the input though.

Lastly, without exception any car north of 600rwhp will gain 20-30rwhp just by using the bigger MAF housing due to the airflow restriction alone even if the MAF wasnt working. A 4" pipe in place of the stock MAF would gain this at WOT. Good enough reason? A Z06 tested by Halltech gained 12rwhp using the 4" housing in place of the stock airbridge and thats only 460-500rwhp. Its all about increasing airflow and the smaller MAF cant flow as well as the 100mm MAF even if you dont care about it doing its metering job.

Tony B4

Spin,

I have a question about the MAF. When accelerating(WOT) as the MAF frequency is climbing as the rpms are increasing why would someone see a drop in the frequency from say 11100 to 10600, and then after 500rpms under WOT it goes back to 11100?

Also, can the MAF frequency be tuned to be as smooth as the MAP(kPA)? Or will the MAF follow the pattern of the Calc CylAir(g/cyl)? Another words, is it possible for a N/A car to have a very smooth MAF frequency?

Thanks,

Tony B.

carlrx7

so what happens when it gets maxed out? did they set a rev limiter and call it a day?

I'm gonna have the same setup +ported fast92mm. what do i do? 100m is required now?

SpinMonster

I would have to see a scan of what you are talking about.

Yes you can have a smooth MAF table. The condition you speak about is when you tell the PCM to assign two frequency values to a given airflow value. This would happen with an MAF table that doesnt keep increasing airflow as frequency rises. A tuner that sells MAF's sent me a table for the MAF and I pointed out that it had higher values at a given frequency and then backs off. He told me the car never hits those values in actual use which was 100% false since my car maxes out the table on every run. He obviously has little or no experience with FI cars nitrous or boost.