i would love to know if anyone makes an adapter that fits the OEM 1bar hole with a simple hose fitting to run out to the new 2/3bar sensor. Lots of s/c kits come with a great setup for mounting the OEM sensor, however on some of them it is a challenge finding a boost port to run out to the external 2/3bar sensor. Not to mention the bigger plug on the 2/3 bar sensor (sounds like speed inc have that covered).

Chris...

 

Ok here is my question - why does an 11psi car need a 3 bar map. 2 should and would give much better resolution.

I have messed with EFIlive and it looks just like the HPtuner stuff in this post above. They already seem to have 2 and 3 bar option working as I saw it on the dyno at PRI in Indy last November

Next why on earth would you want to give up on a MAF when it is the only way to maintain correct barometric resolution? As air density changes a speed density system will not have the proper slue adders to correct for the changes in the amount of air for density changes. Therefore, how does one correct for air density

The MAF is ideal for accurate idle, cruise and part throttle and the 2 or 3 bar
MAP Sensor is best for forced induction that has different ramp characteristics, unlike a centrifugal.

Questions:
How long does it take to physically tune a turbo car, from scratch to completion, once converted to a Hptuner with 2 or 3-bar map

Now you do a cam change - how long would it take to retune

Now change the air temp outside by 40 degrees…… what happens? Even with the factory AIT sensor for air temp correction it can’t correct for density.

With a MAF all the hard work is done for you and it basically retunes itself.

I agree hands down at this point the EFIlive and HPtuner type systems are best for roots type and turbo type forced induction but with a centrifugal, the MAF is hands down the way to go as well as Nat Asp and Nitrous – unless you go dry and big. Does anyone address this in Hptuner or EFILive?

As I was told EFIlive has the ability to maintain target A/F ratio so that seems like the best band aid as well as at this point but a perfect system would be a 2-bar map with a MAF for perfect street use. ACCEL/DFI did this in 1995. They had a system that drove around on the MAF until 70% throttle angle (actually you could set the percentage) and then past that it would go to a 2 or 3-bar map. They seemed to be ahead of their time, as it never really took off back then. I had it on my Paxton blown Mustang and it worked very well. With a Novi2000, 347ci and other typical good parts it made 711 on pump gas with 16 total degrees. On 100 unleaded it made 768 with 22 total timing

Without the MAF, the cruise and drivability will suffer - even though the MAP Sensor tries to correct.

Not looking for a fight – trying to learn and hear opinions and speak with others that are knowledgeable in this field.

 

I was wondering the same thing actually.

 

Everyone knows I make tons of MAFs (as the owner of Granatelli MotorSports)and I did not want to come off like I was Bias. I was very impressed with EFILive when I saw it. I asked them if they could make the meter work with the 2 and 3 bar MAP and they said they could but never thought about like that. It is my opinion that 95% of the customers out there only care about BALL-OUT Performance. Most are willing to sacrifice a little drivablity as long as the car will start and stop, not stall, not over heatand cruise. I look at it all from a 50-state legal stand point. That is not to my existing 800+ hp 04 ZO6 vette is 50 state legal but it has the MAF on it and my wife can drive it and she is non the wiser as to what is done under the hood unless she steps on it. Then she hates it cuz it smokes the tires and trys to do a U-Turn regardless of speed.

I liked it better at 500 for cruising around town but why give up te extra 300hp so I leave it at 800 and drive it when I feel like being a dick. bottom line it will cruise down the road at 14 in/hg and what I find most impressive as will most of you is I can set the cruise control at lets say 130mph, then tap the breaks. Now go down the road in 6th gear at 50 and hit resume. the car goes from 14 in/hg vac to 12psi boost and near sputters or spits once. Granted, while most can't feel it "seat of the pants" the wide band shows a quick flash to 13.2 before it goes back down to 12.2 al the way back to 130.

So get this, it will cruise down the road at 14.4 to 14.7 then in 6th without ever down shifting hit resume and it feels like you got tapped from behind. A/f goes from 14.4 to 11.5 then blips to 13.2 and then stays pretty much at 12.2 until i tap the breaks.

I belive if I had the best of both worlds the MAP and MAF then It would be the ultimate. I am currently working and an LS2 motor and that I hope to put into a 05 Cobalt Pro-stock car and go 6.99 or better. It will be twin turbo'd with either twin MAFs (one on each inlet) or a single blow through MAF. It will also use a 3 bar MAP. while it will be a drag car, i hope to drive it on the street jsut to prove to myself and the locals that we can make 1800hp and still have "some" street manners. I have already priven with a basic stock style cam you can make 1450 and never miss a beat

 

The "street manners" SD point has been proven false time and time again, in Australia Holden HSV released a factory 400hp SD tuned car, there was no uproar that it was a pig to drive.

My personal experience is, I drive a 8PSI s/c 2bar SD setup everyday (and before that a NA SD setup), i have a 245@50 108lsa cam and it idles at 850 and drives along just fine.

Highway cruising fuel econonmy bears little relationship to the airflow calculation method (SD or MAF) as you are in closed loop and the O2 sensors are doing all the work by adjusting fuel trims.

MAF is a good device for saving OEM calibration engineers a lot of work, and when worked in conjunction with a reasonable transient response system (ie. SD system such as in the LS1) the airflow prediction from it is pretty good. There is no reason why you can't spend the time tuning SD and get the same, if not better result. The key here is "spend the time"

edit: i too would like to see a SD+MAF setup work, but the 512 g/sec limit is a big disincentive to put the effort in.



Chris...

 

Chris / Game Over - OK I hear you but of coure we can agree to disagree (and agree at the same time) You talk about "spending the time" and I agree. I hardly think it is fair to say the MAF is only there to save the OE guys a ton of time though. You you basically prove my point. The MAF can do the cruise and low mapping and the SD part can take over under heavier load.

"edit: i too would like to see a SD+MAF setup work, but the 512 g/sec limit is a big disincentive to put the effort in."

You lost me here...this is exactly what I am talking about. Let the MAF go to 500 g/sec and then stop looking at it and go straight EFIlive or HPTuner from there.

 

i syched !
03 c5 vert w/forged 8.7 waiting for ptk te44 twins
my new blitz sbc is going to like it! ill be able just to wick it up w.3 bar map.

that is correct? w/out 3 bar car is tuned for specific boost level and thats it unless load new file?

 

The "street manners" SD point has been proven false time and time again, in Australia Holden HSV released a factory 400hp SD tuned car, there was no uproar that it was a pig to drive.

ALSO I never said SD was or would be a pig. Even Chrysler is going to MAF for thier street cars. FAST, Motec, Accel, AEM - you name it they all offer the ability to work with the MAF.

We also have the ability to rescale the MAFs. Therefore we can set the the 0 to 5 volt or in GM speak 0 to 20000 reference points. As an example - We can make the meter show 20k at 1600 cfm as opposed to 1150cfm

 

Call me.
Maybe we can work something out

 

Us FI'ed guys have been asking for an MAF that could read beyond 512g/s but nothing has ever been offered up....you are here now, but where were you when we were asking for a MAF that could read past the stock GM MAF limits? Why hasn't a extend range FI MAF been offered for sale?

 

i'm sure we can, LOL.

Guys, FYI, Ken has a fetish for a twin MAF setup. HPTuners will not rest until it is satisfied

 

Pro Stock John and some of the other old timers know that I am not big on coming to these sites and posting. I always get bashed. In fact if you look closely very few on the Manufactures OWNERS come on because we get flooded with negative bashing. I had many a spat with John and others . I have been told for years that my MAFs don't work BLAH BLAH BLAH and I was sick of having to defend a product that time in and time out has been a proven winner. I read what a lot of keyboard cowboys say and realize there is nothing tech about them. THIS IS NOT DIRECTED AT ANYONE HERE "YET "

So what is the bottom line? Know one ever called ME or my staff at GMS and said we need a meter to exceed 20k. I have spoken to Lingenfelter, MTI, Katech, Gulstrand, and Mallet – they all said the same thing, “we don’t need it. We know how to tune around it” So I never did it for them. This is why I think a system that could do both would be the way to go.

I dyno’d a LS1 TT motor with Motec and Merc Marine coil on plug system 2 years ago with a single 76mm turbo. It was MAF until 50% and then 2 bar MAP. We made 812 on pump gas and I was impressed on how nice the package turned out. We installed it into a ratty 56 Chevy and before the project was done it car was totaled and I never heard back from the guy.

Mark my words, switching from MAF to SD is just the latest craze that will ultimately land where the true superior package is a combo of both and the first company to do this successfully (we have) will make a ton of happy customers. Our problem is we don’t selling we do it in house. GMS has no plans to do this either. We will leave that up to the LS1edits, HPtuners and EFILive’s of the World. My money is on EFILive based on what I saw at PRI. I have seen HPtuners and it seems very capable as well.

GMS is here to help. We are happy to donate parts tech and knowledge to companies or individuals that our sincere NOT BASHERS

 

:sigh: Play nice...

 

play nice... I think the questions asked are good and useful information has been provided by both sides..

 

So the computer compensates for intake temp changes with the fuel trims in closed loop mode with the 2/3 bar MAP setup?

What about if a car has an open loop tune for race gas? I think that's how the car in the FI section is tuned right?

 

Granatelli

How is your MAF superior to the stock piece? What have your results shown? Do you offer accurate calibration curves to the end user if he/she has the capability of compensating with editing software?

I could be wrong here but the actual MAF itself is not the limiting factor, its the PCM....am I correct on this? Is this why you state you'll leave it up to the EFILives and HPTuners of the world?

Just a few Q's I had off the top of my head.

thanks

 

The PCM is the limiting factor since it can only read up to 512g/sec, say at 12000Hz MAF output for example. A MAF could be calibrated though to output 12000Hz when it's flowing 1024g/sec. Now you would have to half your injector size and any table related to load but, you would basically now have a MAF and PCM that could read twice what the stock setup could.

That is a VERY simple explanation. I've never done this so I don't know exactly what tables would need modded.

 

right, and at the same time you're losing resolution. So can the stock piece still be used at that range, assuming you sent it off to get flow tested and mapped out, or do you have to get an aftermarket piece ala harlan?

 

you are exactly right. The MAF is not the limiting factor, you can make a giant MAF that puts out 50kHz and flows 2000 g/sec but the stock PCM will only read up to 512 g/sec.

I've got nothing against MAFs, they are quite accurate at measuring airflow. What you need to keep in mind is their is a difference between measuring airflow before the TB and using that measurement for estimating the cylinder airmass. This is true for boosted and NA applications. Thats why the SD code is in the PCM, to cover for the MAF during lower RPM throttle transients. Here's a post i did a while ago about this:

http://www.hptuners.com/forum/YaBB.p...num=1101917527

If the upper limit in the PCM was 1024 or 2048 g/sec for the MAF we probably wouldn't be having this conversation, cos people would have both setups already...

 

Hp Tuners keep the good news coming, Frank me and you can figure this out when I get this upgrade....looks like it will be fun to mess with.
J