View Full Version : VE & MAF: How do the Pros do it??


Dave F
11-06-2005, 06:29 AM
When you go into a shop for a $500 dyno tune, I assume they just tune the PE and spark tables???? There is no way they can tune the VE and MAF tables in that period of time.

The exception is for engine "packages" where they can just reflash everything the same, car to car.

Any problem just tuning PE and spark, or am I missing something?

HumpinSS
11-06-2005, 09:23 AM
1. They tune the IFR table to get th trims negative and then fool around with the pe table until the AFR falls in line.

2. They add air to the maf table to get the trims negative and then fool around with the pe table until they get the desired AFR

3. They do both above and aweek later the cars idle goes to hell....

TAQuickness
11-06-2005, 09:30 AM
dyno tunes are primarily focused on WOT. If that is your only concern, than many "pro tuners" will meet your needs. If you have any intention of driving the car on the street, then you need to spend more time with your spark tables, VE, etc...

the best way to tune your car for street, or part throttle opperation, is on the street with your own tuning software. Dyno's don't simulate rush hour traffic very well. I would encourage you to 1) find a dyno-tuner that can tune PT for you, 2) compare the cost of that tune to what it would cost you to do it your self.

Check out the stickies above for help selecting what tuning software is right for you

RedHardSupra
11-06-2005, 09:54 AM
real tuning can take forever, that's why these hacks that call themselves pro tuners (with two notable exceptions that i've managed to come across) just do wot in 20 mins on a dyno, grab your 500bux and call it a day. great business model, but no so peachy for the car and the car's owner.
they try to compensate for lack of knowledge (or just willingness to take the time to do it right) with more hardware. got a low rpm bucking problems? oh, you must get 4.11 gears! can't figure out how to calibrate MAF? throw it out! etc...

the truth is that tuning these cars, as slopilly assembled as they are, is a moving target. weather, altitude, conditions, brand of gas, all contribute to sometimes significant swings in values, so getting a 'dyno tune' is a bad idea, because it's a tune for a snapshot in timespace.

tuning is a process, not a job. most people just want some magical sets of numbers that will make their cars right. not only they don't exist, they're perpetually changing.
that's why you get your software, and scan it till you get a good idea how your car behaves with all the changes around it.

no 'pro' can afford driving around for a month seeing how your car behaves, and than spend days tweaking one parameter at a time and letting it all settle and adjust. it would be impossible to take enough time to do it right and make it a profitable business. i've spent over 10 hrs just tuning idle and 'around town' drivability of a headers and cam car. at shop prices, that would be like a 1000 dollar job. would you pay $1000 so you car doesn't stall or buckle? i wouldn't. that's why tuning makes much more sense as a hobby, not as a job.

ninobrn99
11-06-2005, 10:08 AM
:ripped:Thats a $350 lesson Ive learned :D Then the 550 for tuners and the $200 for EFILive and the $100 for my Actron scanner. Now if I could only get the car to run so I can tune it :jest:

Dave F
11-06-2005, 07:07 PM
I'm not asking for a how-to, as I've done some of my own, and will NOT be using a pro. However, I'm just curious about it.

Assuming the car is not so modded up that the LTRM's can stabilize and compensate properly, won't tuning the PE's work just fine??? I realize getting 0 fuel trims is the goal of life for some of you guys, but aren't the doing exactly what they are designed to do????

Thanks, and flame if you must.

Bombguy99z28
11-06-2005, 07:41 PM
What I don't get is mail order tunes... to me that seems like the most retarded thing ever.

Bink
11-06-2005, 08:03 PM
I'm not asking for a how-to, as I've done some of my own, and will NOT be using a pro. However, I'm just curious about it.

Assuming the car is not so modded up that the LTRM's can stabilize and compensate properly, won't tuning the PE's work just fine??? I realize getting 0 fuel trims is the goal of life for some of you guys, but aren't the doing exactly what they are designed to do????

Thanks, and flame if you must.

Dave - For your type of driving PE and IFR are probably okay - since your in the 3000+ -> 7000 RPM range most of the time.
But for part throttle manners, with a decent cam on the street, there is a lot more that can be accomplished. A big cam can be tuned to surprising driveability........in heavy traffic. :D

ninobrn99
11-06-2005, 08:22 PM
:werd:

slow
11-06-2005, 09:29 PM
PE and IFR tuning, is a clear lack of understanding of the control system.

IFR should only be changed when you change the fuel delivery system.

PE is your "commanded air fuel ratio" you should "set" this to what you want, not "tweak" it to get desired results. You need to change the value that is incorrect, after the fueling is correct, your commanded air fuel is what you want, then the airflow tables need the adjustments.

A "knowledgeable" tuner can do mailorder and be as good or better than some of the dyno shop hacks I have seen in the past.

MAF tuning can be done quickly, the VE takes a lot longer.

Ryan

Pro Mouse
11-06-2005, 09:42 PM
real tuning can take forever, that's why these hacks that call themselves pro tuners (with two notable exceptions that i've managed to come across) just do wot in 20 mins on a dyno, grab your 500bux and call it a day. great business model, but no so peachy for the car and the car's owner.
they try to compensate for lack of knowledge (or just willingness to take the time to do it right) with more hardware. got a low rpm bucking problems? oh, you must get 4.11 gears! can't figure out how to calibrate MAF? throw it out! etc...

the truth is that tuning these cars, as slopilly assembled as they are, is a moving target. weather, altitude, conditions, brand of gas, all contribute to sometimes significant swings in values, so getting a 'dyno tune' is a bad idea, because it's a tune for a snapshot in timespace.

tuning is a process, not a job. most people just want some magical sets of numbers that will make their cars right. not only they don't exist, they're perpetually changing.
that's why you get your software, and scan it till you get a good idea how your car behaves with all the changes around it.

no 'pro' can afford driving around for a month seeing how your car behaves, and than spend days tweaking one parameter at a time and letting it all settle and adjust. it would be impossible to take enough time to do it right and make it a profitable business. i've spent over 10 hrs just tuning idle and 'around town' drivability of a headers and cam car. at shop prices, that would be like a 1000 dollar job. would you pay $1000 so you car doesn't stall or buckle? i wouldn't. that's why tuning makes much more sense as a hobby, not as a job.

Hats Off to RedHardSupra,This is so Freaking TRUE! Been there Done that.Now My Hobby is HPT I love it!I got my drivabilty and Idle pretty close and it took lots of time and playing.I am glad I spent the 500 bucks,Trying to get my Tuner to do what I did would have been Big Dollars between paying tuner and Missing work :bang:

soundengineer
11-06-2005, 09:44 PM
What I don't get is mail order tunes... to me that seems like the most retarded thing ever.


I fixed 3 mail order tunes this past week...and It would have been 4 except for the 1 was locked.....and it was a crappy knocking lean mixture fuel trims way out of whack car doesnt idle right supercharged application...

oh yeah..almost forgot to mention.....
these "mail order tunes" were supposedly from some pretty reputable names and places....god thing I'm not a name basher

wkdivr
11-06-2005, 09:44 PM
PE and IFR tuning, is a clear lack of understanding of the control system.

IFR should only be changed when you change the fuel delivery system.

PE is your "commanded air fuel ratio" you should "set" this to what you want, not "tweak" it to get desired results. You need to change the value that is incorrect, after the fueling is correct, your commanded air fuel is what you want, then the airflow tables need the adjustments.

A "knowledgeable" tuner can do mailorder and be as good or better than some of the dyno shop hacks I have seen in the past.

MAF tuning can be done quickly, the VE takes a lot longer.

Ryan




How else would you change your fueling under WOT other than the PE Multiplier?

soundengineer
11-06-2005, 09:49 PM
How else would you change your fueling under WOT other than the PE Multiplier?


you set PE to what you want it to command..its a direct multiplier of the VE table #'s...
so you tune VE with PE setup just as you want it and dial it in with a wideband...
when you tune the PE at lets say 1.14(or 14.63 / 1.14 = 12.83333...roughly)
and you are tuning your VE then your AFR error which is derived from the commanded and actual AFR's
the the cells that enter PE will be commanding 1.14 or 12.8333333 and fueling will be correct.
you do a wideband to match the MAF as well..same concept..different table...
when the 2 are correct....PE fueling will be right as well.
and it will be accurate and consistent

slow
11-06-2005, 09:51 PM
If the computer knows what the fuel injectors flow,and if the computer knows what your commanded air fuel ratio is, then the only thing that is not correct to get the correct output, is the airflow values.

The maf, and the VE tables are both airflow tables. You want to adjust your airflow values to get the actual air fuel ratio to match what your commanding.

edit: SoundEngineer beat me to the reply.

Ryan

soundengineer
11-06-2005, 10:00 PM
edit: SoundEngineer beat me to the reply.




LOL...I'm good that way...LOL

joecar
11-07-2005, 02:01 AM
RedHardSupra,

Well spoken.
Tuning for daily-drivability does take a LOT of time, and only a DIY-hobbyist will spend that time over and over to get as close as possible (...and not regret it...).

I am wondering something... To get the IFR table right, do I just use the Spreadsheet to calculate it...?
Is there any feedback that will tell me that it is right (when my VE table is not quite right yet)...?

[...Your location is now Calif...? Welcome, and enjoy...].

Bombguy99z28
11-07-2005, 02:08 AM
When in open loop AFR can also be adjusted by the MAF table, because it is still adding fuel based on the MAF table. I've seen it in my vette, I was wondering why my AFR was lean at WOT after I tossed the vararam on, was about +7 ltft in the higher range and narrawbands reading 800-820. Rescaled MAF table and narrowbands back to 920ish. Thats why if you don't tune the MAF table your AF/R will never be right, unless you're going speed density.

How else would you change your fueling under WOT other than the PE Multiplier?

ToplessTexan
11-07-2005, 08:14 AM
When you go into a shop for a $500 dyno tune, I assume they just tune the PE and spark tables???? There is no way they can tune the VE and MAF tables in that period of time.

The exception is for engine "packages" where they can just reflash everything the same, car to car.

Any problem just tuning PE and spark, or am I missing something?

David, I agree with your basic premise. However, I'll throw out the radical idea that your second point can be generalized.

If a shop sees a large enough volume of work and chose to invest some time with whatever small number of "popular configurations" they can justify, this info could easily be incorporated into multiple tunes. (I.e. why stop with just their own packages.) The goal would be to improve the starting point of the iteration such that it could be polished quickly, rather than starting from scracth in each case. The feasibility of this is dependent the percentage of "popular configurations" that roll out their door. If it's 90, then it's a great plan. If it's 5, it sucks.

In fact, building up and using such a database would be a reasonable way for a a tuner to compete with self tuning (and in my book what should have been happening for the last four or five years.) The easier self tuning gets, the harder it will be for them to stay invested in the tooling. If better tuning requires more time, they have to discover ways of automating business process and reusing invested time.

I can believe the data management and analysis aspects of this concept could be a huge barrier for many shops and the principle reason you won't see it practiced much.

soundengineer
11-07-2005, 08:25 AM
When in open loop AFR can also be adjusted by the MAF table, because it is still adding fuel based on the MAF table. I've seen it in my vette, I was wondering why my AFR was lean at WOT after I tossed the vararam on, was about +7 ltft in the higher range and narrawbands reading 800-820. Rescaled MAF table and narrowbands back to 920ish. Thats why if you don't tune the MAF table your AF/R will never be right, unless you're going speed density.

no it cant
If you understand how the MAF works on our LS1's
then you would understand that the Maf is Only used at a "steady state" condition and is blended with the VE...


the VE table is used for throttle transient airflow estimation. The concept is simple.

1. you are running along at part throttle, with good vacuum in the inlet manifold, MAF is reading the amount of air that is entering the engine.
2. you suddenly go WOT and you get a big rush of air into the manifold to fill the vacuum. ie. this air enters the manifold and is measured by the MAF but it doesn't actually go into the cylinders.
3. At this point the MAF is reading far more air than the cylinders actually have entering and the result would be a rich condition, more measured air = more fuel. If you look at your MAF logs you can see this "spiking" during positive throttle transients. The opposite is true negative transients where you are snapping the throttle shut (eg. MAF stops reading airflow while the manifold builds vacuum, would result in a lean condition).
4. Now this is where the VE table steps in and says "the maf is almost right guys, but here's my take on the situation"
5. the two results are filtered together, also taking into account TPS values into quite a long predictive airflow filter routine, with varying coefficients depending what "zone" of operation the engine is in.
6. The net result is an airmass value that the PCM actually uses for the fueling and spark calculations.

If you disconnect the MAF you basically bypass all this predicitive filtering and essentially the PCM uses the airmass value that the VE table calculates at all times. You can think of this as being in transient mode all the time.

I like to think in analogies so here's something that may make it a little clearer. You can think of this whole thing like a sponge when washing your car.

Hold the dry sponge in your hand over your car and turn the hose on it. For a while there you see a constant rate of water going onto the sponge from the hose but nothing is coming off the sponge onto your car (the sponge is absorbing it). After a while as the sponge saturates you will see the same amount of water running off the sponge as you are applying with the hose.

Now think of the MAF as a flowmeter on the end of the hose, and the engine cylinders as receiving the water coming off the sponge. In this dry sponge example the flowmeter (MAF) doesn't accurately reflect the amount of water running off the sponge until it saturates (reaches steady state), and depending on the size of the sponge it may read high for quite some time.

Now imagine you turned off the hose, for a while there water still flows off the sponge as it slowly dries out. But now the flowmeter (MAF) is reading zero (cos you turned the hose off completely) but your eyes can plainly see that water is still running off the sponge.

This is exctly what happens to the MAF when you have a positive or negative throttle transient, only the sponge is now your intake manifold.

The, VE table on the other hand is a "calculation" thats tries to guess how much water is coming off the sponge at any given time - note the big difference here is "guess" rather than "measure" as is the case for the flowmeter. In our sponge case it might weigh the sponge to seehow much water is on it at the current time and look up a table that is outflow vs. mass. The point here is it measures a bunch of other things and does a calculation to guess the answer. In the VE table case it looks at MAP and RPM and looks up a human defined table that says for this MAP and RPM this is how much air is in the cylinder.

So you can see that while things are at steady state (or close to it) the flowmeter gives a very accurate indication of the water running off the sponge onto the car. But as soon as you get into a transient condition it can be wildly inaccurate.

So why bother with the flowmeter at all? Good question. The thing here is that the flowmeter is a universal device that "measures" flow very accurately in the case of water, and reasonably accurately in the case of air. You put one on an engine and you don't need to spend a whole bunch of time calibrating and refining your "guessing" calculation as most flowmeters are temperature independant devices (ie. they measure accurately at all temps). The carmaker can be assured that for the majority of cases across wide operating conditions and applications the engine is performing to the standards required. And if optionally backed up by a decent transient model the whole thing can perform even better giving accurate transient contions (again with very little calibration work). ie. transients are short and generally so long as the transient "guess" is close to the mark once steady state returns (usually very quickly) the flowmeter takes over again (with a smoothed blending in and out).

Bombguy99z28
11-07-2005, 10:25 AM
I did 3 log runs over the course of a few days, all of them lean enough at WOT that I was pulling timing. I scaled my MAF, and I was back to where I should be, 12:1 AFR instead of over 13:1. How else could you WOT AFR be off? There HAS to be another variable involved. My VE table was spot on. If you know how the computer works, then how can my WOT be off from whats commanded by my PE if my VE table is 100% correct? Narrowbands suck but going from 790-820 (which is way lean) to 920-940 (which seems like 12:1ish) with the only alteration being the MAF table and same day/weather conditions, how did that work? Next time I dyno I'll play with the MAF table and see if I'm wrong.

I've also collected lots of data where a car gets a few mods and runs lean at WOT / part throttle without really changing the VE much. You still have to scale the MAF when you're done with the VE or its still going to be out of whack. In my experience, your VE only has large changes when you change the cam, but with boltons you'll have to scale your MAF a lot more to get it dialed in.

I'll do some more logging and see what data I can collect on it.

soundengineer
11-07-2005, 10:31 AM
above 4000 RPM the MAF does do all the work...but any throttle changes below 4000 and teh initial chage from part throttle to WOT above 4k are VE

Bombguy99z28
11-07-2005, 10:34 AM
I should have substituted for 'open loop' with WOT, but that is exactly what I meant. I don't see what was wrong with my initial statement that the MAF affects WOT.

above 4000 RPM the MAF does do all the work...but any throttle changes below 4000 and teh initial chage from part throttle to WOT above 4k are VE

Bombguy99z28
11-07-2005, 03:57 PM
Are you sure its 4000 rpm or is it when the car is in open loop. Because what you are saying is that when the car is in open loop but not above 4000 rpm that the car runs in true speed density (no O2 correction, no MAF correction). I didn't think our cars ever ran in 'true' speed density without being forced to via programming. I've seen MAF affect pretty much any tables except the very very low rpm ones, if you said under say under 2400 I'd buy it but 4000 is pretty high and I've seen a lot of MAF correction under 4000.

I think I have a pretty good understanding of how the pcm works, but I'm always willing to learn.

slow
11-07-2005, 04:09 PM
There are values that tell the maf to take over at 4K rpms, I have proved on the dyno, that maf changed under 4K at WOT do have an effect on air fuel, a 15% change, resulted in a 15% change to measured AF ratio.

Ryan

Bombguy99z28
11-07-2005, 04:30 PM
So the MAF is not a factor in part throttle/closed loop driving under 4k, but is a factor under 4k when in WOT/open loop.

Thats what I thought, but someone pointed out that I don't know how the pcm works. ;)

There are values that tell the maf to take over at 4K rpms, I have proved on the dyno, that maf changed under 4K at WOT do have an effect on air fuel, a 15% change, resulted in a 15% change to measured AF ratio.

Ryan

TAQuickness
11-07-2005, 05:22 PM
So the MAF is not a factor in part throttle/closed loop driving under 4k, but is a factor under 4k when in WOT/open loop.

Thats what I thought, but someone pointed out that I don't know how the pcm works. ;)


Not exactly - under normal circumstances, the PCM will not run in pure SD. Under 4k the air flow value is derived from both the VE and MAF tables. The closer to idle, the more the VE table is referenced. Above 4k the airflow is steady-state and the pcm will rely soley on the MAF table.

AaronR
11-08-2005, 12:03 AM
Are most of these "pro tunes" only affecting the street manners of a car or also the power it makes?Just wondering if my car has more in it, it took all of ten minutes on a dyno.

WS6FirebirdTA00
11-08-2005, 12:06 AM
most shop tunes i have seen only do the PE and maybe some spark. mostly is it just PE and some idle airflow for cam cars. pretty shitty

BrianC98Z28
11-08-2005, 12:33 AM
So TAquickness when do you want to come to Texarkana to tune mine for me when I put the cam in? Id love to see it done once before I tried it myself. We have EFI and the LC1 wideband also.

JimMueller
11-08-2005, 12:53 AM
For $500 (based upon $375 mail-order tune + $125/hr dyno time), I received:

1) Re-flash to stock (they refused to attempt to save my Ed Wright tune)
2) ~25 minute dyno-tune; tweak IFR; tweak PE, remove KR @ WOT; disable necessary codes. 4 pulls total I believe.
3) Broke my MAFT by disconnecting it and leaving it loose to rub against the belt.
4) He refused to give me a copy of my stock tune
5) All kinds of tip-in knock
6) Even after filling in the mod sheet, he still couldn't disable the correct DTC's
7) Wouldn't reply to my calls or e-mail for two weeks, at which point I posted publicly. Gee, that got his attention, but still didn't offer a satisfactory resolution.

When I complained, I was basically told I was asking for more than what I had paid. Luckily for that shop, that 'tuner' moved on.

All I can say is that ignorance is bliss. If you don't know how well the car can behave, most customers will just accept the tuners word as gospel and let the blame remain on the part selection.

RedHardSupra
11-08-2005, 01:03 AM
HA!
my car got a new valvetrain, new cam, some other goodies, and a mail in tune for a 'great' tuner that advertizes here. went to a drag strip to verify the results, car LOST 4mph on a consistent 2.0 short time.
Later I borrowed Autotap from a friend of mine for 2 hrs, car was knocking in the entire range ~4degs.
I checked if i put on the list (of mods) that i have a different MAF, and i did, yet the MAF table i received (as i found out later) was stock. First time i turned MAF off, the car came alive.
i didn't even complain, just got pissed off, read about tuning, picked up HPTuners, and it all works fine now.

to all the mail tuners: FUCK YOU!

APeteSS
11-08-2005, 02:07 AM
4) He refused to give me a copy of my stock tune

What would you do with that?

JimMueller
11-08-2005, 06:37 AM
I never had a copy of my stock tune before it was replaced with Ed's. Since they charged me to obtain the stock tune from the dealer, I felt they should have at least given me a copy. I prefer to start with an unmolested calibration, because until recently it was very difficult to locate all the differences between calibrations. It's certainly easier to just reload the stock calibration than going through all the tables and manually comparing them. My car is slightly unusual in that it's a V8 that came with a speed limiter, and I couldn't locate any exact matching OS's on the internet.

Of course, they probably didn't want to moreso to avoid seeing what they didn't do.

soundengineer
11-08-2005, 10:39 AM
So the MAF is not a factor in part throttle/closed loop driving under 4k, but is a factor under 4k when in WOT/open loop.

Thats what I thought, but someone pointed out that I don't know how the pcm works. ;)


sorry I wasnt able to reply yesterday..was out working all day and night

simply put...
your VE tabel is for throttle changes...your MAF is for steady state.
anything below 4k is a blend between the MAF and VE
IF there are no significant(I dont know what GM considers significant)Throttle changes for a certain period of time then it is considered steady state...and it rely's solely on the MAF..but as soon as you touch the throttle it becomes the Job of the VE to tell teh car what to do...
it still looks at the MAF..but uses Primarily the VE for its calcs....it is definately a Blend of MAF and VE below 4k...which is why it is EXTREMELY important to get the VE correct for Part throttle and throttle respose.

Bombguy99z28
11-08-2005, 03:11 PM
I know that. That has nothing to do with my statement that the MAF is a factor in open loop / WOT situations, which you said 'no it isn't'. I'm just asking you where you were getting that from.

soundengineer
11-08-2005, 03:27 PM
I know that. That has nothing to do with my statement that the MAF is a factor in open loop / WOT situations, which you said 'no it isn't'. I'm just asking you where you were getting that from.


sorry..I just realized I misread your statement from earlier...

the way I stated above is correct...
I though you were taking about open loop and WOT as 2 different things not like saying WOT in Open loop...

in which case WOT is determined by the Highest AFR multiplier...which can be the OLFA table or the PE table...
IF you have the MAF connected it uses that as a reference for the starting point before adding the multiplier into the equation...but only if it has a higher multiplier than the OLFA

Bink
11-08-2005, 05:04 PM
sorry I wasnt able to reply yesterday..was out working all day and night

simply put...
your VE tabel is for throttle changes...your MAF is for steady state.
anything below 4k is a blend between the MAF and VE
IF there are no significant(I dont know what GM considers significant)Throttle changes for a certain period of time then it is considered steady state...and it rely's solely on the MAF..but as soon as you touch the throttle it becomes the Job of the VE to tell teh car what to do...
it still looks at the MAF..but uses Primarily the VE for its calcs....it is definately a Blend of MAF and VE below 4k...which is why it is EXTREMELY important to get the VE correct for Part throttle and throttle respose.



You might want to read gameover's old AIRMASS thread. Good info. --> http://www.hptuners.com/forum/YaBB.pl?board=obd2flash;action=display;num=1078851 555

FWIW.

soundengineer
11-08-2005, 06:07 PM
You might want to read gameover's old AIRMASS thread. Good info. --> http://www.hptuners.com/forum/YaBB.pl?board=obd2flash;action=display;num=1078851 555

FWIW.

I have read that..just couldnt remeber the details...but thats exactly what I was talking about...LOL

02sierraz71_5.3
11-08-2005, 09:52 PM
When you go into a shop for a $500 dyno tune, I assume they just tune the PE and spark tables???? There is no way they can tune the VE and MAF tables in that period of time.

The exception is for engine "packages" where they can just reflash everything the same, car to car.

Any problem just tuning PE and spark, or am I missing something?

I agree with just about everything said above, it took me 1000 dollars to realize if I wanted my truck to run right then Id have to do it myself.

There is a problem with just tuning pe and spark and its the fact that it doesnt take into account air. If the ve table is correct you should be able to set your pe table to 1.131 across the board and command a reliable 13:1 or just do the math to get your commanded wot afr.

Dyno tuning makes no sense for a daily driver as 99.99% of the time your not at wot. For 500 bucks I think a tuner should spend time on part throttle also.

WS6FirebirdTA00
11-08-2005, 10:08 PM
Dyno tuning makes no sense for a daily driver as 99.99% of the time your not at wot.

speak for yourself :razz: jk

yeah, if it was just a track car a dyno tune is good but not great, still have to fix some of the transitions. but a daily driver may get a few WOT runs every day or so, for what? 5-10 sec? then the rest of your hours of driving are all part throttle

Chrisxotic
11-08-2005, 10:31 PM
HA!
my car got a new valvetrain, new cam, some other goodies, and a mail in tune for a 'great' tuner that advertizes here. went to a drag strip to verify the results, car LOST 4mph on a consistent 2.0 short time.
Later I borrowed Autotap from a friend of mine for 2 hrs, car was knocking in the entire range ~4degs.
I checked if i put on the list (of mods) that i have a different MAF, and i did, yet the MAF table i received (as i found out later) was stock. First time i turned MAF off, the car came alive.
i didn't even complain, just got pissed off, read about tuning, picked up HPTuners, and it all works fine now.

to all the mail tuners: FUCK YOU!


Greatest quote EVAR!

I just recently had to relocate back to WV (More stock Chevy Trucks here than mountains) Most common setups are bigger tires and exhaust.
I've been using MAF calc., LT/ST method and recalibrating speedometers on a couple trucks here, with a great response so far.
Most owners looking for better MPG and noticable power, without the headaches of being operated on by a Dr. from 6 states away or ordering a "guess chip"

soundengineer
11-08-2005, 10:33 PM
the major problem is that "dyno tuners" are paying for their dyno...paying for their software..paying for their space...paying for their employees....
and they have to do about 3-4 a day just to break even sometimes...
and with that they just dont have time to do a tune the real way
and on top of it..many of them just plain dont know how to do it properly
they usually mess with the IFR table(which is really used to tell your PCM what size injectors you have) and they mess with the PE table(which they modify to get your "13:1"...but they do it by commanding sometimes "1.17 = 12.5:1" or even richer than that).....so they are not properly adjusting anything.
they add spark to the main spark tables when it could just as easily and more safely be added to the spark add vs AFR vs RPM table....adding spark in teh wrong spots on the main spark tables can cause some issues with ping and knock down low where the car is really not looking for it because its set not to trigger down there....
If teh "dyno Tuner" truely cared then they would hire somebody like myself to take care of the tuning....or hire multiple people like myself....

(If any "dyno shops" are reading this and want to hire me as a full time tuner to do complete tunes....I am interested and willing to relocate for the right place and right salary)

I do full tuning...and then I usually try to have the customer schedule about an hour of dyno time to work on finding at what spark advance their car makes the best power...then I go back to the street and make sure its getting proper fuel at WOT with that spark advance and make sure there is no knock...
I have not had an unhappy customer yet....
I dont do mail order tunes for the same reasons..casue a mail order tune is usually not correct for your car as it sits..I havent even seen one yet that is even close...and I am appalled that some of these companies(some of them are sponsors on here) would even send out the tunes that I have had to FIX.

I helped somebody on here that had a mail order tune and wanted to change to SD...bought their own software...and all teh car did was die when they tried to put it in SD...
I looked at the bin file they sent me....
it made me wonder how it even ran with the MAF...cause about 15 tables were all messed up and so far off that it should not have even been running the way that it was.... teh spark timing had about 8* added across the whole table and in some places as much as 12* !!!!!!! :eek: !!!!!!!
I saw a log he did of the car with the MAF and there was massive knock all over the place....

In My opinion people who deliver a product as bad as that...should stick to their good hardware...and stay away from the world of tuning(just because somebody understands the Mechanics of the internal engine parts does not mean they know how to tune a vehicle....

Bombguy99z28
11-09-2005, 12:34 AM
I was approached by a local shop that wanted me to do their tuning in house, as they send out for a mail order tune whenever they do a car.

I tried to convince him to do 'real' tuning, but all he wanted me to do was make a canned tune he could slap into every car he did. 99% of his customer base wouldn't know the difference (mostly vettes) but I declined his offer, even though I'm unemployed at the moment.. lol

It just feels wrong and I couldn't let myself be responsible for that kind of work. I don't know how these guys can sell that stuff with a clear conscience.