My partner "plan B" tuned my 402 with speed density...its the nutz!! Wash

 

Some answer as to proving SD is not only required for better perfornance but is the best path to tune our Corvettes

Interesting GM used MAF based for the L98 in 1985-1989
for 1990 and 1991 they went to MAP (VE) and found less performance and since 1992 with the LT1 (before EPA required MAF) went back to MAF based and then also with the LT4, LS1, LS6, LS2 and LS7
Without the MAF the PCM cannot even compute the engine load which it needs to make instant calibration changes.

MAF is direct and instant ( no EGR to do math by PCM) where VE based MAP requires PCM to take process time to query values from multi sensors and then has to do more math
VE*MAP*CV*EGR divided by IAT which means its slower to react and make AFR changes and that is if all the sensors are giving correct values
AND all the values of both VE tables have been edited with the correct values. Add changes to/from sealevel and you have a **** making AFR decisions.

What is worse is the VE tables are there as a backup mode if MAF fails and the way PCM knows that is it compares MAF output in grms/second to GM's VE table values. Once those values in VE has been screwed with then EVERY time PCM sees MAF and VE values not agree then it assumes MAF is faulty and forces engine to switch back and forth from MAF to VE modes so that is not good tuning practice and does not give a better performance tune for AGAIN most NA cases.
As to using wacko CAM grinds on the street in ANY case causing loss of low and mid range vaccum is even worse for VE tuned since where stock idle would be around 35 KPA (custom CAM as much as 65 KPA just for idle) and WOT around 100 KPA where now VE has a limited MAP window for engine now for most engine conditions lives around 50-60 KPA so MAP window is only about half of what good tuning with a MAF is.

Again you claim SD is the way we all should tune to so proof it and proof it gives better performance then MAF based tune ?

I sure pity the people who unknowingly buy a used Corvette to find out later how screwed up the engine is with all these unproven tuning methods and wonder why the car cannot pass smog tests

 

No one has said SD is the optimum method to tune all LS1s. It is an option.

GMs changing MAF usage coincides with OBDI and OBDII as well as technological advancements.
The PCM does not have the ability to make calibration changes. It can only reference the supplied tables.

Complete gibberish.
The MAF is inherently inaccurate at lower airflow - a well known fact. In addition it responds poorly to transients. In fact the it is crutched in the PCM to compensate for these inaccuracies. Airmass calculations are not direct.
........................................ ........................................ ................
From gameover :
Under normal conditions (ie. all sensors working properly) in the code i'm looking at it is like this:
(caveat: many of these thresholds may vary between code revs and vehicle type)


RPM > 4000
----------
trust MAF completely and ignore SD calcs (apart from MAF sanity checking purposes)

RPM < 4000
----------
if RPM < 2400 and MAP < 84 kPa then
Steady MAP threshold = 0.0 kPa
else
Steady MAP threshold = 0.8 kPa

If (SteadyMAP) then
Calculate MAFAirmass/SDAirmass ratio (used for Unsteady MAP operation)
Correction Airmass = MAF Airmass (filtered)
else
Correction Airmass = SD Airmass x MAF/SD Airmass Ratio (calculated during Steady MAP conditions)

Transient Corrected Airmass = previous Final Airmass + proportion of Correction Airmass

Final Airmass = fn(MAF Airflow, previous MAF Airflow, prev 3 MAP readings, prev 3 TPS readings,
Transient Corrected Airmass)


There are 9 coefficents to this filter (and a total of up to 16 diffent sets of coefficients depending on operating conditions). It is worth noting that the previous value is weighted heaviest followed by the 2 MAF terms, so MAF dominates IMHO).

There are also a number of checks at the end to make sure things do not exceed certain limits.
........................................ ........................................ ........................................ ........................................ ........................................ ........................................ ........................................ ...........

Hmmm....seems like the airmass calcs are a little more complicated than "Simple and direct"

Ve table values are there to provide dynamic airflow input in all airflow and fueling calculations. IT IS NOT a backup to the MAF.
If the VE values are incorrect then AIRFLOW and FUELING calcs will be wrong.
If VE values (dynamic airflow calcs) and MAF values are out of range (Sanity Check) then VE is assumed correct and is the default table.

Wacko cam grind??

That is the GM designed "Grand Am" cam - used in the World Challenge series.
Funny thing is I run that cam on the street. Idles at ~1150 and 70-75 kPa.The ONLY way to tune for that cam is with a properly calculated VE table.

I've never claimed SD is the all purpose way to tune. It is advantageous with some setups. It has provided better part throttle tuning (crisp throttle response) in many instances.

All of this info is readily available for anyone interested. LS1Tech, EFILive and HP Tuners sites are an excellent resource. It's all there.

boosted_z06 - the Tuning world has passed you by.

 

What Bink sez! Wash

 

What?
No reply of attempted bamboozling B.S.?
(i.e. "If you can't dazzle them with brilliance then bamboozle them with bul*sh**)

 

The BS is how you spend your life jumpping around several forums and TELLING people to go SD. You never even bother to tell them if they have a 2001 or newer that by unplugging the MAF they also just killed the intake air temp sensor

Your so far from the basics that your statement about OBD-II proves that for OBD-II was NOT in effect until 1996 and saying the PCM does not make calibration changes is like saying the fuel trims never get adjusted or the timing does not change as knock, misfire or even engine load changes.

The rest you copied and posted, useless, all you do is quote others but you cannot answer WHY in any detail why someone who knows little about any of this should jump on the SD bandwagon and thanks to people like you there are many cars now that cannot even pass smog and now that the federal highway bill was finally signed and the new EPA smog rules hit next year. I suggest you also give people your phone number so when they fail testing they can have smog shop call you and you explain why SD which you now call an option is totally useless in most NA cases is correct and EPA, CARB, GM and most pro tuners are wrong when they say DO NOT screw with the MAF or its tables and leave the VE tables for what they were designed for so the real method is to tune with the MAF and ONLY when the engine is highly modified and grams/cylinder exceeds the 1.2 in the timing tables stop at then test and compare to see if SD or MAF is bested suited.

SD tuning can cause severe engine damage, ill effects to drive by wire, calculated torque and line pressure which can cause severe safety failures, why because you say to do it when normal tuning methods will get good safe performance gains and will pass smog testing
Your comments are as smart as the drilling the butterfly on a C5 or using the limp mode WOT table for normal WOT you guys spread around

 

This is really the 'argument quencher'. Anyone that has tried to tame a big cam in a stock-cubed C5 knows it is very difficult AT BEST to get a smooth, streetable idle and transitions. Anyone that argues that SD is passe and/or ancient arcitecture and technology obviously doesnt have any real C5/C6 tuning experience under his belt, or just has not really modified his car. I will agree that for the causal DIY guy that is only bolting on a few easy mods but leaving the engine stock will be fine with conventional stock MAF tuning regimes. But if you want to smooth out the burly idle characteristics of a big cam, SD is the only way to go on the fly-by-wire LS1/LS2s. AND, for anyone boosting their C5/C6, even if stock internals, would benefit tremendously from SD tuning. The Sponge Dynamics of a MAF system works against very modified or boosted LS1 cars. I have been tuning LS1s professionally for nearly 5 years but have been tuning strictly SD mode for about 6 months- there is a BIG difference in my big cammed customers cars...very smooth idles, awesome transitions in any heat or weather, and the biggie is the WOT gains. I've picked up 3-4mph traps in some of my long time h/c customers with recent SD tuning. And recently, I installed a cam-only and UD pulley in an 04 A4 C5...he picked up nearly 85rwhp gains- through stock heads, stock 4 cat exhaust, etc, which netted him a 9mph gain in trap speed at the track through his stock 2.73 gears and TC. It is really hard to dispute that kind of data. I never came close to those gains with conventional MAF tuning.

But hey, it is ok to have SD nay-sayers...we like to have someone to beat up on at the track!!!

Robert
www.gen3motorsports.com

 

Great to hear a real world experience Robert....

Some of the comments in this thread reminds me of the time when daylight savings first came in.... "All that extra daylight will fade the curtains."

We collect MAF's here......



I couldn't find a real use for them......So;

 

[QUOTE=Textralia]Great to hear a real world experience Robert....

[QUOTE]

I have the best tuning mentor in the world!!! (wink, wink!!)

I really like the trophies, Peter!! You need any more MAFs?!?!

 

You don't have to unplug the MAF for SD.


No one has suggested that an unknowing newbie try SD.

I happen to like facts..the TRUTH. Gameover's post is the TRUTH.

The rest of your response is not related to anything I've said.

 

An excerpt from Dumb & Dumber: "Kick his ***, Sea Bass!!!"

Bink, sometimes there is just no getting through to some people. The more they argue the more apparent they make their inexperience known. You can trust one thing, aint no one gonna be asking Boosted_ZO6 for tuning advice any time soon!!!!

 

Thanks mate, judging by some of the posts in here, I should need 8 per vehicle but I think I’ll just keep chipping away with what’s available for now…. Accurate AIR & FUEL!!!








This topic has been done to death in Australia.... A thread topic like this is a "blast from the past!" Really!

 

I was very fortunate being able to read some of those Aussie threads (Many thanks to ProStock John on LS1Tech ). Plan B (Peter) was prominent in most of the threads I read. However, I was not convinced back then. I am now.

As Robert has stated there is a place for SD ....bigger cams. But all setups seem to have better throttle response MAFLESS.

The key isn't an increase in HP as much as it is driveablity. MAFLESS greatly improves this. I haven't run my car MAFLESS in the winter months yet, so I can't comment on changes with weather.

Peter knows a heck of a lot more about this than I do-maybe he'll give us a bit more info.

 

PETER!! You posted those pics on purpose just to make my mouth drool!!! DAMMIT!!! Now I want the 8 TB setup!!! When you gonna release these intakes to the public?

Robert

 

Robert - the 4th and 5th pic (down) can be found here ->
http://www.harrop.com.au/root_folder...fd7022-00.html

There's a vid also.

 

Ah, yes. Thanks Joel. You gonna pony up and get one? This is my next purchase without any doubt. My 436 solid roller would LOVE this intake. I am really gonna have to rethink my direct port nitrous because I dont know if I can bring myself to drilling the Harrop!!

Robert

 

Too rich for me. Sure is beautiful though.
I wonder what it's worth ,HP wise, above 6000 RPM?