Guys,

I just competed my 406 engine install and thought I would share with you some of my thoughts. Mainly stemming from the Tune/Maf system. I worked dilligently through the past month or so to get this thing wrapped up before the first Corvette Challenge in NJ this next weekend. One of the items that fell by the wayside was the preperation for roughing in a chip for the new engine setup before its startup. I was using the same injectors and to end that my 350 had so I figured it would be OK for the startup and slight cruising around I would be doing. Till I could start doing my tune with the computer.

Here are a few shot of the engine going in:







Sorry we caught so caught up in the install we forgot to take a picture of it completed

Anyways we got the engine installed. Got the sensors adjusted and started the baby up for the first time. Its got a 406 C.I. 11.8 Comp Ratio, Weisco Forged Pistons, Lunati Forged 5.700" Rods, Plasma Moly Rings, TPIS 242/242 .610 lift Solid Roller, Comp Cams Solid Roller Lifters, AFR 190's, Accell Base and Super Ram P&P, Pro Magnum 1.6 RRs, Taylor 409 Race SP Wires, NGK V-Power FR5 SPs, Wide Band O2 sensor, Dana 44 3.07 upgrade, M/T slicks.

After setting the timing Etc, we took it out for a short trip. I was surpised that the car ran exceptionally well. That night was cut short with the roads being a little wet in spots etc. I parked the car for the night and went out after work monday to give it a try. All I can say is Holy COW! With my street tires, Dunlop SP5000 275/40/17's that grabbed great with the 350 SR/AFR setup they are now a joke. I am yet to go beyond 1/4 throttle and I can blow the tires off it at speeds up to 55MPG in 3rd gear. The power is just unreal.

Corkvette1 is running the same exact setup and with this full car he was just missing 10's last year, and will surely be there this year with his ported base and SR and MAF.

I guess the point I am making is the MAF system is exceptial when taking to modded engines. The throttle response now is impecable, and there is not a hesitation or a buck to be noticed. I am certain that a SD car would have required tons of tuning just to probably idle with that .610 lift cam. Mine idles at 850 RPM like a dream.

All in all, i am utterly impressed with the engine and the MAF system deserves a big A+ for the way it took to the larger CI engine and more air flow.

My WB02 is indicating that idle/cuise is at 14.7. I bought a new computer and was having some problems with it linking to the car, so I am not sure how much adjustment the car is making to the BLMs. I'm sure its some and things can only get better than they already are! Actually I would be 100% satisfied with the tune now, but you know as well as I do, that there is much more to be had most likely from the tune.

I just don't understand the hype behind everyone switching over to SD? I wouldn't trade that MAF meter for the world!
:hail:

 

Glad your happy,
But to state it's better then SD is not logical, until you've done side by side testing. Mike Davis and Mike Rolica, have and both went faster with SD. This is with finely tuned MAF systems, against finely tuned SD.

The MAFs are faster / easier to tune, but there that's due to one of the faults in the system. On the MAF fuel tables, there are about 60 entries, and on the MAP 200. So of course the one with 50 is going to have to be easier to work on. Same with the Spark, At a LV8 of 255 you done with the MAF timing, and that's generally alot before actual max load.

There can also be situations like having too small of injector, that the MAF sensor slightly restricts the air flow just that little bit to richen up the AFR, that wouldn't happen with a MAP.

 

Grumpy,

There is no doubt that the SD offers more features to tune with. However my feeling are does it really make a difference? Those guys very well might have gone faster, but with what? I am not trying to agrue, but I highly doubt the SD system would be as liberal with major changes as the MAF system.

I just think that all the people that say you MUST switch over to SD to go fast, are sending the wrong message. I would bet that 1/2 or more of the people that switch over actually are going slower than they would have been with the MAF system. Just due to the fact the SD is that much touchier.

Case in point, if you were to tune your car at E-town, NJ which is close to or below sea level, then you were to head to a track that is 3000 feet above sea level, I would bet money that the SD car would have issues. Not to mention the day to day changes at a given sea level.

Also why would GM switch back to MAF when its 4x as expensive? I deal with supplying them components every day and trust me, they want everything as cheap as possible. If they could save 400 beans/vehicle X thousands of vehicles, they would in a heart beat. There must be something learking in the background.

Please don't take me as being argumentative, but I would like to discuss others thought and why on this.

 

Tuning MAP is alot more intuitive.
Spend some time with a WB and getting to the real nitty gritty with a MAF system, and then do the same with a MAP system, and the MAP shines. As you go thur the MAF tables and scales the math moves the gm/sec per scale as you tune it. It gets real complex to get right.

Like I mentioned earlier if close is good enough, the MAF has it's points.

Trouble is and will be that you immeditely run out of resolution when you hit an LV8 of 255. If you can live, or be happy with that, then the MAF will serve your purpose.

It really really boils down to the ease of use, and what the owner likes to work with.

The reason GM went back to the MAFs was because of OBDII.
Nothing to do with engine management. GM made the decision to use the MAF as the primary sensor for airflow, and then the MAP as the backup for diagnostics. They could have done the opposite just as easily, but going the route they did, made tampering all the more difficult, which is a good thing in the eyes of the EPA. If you look into some of the GM programming they do both VE and Gm/sec (LV8) calcualtions.

I got a sneek peek into the emissions lab at an oem manufacturer, and talked at length with an oem emission specialist, the EPA is just really out of control now. With no system of checks and balances as an agency it just does what ever it wants based on good and bad science, without concern for the practical end of things.

Then once you mention the CAFE numbers, everything is turned upside down. So while to you and me it's no real issue when your worried about .001 MPG, for them it means lots of money in fines so they have to be unending in research.

But getting back to MAP vs MAF.
I've run early low freq MAFs, late High Feq MAFs, and MAP all on the same car. Even in custom form, for me MAP wins.

On the MAFs you basically wind up with a version of Alpha-N at WOT. As I recall it does vary some from 32-32b, to 6E.

MAF and MAP, contrary to popular folk lore, both generate an engine load calculation. Neither does direct measuring. One measures vac, and the other heat lose across a wire. From that info., the ecm calcs the fuel and timing. Garbage in and garbage out. You give the ecm good info., and good math, and the results are the same.

My 2 cents worth.

 

well using a bigger maf and dubming down the resolution a bit at low flows has worked fine for the tunnign ive been doing. this code limit even exists in most of the S/D systems. it relative to injector size vacum etc. but its there still. i think using bigger mafs solves lots of problems. it is definately more driveable and if you tune the AE vs tps table its just as fast as a map system in term of throttle response. there some things about in the windmill of chnage ive been hearing about like a low cost translator for the maf guys etc that are in the works. ive been trying to figure out how to enable the FQ based reading in the older $32 $32b code to make a convetional GN tranlator a workable idea. im just sort of swamped and paralized right now with a move a new job etc and i just dont have enough time to go around.

ive gotten just a small fraction of the work done on the maf tunning FAQ as well. its just alot to do.

grumpy brings up alot of good points. then again ive never seen truly large mafs run side by side vs S/D in real terms. IE the maf poses 0%-1% flow restriction. i think that when the performance differnce will pop up. the maf doenst handicap top end power outright. it just acts like a really dirty air filter.

my last thing of the day is why not run a Ford motorsports maf. there cheap. easy to clean and supposedly run 0-5 volts and are availble in a huge number of sizes.

 

Dumbing down the resolution is the worst thing you can do.

What code limit are you talking about?.

Thinking, and guessing get you nor anyone else anywhere, do the testing and come back with results.

I've hinted at the MAF answer for almost 2 years now, and still no one is bothering to look. Again reading the hacs and doing some homework would answer things.

0-1%?.
Where did you get these numbers?.

Air cleaners, MAFs, intake tract ducting are all CRITICAL elements.

 

i think thats all about being relative. in terms of cruise yes. in terms of wot no. loosing resolution is not a big deal. it something that the fuel trim can clean up. were working with a .05% eror here by lossing the .5 of a gram. pretty small.


s/d calcualtes airflow based on ve bpw etc. the maximum value that can be calculate in a $42 $58 etc is ff or 255. but thats all relative. as you increase bpw etc you basically move to a bigger multiplier.

no geussing. im busy testing all of these ideas. its hard working 60hrs a work, keeping 3 old high milage cars running and moving from here to there. results will be coming soon.

i know for a fact that the tpi maf systems can run FQ based mafs. you have to change a bit flag. how it affect the calibration is a whole other deal.

this is a thoerical number. what im getting at is that all thing being equla the only reason S/d is faster then MAF is becuase of the flow restriction. reducing that restriction should in effect fix the issue

 

i dont really get this whole notion. if the engine ingests the air the maf is gonna read it. it doenst matter if the maf is 4000 ft away from the engine. it might affect some of the WOT and AE enrichment values but if the engine consumes it its gonna read it. what absolutely affects the way the maf behave is the screens. the screens are the key. the only affect a air filter will have on a maf is putting oil on the hot wire and getting it dirty. i have a $40,000 machine at work that agrees with me based on both osiclliscope and voltage vs cfm readings. the maf doesnt care where it is as long as there are no leaks behind it and the screens are there.

im not doubting for one minute that your picky and right in your book is right. ill get thsoe flow charts up. i perfomred all test with various intake tract lengths. .

 

Well my 2.5 cents may or may not matter but here it is..
In my eyes If you can obtain the same pulse widths with a SD system as you can a MAF ,why not and do so with less air restriction.
I converted from MAF to SD ,yes the Sd system is alot more inlolved - do I mind? not really,I love to play with cars its my hobby so there fore I don't always take the easiest route because it gives me goals and learning capability.
I loved my 165 ECM it worked great for me ,and you may say that you can make 500+ HP with a maf which is great ..
But my point is if you make 500 HP through a 2.875 inch hole with
another air restictor inside,you would probably make 515 with out
that restictor.

 

im not disputing that fact. going to a larger maf though solves the problem. grntaed youll lose resoluton but life goes on. thats what the blm/int are for. the system is supposed to be adaptive. if your 126 126 without the 0.0 decimal place then its not a big deal.

 

Bravo! Dedication...

 

In these masks the airflow term is not used in the BPW calculation. As a matter of fact in the $58 mask when set for an 8 cyl the airflow term will always be zero (0).

The BPW routine uses 16 bit math for a maximum BPW of 499 mSec.

RBob.

 

guys i think you are missing the whole point of discussion is why do you guys swear by the sd over the maf when the maf can whoop some azz with out much of a tune to boot

when you guys are telling other 3rd genners how great it is for them. to only to open up pandoras box and run slower unless they are brain surgeons not to mention the tune you would have to do on a daily basis just to keep up with the maf

so the morral of this story is 3rd gen are still behind the vettes

 

Your making assumptions.
If your happy with 350 HP out of a 400 Combination, that's fine, and I'm happy for ya. And there is SOMETIMES, where you can get close enough that there isn't much difference. But with the SD you have more resolution to tweak the most out of any given combo, all the time.

Your second paragraph is so not at all accurate, period.

and your last paragraph just proves, you enjoy making assumptions, or are just trolling.
Have a nice day.

 

And I do hope that this statement from the very first post has not been missed:

"I am yet to go beyond 1/4 throttle. . ."

Means a lot when you have a small MAF.

RBob.

 

Maybe software tuning looks like brain surgery, having not done it. After you get the hang of it, it's just plain fun...and definitely not brain surgery type effort.

Not sure where you got that tuning on a daily basis is needed, again having not actually performed the task.

I started out Cross-Fire Injection, then upgraded to MAF TPI, then later to SD. I definitely wouldn't recommend SD for a beginner, too many variables between the SD system and the engine. Start out MAF, get the engine and ECM debugged and tuned, then when you've run out of tuning opportunity and it's clear you're up against the MAF (airflow is 255gm/sec on the scanner) go upgrade to SD.

 

Well I am a believer in the SD 730 ecm and also believe that the stock 2.875 maf is a big restriction,but I have got to give big honors to Ski and Corky who both of which I saw today run very respectable times through that small MAF .
Ski 11.15 @ 123 mph

 

I've spent alot of time tuning my car with the stock system, ie MAF, and now have about finished with a MAP version of the code for the same ecm, and have it fairly well tuned.

In the MAF configuration I was running an LS1 sensor, without vanes in a 3" housing, and had spend alot of time tuning it with a WB. Lots and lots of time, getting all the AE stuff just right etc.

And I've spent alot of time now with the MAP code.

There are a few Downsides to both systems.
ie in the MAF stuff it always assumes that at a given flow rate you want a given AFR. So for a car that likes, or needs say 14.7 they are a neat way of doing that.
The MAP oddity is during start up. There is a time between crank and idle where the engine is at say 450 and 90K/Pa. The larger the plenum the longer it takes for the *just running* engine to pump the manifold vacuum down to 50ish. And toss in a few cylinder misfires and it can get sloppy rich when starting. The other thing is during a stall as the engine is coming to a stop the engine again drops to like 400 RPM at 90 K/Pa. Both at exactly opposite in fuel demand. Ever notice some cars are hard to start after a stall?, this is way.

Now for the upsides.
With MAP it's easy to get different AFRs across the entire VE table. You just can't do that with a MAF system.
MAF gets you really clean starting since it's looking at air movement, and there is no pumping down of the manifold needed.

Basically talking about the 6E, and 8D codes here. And in racing applications where C/L is not a concern.

While the MAF will most allows be a slight restriction, for a car that's short on injector, that is a blessing.

In a turbo application nothing will be a MAP system other then if it's morphed with a MAF, for those special situations where the MAF is in fact better. Even MAF with boost sensing loses to a true MAP for the performance end of things.

 

<b>Start out MAF, get the engine and ECM debugged and tuned, then when you've run out of tuning opportunity and it's clear you're up against the MAF (airflow is 255gm/sec on the scanner) go upgrade to SD.</b>

I caught that and was wondering that myself.

I am installing my first TPI setup in a few days, on a pretty modified motor with nothing stock...
Its a daily driver with a carb right now. XE262 flat tappet, performer rpm heads.

I have the Whole TPI setup now, minus a MAF, ECU, Injectors, and fuel pump. SO im at that point where it would be just as much $$ to go either MAF or SD. I have the harness for a MAF but re-pinning that I've heard is no big deal.

Since Ive never tuned a TPI setup in my whole life, should I go MAF or SD?

 

I personally think you haven't lived until you played with both.

Since you already have the MAF, you can always start with MAF system. It will be easier to tune initially than SD for "part throttle day-to-day" driving. You'll still have to play with Power Enrichment for WOT and the spark tables.

Then, when you either feel up to it, or your MAF takes a dump or your 165 dies and you can't find a reasonably priced used one (they are getting harder to find), then you can look at SD.

In all honesty, having worked with both, I spend a lot more time on the spark tables and controlling the curve than worrying about fuel tables. I find the fuel fairly easy, especially if you get a WB O2.

Unfortunately, you are still a "virgin", so you can't try something I've been wanting to do for the longest time - modify a SD 7730 to work on a carb setup. Then I would have the ECM control all the spark function yet can run a good old carb. I'm surprised some die-hard carb guys never tried using the ECM just to control their spark.

You could still use the ECM to even control the TCC for a 700R4.

 

.

I think Doc is doing it right now,and I will be this year after I get the combo dialed in.
Im gonna through it on to see the differance in 1/4 mile times.
Just got my 400 in car wed. and to the track for first time saturday.
Bested 12.27 @ 110.8 ,was a little disapointed but still the first tune so ill have to play some more.
Gained a tenth by taking my SLP cold air snorkle off, noticed KPA was between 89-91 with it on last night at wot.
Gonna have to try with it off and get a scan,see if the 52mm is also to small.

 

Cool. I've been waiting to see someone run a hybrid. EFI is nice, but it can be expensive and time consuming. If a person doesn't have emissions to worry about and they primary aim is to go as quick as possible in 1,320 feet - sometimes it makes more sense to just go carb and use the savings (from modifying EFI) to buy better heads.

Don't get me wrong, I enjoy EFI and there are many advantages to EFI, especially for overall driveabilty and fuel economy. But sometimes people get "locked" into only one method without thinking about other alternatives that may work just as well for their needs.

 

RBob, did run an carb'd engine with an efi ecm some time ago, and wrote it all up and posted it at DIY-EFI.org. You'll have to poke around some, I forget where it is, maybe projects or papers.

Software and from a tuning point of view the only real difference is with one you have a VE table, and the other you use tables and scalers for the MAF.

MAP vs a LV8 calculation. Big deal.
From the hardware end there is a difference.
This attitude about MAP being 10x more difficult, is just an opinion.

 

Hey Guys, don't mean to keep getting off subject but noticed that my TPS voltage @ wot is only 4.25.
Since I have some of the pro's here figured I would ask how I should address it?
I think its because I need the blades open alot at idle for the big 406 that im losing that range of motion.
Should I drill holes in the blades ,or just advance the TPS till it shows 4.5? Is that where PE is engaged? or is it 4.3?


Thanks

 

Ops,sorry I just saw your post to poncho glenn..
Guess it does not matter,I thought it had to be over 4.3..

 

Yeah, don't worry about it. If you want PE/WOT to engage sooner, just modify the table entry. Isn't prom burning much simpler than drilling a hole in the TPS and screwing around with it's position?

Another advantage of learning to burn eproms.