what is better the mass air flow sensor or speed density system on these fuel injected cars performace wise

 

I'm moving this to TPI where it will be more appropriate. I also suggest you do a search, because you'll find that the MAF vs. SD debate has gone on since day one.

 

Dude are you outta your mind asking such a question?


Just do a search on my user name......I took a few for the team,,,,so you could understand the pros/cons.....also you can go from my sig and see what I prefer.....

 

Yeah really do a search. This has been a very heated debate, and nobody really wants to start it up again. Somebody may try to jump in here and make a point, but just ignore it, don't encourage it - the debate will never end. Do a search and decide for yourself.

 

Ski, are you kidding?? What team? You run a vette, you think you're on our team or someth'n? We f-bods die trying to beat your over priced plastic pig vettes. , J/k you know I'd be running a vette if I had the dough. ...I do think the f-bods look better though. lol

 

Always bust'in my *****, Joe...

PS: The team is me, myself, and I.....guess that is why I liked wrestling in highschool/college...Only have one person to blame if things did not turn out the way you antisipated.....

Relevant to the discussion here is an email from a person to and from TPIS. Here is what they have to say....I will by next year press this theory to the limits as well. But for now, I can't say I disagree with their advice....

Q: I have an '88 Iroc camaro with a 5.7L TPI and a modified 700R4 trans with 2400 stall converter. I wanted to ask, with a custom chip, how far can I go using the factory ECM with MAF. I wanted to build either a 383 or 396 short block, which is why I also wanted to ask which induction would be good for that setup with an automatic? I'd really like to use the factory style setup ( big mouth base, large tube or Siamese runners, ported plenum and 52mm TB ). I was really impressed with the dyno chart on page 19 of your 2000 catalog. I was happy to see 400hp with the long runner TPI, but I also read that the ZZX is an on/off cam. Basically I'd like the car to be very quick ( 0-60 & 1/4 ) but also a very good contender for road racing. 1/4 mile is fun and says a lot but top speed and cornering is my drug. I'd really appreciate your advice and help before I lay down any hard cash. Thanks.

A: Well with the TPI configuration on a 383 or bigger motor your peak power will be at 4500 rpm or lower. So you basically have a tow truck motor all torque, and choking your hp potential. If this is what your looking for it does make impressive torque numbers. But typically it will not be useable torque 500+ lbs/ft of torque is tough to put down to the ground, and just is not needed to get the car to accelerate. I would recommend our Mini-Ram intake. The reason it will work better is you will have a broader, flatter, more useable power range. With the Mini-Ram you will see peak hp at around 5800 rpm. The reason is all in the runner length. A TPI configuration has a 17" long runner. A Mini-Ram has a 3" long runner. Night and Day difference. A 383 modified TPI setup will make over 500 lbs/ft of torque at 3200 rpm and 400hp at 4500 rpm. A Mini-Ram 383 with the same heads and cam will make 500 hp at 5750 rpm and 475 lbs/ft of torque at 5000 rpm. And still at 3200 rpm 440 lbs/ft. So you lose 40lbs/ft of torque at the same peak rpm as the tpi configuration. As you can see the Mini-Ram on a 383 motor or bigger will have a more useable power range. There is just no need for 500 lbs/ft of torque especially when your compromising rpm and hp.
As far as the MAF goes you will be fine at the 383-406 Mini-Ram level. If you go with anything over 550 hp you should consider either switching to a GM speed density or a programmable fuel injection system with speed density

Sorta goes along with what I have been saying all along........Not to mention with a SR you can probably stretch that 383-406 even further....and beyond a 550 limit they refer to...

Two things I find very enlightening about this response from TPIS. Here is a company that sells intakes, does tuning, does about everything with regards to performance cars. They depend on people "liking" and "enjoying" their cars...spreading the word to other and getting overall good reviews. Why if their intake, on a 383-406, would max out the MAF meter, [as some saycause horrible problems etc, ]would they condone the USE of MAF?

Second, how many people here are putting out over 550hp on this forum? Moreover, how many of those people that say a switch to avoid the 255g/sec limit is necessary to have a good running car are over that limit?

Just pointing out again the obvious and common sense questions that seem to get overlooked.......Hope you can see the light bajram.

I gave an answer to your question, since I don't like the answer "Do a search." Because as you can see if you did the search, there is a LOT of opinion, not backed with any real world, credible, or proof that there is a need to make a switch over...

Hope this helps!

 

While ski is doing his best to convince you that MAF can go fast, i don;'t see his point. Of course there are fast MAF cars out there.

The question was, which is better:

SD benefits

• SD has NO expensive sensor that can go bad
• SD has no restrictive tube in the intake tract
• SD ECM is dirt cheap and common to many GM cars
• SD ECM is better hacked and understood than the 165
• SD VE tuning is more intuitive than MAF scalar tables

MAF benefits

• Usually requires less tuning for part throttle / cruise

Again, both systems can go fast. So unless you have a specific reason there isn't much need to swap. Also, you can tune WOT with the same table on both systems, so while part throttle might take a little more work on a modified SD car, WOT is exactly the same.

BTW, unless this thread stays strictly technical, it will be immediately closed. So let's keep it to facts only.

 

Yeah it looks like you already have SD, so its definitely not worth switching. Really.

 

Ed,

If you read my post...I am simply conveying TPIS's advice to one of their customers.

There is absolutely no push to go fast in that post? I was simply pointing out how odd it struck me that a company that relies on customers being happy, would recommend the MAF system if infact they could sell the guy not only a tune for a SD car, but probably everything else to make his switch over to SD if it was infact going to be that much better. But to the exact opposite they told him to stick with the MAF system, when you and I both know he's going to be past the 255g/sec with a MR/383 setup.

And if you carefully read bajrams post, he says "the Best PERFORMANCE wise" That to me, while I was NOT pushing going fast in any way, is infact encompasses going FAST.

If you already have Sd then stay with it As I personally do not think its wise to encourage people to start rewiring their ECms..

 

Hey Ski,

Can you post a pic of the insides of your MAF?

I want to see how heavily modifed it is compared to a stock MAF. No sense comparing your results with MAF to that with an untouched MAF.

From my experience (870==>165==>730), SD is easier to target specific load/RPM areas to tune compared to a MAF system. SD has a lot more definition to it and is more refined. That being said I switched from the 870 to 165 for better tuneabilty with a modded motor and then from the 165 to 730 when I blew out my stock MAF.

 

Don't have any pictures handy,,,,could get some, but I can tell you it was far from a precision job, with cutting out the fins. Did when the 350 was in the car. Used a hacksaw blade. The blade in one and and the MAF meter in the other.

Cut as best I could each find off, trying not to hit the plastic, which I did many times, and to keep the cuts as close to flush with the plastic as possible. Which I can tell you they aren't.

But really there is no need to be that picky. When the ported MAF will flow ~750 CFM, and a 406 motor, at 6500 RPM, with 70* air, and 100% efficiency, is only able to pull in ~650CFM. A little fin sticking up here or there or a little ruffed up plastic is far from going to effect anything.

Also Ed, where did you get that the air tube that the MAF meter is mounted on is a restriction..if its not collaping? Its cross sections is only about 4x that of a 58mm TB's openings.....Holy beans!

 

The restrictive tube i am refering to is the MAF itself. However minor a restriction it may be, it's still a restriction nonetheless.

Nobody has ever said you can't go fast with MAF. Thank you for pointing out that TPIS agrees with everybody else that it is possible to go fast with MAF.


Therefore, what's better, performance-wise all boils down to how much you care about having a necked down tube in your intake tract. Beyond that, both can be tuned and run on fast cars.


If i had a MAF car, i'd probably swap to SD, althoiugh i'm sure i would do it with adapters to let me go back and forth easily. Not because of a performance difference, but because to me SD tuning is more intuitive, and also so i would never have to worry about a bad MAF leaving me stranded anywhere.

 

you left out one.

in most streetrods and non stock applications, its usually easier to have SD because you dont have to plug the MAF into the air intake.

 

So what? The times I've seen people run a filter directly to the TB, they lost e.t. And with a MAF in stock location, you can make just as good a CAI as any other in either type of third gen.

 

TPI isnt always in 3rdgens.

 

Just unplug it, drive home.

Curious, but is an SD car drivable w/o a MAP, say if the MAP went bad?

 

you can drive it.... id just run like crap. same for the MAP with a MAF system

 

I honeslt don't know what kind of fail safe is in the SD code for if the MAP goes out. It would probably be ugly though. BUT. I could pick up a replacement MAP from any of about a billion cars in any junkyard or a parts store for a couple bucks.

Relatively though, seems MAPs don't go bad very often at all. You never see someone posting about a bad MAP. A week never goes by without someone asking about replacement MAF options though.

 

i stayed wth my speed density from everyone ive talked to from tpis to engine shops they all said speed density would be alot more benifiacial for my engine setup becasue maf is to restrictave on the amount of power i want to make they also said speed density is alot harder to work with but when u get it right it better then a maf so id stick with the speed density my engine set up isnt extreme but it pushed close to 600 hp and 650 of tourque in the dyno at the flywheel and thats no nos and on a 357 with 11.2 compresion pretty good eh all i wanted to build was a 357 that could still hav higher rpms band but also have low end tourque and im also planning on either adding a supoer charger system on this from procharger or nos im leaning towrds the nos though

 

Bajram, have you not just read what others have been saying and proving about the MAF limits and how this subject is blown wayyy out of proportion? Why didn't you state in your original post that you were talking about YOUR engine? You just asked which is better. In your case SD is better, but you'd really be better off with an aftermarket engine manag. system. 98% of the cars on these boards will never see the power levels for which the MAF becomes restrictive. There 550hp cars running modified MAFs and stock ecms that take about 1/100 (exaggeration) the time to tune compared to SD. Tune what came with your car IMO, until you get to where you're at power wise, then you gotta make some decisions on where you want to go.

Just out of curiousity, what is your combo? You must have some wicked heads, a big cam, and you must take your engine past 6500 to see the kind of power you're talking about. Good job though if you're putting out those kind of #'s.

 

Camarojoe,

Hit it right on the head about exaggeration surrounding the limitation of MAF system....

For me and you can see the number that I am putting out (yeah I know chest beating right....no just pointing what MAF can support in both street application and race application)

I have ZERO driveability problems and if you like I can give you the names of a few guys that have rode in my car...you can get their opinion. My cousin works for GM (upper engineering position) he said after taking my car for about a 40 minute cruise the one night.....that the general should come and take a lesson off this car and he wouldn't be able to build enough of them. Obviously he was just pointing out how impressed he was with it....but in his words....How much power there is, but when you want to just cruise in it, with the AC on etc...its like a normal car.

On your HP levels etc...that is a BUNCH of power to be making and I too would like to hear/see the setup your running. There are VERY VERY few people coming close to those numbers, even with 420 CI motors.....Gotta see what that combo is comprised of..:hail:

 

Apples to apples not oranges.

There were way more MAF systems produced durning the 3rd gen run than MAP (90-92 for MAP and 85-89 for MAF). Hence, why you hear more about MAF problems on here than MAP, also the MAP based cars are newer than the MAF's. their time will come.

Yes MAP sensors go bad, I just replaced one on my 91 Formula. When they go bad the car runs like crap (goes into limp home mode).
MAP systems have more sensors that affect fueling than a MAF system does and makes troubleshooting driveability problems that much harder.

I own and run both MAP and MAF systems (85 IROC & 91 Formula) My MAF car has been nothing but reliable since day 1 when I took delivery back in 85. The Formula however has been a royal pain, it had problems when I got it (used) and I have been slowly tracking down the sources and fixing them.

IMHO, if you have MAF, stay with it, if you have MAP stay with it. To convert from one to the other is just too much work for little to no gains.

 

uuh, what sensors does the SD car have that the MAF does not have?

 

Ed to even make the comparison of MAP to MAF's goining bad is a bit nieve.

As pointed out. There are a bunch more MAF cars out there with many more years on them than MAP cars.

even if my sensor would go bad to me, at 100 more dollars than the conversion costs to Sd still wouldn't justify the switch. You would have countless hours trying to figure out wiring, introduce possible bad connections, and then be faced with countless hours to get back to square one. For what? So I can have resolution if I should decide to go 123+ MPH?? or not loose that 10hp where MAF reaches 255+ g/sec through 1st and 2nd gear for a split second? I have to laughably say I think not.

As said before...if you have MAF stay with it, if you have SD stay with it. When you get a 9sec car...get SD if you feel your going to be needing it. However before you make the decision...As yourself as I'm sure the stang guy asked himself....how many time am I going to be on the highway cruising around? NONE.

SD has its appeal to the tinkerers...and a few that *think* it makes a difference. Beyond that, until someone convinces me otherwise me and my "restriction" will continue to go to the strip together and dazzle the many that come up and tell me I need SD.

 

Same sensors, MAF doesn't use some of them for fueling S/D does.

 

mmk, you had me worried there for a min...

 

Which sytem would most likely be more consistent in a bracket car running in the 12-13 second zone? How about a 10 second car? I would guess that if the weather stayed the same they should both run consisten et's but what about if the weather changed and got real cool or if a passing shower came through and the air went from being dry to kind of humid? Which sytem would be better for a bracket car? As for the sd system I am talking about either the 808 code for the 165 or the 730 not an aftermarket ecm.

 

Well let me know what you think....

My runs:

RT .587
60 1.528
330 4.552
1/8 7.091
mph 96.15
1000 9.317
1/4 11.199 (not bad for ~2800' DA)
mph 119.87 (lower than last weeks 121-122

RT .535
60 1.517
330 4.543
1/8 7.088
mph 95.47
1000 9.317
1/4 11.195
mph 121.80(MPH is back using the same lane! WTF!

RUN3
RT .580
60 1.526
330 4.559
1/8 7.104
mph 95.81
1000 9.333
1/4 11.213 (tried not locking up my converter)
mph 121.73

Second, one at first glance would say, yeah you slowed down though. But did I. Obviously the hook was not great, but nearly up to par. Lets break the slips down in more detail:

RUN_________60'=>1/8__________1/8=>1/4

1___________5.563______________ 4.108
2___________5.571______________ 4.107
3___________5.578______________ 4.109


Ok, now with that shown, how do you explain the near dead consistancy in a DA fluctating between 2600-3000 DA all day long?

Comparing to last weeks obvious better weather, the 60-1/8-1/4 are all within a few hundreds.

I think the MAF system does a dine job even when 100% maxed out to remain amazingly consistant. I seldom if ever get beat in eliminations because my car did not run the ET I expected. Its either I redlight, last time against Corky with a .499 light Or I do not get traction the way I normally do and run slower. But you can see from the breakdown of ETs, taking the 60' time out....I think it runs you could say about as consistant as one can get. This is with me manually shifting it, and as said above the DA changing.

Also I have not adjusted my fuel tune since about 1.5 months ago...and that made little to no differnce. It was pig rich on the WB ~11.9, and now its at 12.8-13.2 through the whole run.

 

Both should run about the same given similar mods and same track conditions.

With all the hacks and programming tools avialable there is really no reason to go with an expensive aftermarket FI.

If you are set on going to S/D I would skip the 808 on the 165 and just go right on to the 730, it would make life much simpler.

 

Why are you guys still arguing about this? I though it was pretty much agreed that the guy asking could do a search and make up his own mind. And you MAF guys are being too sensitive and over-protective. What should've been said, is that if you already have one or the other (which the guy asking did), then keep it. There's no good reason to change. If you have to choose one, do a search and decide for yourself so we don't have to argue again. Seriously.

 

You could call me MAF guy, and my new car is SD. But, I might just be the first guy to take the SD computer, pitch it in the trash and install a MAF and computer just so all of you SD crybabies can have someone to insult and call stupid.

 

I don't understand what that was about, but it was really childish. Especially if you really did something that stupid just to spite some guys who actually share your passion for the same cars. This debate is tired. Grow up.

 

OK, the thread has now degraded into nonsense. Thanks everyone for playing.