hey guys i've been away from the board for awhile, and i changed my name. what is the latest on the mass airflow sensors. i heard someone was comin out with a box to fool the computer, because our stock mafs will only report about 490cfm. obviously i am not totally informed on the issue but i thought one of you guys or someone at the PROM board could bring me up to speed.

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86 IROC-Z
305 TPI
700R4 W/ shift kit
3.23 gears
T-Tops
maroon with gold stickers and rims/ black interior
43,000 miles
flowmaster exhaust, edelbrock headers, gutted airbox, converter, and MAF, K&N filters.

soon to come are 3.73 gears and subframe connecters.

 

U don't even need that much flow, and probably never will if u aren't going to be heavily modding that car or S/Cing it. The MAF is good the way it is for your car.

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89 RS

STILL Looking For:
An 87 IROC-Z28 350 TPI

 

uhhh u must really think i am a moron. i know the maf is the better way to go, and as soon as i graduate college (mechanical engineering) i will be building a 383. anyhow awhile back there was some discussion about some maf recalibration boxes for larger displacement high performance applications. the maf can only report something 500 cfm. there were some real sharp guys on here trying to figure out how to solve this problem by adapting 5.0 mustang mafs or 4th gen mafs to our cars that would report more airflow.

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86 IROC-Z
305 TPI
700R4 W/ shift kit
3.23 gears
T-Tops
maroon with gold stickers and rims/ black interior
43,000 miles
flowmaster exhaust, edelbrock headers, gutted airbox, converter, and MAF, K&N filters.

soon to come are 3.73 gears and subframe connecters.

 

Adapting the MAF itself wont help, its the program in the ECM that is the problem.

 

beat me to it :-)
the MAF can report 6,00 cfm..but if the ECM is only set to accept 490/500,thats all its gonna read....so gettin a MAF to flow insane numbers wont do a thing on its own....

Andy


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The "House" has spoken...
check out my my 88 WS6 Trans Am

We are the seeds of legends,our true origins are unknown...WE SIMPLY ARE...

 

Gads, wrong again.
In oem form the ecm is looking for a frequency range of 30-130 Hz. that can mean 0-255 gm/sec, or 0-1,000 gm/sec..
You can use what ever input you want, and as long as you convert it to that frequency range the ecm will be just fine. The tough part is that the flow isn't linear, that would take tuning of the MAF related items, in the prom to correct.

The easy answer is just using the 808 calibration, and running MAP or going to a 730 ecm (MAP).

 

Grumpy,

You are correct about the MAF signal, but only for the Buick and other V-6 applications. GM powertrain used a Bosch analog output MAF sensor in the 1986-1989 TPI engines. The 0-5VDC signal is A/D converted within the ECM, and the firmware limits of the converter allow for a maximum metered airflow of 255g/S. Airflow can exceed that, and the only tuning at that point is usually done with injector flow or fuel rail pressure.

The V-6 guys are fortunate in that the MAF translators that are pure digital/digital are available widely, and solve the problem of flow limits.

As you stated, the easy way around that for TPI engines is with the S/D scheme.

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Later,
Vader
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"Get UP - Drop the bombshell!"
Adobe Acrobat Reader

 

Interesting.. and if true so far in the past day you are 1-3.

Actually from the above post, looks like you are 0-3. I have lots of posts here, 4400ish... Im sure you can find some others if you keep looking, do a search with my username since its interesting you so much. Funny, I thought you were ignoring me LOL!

[This message has been edited by madmax (edited September 01, 2001).]

 

What does that have to do with is topic...

wait you a mod, I guess that makes it all right...

So 4400ish posts, I wonder how many wern't over who's right and wrong, or other BS posts like that, humm.. 100ish
'LOL', what a conceded loser..

|]amn I'm as bad as you, not posting about the topic, I'm out, peace,

 

So when you have no clues about what is actually going on, you brag about how many posts you've made.
Heck, you've now shown you can't even follow a thread.
Wonderful job your doing.

 

What BS.



[This message has been edited by IROCZTWENTYGR8 (edited September 01, 2001).]

 

FRM, have u thought about switching to SD for the engine u want to put in?? Although u most likely want to find a way to get the MAF to read more as I do also.

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89 RS

STILL Looking For:
An 87 IROC-Z28 350 TPI




[This message has been edited by IROCZTWENTYGR8 (edited September 01, 2001).]

 

Whatever dude, get a life.

[This message has been edited by madmax (edited September 01, 2001).]

 

snippettttt

[This message has been edited by madmax (edited September 02, 2001).]

 

You, "gentlemen", are some of the individuals that are making this an increasingly more difficult place to post. The knowledge of the more experienced users is invaluable. However, the sarcasm and ignorance that often comes with that knowledge is worthless. If you can't share your knowledge without ridiculing those that are less informed, you should not reply to a post. Mr. Vader I am not referring to you

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92Z28
89GTA

 

Back to the topic, in TPI cars the 255g/s limit is not in the MAF but in the 8-bit ECM. And as Vader said the easiest way around it is just going Speed Density. I personally haven't heard of anyone running a "tricked out" ECM to enable it read a MAF flowing big time numbers.

 

Bailey Engineering makes what's called a Translator, it allows using a late model MAF on a GN.
The GNs had the same limit set for them as the 3rd Gen FBods, but with a translator the GNs can read over 500 grams/sec..
Like I said in an earlier post the problem is that their output to what the ecm expects for a given Airflow. So you can't take a Translator (with a LM MAF) and use it with a 3rd Gen unless you go thru all the MAF related stuff.

 

wow lots of info here. so the bottom line is that as of now it is about impossible to make the computer read above 255g/sec. there are mafs that can flow more than that, but the computer won't be able to process the info. so us maf guys are pretty much screwed then huh. for now anyway. i really don't want to go to s/d, it just ins't worth it. i'd have to swap the computer, wiring harness, prom, heck i might as well swap in a built LT1. i want to make about 450 reliable horsepower and about 500 lbs/ft of torque. i was gonna use a long rod 383, so i am gonna end up burning a new prom anyway, but if the maf setup won't accomodate my airflow requirements i guess i need to make a change. i guess the only reason i asked was that there was a big discussion a while back and some guys vader and traxion i believe were talking about fooling the computer into understanding higher airflow rates. i guess i will have to do a little research in the archives and in some tech articles and diagrams, maybe i can come up with something that would work. nothing is impossible. thanks for the info guys!

------------------
86 IROC-Z
305 TPI
700R4 W/ shift kit
3.23 gears
T-Tops
maroon with gold stickers and rims/ black interior
43,000 miles
flowmaster exhaust, edelbrock headers, gutted airbox, converter, and MAF, K&N filters.

soon to come are 3.73 gears and subframe connecters.

 

You are not entirely screwed. It is kind of ghetto, but you can tune using PE. Just hook up your scanner, find out what LV8 your motor inhales 255g/sec. Then go change the "min LV8 to initiate PE" value to correspond. Now tune the "PE vs rpm" and "PE spark vs RPM" fields till you get it where you want it. This is oversimplified of course. It sounds bad, but I have seen some cars run awesome tuned like this. There is a member TODD85 who's vette (383) is tuned like this and it runs flawlessly and consistantly mid 11's. It idles smooth and doesn't ever miss a beat. I saw it in person, run after run after run.

Obviously it is better to convert to SD, but when you have cash(college guy) and other limitations, and you already got it like me you do what you gotta do.

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82' Z-28. 327" w/ flat tops. 216/228/112LS. Pocket ported 041 heads 1.94/1.50 SS valves. World Class T-5 from a 91'. Best run? Runs with 2001 vette to 150mph! Soon to be converted over to TPI w/ supercharger.