I'm confused....what years had one or the other or both. :confused:

 

Lets see if I get this right...

MAF = 85-89
MAP = 90-91 & 90-95 ZR1
MAF = 92-04

 

92-93 MAP, no MAF, Why did they go back to MAF after 93? What is the benefit? I thought a MAP system was considered to be more accurate. Or does is just depend on the injection system?

 

VV90,

Your starting a debate you don't want to start.....trust me. :D :crazy:

Your question is Very legitimate though. They did infact run both systems. The reason is that the EPA mandates the measure the OEMs take to ensure non-polutant cars. The duel system was one that they passed to ensure that if the primary system failed (MAF), the second system would pick up the ball and keep the enviroment clean and happy. :rolleyes:

Why they chose MAF, as the primary system is the dabate I warned you against....I have my own view points but they are not shared by all or many. :cheers:

Good question though.

Jesse


Here is a breakdown of the years and the ECMs (hope it comes through OK)

ECM, EPROM, and Calibration reference
Year (TPI eng.) 1985 1986 1987 1988 1989 1990-1992
ECM Type C3 P4 P4 P4 P4 P4
ECM ID 1226870 1227165 1227165 1227165 1227165 1227730
EPROM Type 2732 27C128 27C128 27C128 27C128 27C256
BIN Size 4Kb 16Kb 16Kb 16Kb 16Kb 32Kb
Mask (Calibration)$1F $32 $32B $32B $6E $8D
Engine Management MAF MAF MAF MAF MAF SD
Baud Rate 160 8192 8192 8192 8192 8192
MemCal No Yes Yes Yes Yes Yes
Bare EPROM Yes No No No No No


Compliments of TGO


[Modified by ski_dwn_it, 11:42 AM 7/1/2003]


[Modified by ski_dwn_it, 11:42 AM 7/1/2003]

 

M.A F
MASS AIR FLOW
in the 1985-88 TPI the MAF sensor uses a heated wire and its measured resistance to measure actual air flow into the engine by the rate at which the air passing over that wire cools it theres a .4 volt-5 volt refererance between idle and full open throttle the ecu has a flow map that controls the injecter pulse width by ballancing the data from the throttle position sensor, O2 sensor,engine rpms and MAF sensor data

the MAP sensor
manifold absolute pressure
is used in the SPEED DENSITY system to measure the intake vacume/pressure the ecu has a flow map that controls the injecter pulse width by ballancing the data from the throttle position sensor, O2 sensor,engine rpms and MAP sensor data

both have advantages and problems
MAF measures actual air flow but the MAF sensor can, be a restriction to air flow, MAP sensors are NOT quite as accurate from my experiances and do not tend to self compensate as quickly once mods have been made and are not as flexible at changing the data... but if the software is set up correctly excellent results can be maintained with the speed density system and without the MAF sensors potential restriction to air flow

MAF, simple,self compensateing,potentially,but slightly restricted, ECU, LEARNS AS IT GOES
.
MAP, relies more on a matched data base ,LOOKS AT DATA BASE FOR INSTRUCTIONS, not as self compensateing yet potentially a slightly more effective system,PROVIDED THE DATA IS CORRECT

keep in mind that the current ECU processors are hundreds of times faster that the first MAF controllers that came in 1985 TPI corvettes, and far more able to make changes to the injectors pulse width /and air flow compensation changes



[Modified by grumpyvette, 6:59 PM 7/1/2003]

 

There was a thread in here acouple of days ago the chronicled the evoloution of the air intake system from maf to map and back. very good and very detailed. Cant find it.....ahhhhhhhhgggg

 

Scorp is close
but 94-04 is Maf and Map

92-93 are MAP aswell as the 90-91 and the 90-95 LT5

 

Ok, I did a MAP 730 conversion to my 89 L98. I did it b/c i've always wanted to do it, and was going to do the LT1 manifold conversion which i just sold. Bottom line is CFM and tuning. Well, my MAF was a PITA b/c every time i wanted to work on the car i had to be so gentle with it, those POS always break, and dirt would hit the wire, relays would go bad, POS system.... very finiky i think. a maf is $300. A Map is $30. LOL, and can handle a Azzz whooping...drop the Map...oh well, drop the Maf...your screwed. so it's also a Problem isssue... less parts = less problems. cheaper parts=:)

 

Mass air systems have both sensors, thats a reason that is better. And airflow restriction is something that wont happen unless you run over 500rwhp on the stock sensor and after that you can buy a bigger one for less than $300.
Cant beat that.

 

Didnt the 84 crossfire have a MAP system?

85 - 89 did not have a MAP with thier MAF systems.

How does having both systems on a car make it better, when one is used in priority over the other?

 

My car was updated with the CALMAP ECM system, which allows for the removal of the MAF system altogether. Any ideas how the system works with no MAF installed at all? I've always been curious about how this is compensated for.

 

Yes, the 1984 Cross-Fire is a MAP system.

Using both MAP and MAF makes it a more failsafe system. It one sensor brakes you will get a check engine light, but the car will still drive just fine using the other sensor.

 

Not to add to a "versus" debate, but then if the way the system is designed, it prefers the MAP readings first, and then uses the MAF sensor as a standby......does this mean the MAP system is more reliable, accurate, whatever???

 

Assuming the MAF sensor is up to snuff it's mass air flow readings require no interpretation as do those of the MAP sensor.

This is why putting a big cam into a MAP system requires recalibration of the chip, because the manifild vacuum values would no longer be a true indication of air flow.

It is also why, usually, moding a MAF system doesn't require recalibartion...till the values are out of range of the ECM.