Need advice on MAF and TB upgrade

Pooch

Registered User
What is the best combo of MAF abd TB to improve otherwise stock 91 SC auto? Should I upgrade the computer chip as well? I have no experience with ODBI. I know ODBII systems ('96 and up t'birds) can be reflashed but I know nothing about chip upgrades or reflashes on EEC-IV systems.

Thanks in advance
 
76 MM Maf and 75 MM TB get the correct sample tube to mate to the injector size. You will need a chip to get the tune right on and it improves perfomace as well

Ken
 
Can you give me some sources? What do I need to know about matching the sample tube to injector size? How about chips - are there custom parameters such as sample tube size injector flow rate and fuel pump pressure? Appreciate any info.
 
Can you give me some sources? What do I need to know about matching the sample tube to injector size? How about chips - are there custom parameters such as sample tube size injector flow rate and fuel pump pressure? Appreciate any info.

Id get a tune. you wont see maximum hp for your mods with out a tune. The correct sample tube in a bigger MAF will get you in the ball park for driveability. A SCT chip will give you the needed flexability to tune any mods for your car you do in the future. For example you can program the fan to come on at 180 degrees and install a 180 degree thermostat. Helps your car run cooler. Most people just assume they ad a modifacation and they dont need to make an adjustment. Anything you change from a factory part will take you further from the factory settings. You will find changing one thing will require more changes. A bigger MAF and TB just means the blower needs to be ported and the Throttle body pleum attached to the blower will need to be opened up or replaced. It just kind of goes on and on

Ken
 
good points but some ppl like the leaning out of the mixture from an aftermarket maf which leads to a bit more power in top end.

with all the mods i have i still have no tune. but im also running stock injectors which i know is dangerous, but i cant afford bigger injectors, fuel pump and tune right now.

and i agree that not much will be gained from maf and tb without some work done to the blower and plenum. but he only asked about a maf and tb. if he wants to know more theres more than enough threads to keep busy reading for weeks.;)
 
Thanks everyone. I am open to further mods that would be required/desired as a result of MAF/TB upgrade. Sounds like an SCT chip and bigger injectors make sense. Someone mentioned other threads to look at. Which forum would be the most likely to have info?

Thanks again
 
I just bought a PP 75mm TB for 120 new but be warn it sticks at times. Really sucks. I need to figure out why.
 
I just bought a PP 75mm TB for 120 new but be warn it sticks at times. Really sucks. I need to figure out why.

i was thinking maybe the throttle blade is backwards. that happened to the tb in my altima when i took it apart to clean it. put it back together and it stuck all the time. flipped the throttle plate around and its been fine since.
 
Thanks everyone. I am open to further mods that would be required/desired as a result of MAF/TB upgrade. Sounds like an SCT chip and bigger injectors make sense. Someone mentioned other threads to look at. Which forum would be the most likely to have info?

Thanks again

You will find that most guys here have done the modifacation thing to some degree or another. Just changing things is not a good way to performace. Would you bake a cake and just start throwing sugar and flour in the mix hoping for good results? You need to decide what do you want to end up with RWHP and or torque. If you say 250 HP than most here can tell you what modifacations to make. If you want 400 than the list is longer. There is a forum here for the Top SCs in the club. Find cars with HP levels you aspire to and look at their member pages. Other than that you will get 10 diffrent guys giving you 10 diffrent ideas, not all good. The Tech forum will get you more information than any other after that the Non Tech forum is fairly good

Ken
 
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i was thinking maybe the throttle blade is backwards. that happened to the tb in my altima when i took it apart to clean it. put it back together and it stuck all the time. flipped the throttle plate around and its been fine since.

I did play with it alittle. I'm going to sand the sides of the butterfly which is where i think it is sticking at. you can see marks where it looks like its digging in.
 
The throttle blade is probably sticking on the intake plenum. Considering its only about 65 or so mm compared to the 75mm TB... and this can actually hurt performance. The MAF would have been a good place to start, and upgrade the TB once you have a bigger intake plenum installed.

If your sticking with stock injectors, and going to the bigger MAF you'll be alright because your not really going to see a big increase of air flow into the motor, until you upgrade the blower by porting or whatever... THEN you WILL need to look at bigger injectors, and that will land you the need for a chip.

As for leaning out, thats not really going to happen in your case with a stock blower. Now if you installed 42# injectors, and the correct sample tube for the MAF for those, and not run a chip, it will lean you out a bit, and screw up alot of other things including timing... not to good a place to be especially with boosted cars. Dave D wrote up an excellent article on exactly what happens with this process.
 
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