MAS options

Mattstrike

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Not for my turbo SSEi.

I'm looking for a MAS that will work with the '98 OBD-2 computers, that has ~ 3" housing I can mount anywhere between the throttle body and air filter. It should also have enough resolution to support 300-350 hp without going over the 11.5khz limit of the PCM. A slim package is preferred.

What I think my options are:
3100/3400 sensor
'04+ grand prix sensor
Lq4/ls2 sensor (not sure what application to find them with a 3" housing though)
Others???

Then the other question is a lot of these are 5-wire sensors, are they compatible with a 3-wire sensor, and what's the difference there?
 

Turbocharged400sbc

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5 wire and 3 wire are only different because 5-wire include the intake air temperature sensing in the math circus it's one less part 1 less connector one less assembly step. a bean counters dream
 

PANDA

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You will probably need to scale the MAF. My stock cam car would max out my LS6 MAF when it was cold out.
 

ZephTheChef

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I was well over that power level (assuming you are talking crank up) when I was on a northstar TB and truck maf, but I believe those are 3.5" or something. The LS7 maf you could put in whatever size pipe you want...so far mine has been super easy to tune in terms of resolution even at idle despite my huge boost/vacuum leak causing it to read wacky.
 

ZephTheChef

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assuming this is a supercharged car, for comparison, when I had the truck MAF setup I was on a chilled intercooled gen V M90 with the overdrive crank pulley and a 2.55" on the supercharger on straight methanol as primary fuel. My fuel flow indicated around 475 crank HP, probably barely over that 300hp hump at the wheels though as I'm sure it took a ridiculous amount of power to turn the supercharger that fast, coupled with other drivetrain losses and inefficiencies (I was significantly overadvanced because it was my first experience with methanol tuning...which is what eventually destroyed that first engine).
 

Handsome Jesus

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assuming this is a supercharged car, for comparison, when I had the truck MAF setup I was on a chilled intercooled gen V M90 with the overdrive crank pulley and a 2.55" on the supercharger on straight methanol as primary fuel. My fuel flow indicated around 475 crank HP, probably barely over that 300hp hump at the wheels though as I'm sure it took a ridiculous amount of power to turn the supercharger that fast, coupled with other drivetrain losses and inefficiencies (I was significantly overadvanced because it was my first experience with methanol tuning...which is what eventually destroyed that first engine).
Calculate the gas HP of the supercharger, I'm interested to see how much HP it took to turn it.
 

ZephTheChef

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Calculate the gas HP of the supercharger, I'm interested to see how much HP it took to turn it.
The equation is roughly (0.004 hp*cfm*psi boost)/compressor efficiency. So at 2.55" upper and 6.75 or whatever the overdrive lower is (somewhere around that size), that's a drive ratio of 2.647 to 1, or 13,764rpm at the blower at my peak power of 5,200rpm. Looking at the M90 chart that gives me 1200 cubic meters per hour (706cfm) at a 50% blower efficiency. That makes the math on the supercharger drive in the ballpark of 85hp. Not as terrible as I thought, really.

Edit: that was figured at 15psi. It would sometimes max the MAP and sometimes not quite so it was right there at that 1bar boost.
 
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Mattstrike

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I ended up with the '04+ GP sensor for now. But what is the 'truck sensor'?
 

ZephTheChef

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I ended up with the '04+ GP sensor for now. But what is the 'truck sensor'?
The LQ4 maf. Which may well be the ls2/ls6 maf as well. I'm really not an expert on the differences. I know aftermarket replacements are often the same part for various similar applications, but haven't investigated whether it's actually the same exact GM part or not.
 

b4black

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When you install a LQ4 MAF, what do you do about the calibration table? Is it close to the stock MAF, or are there tables somewhere to use as a starting point?
 

ZephTheChef

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When you install a LQ4 MAF, what do you do about the calibration table? Is it close to the stock MAF, or are there tables somewhere to use as a starting point?
I think ZZP has the tables on their website somewhere. Or you can copy them from a truck tune that used that sensor. I can get you the values if you can't find them elsewhere...I should have them somewhere, or can pull them out of a stock truck.
 

ZephTheChef

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I actually have an LQ4 Denali on the car lot right now I could hook the laptop up and get the MAF table (or tables).
 

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