The MAF restriction thing was proven a myth years and years ago with dyno/track results. Just FYI. You do you, though.

 

You just re-scale at the cost of resolution...

 

GM 85mm MAF is the GM plastic MAF off a LS6 or Truck.

 

Not really. You might max out the MAF early.

Need to see a frequency table for an OBD2 LT1 or LT4 and see where the PCM stops. The larger MAFs will report 12,000+ HZ.

 

I did not track test or dyno the maf change, didn't have to. More manifol​​d pressure means more air volume which means higher VE which means more power.

Ever consider maybe the car tested had other variables involved?

759 cfm @ 1.5 in/hg is all the 3.5" MAF flows. That means it is a very noticeable airflow restriction over ~400 hp.

Last I checked not many 500+ HP race cars run 750cfm carbs. They move on to 850s or demons.

If the MAF was not a restriction Lingenfelter would not have used TWO 3.5" MAFs on the big block Suburbans he built.

I have also owned a V8 car that had 2 x 75mm throttle bodies as well as two separate intake tracts. Two air boxes, two air filters, and two MAFs. It was only crank rated 420 hp. Even then streamlining the intake tract by installing smooth silicone hoses in place of the rubber accordian hoses and installing K&N filters gave a noticeable increase in both GM/SEC airflow and power.

 

I did not want to make this comparison since it was on a 496 but....
​When I pulled the small block out of my 99 Tahoe to make way for the 8.1 I discovered the 8.1 van PCM was already programmed to use the stock MAF for the Tahoe. I did not have one of the 85mm MAFs laying around. I created my own 4" air intake system using a late 90s 6.5 diesel air box, 4" silicone elbows and 4" aluminum tubing. I used a pair of 4" to 3.5" reducers to put the stock MAF in the intake ducting. I ran the truck like that for months. I stumbled across an 85mm MAF in a wrecking yard truck​​​​​​. I paid $10 for it and took it home along with the pigtail. I cleaned it and swapped it onto the Tahoe. Wrote the factory GMT800 MAF table into the PCM. Datalogging shows noticeably less intake restriction on the ~450 hp 8.1 and the thing only turns ~5,000 rpm MAX. The 8.1 also has a ported intake but the stock TB opening was only 80 mm. I was able to port it out to about 84mm. I used a GM 87mm Trailblazer SS throttle body on it with an adapter from ICT Billet that was opened up to match the intake porting.

 

Again. Cool. Not going to argue. People have tested both track/dyno and there was no difference. You do you.

 

Well then...Stop saying it won't work if you have not tested it. Do you know all the variables? Probably not.....

Maybe the 48mm TB was still in place. Maybe it had intake tubing that was too small. Maybe the filter did not have enough CFM. Maybe the tuning was off for the change.

I have seen too many people gain power swapping to the larger LS6 MAF and ducting on milder LS1 Corvette engines to say the larger MAF that GM created when they created the newer LS6 and newer trucks was not benificial. One of the first thing LS guys swapping 6.0L engines from Express vans do is swap out the small van MAF for the 85mm truck MAF. We also swap out the older truck intake and smaller 78mm throttle bodies for the NNBS truck intakes and 87/90mm throttle bodies. I have tuned a cammed 6.0L that gained nearly 30 hp from that swap. Literally an intake manifold, TB swap, and matching 4" air intake with a little tuning gained 30 HP at the wheels.

I have also tuned a cammed 5.7L LS1 GTO engine in a 1970 Chevelle for a Dorman LS2 intake, 90mm TB and 4" cold air intake setup. Car picked up 25 rwhp.



​​​

 

The topic of larger MAF has been beaten to death a simple google search will show the results. Most will say it's not needed under 500hp including the big name runners who have tested them. Another thing is that larger ls1 MAf work on a different frequency and I believe they max out the lt1 computer even earlier then the lt1 MAF if I remember right.

The point of the screen is to smooth the air flow removing the screen creates erratic readings.

If it were my car I wouldnt worry about the MAF I doubt it is causing you to loose any significant hp at your levels. Hell I made 480 on the engine dyno when I get my car all squared away I'm gona run it on a chassis dyno will see what it puts down to the wheels.

 

K... Had my car dyno tuned in Tulsa by Ed Wright in 1998. I had a ported MAF with my LPE heads/cam making 370rwhp on his dyno. I did so because it was the in thing to do. Everyone on the internets was doing it. Ed yelled at me saying to get that crap off. He gave me a stock one to borrow and assured me it'd make more power and it didn't. Actually there was no difference. Time and time again there have been others who've tested on dyno and track and experienced the same result. Thoughts were the MAF is accommodating enough for whatever CID offerings there are for a GenII LT1 engine.
So, until you...
And prove there's a difference, your argument means nothing, at least to me.

 

I think you would receive less resistance, if you shared examples. Do you have links to sources? I can't speak for others here, but I'd personally love to read through the details before deciding. Im convinced on the 52mm throttle body simply for no other reason than cosmetics as my OEM looks pretty haggard. Any power increase would just be icing on the vagine...

 

My personal results were from the dynos I did with Ed. Only got a printed sheet of the final run. As mentioned you can do a search on this website or google and probably find what you're looking for, or experiment for yourself. These things were argued 15 to 20 years ago. While you're doing that, make sure to also do an experiment on the power losses and increases simply by the engine and coolant temperature. Reason being is there have been those who've claimed the MAF is good for "3rwhp across the board" when you can have as much as a 5, or maybe even 10rwhp loss or gain from engine temperature changes alone.

 

Op

If you have the tuning skills to use a lager MAF and feel that would benefit your engine build go for it.

With that said larger or ported MAF have previously shown no measurable improvement and sometimes a loss on <450 hp motors . I have used the same tuner SS RRR has, Ed Wright, who also advised me not to use one. While the screen is thought of as a restriction, by design it is to "stabilize" the air flow across the wires to give a more consist flow thus signal to PCM

If after testing and dyno pulls shows a larger screen or descreened works for you, great...please post the dyno results

 

I'll have to crunch some numbers before I decide on anything. Since the air has to flow thorough the MAF, it won't do any good having a throttle body with a higher CFM rating...

 

I dont knownifnthats true or not. Ait flow is a funny thing on the bottom of the p51 mustang there is a scoop and everyone thought it was for the engine but it was actually to slow down the air flow going into the radiator because the air was traveling to fast to cool the radiator.

I'm not saying it will or will not and you may need to experiment I doubt you need a 58mm I dont think I do but I bought one off a member a lot cheaper then a 52 would have been. But point being as the air is traveling through the MaF it may be traveling at a greater speed before it hits the 90 as the speed slows down the ability to move more volume may help or it may not. Now if you are running a lid setup then yeah it's a waste probably.

 

more fuel for the fire,
old dragstrip acquaintance claimed .15 ET improvement from a larger TB (don't recall size).
less motor/rpm than the OP (low 300's flywheel hp)
he had timeslips and DA numbers to back his claim...
:shrug:

 

Nice.....a bit higher than I would've expected...…

KW

 

The cam's EVO is 50.5 degress. That cam is performing exactly as it was spec'ed.

KW

 

I think his statement, was based on an inaccurate assumption, that my dyno sheet showed stock motor vs built motor. This was at least partially my fault, as I didnt state clearly, that this dyno graph, was stock TUNE vs dyno tune, on the same motor, same day.

Although I used a single roller SBC timing set, that allowed an option for 1 lever of retard and 1 level of advance OR strait up (dot to dot) Lloyd Elliot told me to time it 0 (dot to dot), so thats exactly what I did.

 

Ok everyone, whos 52mm TB should I run?