What larger MAF should I go to?

**GTO1_OHIO** · 02-18-2009, 09:30 AM

So what are my options going to a larger MAF. I have a 90mm Nick Williams TB and 90mm Fast intake. Am I right in thinking my stock MAF is 75mm and a Z06 is 85mm? Can I get a 90mm? I know SLP has a 85mm but some people have had problems with it and I know Granatelli has one that people have says does nothing. Anyone have any experience with this?

**0rion** · 02-18-2009, 11:56 AM

have you ever thought about going speed density? You're a heads/cam car right? I'm going back to speed density this spring. I ran sd year before last and then ran the maf last year. My times at the track were 5/1000's different and the car ran better without the maf. If you go to a bigger maf you're going to need to tune for it anyhow...why not just go sd instead and get rid of it altogether? The z06,slp, and granatelli are all 85mm maf's but they do make larger ones. I'm thinking the new zr1 runs a 100mm maf or something like that. Let me see what I can dig up for you.

**0rion** · 02-18-2009, 11:59 AM

texas speed carries a 100mm maf and you can probably pm mark from kyspeed (sponsor

) and he can get you a 100mm

**Sarge** · 02-18-2009, 12:36 PM

Screw a MAF......go SD....you will NEVER regret it nor look back...

**GTO1_OHIO** · 02-18-2009, 12:57 PM

Yes AFR 205s and a custom grind from Ed Curtis. The reason I was thinking of going to a bigger MAF is that it is something me and the performance shop that works with me on my car have been kicking around since last spring. ...so a tune is no problem. They've tuned LSx engines for years but don't know how many SD tunes they have done.

**mistermike** · 02-18-2009, 01:19 PM

No MAF beats no MAF at all.

**Stone** · 02-18-2009, 01:47 PM

Originally Posted by GTO1_OHIO

So what are my options going to a larger MAF. I have a 90mm Nick Williams TB and 90mm Fast intake. Am I right in thinking my stock MAF is 75mm and a Z06 is 85mm? Can I get a 90mm? I know SLP has a 85mm but some people have had problems with it and I know Granatelli has one that people have says does nothing. Anyone have any experience with this?

Im still on my stock one. I think its the reason that im throwing lean codes at idle(under long periods of time) but i may be wrong. Im running a 90/90 setup as well making 458/419 at the wheels. I wonder if should think about changing mine out and getting it retuned?

**qwkgto** · 02-18-2009, 03:40 PM

Originally Posted by GTO1_OHIO

Yes AFR 205s and a custom grind from Ed Curtis. The reason I was thinking of going to a bigger MAF is that it is something me and the performance shop that works with me on my car have been kicking around since last spring. ...so a tune is no problem. They've tuned LSx engines for years but don't know how many SD tunes they have done.

Well,I saw this earlier,was hoping for some insite from some all knowing person smarter then me,IMO,best no restriction at all,SD is a far better tune, .tuner takes more time to do it but its a far better tune in the end.Aussies dont use a MAF,I think they just sent us the GTO with Mafs saves them and GM time and money,leaves alot of fine tuning and power to be had.YOu know I have been running Mafless for over 2 years,ILL help you anyway I can.

**mark21742** · 02-19-2009, 02:51 AM

Originally Posted by qwkgto

Well,I saw this earlier,was hoping for some insite from some all knowing person smarter then me,IMO,best no restriction at all,SD is a far better tune, .tuner takes more time to do it but its a far better tune in the end.Aussies dont use a MAF,I think they just sent us the GTO with Mafs saves them and GM time and money,leaves alot of fine tuning and power to be had.YOu know I have been running Mafless for over 2 years,ILL help you anyway I can.

I'm running SD right now. do you keep your STFTs set to enabled, or diabled? also I have my MAF unplugged and code reporting set to no MIL light....is there a way to set it to (3) no error report, so I don't pop any DTCs for emissions?
thanks for any help

**qwkgto** · 02-20-2009, 04:15 AM

Originally Posted by mark21742

I'm running SD right now. do you keep your STFTs set to enabled, or diabled? also I have my MAF unplugged and code reporting set to no MIL light....is there a way to set it to (3) no error report, so I don't pop any DTCs for emissions?
thanks for any help

I turned my to disable,all I have and i replaced it was the IAT moved it right after the intercooler,but if I was Na id move it closer to air filter,damn heat soak. as far as rest your cars a 04 some lil things are diffrent ,you will need to just experiment with the STFTS see what your likes,hell been so long since i messed with mine I cant say for certain.these cars a have a mind of thier own sometimes,I have a 2 bar map, sometimes it throws the light for that as well.

**Sarge** · 02-20-2009, 04:29 AM

I have a 2 bar/IAT right next to the air filter and have never thrown a light.

**0rion** · 02-20-2009, 05:41 AM

Originally Posted by mark21742

I'm running SD right now. do you keep your STFTs set to enabled, or diabled? also I have my MAF unplugged and code reporting set to no MIL light....is there a way to set it to (3) no error report, so I don't pop any DTCs for emissions?
thanks for any help

the pcm has to see the dtc in order to go into sd so you have to set 101,102,and 103 to fail on first no mil light. STFT's are different than SD. That would be an open loop deal so leave those enabled if you still want to run in closed loop. I disabled LTFT's on mine when running the MAF after I had my WOT fueling on so there wouldn't be any extra fuel added at WOT if it was showing positive trims cruising.

**mark21742** · 02-20-2009, 06:17 AM

Originally Posted by 0rion

the pcm has to see the dtc in order to go into sd so you have to set 101,102,and 103 to fail on first no mil light. STFT's are different than SD. That would be an open loop deal so leave those enabled if you still want to run in closed loop. I disabled LTFT's on mine when running the MAF after I had my WOT fueling on so there wouldn't be any extra fuel added at WOT if it was showing positive trims cruising.

will those codes make me fail emmissions? that was my only concern. right now I have stft and ltft enabled and reading the histograms I have the VE table dialed in pretty close, ltft stay right at 0, some go -1-+1 and wideband is holding between 14.5:1-15.0:1 crusing, with WOT holding between 12.8:1-13.1:1.
I copy/pasted my high octance table to the low table and advanced my timing a few degrees (27° WOT) with 0 knock retard.
am I missing anything with the tune, or is that about it?

**0rion** · 02-20-2009, 06:58 AM

Originally Posted by mark21742

will those codes make me fail emmissions? that was my only concern. right now I have stft and ltft enabled and reading the histograms I have the VE table dialed in pretty close, ltft stay right at 0, some go -1-+1 and wideband is holding between 14.5:1-15.0:1 crusing, with WOT holding between 12.8:1-13.1:1.
I copy/pasted my high octance table to the low table and advanced my timing a few degrees (27° WOT) with 0 knock retard.
am I missing anything with the tune, or is that about it?

looks like you have it pretty well covered. I have zero experience with emmissions so I'm not the person to answer that question. I would think any code they see would fail you but I can't be certain. Have you ever tuned your maf? If so why not hook it back up long enough to pass and then fail it afterwards? You guys only get tested every couple of years right?

**mark21742** · 02-20-2009, 10:21 AM

Originally Posted by 0rion

looks like you have it pretty well covered. I have zero experience with emmissions so I'm not the person to answer that question. I would think any code they see would fail you but I can't be certain. Have you ever tuned your maf? If so why not hook it back up long enough to pass and then fail it afterwards? You guys only get tested every couple of years right?

yup we get hooked up to the computer every two years.
I never got the maf calibrated......i tried, but a/f ratio goes to 20+:1 when I hooked it back up and can't get it any lower.
the only thing I could think of is a massive air leak from the intake tube to TB......im going to get a new coupler here in an hour or two and try again

**0rion** · 02-20-2009, 10:44 AM

are you using a wideband? You can get that maf nailed down in just a couple of logs. It goes really quick using the maf histogram.

**mark21742** · 02-20-2009, 10:58 AM

Originally Posted by 0rion

are you using a wideband? You can get that maf nailed down in just a couple of logs. It goes really quick using the maf histogram.

yup I have a wideband and lc-1 hooked into hptuners. start the car up with the MAF plugged in and looking in the histogram is where I see it going 20+:1m so I didn't want to run it any more with the maf till I was able to get the intake tube after the MAF sealed good......then hopefully my a/f ratio will come back closer to tuneable

**mistermike** · 02-20-2009, 04:56 PM

The 800 Lb gorilla in the room is the fact that you have to do a thorough SD tune before you can calibrate your MAF table correctly. Most people don't do this for obvious reasons. Those that do, generally see no compelling reason to put the MAF back on. It's a bit of a catch 22.

**0rion** · 02-20-2009, 05:11 PM

Originally Posted by mistermike

The 800 Lb gorilla in the room is the fact that you have to do a thorough SD tune before you can calibrate your MAF table correctly. Most people don't do this for obvious reasons. Those that do, generally see no compelling reason to put the MAF back on. It's a bit of a catch 22.

I think you can make a car run pretty decent with a good maf tune as long as your ve isn't way off. The ve is only looked at during transitions for the most part and isn't used at all in PE. Granted, it won't be perfect but I think on a bolt on car you can get by with just a MAF tune. A cam car I would do a ve tune no question but on a bolt on car I don't think it's mandatory.