Patrick G

iTrader: (14)

This isn't going to be a newbie type of MAF thread. I've got Autotap and many other resources to test and verify my tuning.

I have a heads/cam stock displacement LS1 that makes 408 rwhp. I have very good heads (SAM) and a decent street cam (Lunati 221/224, .560/.560, 113LSA) 1 7/8" Whisper Headers running through gutted cats. I have Ed Wright tuning and a stock, unported MAF. There are several reasons why I haven't tried a ported stock MAF.

1. With 10.90-1 compression, I don't need more timing than my 26 degrees I have right now (more timing and the motor will ping on 93 octane).
2. My O2 mv is in the .890-.910 range which is perfect in my experience.
3. Biggest reason: My Ed Wright tuning has the L-Trims locked in at 0%. That means it won't correct for any airflow changes like a ported MAF would bring. All a ported MAF would do with my tuning would be leaning the hell out of it. It can't correct past 0%. Wierd huh?

So here's the question: Purely from an airflow standpoint, is there any power to be gained on a 400 rwhp motor by going to an oversized MAF like a calibrated Pace or SLP MAF? My motor runs out of breath at 6200 rpms and falls on its face quickly after that (really shows up on the dyno). I've got plenty of airflow in the heads (305/230 cfm at .500 lift), LS6 intake, good exhaust, lots of spring pressure (140 seat, 375 open) and plenty of cam...the motor just won't rpm. Any thoughts?

onfire

iTrader: (17)

The ASA ls1's only jumped 5 ENGINE hp going from a screened 75mm to a screened 85mm maf with tuning.....they have less hp then you though...Are you using the screen? You'll see some hp improvement going to a calibrated 85mm but not huge numbers...less pressure drop = more hp....I would bet 5-8 rwhp at the most.

[ December 05, 2001: Message edited by: onfire ]</p>

Patrick G

iTrader: (14)

Onfire,

I'm running a screenless stock unported MAF.

Ragtop 99

iTrader: (7)

Patrick: Sorry to be slightly off-topic, but why did EW lock the Ltrims at 0%? Doesn't it just force the STrims to make a bigger adjustments?

Patrick G

iTrader: (14)

Joel,

I guess by locking the L-Trims at 0%, he's able to tune the motor to only be in the best a/f cells as much as possible...and to answer your question, yes, I'm sure the S-Trims have to work like a **** for changing conditions. It's no wonder E W doesn't recommend running non-stock MAFs (unless he knows about it). He locks in his tuning for a MAF he knows and you won't see the L-Trims budge off that 0% mark...even if you throw on a ported stock MAF...really crazy.

Patrick G

iTrader: (14)

Let's keep this discussion going...please!

onfire

iTrader: (17)

You can go look at our flow bench data at www.installuniversity.com for various maf's. IMHO if you are tuned for a stock screenless maf you're not going to gain much if any to a stock screened 85mm....the pressure drop isn't that much different. I you want to try a 85mm truck screenless maf (you'll need a MAFT) I'll send you one to dyno( I think I've kept the ones we flow tested).....IMHO if you're tuned perfectly for a screenless 75mm it's not worth the hassle but if you want to try it let me know....if you want to do a real dyno shootout of maf's I'll send all of them to ya!

Trevor @ Texas Speed & Perf.

iTrader: (3)

He locked my L-trims at 0% at WOT, too. I just don't understand why he does this. The only way I know that you could add the larger MAF would be to buy a MAFT and put the car on the dyno with a wideband O2.

RPM WS6

iTrader: (3)

Patrick, I know this has nothing to do with MAFs, but have you tried porting your TB for more air also? Sounds like with such a free flowing intake setup and huge headers that the weakest parts would be the stock MAF and the stock TB. Maybe both should be addressed?

Patrick G

iTrader: (14)

RPM WS6,

Sorry, I forgot to mention that I already have a ported throttle body. I also have a stock screenless 85mm SLP MAF to try out (vs. my stock screenless 75mm MAF). These locked L-Trims are pissing me off though. <img src="images/icons/mad.gif" border="0">

Patrick G

iTrader: (14)

Onfire,

I can't open up the installuniversity page. What are the flow numbers of a stock MAF w/screen vs. screenless vs. Stock 85mm MAF vs screenless 85mm MAF?

Ragtop 99

iTrader: (7)

Mikey at Rapidmotorsports got a total of 6 HP out of a 85mm MAF & BBK TB on his 346 motor.

Patrick: Did you have you wideband when you dynoed? OnyxSS had Ed's tuning and it looked great on ATAP (timing, O2s) but a wideband showed he was running real lean above 6000 rpm; he basically had run out of injector. I realize that you have the '98 with bigger injectors than his '00, but I doubt that MAF flow is killing your power. I don't think you'll find the lost high-rpm hp unless you have a bad MAF, by switching.

BTW, I was going to try the 85mm MAF on the dyno at Cartek until my appointment got canceled. See the "Hey NJ" post in Eastern Forum for that clusterfuck.
<img src="graemlins/gr_judge.gif" border="0" alt="[judgement]" />

Black Sunshine/ 00SS

iTrader: (1)

I dont know why, but my car responds great with the ported MAF, 2 tenths. I thought they were supposed to be locked in also, but I can tell a crisper throttle, and revs quicker. Last dyno showed 920 on the o2s, got that down to a 870 with the MAFT.
I tested the PMAF to the stock MAF all summer & I ALWAYS ran quicker with the PMAF.

Patrick G

iTrader: (14)

Black Sunshine,

If you don't have Ed Wright tuning, I don't doubt that your car picked up with a ported MAF. All my previous cars did too (more timing and leaner a/f were the main reasons). With this blasted program though, I'm screwed from running anything but a calibrated MAF. So it all comes down to airflow. Is the stock screenless MAF a restriction on a 400 rwhp motor with a good lid, ported TB, and LS6 intake?

John B

iTrader: (10)

Patrick G, when I bolted on a PACE screenless '02 ZO6 MAF & tweaked my MAFT my stock LS1 picked up a documented 13RWHP & 15RWTQ on the same dyno as previously tested. As for SOTP meter, the car now instantly boils the tires in first gear where it wouldn't with the stock MAF & tweaked MAFT. I would have to believe there is opportunity on a modified motor like yours.

Colonel

For whatever it's worth...

Not that we spent any time dialing either in, but at MTI we saw ZERO gain on the dyno with the 85mm GMS over my home ported standard GMS MAF. And this was with an MTI 422 sucking through it.

I don't think there are good gains to be had from 85mm MAF sensors due solely to their increased airflow potential since the intake manifold inlet continues to be a restriction.

Yes, I still use the 85mm sensor just for the theory of it but I honestly think I could run just as fast with a standard GMS MAF.

RyanJ

Black Sunshine has an Ed Wright program i believe. Im not smart enough to gove to this thread any other way. <img src="images/icons/frown.gif" border="0">

Ryan <img src="images/icons/smile.gif" border="0">

Patrick G

iTrader: (14)

Black Sunshine must have gotten lucky and not had his LTrims locked at 0%. The car would run incredibly lean without a MAF Translator (which I understand he has).

boss99ta

I don't know why they do not perform well on dyno's, but I'm a big fan of the 85mm maf.

At the track in 1/8 mile I went 84.6 mph with stock maf, went 85.2 mph with Gmaf, and then went 86.4 mph with the 85mm maf from SLP. Now this was the same night at the track in back to back runs. I think that is the best way to test anything, dyno's are good but will not tell you the whole story.


The test we did says alot for the SLP 85mm mass air, but that is just our results.

[ December 07, 2001: Message edited by: boss99ta ]

[ December 07, 2001: Message edited by: boss99ta ]</p>

2001 Pewter WS6

iTrader: (43)

I also have Ed Wright's tuning and ran a ported MAF. No pinging. It may have something to do with the 2001 cars. Mine and Black Sunshine's are 2001's. By the way, I switched to a Pace 85mm VV MAF and the car runs great on it.