Chris99WS6PWTMET

that a stock ported MAF causes tranny damage?

I've been abusing the search feature gathering info on the ported MAF and I wanted to make sure I get good info.

I know it tends to lean the cars out a bit. Raughammer runs (or has run) the ported MAF with no problems that I've seen posted. This is a topic which you have done MUCH research on so I wanted some of your ideas on it.

The car is a 99 with a lid, JBA's, no cats, SY3500, beefed up tranny with mild shift kit. It was a little fat on the dyno last week so I figured what the heck I'll port the MAF and see what happens. I have yet to drive it. Tonight I was doing more research and came across some of your old info and now I'm wondering if I made the right decision in gutting it out last night.

Any knowledgeable opinions would be appreciated. Thanks.

Patrick G

iTrader: (14)

Sad to say, the ported MAF ends have been linked to premature tranny failures right and left. I say sad to say because I've been a big fan or ported MAFs since 1998 on these LS1s. Only until recently, have we found the long term damage they do to trannies. By tricking the MAF into reading less incoming air, this tells the pcm there is less of a load. With less of a load, the pcm will increase timing (good) and decrease transmission line pressure (bad). I loved the increased timing and leaner fuel curve (especially on a '98 LS1) that a ported MAF brought. I would easily pick up a tenth with a ported MAF.

Problems get uglier when you add a ported MAF with a big cam. The pcm looks at the MAP sensor as well and a big cam changes MAP sensor readings for the worse...again lessening line pressure. It's like adding insult to injury...only to your tranny. Guys like Steve Harmon (Just Me) figured this all out years ago and are still running on their original stock trannies...even after years of power adders and forced induction.

Best advise is to tune with a MAF translator and lean out your A/F ratio that way.

Colonel

"Best advise is to tune with a MAF translator and lean out your A/F ratio that way."

And as far as the ECM and transmission are concerned, how is it different lowering the reported load via porting of the MAF sensor or through use of a MAFT?

BYBYC5

good question col. id like to know that too,so in theory if line preasure was decreased could you not increase it with an HPP3.

TanRchy

Pat G : what do you think of the Granatelli MAF and the SLP Mass airflow sensor? These are offered on Tbyrne website. good purchase or no? will these have the same long term affects on a tranny as a stock ported MAF? <img src="images/icons/confused.gif" border="0">

[ January 30, 2002: Message edited by: TanRchy ]</p>

Red2000SS

[quote]Originally posted by Colonel:
<strong>"Best advise is to tune with a MAF translator and lean out your A/F ratio that way."

And as far as the ECM and transmission are concerned, how is it different lowering the reported load via porting of the MAF sensor or through use of a MAFT?</strong><hr></blockquote>

Good point, I don't see how there would be much difference. Seems like you could leave the MAF stock and lean out the mixture with custom tuning using LS1-edit. This would allow you to lean out the mixture for more power without screwing with how the ECM perceives load and affects the transmission line pressure.

Just a thought, Patrick G jump back in here...

just me

My best advice is to use a-tap to monitor the pressure solenoid amps whenever you run any sort of ported meter, meter calibrated for larger injectors, or MAFT setup lean for larger injectors etc.
At wot the pressure control solenoid amps better drop way down to near the max pressure which is .1 amp. 1.1 amps represents minimum pressure.
For a long time I used a manual switch to keep full pressure in the trans with ported maf's or maf's calibrated for larger injectors.
Obviously this is not a concern to m6 guys.
ls1-edit should be able to cure this problem I hope.
Stock 98 trans with trans-go still going strong. <img src="gr_stretch.gif" border="0">
Steve
www.tech-ls1.com

Patrick G

iTrader: (14)

Ported Throttle Bodies are fine! No detriment to the trannies.

Yes, these trans issues are A4 specific.

mmiller

iTrader: (1)

Patrick,

So what you are saying is to put the stock MAF ends back on and adjust the WOT AND base? Go monitor the changes on the autotap and everything should be fine?

On my HPP III, I run the tranny line pressure at 0%. Should I increase it to 100%? As I understand it, the tranny pressure goes to 100% anyway under full throttle. Do you want it at 100% all of the time?

Nine Ball

iTrader: (38)

Ahhhh, chalk this one up as another advantage of owning a 6-speed car. <img src="gr_grin.gif" border="0">

Tony

JAS BLK 98 TA A4

[quote]Do you want it at 100% all of the time<hr></blockquote>

The HPP3 100% does little in this case. For example, if you are only seeing .64 amps at WOT, then you'll see about .54 with HPP3 set to 100%.

www.TECH-LS1.com

John

[ January 31, 2002: Message edited by: JAS BLK 98 TA A4 ]</p>

JAS BLK 98 TA A4

[quote]If you only adjust the WOT setting, you will not affect timing or trans line pressure<hr></blockquote>

Patrick, you may want to recheck that...

Marty

[quote]Originally posted by Patrick G:
<strong>Ported Throttle Bodies are fine! No detriment to the trannies.

Yes, these trans issues are A4 specific.</strong><hr></blockquote>

Would the ported MAF cuase a problem with my TH-350?

DanZ28

iTrader: (5)

This shouldn't be a problem for the TH-350 as it's not manged by the PCM..

AFTICA

iTrader: (8)

Why wouldn't adjusting the MAFT WOT a couple of clicks lean affect trans line pressure?It would seem like the MAFT set lean would tell the PCM the same thing as the ported ends.

Patrick G

iTrader: (14)

mmiller said: [quote]So what you are saying is to put the stock MAF ends back on and adjust the WOT AND base? Go monitor the changes on the autotap and everything should be fine?<hr></blockquote>With stock MAF ends, your L-Trims should be very close to 0%...therefor, all you would need to adjust would be your WOT pot on the MAFT. If you insist on running ported MAF ends, you will need to adjust your MAFT base setting to bring your L-Trims down to 0%, then adjust your WOT a/f ratio to where you like it.

[quote]On my HPP III, I run the tranny line pressure at 0%. Should I increase it to 100%? As I understand it, the tranny pressure goes to 100% anyway under full throttle. Do you want it at 100% all of the time?<hr></blockquote>
Adjusting shift firmness only applies to low throttle positions and does not increase line pressure at WOT to any great extent. It's not enough to compensate for a ported MAF in my opinion.

Patrick

just me

hpp3 shift firmness at 100% is about a 10% line pressure change at best.

gwj

Some very good information. I didn't know there was an option to check solenoid current on the trans via Autotap? I'll have to check that out.

DanZ28

iTrader: (5)

So, ported MAF ends makes the car run richer thus needing a MAFT to lean it out at WOT? Let's say your A/F is right on par with ported MAF ends and no MAFT, does the line pressure still drop because the MAF thinks there is less in-coming air due to the larger than stock diameter MAF ends regardless of what the A/F is?

Patrick G

iTrader: (14)

Dan,

You're close, but backwards. A ported MAF will trick the motor into a lean condition. It's up to the O2 sensors and pcm to add fuel to get it back to 13.0 a/f ratio (or .890-.910mv). This addition of fuel is what gives you positive long term fuel trims. Running a non-calibrated ported MAF usually brings your L-Trims up in the 15-20% range.

Now let's say you have a ported MAF and the a/f ratio is perfect without a translator...you're still stuck with less calculated load and hence, less tranmission line pressure. This is the bad part of the equation. Ported MAFs are kinda like smoking cigarettes. They give nice short term gains (like leaner a/f ratios and more ignition timing), but they can have a 2 pack a day impact on transmission life...especially when you start turning a lot of rpm or running a power adder.