Jump to content

For the LS1 guys considering a SLP 85 MM


DTM Brian

Recommended Posts

yes but when your racing and the MAF decides to go south on you and run your fuel trims at -25% then thats bad for my engine. which is what mine did when i was at nelson ledges last year. i wouldn't be surprised if that was a playing factor in my ring issue that started not long after that.

 

 

What codes did you set?

 

If you have a decent SD tune, then enable the MAF and dial that in, if the MAF does fail the VE table takes over and your tune is still pretty close anyways since your VE table was tuned and not "guessed tuned"

 

If your are at -25% Ltrims that means your PCM is pulling up to 25% fuel out since your VE table is not correct and your still using your NB O2 sensors as inputs for closed loop mode.

 

Depending on the car and mods I can spend anywhere from 3-6 hours tuning a car, its a very time consuming process.

Link to comment
Share on other sites

the MAF failed before i had it tuned. p0171 and p0174 IIRC were the two being set. was watching it on the tech 2 at work and unplugged the MAF and long term trims went to 2%. with there still being a junk MAF in my car for now just for the air temp sensor i'm not replacing it. i replace alot of MAF's that go out and don't feel like wasting money on one.
Link to comment
Share on other sites

From a performance standpoint I would recommend to anyone to remove their MAF and go Speed Density.

 

MAF:

 

1) Causes slower fuel/throttle response

2) Is a restriction to the engine

3) Cannot accurately and consistently meter airflow in high horsepower forced induction and large cam cars

 

You bring up the point of why GM uses MAF's and spent x millions on them and here is your reason.... They have to make their vehicles operate perfectly in a wide range of elevation/temperature and still pass emissions in these conditions :-)

 

How many true race cars use MAF's at the track???

 

Eric

Link to comment
Share on other sites

Hey brian, Hobby tuner question.

 

How long does it take you to scale a maf? It seems to take me hours upon hours. I think I'm going about it the hard way.

 

 

For anyone who's curious why a MAF is supoer important look up Hot Wire MAF. It will explain to you why simple changes such as a CAI will cause major problems if not calibrated for the car.

Link to comment
Share on other sites

Hey brian, Hobby tuner question.

 

How long does it take you to scale a maf? It seems to take me hours upon hours. I think I'm going about it the hard way

 

Please be more specific Mr. Thorne. Why is it taking you hours?

Link to comment
Share on other sites

Please be more specific Mr. Thorne. Why is taking you hours?

 

Well what I end up doing.

 

Log all fuel trims / Wideband / MAf Volts / Commanded AFR / RPM / Load(Calculated)

 

I have to go into Drive X range lets say the Lower portion of the range. DRive around for a while get some logs go back in make corrections based on Fuel trims. Smooth out that portion and continue up the Range(Maf Volts)

 

I've got a scaling tool in rom raider I've used but it requires me to drive around for a couple hours and it will get a pretty descent Rough calibration assuming you drive the car properly.

 

 

When I dialed in my CAI I spent 2+hours. I'm sure its partialy due to lack of experiance scaling mafs. I've only scaled a total of 4. 2 of wich were diffrent intakes on my own car. the other 2 where a project car.

 

I've done Big MAF rescaling (to get around 5v limit by using a larger maf housing)

Link to comment
Share on other sites

As long as you understand the IAM Portion of a subaru any tuner could tune one. That IAM portion seems to get allot of first time subaru tuners hung up.

 

(1.0 * KC table) + MT = Total timing

Initial is normally .5 or .7 so I've seen quite a few tuners who tune the timing wrong.

Link to comment
Share on other sites

I guess I wasted a lot of money taking tuning classes then....

 

If you are referencing SD tuning (Or lack-there-of) then yes you did :)

 

Just out of curiosity when did you take the classes and who was teaching them?

Jeff

Link to comment
Share on other sites

I'd think every bit helps, personally.

 

As for the MAF versus SD debate, it depends on the application. My green car is SD obviously because of the boost. My blue car is SD and sucks when there's a severe change in climate, which is what Ohio is known for. It's going back to a MAF here shortly.

Link to comment
Share on other sites

I'd think every bit helps, personally.

 

As for the MAF versus SD debate, it depends on the application. My green car is SD obviously because of the boost. My blue car is SD and sucks when there's a severe change in climate, which is what Ohio is known for. It's going back to a MAF here shortly.

 

For a street car in Ohio, MAF > *. Just my two cents.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...