Mister Gray

iTrader: (1)

Is there a point where boost can only be so high before going SD?

I've been told by many that once you go over 8lbs that you have to switch to SD to prevent lag. Any truth to this?

lordrazo

iTrader: (18)

i can tell you what i know and that is my car hit a wall on the mass air so i went to sd(fast xfi) but not at 8 lbs hell i went 12 lbs on the stock motor and no changes lol but there is a limit and depends on the tuner too some will give up early because they dont know what to do

Higgs Boson

iTrader: (3)

It depends on the engine, the MAF, and the injectors.

The tune can be scaled to get the MAF to "read" the airflow but only to a point. You can install a larger MAF and get more headroom or go to a custom operating system (2 or 3 BAR SD - preferred option).

It's not a boost problem, it's an airflow issue. Boost is not the same thing as airflow.

c6matt

iTrader: (1)

Yes, I converted to a card style maf in a 3.5" tube, good to go with my TVS.., my buddy runs the exact same maf setup as me on a TT ls3 thet puts 600 to the tire.. and drives like a stocker..

BOTTLE ROCKET

iTrader: (4)

I am around 10psi, but ran out of MAF table around 5200 (less than 10) Like stated above, it is the amount of airflow. My tuner had "hacked" my tables to make it "safe".
I went SD and make good safe power (I'm around 700rwhp)

Slowhawk

iTrader: (12)

Depending on flow it can max from 4-10lbs depending on the setup.

A good tuner can easilly tune it as high as you want. The MAF maxes so you tune the other table's. I just did a truck that runs 16lbs of boost with the MAF in place and on the stock MAP.

People nowadays are spoiled with the 2-3bar tuning options.It is easier but the vehicles CAN be tuned with the MAF in place.

We had to tune them this way years ago.

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Once the maf sensor is maxed the correct way to tune it is Speed Density.

If correctly tuned Speed Density the air/fuel ratio will remain consistent at any boost/airflow level.

If you are running on a pegged MAF it will not have the ability to account for any variance in airflow.

Frost

iTrader: (45)

or any other variables such as temp/altitude

khaotic

iTrader: (2)

I would like to hear more on this I ran into same thing and thinking same thing read a little more, and seemed to me that you can tune other tables to achieve so I applied the other tables to get my afr where it was needed. Cause in the maf table in the last 3 cells dont you change those to a certain numbers, then when tps is at the point of where you have it set for pe it goes open loop and primarly reads from your power enrichment table along with a few other ?? Good question, I did apply what I thought but still working on it but seemed to work great ???

c6matt

iTrader: (1)

the point i was making is the maf being maxed is a hardware problem, if its maxxed out you need to get a bigger maf, or maf housing, i am not suggesting you run on a pegged maf... after getting an appropriatly sized tube/maf passage for your airflow needs, then you re-scale your freq vs airflow relationship in the ecm. there is no "limit" to a maf's flow, if its sized appropratly, just like anything else in an engine.

slow

iTrader: (7)

Get a maf with more range, and then scale in the pcm if you have a airflow limitation such as the ls1 with a 512 g/sec limitation

I ran a BA2400 (supports 2400 kg/hour ford maf) on my 98 ws6 as a test with a voltage to frequency converter box years ago to prove it could be done. The new ls3 card/slot style maf works great when you can put it in a larger tube to increase the airflow range.

Ryan