evotomig

What have you guys found to be the limits of the stock MAF/ECU as far as whp, but more importantly, MPH in the 1/4 or 1/8.
I said that, because whp on the dyno does NOT always translate to real world performance.

Thanks

Ted B

iTrader: (6)

So long as the ECU can control fuel and spark within the specified rpm range, there are no limits.

MalibuJack

iTrader: (5)

I realistically doubt most people will produce enough power to exceed the limitations of the ECU.. Tuning is tuning, if you can get it to use the fuel and spark you want, it'll work..;

THe MAF on the other hand can become a restriction when the airflow required by the engine, can no longer be accurately measured by the sensor (either due to out of range readings or turbulence) So far I think people give up on the ECU/MAF before anyone has found its true limits.. But the common estimate for the maf is around 400whp (Its likely a bit more, but I suspect airflow restrictions become the biggest problem beyond that point)

I agree with Ted though.. your limits are only those of tuning, and the people doing the tuning.. If you can get the engine to operate within your target, then engine management is pretty Irrelevant.. There are some "Features" that may work better depending on your engine management selection though..

fre

iTrader: (4)

I'm curious why you ask, because I'll be using only an safcII with my gt35r kit, so I'm hoping I won't have problems I believe people have made 500whp fine with the stock ecu though, although getting a lot of fluxuation at that level. I think my goal of 430 or so should be okay.

evotomig

Thanks, Ted and Jack.

Would it be fair to assume then that one could possibly run LOWER MPH at the track with MORE hp because the MAF either overflows or because readings are out of range?? (whp is well over 400 in both instances)

Nad1370

iTrader: (1)

Switch to speed density and EMS is a must at that HP level if you want a smooth consistent power band.

fre

iTrader: (4)

Well he said well over 400hp so I'm hoping my low 400hp goal will be low enough for the stock ecu. I assume the poster is running stock ecu then? Did it run okay at near 400 hp? If you have data on this, that would be great.

MalibuJack

iTrader: (5)

The MAF sensor is a bit sensitive to airflow, vibration and loud concussion pressure changes, so its possible that under hood air pressures (airflow into the MAF sensor) could become affected by a low pressure or high pressure area that you wouldn't experience while dyno tuning, which could affect your top-end performance in real-world runs..

I tend to believe that if it runs well, it will run well regardless of engine management so I don't think there should be a difference..

Generally if the sensor goes out of range, the tuner would likely experience that while tuning and should be already compensated for.. Vibration or anomolous airflow readings due could have an impact though..

I didn't really answer the question, but its only because I believe it really shouldn't make a difference other than the reasons I've stated.

evotomig

It ran great at 410whp (470 dynojet) @122-124mph, but erratic and inconsistent at 460-470whp level; which leads me to believe that somewhere in between-probably closer to the 410 level the MAF is maxed out.

Your $$ might be well spend on a standalone if you're getting the 35r since at only 20lbs. that turbo only starts breathing.

evotomig

There are no limits to how much air the factory MAF can handle?

MalibuJack

iTrader: (5)

there's no question the MAF can be anomolous, and have trouble at extremely high air volumes.. on a street car with average mods things like an EMS and upgraded MAF or Speed density conversion might be overkill, I think that was his entire point.

Once you get beyond the "Average" mods, you will very quickly see the limitations of the MAF sensor.. Only there are alternatives that don't require an EMS, but the expense of the alternatives quickly adds up and at some point you have to see which compromises your willing to make.. If being smog legal and retaining OBD-II is a requirement, then you have to consider a blowthrough MAF upgrade (Maf-Translator, Pro-Flow, or one other product I can't think of), or a speed density converter (2G HKS VPC, MAF-ECU, or another product i can't recall the name of) All of these items and a piggyback of any sort quickly add up to the cost of the EMS, however they allow you to retain your stock ECU which means it will stay OBD-II Compliant.

If you could not do speed density on an aftermarket standalone, or aftermarket speed density or MAF conversions as bolt-ons were more cost effective, you wouldn't see these sorts of discussions pop up as often.

Ted B

iTrader: (6)

This statement is absolutely false and untrue.

Ted B

iTrader: (6)

You haven't elaborated on your intended path, but an safc alone is insufficient to provide proper tuning for a GT35 kit. I certainly hope that you intend to get at least a reflash to go along with that...along with other pertinent, supporting items.

To be frank and candid, if 400whp (DJ) is your goal, a GT35 is headed in the wrong direction. This is like trying to shoot a rabbit with a .50 cal. You would be far better off with a 3071 or 3037 and a more capable means of tuning than a huge turbo and a 'band-aid' tune. With a sharp tune, a 3071 or 3037 is far more realistic and will give fab all-around performance, including part throttle performance. On the other hand, a huge turbo and a compromised state of tune is asking for problems, and won't be much fun to drive.

Ted B

iTrader: (6)

Should the factory MAF become a limitation, it would be realized in the form of loss signal resolution ahead of physical restriction. A larger aftermarket MAF (e.g. Pro-M 80mm) can be calibrated to match the factory MAF response curve.

MalibuJack

iTrader: (5)

I can vouch for that one, that is what I'm running.. there's other products out there that you can use to remove the stock MAF for another sensor or speed density.. All are a little expensive and not for everyone..

I did it as a precautionary measure though, I actually didn't experience any issues with the stock MAF besides anomolous readings and stalling due to low airflow readings or reversal of airflow through the sensor, that happens to almost everyone who has an upgraded intake pipe..