there a limit in Hz for 1g mas?

CarPsyco84 · 09-22-2008

I was just wondering cause I hear alot of talk about them skipping counts and other funny stuff at high air flow... Im seeing about 2100Hz on my car, should I be worried?

Spyderturbo007 · 09-23-2008

Based on the DSMLink logs I've seen, it's a pretty gray area when dealing with the 1g MAS. Most people run into problems above 1600Hz, but some are able to hit 2000Hz on a 1g MAS with no problems. You really have to take a look at the logs to see where yours starts to overrun. I would suggest going with a 2g MAS which will allow you to push upwards of 2800Hz before you start overrunning the sensor.

Just make sure you have some type of tuning device to compensate for the additional airflow that bypasses the 2g sensor.

**Goat Blower** · 09-23-2008

Quote:

Originally Posted by Spyderturbo007

I would suggest going with a 2g MAS which will allow you to push upwards of 2800Hz before you start overrunning the sensor.

2G mas goes a lot higher than that.

Spyderturbo007 · 09-23-2008

I'm going to have to disagree with you on that one. Technically, the 2g MAS should overrun at it's 2400Hz clamp point, but empirical data over on the DSMLink forums shows the 2g MAS overrunning around 2800Hz. Hack the MAF and you should be able to get another 10% out of it before it starts overrunning.

**Goat Blower** · 09-23-2008

We had to remove a couple of honeycombs and retune for it, but we've got logs showing 4000hz on my 2g MAS, that's the highest Link will log apparently. Yeah, we've got fake MAF checked and I don't remember exactly where it was going funky, but it was a lot higher than 2800hz.

**Shane@DBPerformance** · 09-23-2008

I have seen totally stock unhacked 2G MASes not start hitting overrun or going flaky until around 3700hz. Both me and Steve run hacked 2G MAs setups.

The stock 1G MAS maxes out very early though. I don't remember exactly when, it's been a long time since I tuned or run an unhacked 1G MAS. For some reason though, I thought it was around 1900-2000hz, but I could be wrong.

**Shane@DBPerformance** · 09-23-2008

Steve, I don't think fake MAF is being used on yours. Once we hacked it, it worked fine on it's own.

123abc · 09-24-2008

Does the factory 1g ecu only read up to 1600hz? Thats the highest mines ever been at. I get fuel cut from that pile of shit too.

Spyderturbo007 · 09-24-2008

No, the sensor counts higher than that, but you'll only see a max of 1606Hz on the logger.

I don't know your mod list, but most people run into fuel cut when they have a boost leak.

dsm9sec · 09-24-2008

Quote:

Originally Posted by Spyderturbo007

No, the sensor counts higher than that, but you'll only see a max of 1606Hz on the logger.

I don't know your mod list, but most people run into fuel cut when they have a boost leak.

Why is that?

Spyderturbo007 · 09-24-2008

The ECU has an embedded airflow cap designed to protect the motor in the event of a failure, such as the wastegate not opening. If the airflow seen by the ECU exceeds this value, it imposes fuel cut. For example, the 2g ECU's airflow cap is 2.55g/rev.

A boost leak bleeds airflow from the system, causes the turbo to work harder and flow more air to compensate for the leak. Because of this additional airflow, it's now much easier to hit the ECU's airflow cap. Fix the leak, the airflow numbers return to normal and you no longer hit fuel cut.

**scheides** · 09-24-2008

I love that this turned from a 1G mas discussion to a 2G mas discussion :P

CarPsyco84 · 09-24-2008

yeah, but I get the idea... around 2000 is about what you can do, I used to pull over 2200hz on my old AWD 1g, but It started being funky, i assumed it was just too much air for that sensor. Sounds like I need a 2g one soon.

**Goat Blower** · 09-24-2008

This is all kinda new to me too. I never even used a 1G mas, I've had speed density up until recently.

dsm9sec · 09-24-2008

Quote:

Originally Posted by Spyderturbo007

The ECU has an embedded airflow cap designed to protect the motor in the event of a failure, such as the wastegate not opening. If the airflow seen by the ECU exceeds this value, it imposes fuel cut. For example, the 2g ECU's airflow cap is 2.55g/rev.

A boost leak bleeds airflow from the system, causes the turbo to work harder and flow more air to compensate for the leak. Because of this additional airflow, it's now much easier to hit the ECU's airflow cap. Fix the leak, the airflow numbers return to normal and you no longer hit fuel cut.

I see. I should brush up on my stocker info. I've run Link/GM MAF and AEM for a long while now, I forgot a lot of what I learned.

**scheides** · 09-24-2008

Quote:

Originally Posted by Goat Blower

I never even used a 1G mas...

...says the uber-dsm-veteran of what, 12 years steve? There's one for the history books!

**Shane@DBPerformance** · 09-24-2008

I used to run a very hacked 1G MAS on the 1G Talon until last year when I switched to a 2G MAS. I think I was running 26-28psi with a 50-trim turbo with the 1G MAS.

**Goat Blower** · 09-25-2008

Quote:

Originally Posted by scheides

...says the uber-dsm-veteran of what, 12 years steve? There's one for the history books!

Well, I had one for a little bit in 1997, I hacked it with the free mods of the time and cut the aircan. I never had any fuel management on that car though. I bought my GSX in 1999 and it came with the VPC, I never looked back. To clarify, I never got to really tune with the 1G mas, I did all the TMO stuff in conjunction with the VPC.