Tommy'Z 6speed

I've logged my car with both Freescan and DataMaster and it max's out the MAF (255 Gr/Sec) on both at around 5000 RPM. Is this normal for a mild motor like mine?

Max value displayed was 267 Gr/Sec at about 5400 RPM. If you assume an AFR of 12:1 and a BSFC of .5, that's about 350 HP. Sounds a bit high to me.

Thanks!

SABLT194

Very unlikely to peg your MAF on an NA car.

Steve

jonota

What do you mean, maxed out? The max MAF g/sec reading that I was aware of was 512. Also, it is common for ported MAFs to read incorrectly unless they are recalibrated. Has yours been ported?

Jonota

95Blackhawk

The no's sound a bit high, but not out of common bounds. If you are running beyond 200 g/sec, then you are in PE mode anyway. The only thing that matters at that point is making sure your PE AFR is good in this range.

Tommy'Z 6speed

I also thought the LT1 MAFs were perhaps 512 GPS but my LT1 ScanMaster stops at 255 and I think 255 is the range in TunerCat tables also.

I don't understand : "If you are running beyond 200 g/sec, then you are in PE mode anyway."

Doesn't the MAF still respond as an increase in Frequency/GPS in the PE mode? I know it's not used for fueling (perhaps that's what you meant) but it still indicates an increase in airflow.

jonota

In tunercat, the max allowed value in the tables is 512. I believe with the stock calibration, the highest stock value is in the mid 400's. What do you mean, these aren't used in PE mode? It is the only way that the engine knows how much air is coming in (unless you think it uses IAT and VE tables?), and it uses the air to make the intended AFR...

Jonota

madwolf

The "guesstimate" used for guessing horsepower based on the AFGS reading is AFGS*1.1 for rear wheel horsepower, logged on the street and provided you are naturally aspirated and your MAF is stock. (non ported, and screened)

So with a value of 267, the result is 293.7 which sounds just about right for your setup.

While a value over 255 may be over scanmaster's display range, the MAF does not max out at 255.

Tommy'Z 6speed

Madwolf - OK. I wasn't sure if 255 was the MAF's max or just the Scanmaster max.
It just seems to stall at 254.xx GPS for several hundred RPM. I would expect it to increase in a somewhat linear fashion.

I converted GPS to Lb. per Hr. and used an assumed BSFC of .5 and an AFR of 12:1 to calculate fuel used in Lb.per Hr. This will give flywheel horsepower.

Jonota - I didn't mean to imply the MAF wasn't used, I was just trying to figure out what Blackhawk meant when he said " you are in PE mode anyway".

BTW, maf is stock, unported. I may have removed the screen, can't remember!

95Blackhawk

Maybe I should have read your post a bit slower. You had MAF and AFR, in my mind, related to each other. Looking again, I guess you did not imply this.

Thinking about it, I may have had a beer or two that night also...

1982z28with18s

Thats awesome if thats the case, when I was datalogging the 383 it was hitting 370ish all before 6,000rpms. I'll compare my rwhp dyno chassis #'s to the "guestimate" by looking at my old logs on the old setup(thats in the sig).

madwolf

If I were to guess, you will probably not see more than 385-390 at the very most on a dyno. Joe's cams work a little different, especially in automatics. They don't make crazy power on the dyno, but they kick *** on the track. I've tuned a convertible A4 and it only put down 385 RWHP but it trapped at 117 just like yours. With your 60', he'd probably have a better time than yours. Of course, he has a slightly bigger Joe O cam. but still a convertible!