Mercedesben

I was curious to see if anyone out there has upgraded their turbo without going to a maf or map setup.
What kind of limitations does the air flow meter have?

Perry 951

If nothing else, you'll get better throttle response going to a MAF when you change turbos. I ran my first stage with a stock setup and a clipped 26/8. Made about 250/240 @ 16 psi. Tuned the MAF and got 280/280 and a much crisper throttle. I'm now running the 27/8 and seeing 330/330. I'd hate to drive it with an AFM.

Tom M'Guinn

The problem is that the barn door can't open anymore than it can open. Once it opens all the way, it will produce its max signal whether you are flowing X amount of air or 3X of air. If you tap and log the AFM signal, you can watch to see if it is maxing out and/or if you still have some headroom.

hacker-pschorr

FWIW I'm making 311rwhp with the barn door still in use.

Oh wait - wrong forum, and it's supercharged.

guardsred951S

My car makes ~258 rwhp, 275 rwtq with the stock afm and K26/8 Turbo. But as mentioned above, a bigger turbo that can flow more requires the elimination of the bottleneck that is the stock air flow meter.

Andial951

the numbers in my sig are fom using the stock AFM.....I havent dynoed since installing the MAF but I'm wouldnt expect tot much gain.

944CS

the car does not look at the afm signal at full throttle, so the only time it maxes out is when the engine requires more airflow than the box can provide

Rogue_Ant

???

Exactly how does the DME provide fueling @ WOT then?


Rogue

eospeed

I made 296 whp with my AFM an 26-8

Mercedesben

I had a k26-6 with a maf on my last car and the maf greatly helped throttle response, but the car did not seem like it picked up much hp. I would like to try a larger turbo with mbc, injectors, 3 bar fpr vitesse chips and run the afm. I woud be happy to be around 320 rwhp at 16 psi and 93 octane pump gas. I think this might be possible.

944CS

WOT has a set map that it goes to, it ignores the O2 sensor. I believe it calculates rpm/time, don't quote me, ask John at Vitesse I'm sure he knows

fast951

AFM (or MAF) signal is used under WOT.

Ski

IIRC, Cervelli built a 2.5 with the AFM and it put down something like 358, not sure what the boost was or turbo. In the years of being here, I think the general consensus has been 350 is the max that the everyday person would try to obtain with it, racers/tuners can get a bit more out of it if they had to pass the rules checks, something like 380-390 - all budget dependant of course.

944CS

ok, so once the door is open fully the computer is still looking at that signal to verify that the door is fully open, however it is also taking into account other signals to calculate exactly how much air is flowing through there?

hosrom_951

Please do a search on signals/electronics, or look at the Bosch Motronic book.

This has been covered several times, there are lots of info in the archives and more threads are turning into electrical related other than the title.

Not being rude, sorry of i was