Larry Weinstein

Wondering if anyone has had any experience with the APE Mass Flow Sensor? Expented HP and Torque increase with a secondary muffler bypass?

J richard

Larry,

I've got the Autothority Performance Engineering Mass Flow sensor on my 93RS. I also have a custom mapped chip, adustable rate pressure regulator, enlarged throttle body, cup flywheel and B&B exhaust as well.

The car does seem to have considerably more power than other C2's I have driven but it is hard to tell which mods contributes the most. My guess is exhaust first, intake second.

The car tends to hunt at idle, although I hear that this is common with stock cars as well. I was a bit skeptical at first that it would flow any more air than the stock system, but looking down the throat of the sensor, there is no obstruction whatsoever, and a very large intake bell similar to the GT2 race car intakes. It can't hurt.

Two things I don't like:

1.the intake noise, it tends to sqeal like a vacume leak at part throttle. I've checked around and had my mechanic look at it, some guys get the sound and some don't. Don't know why, but with no restriction to the throttle body intake noise is predictable.

2.The kit comes with a K&N filter. I know it flows a lot more air but I think a stock filter will keep more crap out of your motor over the long hall. I am running a off road filter sock over the K&N just for extra measure. I run K&N's on 2 strokes shifter karts in place of air boxes but they still tend to get some grit in the intake. A paper filter would not allow that through.

There is another kit available that uses the 993 box and bosch sensor. It looks like higher quality stock components. A lot of guys drill the airbox lids, or you can get a motorsport intake lid from PP or Pelican.

Anyway hope this helps.

GP964

Hi J.Richard,

I just picked up a Autothority Mass Air Flow unit for my 90 C2 and had it installed today. Everything was perfect until i started the car. First of all, the engines idle would raise to 2000 rpm and drop to 800 rpm and up to 2000 rpm and 800 rpm and would not stabilize. Tried adjusting the hammer .2-10 ohms, didn't work. Had someone hook up a BOSCH Fault reader, and came out as the idle sensor was reading a fault. So the mechanic removed the O2 plug and ran the car for 5-10min, everything was great no more intake noise (from the drilled air box), acceleration was smooth. Came back idle was fine but alittle high @ 1000 rpm and stayed there, so we installed the O2 plug and everything was fine. I notice once we installed the O2 plug the engine would "ping" under med and hard throttle (i use 91 octane here in so.cali). My mechanic advised being that I now have a high performance intake set up and Autothority's Hotwire Chip the system requires 103 octane to prevent "pinging".
So i bought a bottle of NOS fuel additive which claims 4-7 octane points and also a bottle of 104+ (black bottle), it did help, no more pinging or knocking but is there away that i could use super/premium gas (91 octane) and not have it ping.
I spoke to my mechanic and he said that, the chip w/ the MAF advanced the timing. I was thinking of just removing the O2 plug so it won't ping ????.
Any suggestions ?
Thanks

J richard

GP964,

I would get back with autothority right away and tell them about your problems. It turns out that they can easily tweek the chips to adjust for different timing and fuel settings. I had to have a chip remapped from the standard mass flow chip to help with the lightweight clutch stalling problem and to pass emmisions. It took two chip adjustments.
The info that came with mine states that 92 octane is all that is required. If you can only get 91 you should let APE know that and they could knock the timing back to compensate. The motronic will retard the timing to eliminate the pinging but the system will be working against itself. The bottom line is that the factory did a pretty good job of getting the cars to a level of tune, when the tuners tweek the curves they take out the margins that the factory uses to allow for engines varying and a different state of tune for each. I had seen on a previous post on the 911 BBS that the 3.2 motors do run better without the O2 sensor hooked up. As long as you put it back before emmisions tests I don't think it will hurt anything. (I think I might give it a try and see what happens...) The idle hunting is supposed to go away as the motronics get used to the chip, you are supposed to drive it at all different rpm ranges, takes a few days. You may want to check the Idle microswitch, this is how my car behaves if the pedal is held just off idle and the switch is open.

How do you like the mod? Am I understanding you correctly that you are running the mass flow sensor with a drilled factory box? How did you get it to fit? Thats the ticket I would like...

Kevin

Larry
I have a 93RSA, I have a similar setup as J Richard. I am running a modified 993 dual exhaust, and lightweight Cup flywheel. I have the K & N filter, I hate cleaning it. It does compliment the opened up exhaust. I did my conversion in different stages. Autothority redid the chip on every upgrade. My idle is pretty good, on colder days it hunts a little. I really like the conversion. Autothority claims 30 HP increase at the rear wheel, and 34ft lbs of torque. I have not put my car on the dyno yet, but I will soon. I have a 98 C4S, and my RS will eat its lunch on any day, lastly the engine revs quicker and feel much more responsive.

GP964

Hi all,

Thanks for the replies,
Update, since i've added the 104+ octane and driven it for 2 days now, the car is a rocket and pulls throught-out the rpm range , and i left the 02 plug on, but haven't heard any ping or knock. I'm trying to find some avi-gas or race gas which is they say is 100 octane. or probably mix 15 gas of 91 and 5 gallons of 100 octane.

When the cars warm, where does your(s) idle?
mines at 900-1000 rpm.

thanks again

aeroman

Av gas has lead in it. Find a local race track, preferbly that has drag racing and for sure some of the gas stations will sell high octance (and cost) gas. I pay 5.50 for 104 by my house in Auburn. Fill the tank to just below 3/4s with 92 and then the rest at 104. No more ping and 4th and 5th seem to pull a lot harder.

N51

Obviously, you've put a great deal of thought to your reply.

Noah