Shark Attack

Does anyone know first hand the differance? I bought a set of RPM and they did make more "feel it in the seat of your pants" power. Autothority seems to be the bigger name though. Thoughts?

Mike Frye

Hey SA,

I bought a set of the eBay knockoff performance chips, then when I opened up the box I found that there were Autothority chips in there already. If you want we could try to compare the timing at different RPMs. I don't know if that's the only thing that gets adjusted though.


Or we could race.

BIMMERMIKE

Sorry, I can't help, however I have a set of RPM chips (not instaled) I purchased from Rennlist member 'Touque'. He said they were a good improvement over stock chips with no dyno runs to substantiate effect.

PorKen

The RPM chips are most likely AA clones?

The EZ-F chip makes the power, roughly 10 RWHP on top. It also makes the car livelier in the lower rpms, and takes away that initial 85-86 bog on acceleration. The LH chip provides just a few extra ponies, has a decent 13ish air/fuel ratio at the top end (tested with X-pipe), but richens up a bit too much when accelerating. Just installing the EZ-F chip, with the stock LH chip, works pretty well.

Panzer9

I went w/ Genuine Autothority chipset- They've done the engineering R&D, with performance documentation, and a solid reputation in the industry.

Peter F

And was the difference enough to be noticed?

/Peter

Panzer9

Certainly

Peter F

Thanks for sharing..

/Peter

The_Remora

Any objective performance difference verified on dyno or g-tech, or just seat-of-the-pants? I have heard that chips are worth getting for the 85-86.5 928s but not enough difference on the 87-> models so I haven't really considered buying one. What kind of performance boost does a chip provide for later models?

dr bob

8 or 9 years ago when DR was firts getting his signs up and the OC was conceptual, there was a "group buy" through DR on AA chipsets. Phil Tong bought a set (as did I and many others). We installed them in Phil's GT between dyno runs at a Devek Day event and compared the before and afters. The peak numbers were not changed muc. Close enough that they could be considered normal pull-to-pull variations. There was a noticeable bump in midrange torque and power, though. I don't remember the exact numbers.

Fast-forward to a month later when I finally got around to installing the chips in my own car. Very satisfying midrange improvement, using the ***-o-meter. I had not previously done any foot-to-the-floor accelleration testing, so no real comparo. The throttle felt a little sharper and the exhaust note was different.

On hot SoCal days with the AC on and low-mid RPM pulls in traffic, it pinged. A lot! So DR arranged for a set of GT chips as replacements, a little fatter mixture in the low-midrange to work with the longer-overlap GT cams, did the trick nicely and the pinging was gone.

I pulled the Autothority chips several years ago when I was having trouble meeting NOx limits at smog testing. That change helped only very slightly, but I haven't quite gooten around to putting them back in. The spare LH brain may get them one of these days when I swap it in, just for grins. For the way I drive (white-haired guy with a soft foot) they are an unneeded improvement. If you drive the car harder then they would be a plus.

From my foggy memory...

John Speake

Hello Bob,
It's logical that the GT EZK chip would help with pinging as they have less advance than S4.

This is why they can be useful in stock GTs's that are prone to ping.

James-man

Foggy memory maybe but golden experience. I have a vague recollection of Porschefans & Phil Tong. So does that make us old timers?

dr bob

We aren't old timers in the true sense, since I've only had the car for ten years. I started my research midway in the purchase process. That was usenet rec.autos.porsche, and 'list. John D fired up 'fans to take over when porschelist was crashing and burning too often, and we migrated into Rennlist later. Meanwhile, Phil's 928 website was a handy reference. I was on a project in Asia at the time, and snuck home to clean my car and get it up to Devek for my first taste of what "other" 928's looked like. As much as I love to spout off with tidbits here, I've only ridden in a few of these cars. I can count them on one hand actually. Many more cars than that have come through the garage here for various reasons. I just don't drive or ride in them. In fact I think I've only actually driven one 928, my own.

So I've had the pleasure of seeing the development of several online resources for the 928. Rennlist is by far the best. Phil's 928S4VR website lapsed a year or two after he sold his GT following the tech stock crash. Another group revived the website from archives and have made some of the dynamic stuff work, but it isn't being updated. The message board is maintained separately at http://members3.boardhost.com/928s4vr/ and is still used by some who may not want all the volume and chatter that happens on rennlist.

Old timer? OK, I guess...