Hey folks. Well the dyno day was a success, even if almost everyone was a no-show. We only had 3 928's to dyno, so we let a Mustang and a Honda fill 2 more slots. They were nice guys, and were pretty impressed with the 928's.

Out of the 3 928's, 2 were '86.5 5 speeds, with one '85 5 speed. Both '86's posted very respectable numbers, almost more into S4 territory. One had chips, and the other will soon be chipped and RMB'd!!!!!!!!! The '85 was down on power a bit, most likely because of a plugged "original" cat with approximately 170K on it. It will soon be uncorked, and should be a monster then.

The intreresting part of the event was to get to see back to back dyno runs on the '85 stock and then with a set of Autothority chips from Dave and Jeannie at 928 Specialists. The car picked up 15 hp and 30 ft lbs of torque with the chip change!!!!!!!!!!!!!! For anyone with an '85-'86 928, this is definitely a best bang for the buck upgrade!!!!!!!!!!!!!!!

One more 928 showed up at the house for the cookout portion of the day. An EXTREMELY clean '89 S4 5 speed. We had lots of great food, a few cold beers, and talked ourselves silly about all things 928. All in all, a great day!!!!!!!!!!! A BIG thanks goes out to all you folks that showed up for the event. I'm sorry that the date was changed at the last minute, disrupting most of you folks cheduling for the event. Hopefully that won't happen next time.

 

Thank you Chris for organizing the annual event! I thought it was GREAT!!!! It was super meeting some new 928ers and it is striking how deeply rooted our love of 928s are - immidiate common bond between 928 bretheren. I also enjoyed chatting with the non-Porsche guys and learned a thing or two. Glad they were there.

I was very tempted to do a second retro-dyno run just to see what numbers I would run with stock chips. But ultimately decided that I didn't really need to know. Was interesting to see the "marketing curve" on both the 85's and my dyno sheets.

After replacing one ignition coil last week, my car was in a better state of tune than it has been in a long time. Just in time for the event.

At the end, the Dynojet operator let me do an extra "top-speed" run where I ran through all of the gears and took 5th to over 6000 RPM. That was pretty cool. He said that I hit the magic 200mph limit, which of course is impossible in practice without 200mph tailwinds. My picture may get posted there for the 1 minute of fame.

Am I supposed to post my numbers here? Not sure whether I should kiss-and-tell or not. Regardless I am very happy, especially considering that this car is 19 years old.

Thanks again, Chris, for hosting this event and bringing together a nice group of folks!


James 1986.5 Black 928s 5sp P-chips, RMB and those fancy Red ignition wires.

 

You are definitely welcome James. The whole reason I try to put events together is for everyone to have fun, learn something new, and meet new folks. It's a wonderful group, that's for sure.

I would definitely post your numbers, as they are very healthy for an early 32 valve car. I've seen several S4's with less power.

 

Groovy.

I don't have my scanner hooked up - not groovy.

Dyno graphs for the two chipped cars, my 86.5 and the 85 (both with rear muffler bypass believe it or not), had a trippy torque curve with a nice little HP bump between 2500 and 2800 rpms. Autothority guys must have known the importance of seat-of-the-pants sensors to keep purchasers from coming down with buyers' remorse. Peak torque was at 2700 RPMS (just like in the owners manual) - but it looks like they tuned so that the car comes alive stronger in this narrow range so that we can actually feel the difference on the road. This corresponds fairly well with my observations when first chipping at least 8 years ago.

What is remarkable is how much the torque falls off from 2700 to 3000. It dropped from 275 to 240, then resumes a gradual climb back up to about 265. Trippy. I wouldn't have expected these shapes without a flappy valve. Putting the early RPM volcano-shaped torque peak aside, the next highest torque range was 4200 - 4600 rpm.

Anyhow, here are the numbers.

Run 1
RWHP 264.4 @ 6,000 RWTQ 273.1 @ 2,700

Run 2
RWHP 270.9 @ 6,200 RWTQ 275.4 @ 2,700

Run 3
RWHP 270.3 @ 6,000 RWTQ 272.9 @ 2,700

I can round my best run to 271 RWHP right? Round or not, this is much better than I had anticipated. I had conservatively estimated that with chips and RMB, I would be running 300hp "or so" with 288 being the inital reference point. Assuming 15% - 17% crank to wheel losses, that calculates to 319 - 326 chp on the best run. Way beyond what I had expected.

I am pretty sure that I had the A/C turned off on the first run.