This is just a short video of the footage I gathered at Barber a few weeks back when Len killed the field and swept an overall win in FP..

We didn't have much competition and hadn't been to the track before, so we were trying to gather some data about temps and etc for when the time came and we did have competition and elevated temps..

We have several stock, highly modified fans for this engine that are used for different conditions and track configurations so its important to know what works the best and keep records of them.

In this qualifying session Len is ahead of the entire field and taking advantage of the clear track to see what kind of times he can bust off as the day before it had been raining and was just a nasty day... He was on the hammer very hard banging the rev limiter constantly and lets just say that he found the weak link..

In the video you'll see Len hit the rev limiter hard at just over 8K (8250) at the start finish line and then the camera actually shuts off for a split second. The impact was so great that the camera stopped rolling film!!!!

http://www.youtube.com/watch?v=i6wfTmiethg


I have never seen, or heard of a stock fan exploding due to RPM before and no one else I have talked to has either... Thats primarily due to the fact that it only sees crank speed and isn't multiplied like most other non direct drive unit.

We chose to use the stock fan because we haven't had an issue with overheating of the FP engines in the past, plus its simple with no belts or anything else to fail during race conditions. We haven't needed a DTM, so we chose to keep the center of gravity down and keep it stock.. Even after this failure we have chosen to continue with this.

This was a unit being used for testing so it hadn't been polished or lightened like our ohther fans, but it had been balanced.. I feel that if this fan would have been treated to a few more minutes of prep, like our others that it would not have failed.

Finding these weak links is the biggest reason why I engage in racing, the mechanical challenge is much more staisfying to me than the 5 dollar trophy...

I live to destroy parts, the thrashing that followed this scenario while trying to get back on the track was the most enjoyment I HAVE EVER had in the past 3 seasons of our SCCA adventures...

BTW- the rest of the fan bounced off the track and is still somewhere in Alabama

Booya!

MANNN that thing was sounding good!!

Thats just a taste..
We turned the RPM down for this track, the limiter is usually 500 RPM higher! Our gearing wasn't optimum there.

hey - wait a minute - is that an ad at the end of the video ; )))

looks like someone will be making billet cooling fans soon ???

j

No need for a billet fan.. This was an isolated incident that probably would have been avoided if the fan had been prepped as well as our others were that had impeller blades removed.

Hey, I could have put the ad at the beginning and made you sit through it :-)

Metal fatigue? Bad casting? Maybe the screwdriver monkey turned the engine over with the fan in another life time.

Just a 35 year old part.. It had a notable stress riser right at the separation point.

Wow!

That thing was really spinning.

Was there any other harm done? Is it unreasonable to expect a 40 year old cooling fan to explode at 8k rpms when they were designed to handle 5.6k rpms?

That car sure looked quick too. =)

pretty cool stuff!!!

That was cool!

The engine wasn't hurt as far as we can tell.. We threw it back together and got back on the track for the race that day..

I abused the shit out of it on the chassis dyno yesterday, and it was down on power by a few ponies from it's last verification run, but thats to be expected after a full season of 8, 000 RPM running.

It only has to live through one more race...

I think the rev limiter had something to do with it, too. It's not a very soft limiter, and I really shouldn't have been banging it so hard. We weren't geared right for this track and I was being pretty aggressive (as I'm prone to do when I have confidence in my engine builder ;-). We got the series points we needed the day before, so I was having fun with a clear, dry track for the first time that weekend. It sure gave me a start when it let go!
The thrashing to get it fixed was unique! We didn't think it was the fan. We thought it must have tossed a balance wt off the clutch. So what did we do? We pulled the tranny and the clutch! Then we found the hole in the blower housing! But get this... we pulled the tranny and clutch, (which also requires removing the exhaust system) put it all back together, then replaced the fan while my dad patched the blower housing, and even repaired the damage the idiot tow truck driver caused when he towed us back to our paddock. And after all of that we were the first ones on the grid for our race. That made me more proud than lapping under the F-Prod track record! What a great team!

That has got to be the understatement of the day. That sucker sounded straight up bad ass!!!

Yep!! I was proud too!! Pull the whole drive line apart down to the flywheel and repair the fan/ patch up the shroud and back on the track in 2:15 minutes!!!

That was a BLAST!! I love INTENSITY!

Barber is a PERFECT 914 track. Good to see you coming over. I hope I can get down there when you come back (no "if" option, sorry).

Len- you wuz hammerin' that thing (oh, thats a pun, too. Hehehe)!

..and listen to him banging those gears!! This shifting arrangement is THE BEST I have ever seen in any 914!! Half the videos on youtube of 914s on the track finds people missing gears or hunting for a gear at some point in the video, not this one!

I have video of the way I dyno this engine before a race.. No one here would believe that it survives it!
Yesterday when it was on the chassis the director of the EMS for my county sent me a text saying it was so loud that they gave up on the meeting they were having in his office. They are 3/8 mile away with a huge tree line to block the sound!

You are getting pretty famous Jake, went for my first run with the Porsche Club last Sunday and your name came up! Can't wait to get one of your engines.

Ian Stott
Moncton
Canada

Hmmn, was it for air cooled or watercooled engines ?? :-) LOL