Bonneville - Yup, I'm going to try again.
 

I must be nuts, but I've decided that I've got one more trip to the Bonneville Salt Flats in me yet. Our 216.63547 MPH record in 2011 has stuck in my craw for a long time now, because I had two different engineers telling me that I could expect to do over 240 MPH if we had ideal conditions. Well, we didn't, and I know we can do better - much better. I plan on being there for ​​​​Speed Week: August 10th-16th

The friends I made in my four trips to Bonneville have been feeding me good info regards course conditions, and it appears that the salt that they have been adding to the race course each season is having a positive effect. I'm told that last year the salt was hard, thick, and smooth and many records fell. Here's hoping for the same this year. As always, the weather is a crap-shoot you cant do anything about, like in 2013 and 2014 when we were flooded out. I have a book about our 2010 through 2014 Bonneville exploits if you are interested - and thanks to all of those who have already bought it.

If you have been watching this thread: https://rennlist.com/forums/928-foru...t-of-fuel.html then you know we are sneaking up on 1000 WHP, a little over 1200 at the crank. I've been working out the last fuel delivery issues, and I think I've got it now. I will be going back to the dyno to confirm it soon.

BUT FIRST: before I do, I'm changing my FDR. I have a 4.11 gearset in the diff which is a holdover from when we ran a T56 6-speed. Now I have a TR6060 trans, and the 4.11 FDR is just way to short for Bonneville when I calculate my Total Final Drive. So, out with the Getrag differential and away it goes to get a 2.73:1 gear set put in it. I want to get this done before I go back to the dyno because with the 4.11 gearset I get so much torque that we spin the tires on the dyno and it makes it impossible to get a good reading and a good tune. (Yes, even with those fat 345's on the rear) The 2.73:1 gearset I am going to will reduce my torque at the tire and tire slip at the dyno should no longer be a problem.

Hear are some pics from today, The fuel cell is out, giving me access to the diff, and the differential is out.

https://cimg1.ibsrv.net/gimg/rennlis...cd6572a6fc.jpg
The Getrag differential out of the car.
https://cimg2.ibsrv.net/gimg/rennlis...7ac2414e9a.jpg
A look down from the top at the back of the transmission.
https://cimg3.ibsrv.net/gimg/rennlis...feb98d21f1.jpg
A look up from the bottom after the fuel cell is removed.
https://cimg4.ibsrv.net/gimg/rennlis...b8ebb08904.jpg
That's the widest Hoosier racing tire they make.

You run those tires on the flats? I would have thought a narrower tire would be faster.

You are correct. Those are my road-racing tires. My landspeed tires are very narrow (and rated to 300 MPH) . Here is what they look like.

https://cimg6.ibsrv.net/gimg/rennlis...26909e7949.jpg
https://cimg7.ibsrv.net/gimg/rennlis...2ec8fa5c01.jpg
https://cimg8.ibsrv.net/gimg/rennlis...4335745be8.jpg
https://cimg9.ibsrv.net/gimg/rennlis...65011de291.jpg
https://cimg3.ibsrv.net/gimg/rennlis...cafc739f8.jpeg
https://cimg5.ibsrv.net/gimg/rennlis...3b95f0903.jpeg

GO!

Can you tell us more about the wing on the back? I'm curious what led you to such a big wing at such a steep angle. Of course I'm no expert but that has got to create a lot of drag and possibly some nonoptimal fore/aft balance issues. Even the size and placement of the vertical fins can drastically alter drag and performance, and that's not even mentioning airfoil sections (flat plates are not ideal). Have you modeled this or done wind tunnel testing? No criticism here, really quite curious as getting the aerodynamics right at 200+ MPH is a huge and critical science project all by itself that requires a lot of technology and expertise (and could help you unlock those extra MPH!)
GOOD LUCK at the event!!!!
Cheers,
Rick

Maybe it is to do with getting the drag chute clear when things go pear shaped at close to 200 mph?- remember Carl has been sideways at speed in excess of what most 928's can do flat out and he wants to go back for more?- huge gonads! :roflmao:


On a more pertinent point, Carl did quite some aerodynamic studies not to mention the testing in a wind tunnel. If his book is anywhere near as good a read as his Pike's Peak book I am sure you might find it well worth the investment- indeed try to get both if you have not read the first one- it was a very interesting read and I found it really put you in the seat as it were and I look forward to reading his latest scriblings in the not too distant future.

Just wish I could be there to support him in August - for sure I will be there in spirit!

Maybe he could rig up a live web cam broadcast given today's available tech? - now that would be something to stay up for on the other side of the world!

Ready - Aim - Fire!

Major respect for your effort's and accomplishments! Life is short... Go for it!


https://cimg1.ibsrv.net/gimg/rennlis...db059e866d.png

Go get 'em Carl.

Then you can write an epilogue for the book.

Good for you Carl, we are all pulling for you. Go get it!!!!

Lick the stamp and SEND IT

Test fit the spare tire for the trailer before you head out. :icon107:

In my class, modifications to aero behind the cowl are not allowed except those that are deemed necessary for safety. This is one of those. The rules book offers us one of two rear spoiler designs, and very specific directions and dimensions of an approved spoiler. (Note, it is not a s wing.) The function of this spoiler is to keep the car down in the event of a spin. The high uprights help prevent or slow a spin, and when the car is perpendicular to the course, it will create a vortex over the back of the car that will spoil lift. In 2012, this spoiler kept my ares on the ground and a spin at 208 MPG turned into a lot of nothing as a result. Google search "928 spin at Bonneville" if you want to watch the spin.

Here is the page from the rules book.

https://cimg4.ibsrv.net/gimg/rennlis...883c79696f.jpg

This competitor learned that his rear spoiler was inadequate the hard way:


That said, he is/was in a different class that me, and I do not know whether he was allowed to have such a spoiler as mine.

For those of you who have not attended one of these events... It is quite a high energy spectacle - with this years outlook of having excellent salt, it would be worth your time to check it out.

Easy drive out from Salt Lake City to the venue... Just remember to bring lots of fluids, super dark sunglasses, reflective clothing and sunscreen for exposed areas of skin...

You can talk to the racers and get close to the cars as well. Highly recommended...