Duke's '72 510 (Carbed KA Autocross/Hillclimb car)

[Farmer Joe]

what kinda of breakaway torque does the LSD have? i wouldnt think it would let loose, unless the diff is having issues, or if its just a very low breakaway limit. 

 

is its a viscous or clutch type LSD? 

[Icehouse]

Duke could you move the sway bar pick up points outboard a little more?  To me it looked like Keith's sway bar mounts were basically on the ball joint.  That would help I'm just not sure by how much.  

[Duke]

what kinda of breakaway torque does the LSD have? i wouldnt think it would let loose, unless the diff is having issues, or if its just a very low breakaway limit. 

 

is its a viscous or clutch type LSD? 

 

It's a clutch type.  From what I have read breakaway torque is around 30lbs.  I may have to rebuild the diff in the future and increase this, but I'm hoping that won't be necessary for a while.

 

Duke could you move the sway bar pick up points outboard a little more?  To me it looked like Keith's sway bar mounts were basically on the ball joint.  That would help I'm just not sure by how much.  

 

That is exactly my plan, but to a bit of an extreme.  I'm going to mount the sway bar links directly to the strut, which will give me a 1/1 ratio, effectively stiffening the sway bar.  It just so happens that this change in ratio gets me very close to the roll rate I am shooting for.

[Duke]

I have been working on modifying the sway bar mounting points for the last week or so.  As a recap, I am moving the mounting points for the front sway bar from the control arms to the strut tube to effectively increase the stiffness of the bar without having to make a new one.   After a little thought and bouncing of ideas between my dad and I, we came up with a mount that would enable me to run the longest links possible, would be easy to make, and would be easy to remove if it didn't work out as planned.  I modeled up a concept in CAD and this is what I came up with.


 

It clamps to a 2.5" coilover spring adjuster nut which is then threaded onto the coilover sleeve below the nut which supports the spring.  This nut is then jammed against the nut supporting the spring, securing the sway bar mount between the two.  The link mounts to this with a 3/8" shoulder bolt which threads into a counter bored hole so that the shoulder of the bolt, not the threaded portion, is taking the load of the sway bar.  A little time on the mill and this concept was brought to reality.


 

With this setup I was able to use very long end links which helps with the sway bar geometry and helps reduce the influence that the sway bar would have on steering.


 

First drive impressions are very positive.  Front roll stiffness is noticeably increased and the influence of the sway bar force on steering is not minimal (I'm sure there may be some, but I can't feel it while driving).  The real test will come this Saturday at the next auto-x event where I'm hoping that the extra roll stiffness will help keep the body roll I was experiencing after switching to R-compound tires under control.

[ATP]

That is awesome.... I really like what you came up with there. This is a much better design than most sway bar links I've seen and it's extremely universal! Very interested to hear how it performs.

 

 

Andrew

[Duke]

There was another auto-x event this past Saturday.  To cut to the chase, the new modifications to the front sway bar mounts worked just as I had hoped.  The car was much more controlled and neutral, and the inside rear wheel spin that I was experiencing earlier this year was totally gone.  The course was very fast and flowing with a long slalom (which was also very fast, I was taking the whole slalom flat out and shifting into third in the middle).  It the whole course was so fast that I only used the brakes once, instead choosing to try and carry as much momentum as possible.  In the morning session I was able to set the second fastest time (the only car faster was a Van Diemen Formula Ford who was about 1 second faster than everybody though out the day). To say I was happy with this result would be an understatement.  In the afternoon "fun run" session I continued tested a few different tire pressure setups as what I was using at the last event didn't feel good with the new car setup. It was very interesting to see the difference that 1-2 psi made in the feel of the car.
 

I am very happy with my current setup.  It will be interesting to see how it works on a tighter course, but on a fast course like the one on Saturday, I don't really see much room for improvement.
 

Here are a few pictures from the event.  If you compare the corning attitude of the car to the pictures from previous events, it is obvious how much the body roll has been reduced.









I'm hoping to corner weigh the car before the next event and I may also be replacing the engine in the near future because the one I am currently running is no longer holding very good oil pressure.  The next event is in a month so hopefully I will have the time to get this all done by then.

[q-tip]

Lookin good duke, awesome that the sway bar mods worked as planned

[Duke]

I have wanted to build a new intake manifold for a while.  The old one worked fine, but I wasn't really happy with how it looked, and I wanted to do something different with the water outlet.  I had cut the flanges a few years back while I was still in college and they had just been sitting since then.  I am glad that I waited to do this, as my welding has improved since then.  My dad and I recently purchased a new to us welder (Miller Syncrowave 350LX) so I thought that this would be a great first "big" project for it.  The main concept is pretty much the same as my old one, but the flanges are a little thinner (3/8" plate vs 1/2" plate to make welding a little easier) and the design of the water outlet is a little different.  I have also included threaded bungs on the intake runners for the MAP sensor on my ignition and bungs on the water outlet for bleeding the cooling system and the temperature gauge.  Overall, I am very happy with the end result.  I didn't remember to take any pictures before I mounted it, so here are some of it bolted to the engine with all peripherals installed.











I will soon be bolting on a set of 44mm Mikuni's to replace the 40's that I have been running in the past few years in hopes that they will give me a little more top end punch.  In addition to this, I recently dropped in a fresh "rebuilt" (I put in new bearing and a new timing set and head gasket, every thing else looked perfect) engine to replace the old one that had been on it's last leg for a while (the last engine was a conglomerate of the good parts of two blown engines to make one good one).  The new engine runs much stronger than the old one.

[]2eDeYe]

So nice :cool:

[Cpl620]

those runners look freaking sick! I keep asking people with fab skills like this...ever think about welding a bung to the head that separates the water outlet from the runners? this would keep the temps of the runners much cooler along with a thermal gasket between the head and manifold. i guess the only point would be if your worried about detonation in a high boost engine, but still, cooler air is always better.

[Duke]

Just sent off my entry for the Cascade Lakes Hillclimb on June 28th and 29th and the Hoopa Hillclimb on July 19th and 20th!  Can't wait!

[q-tip]

The Mani is lookin good duke. Man, wish we has hill climb events around here

[FirstDime]

sick build, giving me lots of ideas.  

[Duke]

The following is my report from the Cascade Lakes Hillclimb.  Warning:  It is be a bit long winded, there are no pictures (I'm not very good a remembering to take them) and the videos I do have are of such horrible quality that I most likely won't bother posting them.  There were people taking photo's though, so if I come across any, I will post them.

This last weekend was the Cascade Lakes Hillclimb.  Located just outside of Ashland, Oregon (about a 7 hour drive when towing a trailer) this is the farthest I have traveled for a race.  However, it is one of the closest hillclimbs to the bay area (the others being Hoopa, which I will be going to, and Virginia City, which seems to be dominated by the Ferrari/Porsche type crowd).  Having done Hoopa last year, I had a little hillclimbing experience coming into the event.  I opted to trailer my car, and my Dad was kind enough to come along with me to act as pit crew and truck driver, making the weekend a little less stressful for me. 

We arrived at the hill around 5pm on Friday and unloaded the car for tech inspection and to take a few leisurely drives up the hill so I could get a lay of the land.  The event is cool in that race central is at the top of the hill in a large gravel lot where many of the competitors camp for the weekend, giving it a very unified and welcoming feeling, and also allowing you to save a few bucks by not needing to get a hotel room.  Tech went by without any problems, and my dad and I loaded up to check out the hill.  The only other hillclimb I have done is Hoopa, which is very steep and has mostly tight corners, making it a kind of point and squirt type of deal.  Upon my first drive of the Cascade Lakes course, I could tell this would be much different.  It was no where near as steep, and many of the corners were fairly fast (~3rd gear) and I could tell that carrying as much speed as possible would be key.  After a few laps, I felt ready for Saturday's runs, but knew that I would be primarily using them to familiarize my self with how the hill felt at more of a race pace.

My primary goal for the weekend (beyond keeping the car in one piece)  was to go below 2:10, which would give me the record for my class.  After watching video of other 510's on the hill, I knew that this would be possible.  On my first run I generally took it easy, driving about 7/10ths, trying to learn the hill as much as possible.  I was rewarded with a 2:12.84, right around my goal time for the weekend.  For the next run I attacked a few sections a bit faster than the first and my time came down to 2:05.49.  That gave me the hill record for OSPU, and put me about 5 seconds ahead of the other car in my class.  I didn't have a work station for the afternoon runs, so I used the time to check over the car and watch the video from my second run to see if I could pick out sections where I could improve.  I was able to identify a few key areas where I could pick up speed. Then after the second run group was finished, I hiked down to the bottom of the hill and walked the course to get a better feel for the intricacies of each of these areas.  I did another two slow laps of the hill in my car after dinner.  I felt ready for the next day, confident that I could take a few more seconds off of my time.

After working turn 4 during the morning run group (which was nice because it was one of the corners I felt I could improve on, so it gave me a chance to see the lines other people were using) I got ready for my last two runs.  On my first run of the day, I felt spot on for the first half of the course, but made a few mistakes during the top half, including a 2 second penalty for hitting a cone in one of the chicanes.  Despite this, I still went faster than the day before, recording a 2:03.02 (including the 2 second penalty).  After seeing this my goal for the next run was to make it under the 2 minute mark.  I knew to do this that I would need a clean run and to perhaps take some chances in a few turns.  My last run went great.  I felt fast through all the key areas and hit both chicanes cleanly and quickly.  However, there was one thing that slowed me down a bit.  The road surface had been deteriorating though out the weekend, and some of the corners seemed to be developing patches of loose surface, which does not inspire much confidence when you are trying to attack it at speed.  I finished my last run with a time of 2:01.27, not quite my goal, but still good enough to win my class by 10 seconds and drop the record by about the same amount.  I ended up finishing 12th out of the 40 cars in attendance, which included some pretty fast machinery (some high powered home built cars, fast Porsches, and a few new Corvettes).

On the whole, it was a very fun weekend.  I was able to keep the rubber side down (along with everybody else, as there were no big accidents the whole weekend) and my car ran beautifully.  It was an awesome venue and the Siskiyou Sports Car Club did an excellent job of hosting.  Definitely an event that I would like to come back to in the future, hopefully to get down below that 2 minute mark.

Attached are the full results.

 

[510T]

Sounds like you had a good time!  I don't care how bad the quality is on the video I still want to see it! :D

[Duke]

This last weekend (July 19 and 20) was the Hoopa Hillclimb.  I did this event last year and was really looking forward to doing it again.  Last year my fastest run was a 2:33, so for this year my goal was to get down below 2:30.  I knew that with the upgrades I have made since last years event (stronger engine, larger carbs, r-compound tires) I had a pretty good chance of achieving this.

Arriving Friday night we (my Dad came with me again) cruised though tech and registration then went straight to the hill to do some recon.  I had been watching my videos from last year and had a pretty good grasp on the course, but I wanted to really dial in a few key sections.  I walked these areas several times to really familiarize myself with them, and felt ready and confident for the next day.

Saturday was sweltering (100*F) and being in the second run group, I got to bear the brunt of it.  My first run went well, but I was cautious in a few spots, and I knew that I was still leaving some time out there.  Never the less I finished with a 2:31, faster than last year, but still not my goal.  On my second run I pushed a little more and was able to drop a couple of seconds to get down to a 2:29.  I was stoked!  However, I knew that I had made a few mistakes, and that with a cleaner run I could go even faster.  That evening the club that hosts the event put on an awesome dinner.  The highlight of the night (beyond the great salmon and tri-tip) was getting to talk in depth with Craig Lamothe, a fellow Datsun head who I autocross with regularly.  He raced ITC back in the glory days of the 510 in that class, and he had many great stories about it.  It was really cool to hear about the close racing action, and all the little things they did to gain the edge on the competition.

Sunday came with the promise of cooler temps (only mid 90's) and hopefully faster runs.  I was also running in the morning, so I hoped this could give me that little extra bit of power on the hill.  However, we were a bit delayed when there was not 1, but 2 rollovers in turn 11 about 5 runs apart.  Despite this I was still feeling confident and ready for my runs.  First run of the day I felt faster though much of the course, and really nailed the key sections.  I was able to drop a couple more seconds to finish with a 2:27.  For my next and final run, I wanted to push harder though a few of the faster turns and push my braking zones a little deeper.  During my last run I had a great feeling the whole time.  I realized that I had really begun to learn the hill.  I knew what every turn was like before I got to them.  I knew which line I need to take and where I needed to brake.  It felt almost euphoric.  This confidence and familiarity helped my finish my final run with a 2:26.29, over 7 seconds faster than my fastest run last year!

I was able to walk away with the OSP-U class win, but more importantly, I was really happy with how I drove and how the car ran for the whole weekend.

Here are a couple of videos.  The first is me going though turn 6 (I take a wide line to maintain momentum and avoid the rough pavement on the inside) and then down the straight after turn 10.  The second is the in car video from my fastest run.  I apologize for how shaky the camera is.  I think it may be time to invest in something better.

[Duke]

The Mani is lookin good duke. Man, wish we has hill climb events around here

 

Thanks!  There are a good amount of hill climbs in your general area.  Most of the NHA events are closer to you than they are to me.  Check out their schedule at their website.  I have heard that Mary Hill in Goldendale is one of the best hills around.

Here is the NHA site:

http://www.nhahillclimb.org/

[q-tip]

Link doesn't work, weird....

 

 

I will look into it for sure, I need to get back into autocross too....

[Duke]

Link should work now.

[q-tip]

Sure does, thanks man!

[]2eDeYe]

Man that car sounds great. Congrats on the win. :thumbup:

[Duke]

Found a bunch of photos from Hoopa.  Just going to dump them all here.  All of these are from turn 9, which is one of the faster (very top end of 2nd gear) and less steep of the switchbacks.  This turn leads onto the longest straight on the course so it is very important to carry as much speed as possible though it.

[q-tip]

Lookin good!

[Spoona_Jay21]

this is one of the most well done 510's i have ever seen. Love it man!

[Busta Nut]

^^.......x2