In reply to frenchyd :
I understood it a bit differently. The Morgan cars have a wooden frame for the thin aluminum body panels, but underneath was a steel ladder frame (and later an aluminum monocoque). I don't know how stiff Morgan cars are when compared to their contemporaries.
https://www.autoweek.com/car-life/classic-cars/a31118918/are-morgan-cars-still-made-from-wood/
Morgans have a steel ladder frame chassis but have ash supports for the body. The wood is not the chassis.
In reply to YoursTruly :
Well you've got that right but a steel or aluminum ladder frame isn't exactly stiff. It's supposed to rely on the body to add stiffness and well, there is a real reason most manufactures gave up that style of construction in the 1920's
I love Morgan's. ( and my MGTD which is built the same way except with a stiffer steel frame )
But stiff they are not.
I think my conclusion is this: Add stiffness and do it as light as possible.
Replace the front bumper beam with something actually better and have door bars fabricated/installed to tie my a-pillars to my roll bar. In the meantime, make setup tweaks to try and reduce the symptoms.
In reply to YoursTruly :
Yes to making it rigid with an eye on weight but rigid is the primary consideration.
Here are two examples:
Back in the 90s a 2 car SCCA GT3 team, one of the cars was for a well known actress the other for a RunOffs contender. The RunOffs car was as light as it could legally be, the actress' car had added bars in the cage for safety, I believe it was 100lbs or so heavier. On one occasion the RunOffs car broke so the actress gave up her car so the other driver would be sure to qualify for the RunOffs. The driver went faster in the heavier stiffer car.
In the early 2000s I ran a single seat sports racer; weight limit for the class was 900lbs with driver. Our car was 1056 with me in it. A key component was massively stiff chassis & suspension components, it allowed us to tune the suspension in such a way that, unlike other cars in the class, you could pound over the kerbs. I managed to set a lap record with the car against a couple of the cars that had manged top 5s at the RunOffs.
YoursTruly said:
and no toe - I don't know nything about Miatas but IME a bit of toe in is needed on a road race car.
Also, what do your tire temps look like?
Tom1200 said:Back in the 90s a 2 car SCCA GT3 team, one of the cars was for a well known actress
Marsha Mason?
L5wolvesf said:and no toe - I don't know nything about Miatas but IME a bit of toe in is needed on a road race car.Also, what do your tire temps look like?
Since my spring rates are similar to a spec miata, my alignments have been based off what they run. Some spec miata guys do 1/16" toe-out on the front and 0 to 1/16" toe-in on the rear. Since I have aero, I opted for no front toe because I don't feel the need to make the car turn in harder, and no rear toe because I don't feel like I am fighting oversteer.
Slight rear toe-in might reduce some of the dead center feeling and I am willing to give it a shot after next event when it looks like I am spending a couple months disassembling my car to verify damper travel and fab a front brace/new intake/new rad ducting.
At NCM I was having to run a full 2:50+ slow lap before I could come in, so by the time I measured temps they had often cooled off a lot. I also expect that the camber kept the inside of the tires a lot warmer during this time, so the data is muddy. These measurements must therefore be taken with a grain of salt.
All temps in Fahrenheit. If viewing from the top of the car with the nose facing the top of the page:
All in all, I am not surprised or bothered by a 15 degree spread across the tires given the conditions. I expect they were running much higher temps when I was at pace because the RC-1 would be a hockey puck at only 100F.
A bit of rear toe in would probably help with that loose feeling on transitions. It's harder to play with than damping settings, though!
It doesn't take long to confirm shock geometry. Just pull the springs on one corner and put a jack under the upright. Might be a couple of hours by the time you're done, but it's something you can do in an evening instead of waiting until you've torn down the whole car for a major job.
L5wolvesf said:YoursTruly said:and no toe - I don't know nything about Miatas but IME a bit of toe in is needed on a road race car.Also, what do your tire temps look like?Tom1200 said:Back in the 90s a 2 car SCCA GT3 team, one of the cars was for a well known actress
Marsha Mason?
Yes..............the story was passed to me by one of the tech guys.
I ran a very similar setup to yours (spring rates, alignment, de-powered rack, etc) for several seasons of time trials. The car was street/track dual duty with Hard Dog/Bethania Garage roll bar and their integrated bolt-in door bars. Also ran the FM rails/butterfly brace during that time. In my opinion, the door bars provided a more noticeable improvement in rigidity than the butterfly brace.
After witnessing the collapsed A pillars and near disaster on a competitors car that rolled, I changed my tune and went for the full cage. Of course the cage was more rigid, but It was more than worth it for the safety factor alone (you can't buy a new neck). I kept the car registered and still drove it to events.
For reference, my car was 2,450 Lbs with a full cage, trailer hitch, all the turbo extra's and mostly full interior (2 racing seats & harnesses) on a 1/2 tank of gas.
One more comment on your loose on-center feeling - There's a spring steel loaded coupling in the pinion segment of your rack that is not needed for de-powered setup. Some people weld that coupling to remove the slop and tighten up steering response. Might help.
Dashpot said:I ran a very similar setup to yours (spring rates, alignment, de-powered rack, etc) for several seasons of time trials. The car was street/track dual duty with Hard Dog/Bethania Garage roll bar and their integrated bolt-in door bars. Also ran the FM rails/butterfly brace during that time. In my opinion, the door bars provided a more noticeable improvement in rigidity than the butterfly brace.
After witnessing the collapsed A pillars and near disaster on a competitors car that rolled, I changed my tune and went for the full cage. Of course the cage was more rigid, but It was more than worth it for the safety factor alone (you can't buy a new neck). I kept the car registered and still drove it to events.
For reference, my car was 2,450 Lbs with a full cage, trailer hitch, all the turbo extra's and mostly full interior (2 racing seats & harnesses) on a 1/2 tank of gas.
One more comment on your loose on-center feeling - There's a spring steel loaded coupling in the pinion segment of your rack that is not needed for de-powered setup. Some people weld that coupling to remove the slop and tighten up steering response. Might help.
I welded up the spool valve in the upper portion of the rack while it was out and compared to a rack with looped lines, it is noticeably tighter on center. I agree and recommend welding the coupling/spool valve to anyone doing a depower.
In my case, the dead feeling was coming through the seat moreso than the steering, which still points me in the direction of chassis flex or something wrong with the suspension setup.
Was your car 2450lbs with you in it, or on its own? My car is 2360 with me in it.
My lame excuses for not having a cage yet:
Keith Tanner said:A bit of rear toe in would probably help with that loose feeling on transitions. It's harder to play with than damping settings, though!
It doesn't take long to confirm shock geometry. Just pull the springs on one corner and put a jack under the upright. Might be a couple of hours by the time you're done, but it's something you can do in an evening instead of waiting until you've torn down the whole car for a major job.
I don't want to change my setup to something unfamiliar before this event in a couple weeks. Once I get through the Pine Mountain Hillclimb, then I can replace my eccentric bolts with the new ones I bought last year as well as inspect and lube my poly bushings. If the arms are basically out, then it is couple more bolts to drop the dampers and pull the springs off them to analyze and adjust travel.
Also, I have free access to a local track for testing. I can bring some toe plates and a friend for a day of playing with dampers and alignment.
In reply to YoursTruly :
First a bit of a pedantic point; I run a Formula car and it most certainly has a front hoop. They are simply a low front hoop. We have to pass a broomstick test. Just make sure that when you're fully belted in you are below the line from the hoop down to the dash / front cowl. Kudos to you for using more gear than the rules require.
As for the cage; isn't a kit around $1400-$1600. Many moons ago I used an Autopower kit in the Datsun. I notched everything by hand and then had my fabricator weld everything. This might be a way to cut the cost of a cage install.
Finally I whole heartedly agree with leaving the car as is for your next event and then doing some testing. That's sounds like a really good plan. You know how the car handles now and drive accordingly. Trying to come to terms with changes while trying to set times is usually a recipe for disaster.
IMHO, running hillclimbs in a Miata without a full cage is nuts. But, it's your choice, certainly. I've looked at a couple of hill climbs out here and decided I'll stick to TT on a track with runoff.
There's more than one way to skin a cat... My cage was ~$600 in materials. But I already had the tubing bender and MIG welder. You can buy all the tools you need and the materials for ~$2k. Yes, it was a lot of work, but absolutely worth it. And you get exactly what you want, not a generic kit.
As noted, it doesn't make sense to dig into things if you have an event two weeks out.
Miatacage offers good "you-weld" pre-bent cage kits for Miatas. They take some fine-tuning but it's a good mix of quality, effort and price.
In reply to Keith Tanner :
Just had one of these put in. I'm not a welder nor do I want to learn on my safety stuff, so had a respected (locally) shop do it for me. Install cost as much as the parts. They had to do some cutting as some parts are left long to be fine tuned. They also added a small bend in the halo(?) at the top of the door, allowable per rules and very slight. In the end I'm really happy with how it turned out. Not as fancy as a BBFX cage, but better than quite a few custom cages done by non-Miata-specific shops that I've seen. If you go this route opt for the package shelf version.
Also +1 to a cage for hill climb. IMO the rules at most orgs are far from "cutting edge" and shouldn't factor in too much on whether or not your setup is safe - aim higher.
In reply to YoursTruly :
Weight was without driver. On 2nd thought - during corner-weighting while I wasn't around, so somebody was in that seat.
Rollover was due to a wheel that broke during a high load downhill turn. Stuff happens.
Tom1200 said:In reply to YoursTruly :
First a bit of a pedantic point; I run a Formula car and it most certainly has a front hoop. They are simply a low front hoop. We have to pass a broomstick test. Just make sure that when you're fully belted in you are below the line from the hoop down to the dash / front cowl. Kudos to you for using more gear than the rules require.
As for the cage; isn't a kit around $1400-$1600. Many moons ago I used an Autopower kit in the Datsun. I notched everything by hand and then had my fabricator weld everything. This might be a way to cut the cost of a cage install.
Finally I whole heartedly agree with leaving the car as is for your next event and then doing some testing. That's sounds like a really good plan. You know how the car handles now and drive accordingly. Trying to come to terms with changes while trying to set times is usually a recipe for disaster.
I don't think you are being pedantic. It is a good point, and one I have looked into. My front shock towers and firewall/bulkhead would serve a similar function to the low front hoop on a formula car based on how low I sit in the car. I can't comfortably put my arm over the door when belted.
I am local to a very experienced cage builder. I have had the sad opportunity to view one of his cages before and after a nasty bout with the wall in turn 1 at Road Atlanta, so I know his work and the materials he uses are top notch. He made my roll bar and several cages for teams I have been on in the past, so I intend to use him going forward. I have doubts that I could do as good a job starting from a prebent or even bolt-in kit.
Yeah, I may make some changes to the car when I know I have test/tune time.
In reply to Rodan :
It is allowed based on the SCCA's experience and the venue being used. My goal here is to get my Hillclimb License, do a hillclimb for the experience, and have fun. I plan to run at 80-90% speed. I have not seen evidence of someone touching the podium on their first hillclimb. Even in last place, I am running laps around people at home so part of my safety equipment is definitely going to be my attitude on course and my respect for the risk involved.
Sadly, I don't have suitable workspace, electricity, or fabrication skills to build my own cage. Rarely do I choose to leave something to the experts, but I think this is one where a proper cage builder needs to take the reins.
Keith Tanner said:Miatacage offers good "you-weld" pre-bent cage kits for Miatas. They take some fine-tuning but it's a good mix of quality, effort and price.
I have looked into the miatacage kits and if I my cage builder wanted to use their kit, I would trust that the materials and sizes used are of good quality. My concern would be my ability to weld it in. I certainly don't trust Joe Schmuckatelli's Trailer Repair to stick my safety equipment together.
A poorly assembled/installed kit from a reputable company might be less safe than my custom roll bar from a reputable company.
spedracer said:In reply to Keith Tanner :
Just had one of these put in. I'm not a welder nor do I want to learn on my safety stuff, so had a respected (locally) shop do it for me. Install cost as much as the parts. They had to do some cutting as some parts are left long to be fine tuned. They also added a small bend in the halo(?) at the top of the door, allowable per rules and very slight. In the end I'm really happy with how it turned out. Not as fancy as a BBFX cage, but better than quite a few custom cages done by non-Miata-specific shops that I've seen. If you go this route opt for the package shelf version.
Also +1 to a cage for hill climb. IMO the rules at most orgs are far from "cutting edge" and shouldn't factor in too much on whether or not your setup is safe - aim higher.
I will look into the package shelf versus standard versions. I am not sure how they differ.
EDIT: I looked at the package shelf version of the miatacage kit. Yeah, that is really nice and worth the extra investment when I get there.
Package shelf is definitely the way to go in a Miata.
YoursTruly said:I am local to a very experienced cage builder. I have had the sad opportunity to view one of his cages before and after a nasty bout with the wall in turn 1 at Road Atlanta, so I know his work and the materials he uses are top notch. He made my roll bar and several cages for teams I have been on in the past, so I intend to use him going forward. I have doubts that I could do as good a job starting from a prebent or even bolt-in kit.
You are spot on: the cage in my Datsun 1200 only needed to be 1.5 tubing but I went with 1.75. We mostly used a kit because at that time my fabricator didn't have the ability to bend 1.75 tubing. While it was a kit we added gussets to all the corners and larger plates to the mounting points; it's basically a rally spec cage.
I figured I used up way more than my share of 9 lives motorcycle racing.
All of the notching I did was under the supervision of my fabricator because I'm not great at fabricating stuff. It took me 3 times longer than it would have taken him but it saved me some coin. I actually think he cut me some slack just for the sheer amusement of watching me struggle through it. I'm sure the look on my face after he pointed out the errors was priceless.
I ended up unable to complete in the Pine Mountain Hillclimb, but I was able to test the car at an autocross. I figured since transitions were the issue, let's go where I see many of those.
Reducing the rear dampers from 100% to 75% really helped the car out and made it more predictable in the slaloms. Additionally, I softened the front bar because I was experiencing a lot of understeer at low speed corner entry, and I dropped a link on the rear bar to make the OE torsen diff work better on corner exit. The car rotated beautifully, transitioned aggressively/predictably, and set a new personal sustained lateral G number.
Another thing I learned is that I do not have a bound travel issue. My tires were able to touch the top of the inside of the fenders and wear the paint off.
I plan to be at Barber for a TT this month with the following changes based on what I have learned:
Justifications:
Mazda once won the 24 hrs of LeMans. They entered two cars. The drivetrains were identical. The heavier car won.
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