OK I dunno if I ever thought about this before so I don’t remember blogging about it if I did, but I was contemplating earlier this week about the wreck (that thing that’s never far from my mind no matter what I’m doing because it literally defines my life into 2 sections, before the wreck and after) and I was thinking about why I didn’t bleed out from the gaping hole in my left leg where it was blown apart while all those people were just standing around staring at my body in the street. And then it struck me that while I was “dead” I had no pulse, no pulse means no heartbeat, and no heartbeat means I wasn’t pumping my blood out in the street instead of keeping it in my body. So QED, dying saved my life. If I hadn’t been dead for those 2 minutes there might not have been enough blood in my body to save me when I got to the hospital. I was in bad enough condition when I got there as it was, can you imagine what it would have been like minus a few pints more? I barely pulled through as it was.
I was also thinking about the Sprint T that I’m never going to get to build now, so I said to myself “If money was no object, how would you build this car?” meaning picking the “best” components for the build regardless of the cost. And I was really getting into what would be the “best” thing for a specific use, and if compromising in one direction or another would invalidate another use of the vehicle. So I went back to the premise of the build: “A car that’s fun to drive, that can be driven across the country on highways, then raced in SCCA Solo events or Goodguys autocrosses with minimal preparation and quick return to street configuration.” Then I listed what characteristics went with each parameter of “fun to drive”, “can be driven across the country”, and “raced in SCCA Solo events and Goodguys autocrosses with minimal preparation and quick return to street configuration” then see what characteristics were shared and what characteristics were contradictory.
So, “fun to drive” category is first and shortest.
power-to-weight
good brakes
good turn-in response
good grip overall with a controllable break when exceeding limits of grip
Comfortable seating and driver ergonomics
pleasant exhaust note (muted rumble at idle with definite rumble at full throttle)
“Can be driven across the country” is different.
fuel economy
reliability
weather protection
large fuel tank (range)
easy access to refuel
luggage space
tunes
comfortable seating and driver ergonomics
not-loud exhaust (not a cop magnet)
not harsh ride
“Raced in SCCA Solo and Goodguys autocrosses with minimal preparation and quick return to street configuration”
power to weight
good brakes, both at first and after several uses (no fade)
good initial turn-in and stable in the middle of the turn
good grip in all directions
comfortable driver’s seat and ergonomics
something to carry race tires and other parts
quick-change mounts for shocks and springs
roll cage that meets SCCA standards
Common requirements
comfortable driver’s seat and ergonomics
power-to-weight
good brakes, both at first and after several uses (no fade)
good initial turn-in and stable in the middle of the turn
good grip in all directions
And basic parts needed to make the car are the body that defines the car. The rear brakes needed for street legality. If I use the Wide 5 version of this rear axle with the aluminum axle tubes and the drilled drive axles I will combine light weight, both unsprung and total, with the ability to switch from a tall drive ratio for getting to the race to a short (high numerical) ratio for racing. It allows the use of these rear hubs for lower unsprung and rotating weight. A quick steering box will be needed no matter what else I use.
If I decide to go with an independent front suspension I’ll need to use this spindle so that I can mount the lighter Wide 5 hubs or this spindle for a tube front axle. The tube axle is lighter than the independant front suspension but has higher unsprung weight for the weight concerns, but has perfect camber control for the turning concerns. And both spindles are compatible with these front hubs for lower unsprung and rotating weight.
I’m sure that those who read my blog for the bicycle news have little or no knowledge of suspension dynamics are wondering why I am stressing so much about unsprung weight. That’s because unsprung weight has impacts on both grip and ride comfort. As the wheel goes up and down over imperfections in the road/track lower unsprung weight allows the wheel to move more quickly without transferring the motion to the rest of the car. Going up and down more quickly means the tire stays in better contact with the surface making for grip (no contact = no grip) and not transferring the motion to the rest of the car means better ride. Now rotating weight obviously affects any change in speed as rotating weight has to be changed first before the car can go faster or slower.
The engine is a big question, as this will need high horsepower reliable engine with a good low end torque band, which means cubic inches or supercharging or a hot cam and lots of work with the shifters.
I could “put a Hemi in it” or go with a modern legend or the successor to that legend or a hot cam in a slightly smaller, lighter, engine.
And the engine choice has a direct effect on the transmission choice. The GM engines will require either the 4L85E or the 4L70E transmission, while the Hemi will require a compatible donor vehicle to have the electronically controlled automatic transmission because the transmissions are not sold as a crate part.
Another question that needs answering is frame materials. Aluminum is lighter, but there are two flies in that equation. First is SCCA rules prohibit aluminum rollover structure. Second is the frame will have to be farmed out if made from aluminum because my aluminum welding skills are lousy. Even with money as no object I still want to build as much of this car as I can. Then there is the interface between the SCCA required Chrome-moly rollover structure and the aluminum frame, and preventing galvanic corrosion. I know what to do and how to do it, I’m just concerned about the failure modes and what they would do to the longevity of the car. Sticking with steel everywhere for the frame material eliminates all those problems at a slight weight penalty. Also staying with steel means I can do more of the fabrication myself if I want to and that in case of a wreck the structure is more repairable: bent steel can be straightened, bent aluminum has to be cut out and replaced.
Then there is the requirement to have some way of toting the tires and other parts needed for racing with the car while it isn’t racing. That implies a trailer (or the ridiculous notion of lashing the tires to the back of the car somehow for a thousand mile (+/-) road trip.
And this has made for a very long blog post for a Sunday and I’m not even halfway done, but I will end it now.
PSA, Opus the unkillable badass Poet
Witch on a Bicycle 