Track Day 26 -- The Ridge -- DIY Wing and a Bunch of mods!

White and Black C5 Corvette on aluminum open car trailer. The corvette has a Nine Lives Racing splitter on the front, and features DIY Chassis Mounted Wing on the rear

After a several month "Dry" spell of not having track days, the wet weather of the PNW relented for a spell opening up a surprise track weekend in early February at The Ridge Motorsports Park. Not only did the cruddy weather part though, but a bunch of projects on the Corvette all came together just in time for the track weekend. I'm looking forward to getting back out to the Ridge as well, since i've only been there on a sportbike, and getting back will be nice!

Modifications Between Track Days

Installed a True Focus Fabrication Coolant Overflow Tank

True Focus Fabrication coolant overflow tank on the C5 Corvette.

So I've been struggling with coolant temperature problems for a bit, mostly ever since I installed my 9LR splitter. A big chunk of it wound up being that the OEM expansion tank cracked right at one of the ports (pictured above) preventing the system from pressurizing. I was able to JB weld it up to hold up a bit longer and better for races, but that was definitely a bandaid on a bullet wound.

C5 Corvette Coolant Expansion tank that cracked, was fixed with JB weld... and failed again.

I went with the True Focus Fabrication expansion tank for the C5 Corvette. I could have gone back to a new OEM style plastic tank but... buy once cry once on this one. Just get it done and solid! This tank is pretty solid in construction, with very very heavy duty AN style fittings throughout. It installed reasonably cleanly and overall I'd recommend it to anyone tracking these.

I would like to see some revisions added to the unit that I'll list for your consideration, but please do know I ultimately am going with this product and trust it at the moemnt.Firstly, the barb pictured above that cracked on OEM is not a replacable fitting on the truefocus expansion tank, so if it cracks there again I'm a bit hosed. DOH. Would be nice if it that bit was a replacable fitting. Secondly, the oem unit had a low coolant level sensor, and this unit does not have it. You can live without this sensor, and most do, but it sure would be nice to get a heads up if my car starts puking coolant out. Lastly, the AN style fittings on the bottom of this are pressed right into the OEM wiring harness that runs right below this. I'm sure it's fine, but it would be nice if there was a bit more clearance there. Not sure what could be done to make that work, but it would be nice to help ensure there isn't warm aluminum fittings pressed right against your wiring harness. Oh and one thing of note, you need to jumper the connector that went to the OEM low coolant sensor or you'll get warnings on your display. I used a piece of safety wire bent into a thight U shape to make it work and it performed with zero issues.

C5 Aero Modifications

Rear view of a C5 corvette with a DIY Chassis Mount Wing.

So I've been updating a blog post about this DIY C5 Chassis Mounted Wing for the last month or so, and it finally came together, and just in time for the track! I'll be testing it out and hopefully it results in a car that drives well and handles great!

How The Track Day Actually Went

So the track day itself began a bit rough. The temperatures were quite cold, the track was very damp, and it hadn't been ridden on in many many weeks so there was some buildup on the track. A fellow going out in the first session put their BRZ sideways into the wall, and everyone coming off the track warned me that it was really slippery out there. That all didn't create a confidence inspiring situation, and rightfully so. I got on the track for the first session and it was silly slippery. Turn in for the turn, understeer. Throttle a bit through the turn, oversteer. It made it impossible to judge anything I'd done to the car, and not terribly fun to drive in either.

There were a few benefits I suppose to the track being this difficult though. I could get out there and explore allt he various lines and build visual memory of the track without having to worry about pissing folks off being off line. This unfortunately caused it's own problems though as some lines that worked in the wet became probematic as things began to dry. For example, the bottom out at the bottom of Turn 7. I would normally take Turn 7 quite close to the rumble strip... but I actually found I had to stay wide and entirely away from the apex at speed as I'd belly flop my splitter at the bottom of the hill!

Once the track dried out around noon and temperatures picked up a bit, the party began! Folks were finally able to trust their cars and traction and have a lot of fun. I was also able to much better discern the line, as things that didn't make sense at low speeds now were easy to hit with speed. I was able to click off several 1:56 laps with passengers out there and had a blast overall.

Video From the trackday:
(pardon the wind noise, forgot to put anti-wind foam on the gopro!

Some assorted pictures from the track day:

How did the most recent Modifications and everything else hold up on the track?

The wing definitely did the trick. I never had oversteer, save for low speed turns where I intentionally introduced rotation into the car through weigh transfer. I possibly could have backed off some on the wing and still had plenty of downforce and reduced drag but... eh why mess with something that feels this great?

The new coolant tank seemed to really help my cooling. Oil temperatures never exceeded 237 degrees, and not once did I smell any coolant weeping. I did not pay attention to radiator temperatures however, but given I was pushing oil temperatures in excess of 275 degrees before my coolant temperature picked up, I'd say things are fine.

The Carbotech XP10 brakes have proven to excellent endurance brake pads for track use. This track day was my 9th track day on these brake pads, and I could arguably sneak one more day out of them if nescessary.  My prior brake pads I was lucky to get 3 days out of, so getting 3x the durability surely justifies them costing twice as much.

Takeaways from the track day

I've got mid turn understeer. Coming into the turn, I could feel the weight bias on the front tires really helping the car grip. I'd then lift off the brakes, especially if I had been trail braking pretty deep, and begin to transition to maintenance throttle onwards to acceleration. The more I accelerated though the weight distribution went to the rear of the car, and the front would begin to understeer. Thinking about it, increasing front rebound speed might help as the front tires will get their pressure down sooner. I'm also considering left foot braking a bit potentially as the solution, but even just writing that it seems like a waste of brakes over just getting the suspension and rake just right... also from what I'm reading I should actually slow front rebound to keep weight bias on the front, stiffen rear so it's more inclined to stay on the front tires a bit longer. TBD on what I do and what the results are!

Next modifications... get the accusump installed for extra piece of mind, and try out the EBC SR11 brakes. Maybe modify the front bumper air inlet for the radiator to improve airflow to that area, along with add a slight cutout to help try and direct a modest amount of air to the cold air intake.

Data logging would also be awesome... someday... maybe.