Found that the tank was becoming pressurized while the engine was running. Drilled hole in cap and fitted a breather pipe to connect to a flexible tube. Used special epoxy to seal breather tube as well as the threaded connection between the fuel tank and male fuel filler (where the cap mounts on to). This is an attempt to reduce pressurization of the tank and fuel being pushed out of the spots where there is air leakage.
Took the car for a drive yesterday and had one of the differential mounting point fail during a quick acceleration from stop. The mount on the front of the differential close to the driveshaft connection pulled apart and let the driveshaft move up and bash part of the chassis. No major damage but have to put in a new mount that can take both tension and compression forces. Installed mount followed the Saturn Sports Car guide recommendation, but the component was not designed to take any tension so pulled the rubber apart. Photos below.
Trying to solve the fuel starvation issue which occurs at heavy throttle around a right hand corner (highway on ramp). Removed the fuel tank and drained it of fuel. The plan is to create a new baffle in the tank by cutting a slot 4 inches deep and 4” from the he end of the tank all the way across the tank then sliding a flat aluminum sheet in and welding it shut. This will create a baffle next to the fuel pickup. As the fuel return line will deposit into this chamber, we dont think pass thrus in the baffle are necessary ( CORRECTION – passthroughs are not optional, as small chamber would empty before the rest of the tank, two 1/4 holes were drilled near the bottom of the baffle plate to allow refilling of the fuel pickup chamber.
Took out the existing steering rack mount and built a new one. Old one was from the Saturn Sports Cars/Book guide, which was meant for a escort rack and had the opposite mount to pinion angle. Meaning our Miata rack had a large angle kink between the pinion and steering shaft. The existing mount was quite flimsy, and we saw 1/4-1/2” of movement when turning the wheels at standstill. New rack is made with 1x2x1/16” thick rectangular tubing welded to the chassis and then 1/16” straps to further increase stiffness. New mounts are much stiffer and reduce the angle between the pinion and steering shaft.
Alignment sheets show the car only has about 1 degree of caster. The Saturn Sports Car guide for this build suggests that a small amount of caster adjustment is possible with the built in adjustable suspension parts. I’ve adjusted to the lower front a-arms to increase the amount of caster to improve the self-rightening of the steering wheel when turning. Minor adjustments have contributed to minor increases in the self-rightening effect.
Noticed the steer rack mount twisting slightly when turning the steering wheel while parked. Seams the Haynes steering rack mount design is not overly solid. Will need to add more bracing to the system to restrain it from moving around.
During a longer right hand corner with a half empty fuel tank and punching the accelerator, the throttle cut out again. The fuel pick up is on the right side of the tank, and there is only one baffle in the tank at the middle. I think pump is running dry or getting air in the line in these cases. I will need to keep the fuel tank topped up, until I sort some modifications out with the tank.
Some ideas for better fuel tank performance:
- Well at fuel pickup
- Baffle around fuel pickup
- More baffles
- Fuel Cell Foam
Installed a new high flow/high pressure fuel filter. Engine was cutting out at high load. Had a cheap wix filter installed with priming bulb upstream of the fuel pump. Removed that, and put the high flow/pressure Summit Racing fuel filter downstream of the fuel pump. The engine no longer cuts out, and it seams this has helped get rid of air that was running through the pump. The fuel pump now runs much quieter an is likely much happier.
Noticed our home made exhaust gasket between the header and pipe was cracked. Ordered a new one from the local parts store, but the holes and alignment with the exhaust was off unfortunately. Had to enlarge the holes with a dremmel tool to fit on the studs and align better. Not sure why the factory gasket didn’t fit correctly.