Project Infiniti G20 Racecar: Keeping It Running


To protect our heat exchangers, we fabricated our own foreign object damage (FOD) screen out of coarse stainless steel wire screen from HRP World and 1/8” x 1” aluminum bar stock from your local Big Orange High Performance Superstore (The Home Depot).  Do not use door screen for this purpose, as it does not have holes large enough to allow for sufficient air flow for cooling purposes.  
Project Infiniti G20 Racecar FOD screen radiator intercooler koyo
Our FOD screen made of coarse stainless steel mesh from HRP World and 1/8″ x 1″ aluminum stock from your local Big Orance High Performance Super Store (The Home Depot).  The extra heat exchanger seen here is to help us win more points with the car show judges…
Since the transmission is also a major source of reliability concern on any FWD SR20 Nissan, we took measures to protect it as much as we could by filling with Redline Heavy Shockproof.  This gear oil, lovingly dubbed “Pepto Bismol” for its molasses like consistency at room temperature and pink color, is specifically designed for heavily-loaded and problematic gearboxes.  With a film thickness greater than a 75W250 oil, but with a fluid friction like a 75W90 oil, Redline Heavy Shockproof helps to cushion gear teeth to prevent breakage.  Unfortunately, it is not recommended for synchromesh transmissions.  However, we have used this oil in our street cars for tens of thousands of miles with no discernible difference in synchro wear.  
Heat exchangers galore are wonderful for helping your car last through a race, but you still need to keep an eye on things to make sure it’s all working.  Seeing climbing coolant temps, or low oil pressure can mean the difference between a minor repair and a car-b-que from a ventilated block.  To help us with this task, we installed a set of venerable Autometer Ultra-Lite 2 5/16” gauges to monitor oil temp, coolant temp, oil pressure, and a 5” tachometer with shift light.  To simplify installation, we went with electrical gauges over the mechanical variety.  While the resolution on the gauge is lower than a mechanical unit, we were more interested in seeing a problem rather than getting exact data points.  The Autometer gauges have never missed a beat, surviving all manner of abuse including a minor engine fire, and were extremely easy to install.  
Project Infiniti G20 Racecar Autometer Ultra-lite gauge oil pressure temp water
Our suite of Autometer Ultra-lite 2 5/8″ gauges mounted where the stock HVAC vents and other controls once lived. Make sure your gauges are mounted high so you don’t need to take your eyes off the track for very long.  We chose Ultra-lite electrical gauges for legibility, ease of installation, and excellent price point.
To install our gauges, we used an assortment of products to get our 1/8” NPT sending units plugged into our BSPT-prone Nissan engine.  Our water temp sending unit plugs into a Custom Steel water temp adapter.  This unit is sandwiched between the stock upper water neck and the cylinder head and is perfect for temperature sensors and turbo feeds.  

To adapt our oil pressure sending unit, we installed a 1/8” NPT female to 1/8” BSPT male adapter from McMaster-Carr (part # 4092K11).  Rather than plug our sending unit directly into this adapter, we used an Earl’s 1/8” NPT to -4AN adapter, and remote mounted the sender at the end of a 1’ -4AN line (with another Earl’s 1/8” NPT to -4AN adapter) to the bottom of the oil filter housing.  Once again, the Big Orange High Performance Super Store came to the rescue with a conduit mount that had the perfect ID to clamp our Autometer oil pressure sending unit.  The clamp was then bolted to the oil filter housing.  Why go through all this effort to remote mount an oil pressure sending unit?  Since the sending unit is larger than the OEM unit, and racecars see lots of vibration abuse, we decided we didn’t want to trust just the adapter with the task of living up to this abuse.  By remote mounting the sending unit, we ensured that the fitting would only need to support a small amount of -4AN stainless hose and the Earl’s adapter.   


Project Infiniti G20 Racecar oil pressure sending unit earl's autometer -4AN NPT BSPT
Our Autometer oil pressure sending unit tucked away underneath the intake manifold.  We remote mounted the sending unit to decrease the likelihood of failure with the relatively heavy sending unit hanging from the end of the BSPT to NPT adapter.  A pre-assembled 12″ Earl’s Speed-Flex line was used here.  You can also see our replacement silicon water pump inlet hose here.


The oil temperature sending unit was plugged into the feed line to the oil cooler with some more Earl’s NPT to AN adapters and a three-way T.  


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