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Have you ever called around to your local exhaust shop asking to have a 3″ mandrel-bent exhaust built? You'll usually get “no we don't do that or we can build you a 2” crush-bent exhaust.” The conversation delves into the shop having to explain how a crush-bent exhaust “isn't really” any different than mandrel bends. We're not even going to mention the arguments we had when we told them the 3″ exhaust would go on a 4 cylinder.
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| All the industry and race folks look at this as no big deal but this type of race hardware never made its way onto most “Sentra's” I've always been sort of nuts with this car. |
Leaded race gas kills O2 sensors and catalytic converters. We can get around the O2 sensor by swapping in a discarded one off another SR20. This will cause the ECU to run in full open loop mode, killing gas mileage but full throttle racing conditions with our fuel-gulping 72lb injectors negates any idea of double digit fuel mileage. The bigger problem is unbolting the catalytic converter after we've just driven to the track. Thankfully there's a really easy solution with V-Band clamps. The V-Band simply takes the flanges on each pipe and squeezes them together forming an exhaust seal. Loosen the single lock-nut on each V-Band and the cat drops right out, put in your straight pipe and you're done. The whole process takes 5 minutes. Our last obstacle was trying to overcome droning noise during steady cruising on the highway. We sourced the largest 3″ muffler we could fit and used it as our resonator.
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| Ten years ago is was nearly impossible to find a place that would do a no-compromise 3 inch exhaust. Check out the OG Suspension Techniques sway bars. |
At the end of the system we used a stainless resonated muffler. This muffler also incorporates a reducer we thought would be handy as a last effort in case the noise was just too much. Finally, we topped off the whole system with a flat BBQ Black paint to avoid attracting the wrong types of looks.
Our efforts towards making a relatively quiet 3″ exhaust worked for the most part. At 65 and 75+ MPH the exhaust is fairly quiet but at 70 it does drone a bit. This is acceptable as we made no compromises in terms of performance and it's probably better to stick closer to the speed limit in a bright red car with a loud exhaust anyway.
| Before we started with the turbo hardware, we wanted to tackle our transmission buildup. SR20 pro George Peters assisted with the transmission work by cryo treating the gears and re-shotpeening them to increase gear strength. As a last resort in terms of trying to keep the transmission together we're also using Redline's shockproof heavy gearoil. Compared to other transmission fluids the shockproof heavy is extra thick and designed for extreme conditions, this extra oil weight provides cushion for the gears. An interesting side effect of this oil because of its thickness and color is, if you spring a tranny leak, it literally will look like the car's bleeding in agony! The gearoil takes about 5 minutes of easy driving before it starts shifting smoothly. The upside of this oil, once it warms up you can definitely tell when the car is in gear vs. thinner bodied gearoil that sometimes has vague gear engagement. |  |
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| Rather than opting for an ultra-trick custom made set of straight cut gears we strengthened the stock parts as much as possible. | |
The clutch used is made by ClutchNet; it has carbon kevlar on one side of the disk and a segmented material called Fibertough on the other. Fibertough is supposed to have an extremely high coefficient of friction but should also be fairly easy on our transmission (the weak link of the sr20) and JUN 10 lb light flywheel. Just to make sure the power makes it to the tires we topped the clutch off with a single diaphragm 2,200 lb pressure plate. Engagement is surprisingly stock like and when prompted the car will chirp 3rd gear. George tested this feature out multiple times!
