This Saturday we installed the Nissan Motorsports header. It’s made by Hotshot and it’s their fifth generation design. The install was pretty painless until we snapped the lower right mounting stud where it threads into the cylinder head. Some careful work with a right-angle drill and a new stud saved the day.
On Sunday, we autocrossed in Ft. Pierce with the Central Florida region of the SCCA. The course was fun, but a little horsepower-friendly, with long straights followed by sweepers, followed by straights. Here’s a rule of thumb as to what determines a straight: If the guy in the pick up truck on street tires can take a slalom at full throttle, it’s not a slalom. Despite this, we had fun, turned some decently fast times and didn’t break anything.
On Monday, we visited the dyno again at Projekt7 Tuning. We tested the car first with the timing advanced to 19 degrees BTDC and then back to 13 degrees and then back to 19 degrees. With the timing advanced, we topped out at 134.9, while without the timing bump, we peaked at 129. So, did the header only give us 1 horsepower? We don’t think so.
Last week, we played around with the MAF sensor, unbolting it from its adapter and regrounding it while we were at it. The ghetto-fabulous intake that we used has a smaller MAF adapter than the factory part that is pop-riveted into the stock airbox. When we unbolted the eBay piece and then reinstalled it, we partially blocked the air’s route through the hot wire sensor itself. This leaned our mixture out to the point of being dangerous. The eBay intake system might be cheap, but the MAF adapter that it comes with simply doesn’t work well in this application. Even looking back at our dyno curves and air/fuel curves when the intake was originally installed, the mixture went very lean on the subsequent runs.
So, what to do? The eBay tube that is attached to the throttle body certainly works ok, the filter is OK and the rest of the PVC routing is ok, we just needed to redo how the MAF is hooked up. Being cheap bastards, we drilled out the pop rivets that attach the factory MAF adapter to the stock airbox and attached this piece directly to our air filter using JB Weld. The air’s route through the MAF sensor is now much cleaner and will have less turbulence. We’ll be taking the car back to the dyno to see how rig worked.
After this is all sorted out, we’ll be installing a Magnaflow high-flow catalytic converter. It’s legal both for the street and the STX class that we’re running in.
View all comments on the GRM forums
You'll need to log in to post.
