RallyB13 wrote:FlatBlackIan wrote:Well there are a few reasons. First being inlet temp control. Rally stages can be hot, and engine bay temps tend to get pretty high. Another big thing to worry about is water. With just a filter, any large water splashes run the risk of hydrolocking the engine, or bending a rod. The box will isolate the throttle bodies, so if I suck water, it doesn't go straight into the engine. There are also issues with smaller filters clogging because of lack of surface area. They tend to pack with dust, limiting power. The box also gives me a place to put the IAT sensor, and valve cover breather.
I was shocked at how hot the engine bay got in my Sentra at Nemadji, and I already had my exhaust heat wrapped. The skidplate under the engine has a lot to do with limiting air flow. I really want to find an evo-style hood vent to allow air to flow better, but I may just shim up the hood hinges a little before OFR to allow more heat to escape that way.
Having hydrolocked an SR20 in the past, I tend to be a little paranoid about doing it again. But with the underhood temps so high I know I'm robbing myself of power with the "short ram" style intake. Gotta find a proper way to do a protective liner (I tore out both my finder liners on the transit to the first at Nemadji) and swap to a CAI. Probably a winter project along with rebuilding the second engine (so I'm not running a 180K old stock longblock)
Indeed. My underhood temps actually stayed at an exceptable level. They were high, but not excessive. I believe my cooling problem is many fold. First, the hole I cut in the hood works well for venting heat at low speeds, but because the back of the hole is higher then the front, I believe that as speeds increase, airflow is being forced into the engine bay. Air in good right? Well, if Im shoving air into the engine bay, pressure is going to increase. More pressure inside the bay means less air flowing through the radiator, instead of going around. Last night Broc and Dustin fabbed up a flap for the vent. If it goes to plan, it should generate a low pressure area above the vent, helping air to be sucked out of the engine bay, thereby increasing flow through the radiator.
Secondly, when I installed the radiator, sans A/C condenser, it left gaps at the top and sides of the radiator. I believe this allowed some air to go around the radiator and into the engine bay. I have already sealed the top, now just need to do the sides some how.
Lastly would be the tuning. I noticed on the first stage at Nemadji that my high RPM A/Frs were unhealthily lean. 13:1 is ok for short stints, but on stage I think its too much. I babied it back, and added some fuel to the map at service, and I was able to push harder on stages 3 and 4.
Hopefully remedying all of these issues will solve my cooling problems, and I can go buck wild at OFR.
As for CAI, I may build one down the road, but for the moment I plan to suck my "hopefully" not too hot engine bay air.