Air intake setup and ventilation on REW swap RX-8?

Hi all, just wanted to pick some brains. I have an RX-8 REW swap single turbo.

Turbo sits quite forward in the engine bay. Intercooler in front of radiator. In general not a lot of room!

What I was planning on doing initially was to put some vents in the bonnet to get hot air out (mainly from the turbo). But I also want to address the intake - ideally to run a full cold air intake.

I’m wondering what the best design would be? If I put a scoop in around where air filter is and also make a box around the intake - using vents or scoop in the bonnet a good idea? The only place I think I can get cold fresh air from is the top (bonnet) as there is virtually no space under the air intake, or space to run pipework to front of car etc. need to also consider when it rains, how to I prevent water getting into engine.

I can’t move intercooler, radiator or turbo.

Pic attached…

thanks in advance.

Glenn,

The current turbo placement is hurting intake, radiator, and intercooler so I would redo the turbo kit to place the turbo in a more typical location on the right hand side which allows for cold air from the right hand side and V mount with the top exchanger ducted to a hood vent. That solves all the concerns.

With that out of the way, if you're set on the current arrangement, we can still try to help.

You mentioned it needs to work in the rain, but please let us know is this for street use, road course?

What's the power goal, on what fuel, what turbo is it?

With that info I can make better suggestions. Power, turbo, fuel help me understand airflow and intercooling needs.

Hi again Mike,

Yep - it isn't ideal where everything is located. For the foreseeable future everything will need to stay where it is in the engine bay.

Street use and Track Days - hence needs to have some rain protection so I'm reluctant to put any vents directly above the intake.

Power 400-450hp, pump fuel, 9180 EFR IWG.

As I'm pretty restricted for where key components are located in the engine bay, finding ways to get hot air out and cold air in I think are the issues I want to address. I have ordered some vents to run along the bonnet (as per my pic.) - and I have some ideas for the intake itself around the air filter, but I'm worried about the right thing - running shark gill style vents above the intake? or a recessed vent... like this: https://www.merlinmotorsport.co.uk/p/naca-duct-large-naca-12 (along with the air filter having its own 'box' as such to stop it drawing in hot air from around the engine bay).

Glenn,

Starting with extremely hot intake air coming off the back of the radiator sets the whole system up for failure so I would likely focus on that first. Given the placement an inlet duct in the hood to a sealed box seems reasonable, but there doesn't appear to be much room for a box. With small box volume you can end up in a situation where pressure at the turbo inlet varies a bunch.

Due to this setup, having a decent size box would make the blockage on the back side of the radiator even worse though, which will really hurt flow through the intercooler and radiator.

Perhaps you could make the airbox relatively tight to the filter on the lower 180 degrees, then flare it out to add volume on top of the filter. I can't tell how much hood clearance you have from the pic though.

If the hood vents are placed to the sides of the airbox and create a low pressure zone, they will help extract engine bay heat in general, and hopefully avoid high engine bay pressure.

I would also make sure the bumper inlet is fully ducted to the intercooler and radiator so you have as much pressure on their front sides as possible, because the turbo kit/airbox situation is likely increasing pressure locally on the back side of the coolers.