If you own an FL5 Civic Type R and do track days, you know of its tendency to run hot. On hot days it is relatively easy to get it to go into limp mode. This issue worsens when running a larger upgraded front mount intercooler, a common mod. Larger front-mount intercoolers can obstruct cool airflow to the radiator and heat the air going into the radiator more making the tendency to overheat in tough conditions worse. To combat this, CSF Racing has developed a higher capacity drop in performance radiator for the FL5 Civic Type-R. The radiator also fits the DE5 Acura Integra Type S.
The internal construction of the CSF radiator’s core has some innovative features. One of these is the B-Tube. On a conventional radiator, there are rows of oval-shaped tubes. Factory radiators usually have two rows and aftermarket performance radiators have as many as 4. This gives more cooling area but the air has a problem penetrating the core and doing heat exchange, especially in the rearmost rows. The CSF core has one big tube in a single row with a center divider. CSF calls this their B-Tube. The B-Tube starts off as a sheet of aluminum that is folded back onto itself to form a B shape to the desired width. After forming, the seam of the tube is furnaced brazed to make it one piece and leak-free. The B-Tube gives the ideal ratio of fluid-to-air exposure with the center B pillar giving strength and an additional conduction path for heat to follow from the fluid to the outside of the tube. The internally smooth, one-piece construction also makes it easy for air to easily penetrate the core, greatly helping with heat exchange and cooling. Technically the B-Tube could be called a two-row core due to the center pillar. The B-Tube is about 15% more efficient than traditional multi-row oval tubes.
The FL5 radiator uses CSF’s latest fine pitch 5mm fin cooling technology. The new fin design increases the heat transfer area of the radiator by 20-25% over other larger fin designs. Although fine-pitch fins sometimes reduce the airflow through the core, the direct airflow through the B-tube allows the finer-pitch fins to flow air well.
Like all of CSF’s direct-fit drop-in radiators, the FL5 radiator has provisions for the OEM mounts and fan shrouds.
The CSF radiator has clean Tig welds and every single radiator is pressure-tested before it leaves the CSF factory.
10 comments
Would love to know if CSF has any plans to make replacement radiators for the BMW F chassis cars with the B58 engine.
They do and we have tested them here.
y’all plan on testing the Acuity reverse flow radiator hoses?
It is an interesting concept, and if given the opportunity I would like to try it.
How much did this decrease instances of limp mode?
possibly all of it. at least with a stockish motor
Can you share which front mount intercooler you used? I’m running the PRL intercooler and stock radiator on my DE5, and debating if I should swap back to OEM intercooler (less airflow blockage to the radiator I’m told) in conjunction with a beefier radiator.
The car the radiator was tested on was running the stock intercooler. Currently the only cooling mod is the CSF radiator (still on stock coolant too). The CSF radiator alone may take care of your temps and allow you to continue running your aftermarket intercooler. FYI, CSF is also currently developing an oil cooler kit.
Having a ton of experience tracking the FK8 (same drivetrain) you will need a secondary radiator and dual oil coolers if you actually want to push for 15-20 minutes and are setting fast lap times. A radiator alone will not do it.
https://www.civicx.com/forum/threads/grimace-build-thread-lap-time-modification-tracking.43196/