Jump to content
SAU Community

Recommended Posts

Is it worth replacing the stock engine fan on a rb20det with an electric unit to gain extra power ? Is this a common mod or do most people not bother?

I've heard you can expect 10-15 hp more from an RB26DETT. Not sure how the stock fans compare between this and the RB20, but I'll bet you'd realize a gain.

My experience has been that it's not worth an engine for the sake of a few kW. I could not keep the engine properly cooled after I installed a thermo fan. All was OK once I re-installed the factory fan.

Cooling is a dangerous thing to fiddle with, I have recently converted to thermos and have had few problems however so far (grasps wood with both hands). There is a little power improvement but that vanishes whenever the fans come on (which seems to be never when the car is moving so far). I did it because my stock fan had turned to rubbish. This is on an RB26, leave the stocky unless you need to change it.

I used the 16 inch davies craig thermo. It is easily as good as the factory fan and fits in the shroud with very little modification.

The key is to retain the fan shroud or make up a new one, otherwise the fans aren't as efficient at drawing air through the radiator.

I think you'd LOSE a little bit of power if the RB25 pushes more air. =-]

Not necessarily, if the fan blades are more efficient, you can get more airflow with less drag on the pulley system.

but craved is right, I swapped it over onto my rb20 and noticed it gave better cooling... its a slightly better design, like many things on the rb25.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Similar Content

  • Latest Posts

    • Yeap, not as doorty as ITB's, but alot more doorty than before, induction sound great when I'm up it 馃
    • Any difference in induction noise?
    • I think you know exactly who I mean.
    • If I got a dollar for every flipped commuter missile I've driven past I'd have two dollars   Some people get into wild adventures on the road and I doubt it's gender or ethnicity specific. I'm just glad I don't usually drive during peak times.
    • Just got the car back and gave it a good run back home Power wise, whilst it only made a extra 5 killerwasps up top at 7200 rpm, it made more power everywhere from 2500 rpm and kept pulling much harder all the way, to the point of me relearning when to shift so I don't hit the 7200 limiter, with the old intake it seemed to take alot more time to rev out, and, throttle response is also much improved  As I didn't want to remove the bumper every time I serviced the air filter (basically every aftermarket and fabricated CAI has the filter behind the bumper) it currently has a hektic exposed pod in the engine bay sucking in hot air, this will be rectified shortly after some some of my CAD (cardboard assisted design) for a alloy heat shield feed by the OEM intake tube behind the bumper, this will cop some wrinkle black paint, as well as the intake pipe for that totally OEM look... The only fly in the ointment was that the OEM "strut" brace doesn't fit over the rear runner of the new intake with the 2.5 engine is in the engine bay, as the 2.5 raises the engine up by 20mm, it's not a war stopper, and I didn't notice any difference without it in some twisties, but....... MX5 Mania is bringing in some GWR "fancy pants" braces that apparently do fit, if it bolts up I'll grab it, it is also stiffer than the OEM one, which is a bonus All in all I'm happy with the outcome      Fancy pants "strut" brace that gives the required clearance      This is where the clearance issue was, the GWR extends out past this
  • Create New...