Air scoops and fans - Page 3

biltforspeed · #41 (**permalink**) 08-28-2009, 06:52 AM

Quote:

Originally Posted by ZeroGara

The questions that remained was why di Honda have those fans run inwards?

Pretty simple, at higher speeds the "cooler" air is being forced into and between the upper forks thru the radiators from the inside to the outside keeping the temps low and the fans ARE NOT RUNNING....when the bike stops at a light or slows down, no ram airflow from the front so the fans job now is to turn on at 119 degrees and suck the "cooler" air IN from the outside and thru the radiators to lower the temp just like a car does!

ZeroGara · #42 (**permalink**) 08-28-2009, 09:13 AM

To each its own I guess. When the bike is just rolling 10-25mph the fans are useless and might as well not be there as they block flow when running. That is a very realistic situation in any urban/suburban environment. What is one supposed to do, per Honda, stop and let the fans bring the temp down to 210'! Then sprint again to the next 220' and stop?
Reversing the fans does in fact reduce the efficiency of the cooling as they draw warmer air from aound the front cylinder, and have less volumetric efficiency drawing to than sucking through the radiator, but at least it does something when stopped and it definitely works once rolling. The faster you go the better for the fans. If you reach 220' while doing 50mph all you are doing is trying to burn up the fans, as I doubt they will turn at all if not backwards!
Will 220' destroy your engine? No, but it sure takes a tall on the oil, cooling to 175 then jumping to 220 and then back (whatever temperatures relate to oil at those water temps). At 200 I feel no heat while stopped on the bike, at 220 I sure feel it, and so does the plastic around the engine which will turn harder and harder till they crack.
I have been to Tucson Az, and the hotter it got the less traffic there was. Which means you can be doing 50 instantly after the light turns green. I'm sure you have noticed higher temps in the Boston area in the Spring than in Tucson in the summer.
Go and look at what the VFR guys are saying as well, and they are not riding a street legal race bike but a bike that was meant to go from Boston to San Diego twice a year.

biltforspeed · #43 (**permalink**) 09-01-2009, 12:52 AM

Negative!!! My bike has been running a lot cooler ever since I left the desert, there is a huge difference between 85-90 degrees with 80% humidity and 110 degrees and 20% humidity....I think she loves the cooler temps here

In fact I just installed some Sato's and a DynoJet PCIII w/ Dan Kyle's map and now the bike is running even cooler...maybe a little richer? Not sure but who cares, the sound the Banzai's make is all that matters!!!

DesperateSP2 · #44 (**permalink**) 09-01-2009, 02:44 PM

Well, here comes the bad news... apparently not just SPAL USA is out of these particular fans.
My auto parts shop gets them straight from the factory and they just rang to tell me there aren't any available even straight from the manufacturer.
I'll either have to wait a few months to see if they'll restock it or shop around.
The hunt is on...

Ika-kun · #45 (**permalink**) 09-02-2009, 11:10 PM

Quote:

Originally Posted by DesperateSP2

Well, here comes the bad news... apparently not just SPAL USA is out of these particular fans.

+1. However, I lucked out and messaged a SPAL fan ebayer if he had any of those in stock. He had two that had the plugs clipped off (for a different project he never finished), but were completely unused. Bought both (for $32 shipped) and simply spliced my OEM plugs on them - now I've got 2 brand new SPAL fans for $32!

Truth be told, running both SPAL fans is the most practical mod I've done yet. Reversing polarity on stock fans is total and utter BS - just doesn't work. My temps have dropped 15~20 degrees!!!! And the weather's getting hotter all the time!

SPAL fans. You don't have to run 2, but the upgrade over stock (reversed polarity or otherwise) is well worth it!

selfinfliction · #46 (**permalink**) 09-03-2009, 11:43 AM

Quote:

Originally Posted by Ika-kun

+1. However, I lucked out and messaged a SPAL fan ebayer if he had any of those in stock. He had two that had the plugs clipped off (for a different project he never finished), but were completely unused. Bought both (for $32 shipped) and simply spliced my OEM plugs on them - now I've got 2 brand new SPAL fans for $32!

Truth be told, running both SPAL fans is the most practical mod I've done yet. Reversing polarity on stock fans is total and utter BS - just doesn't work. My temps have dropped 15~20 degrees!!!! And the weather's getting hotter all the time!

SPAL fans. You don't have to run 2, but the upgrade over stock (reversed polarity or otherwise) is well worth it!

i bet with two of those bastards it takes about 3.4 nano-seconds to cool back down and shut them off

ZeroGara · #47 (**permalink**) 09-03-2009, 11:58 AM

Quote:

Originally Posted by Ika-kun

Reversing polarity on stock fans is total and utter BS - just doesn't work. My temps have dropped 15~20 degrees!!!!

Please explain how you came up with this conclusion on reversing fans. What is it that doesn't work?
Did you install a switch for the Spal fans and turn it on at 200-205 and off at 190 or so? Otherwise even if you installed 4 fans the ECU will not turn them on till the factory set temp hits 220 and turns them off at 210 again, so no real difference other than maybe going from 220 to 210 faster.

**mrgrn** · #48 (**permalink**) 09-06-2009, 03:58 AM

the sp1 and sp2 fans don't work the same way and the idea od sucking was to pass coller air over instead of blowing hot air through a hot rad

run a proper map and don't ride behind cars and you will be fine

this temp issue is a fad that circles like every two years and was hashed to death in 2000 and early 2001

Ika-kun · #49 (**permalink**) 09-08-2009, 08:01 AM

Quote:

Originally Posted by ZeroGara

Please explain how you came up with this conclusion on reversing fans. What is it that doesn't work?
Did you install a switch for the Spal fans and turn it on at 200-205 and off at 190 or so? Otherwise even if you installed 4 fans the ECU will not turn them on till the factory set temp hits 220 and turns them off at 210 again, so no real difference other than maybe going from 220 to 210 faster.

As MRGRN pointed out, the SP1 fan (and polarity mod) may be totally different from my SP2 fans. When I reversed the polarity on them, it just <kinda> blew air every-which-way and was quite weak at that. My bike saw the highest temps it ever had in my 3 years of ownership - 242 street riding!

Now that I have SPAL fans, the temps never go over 221. That's the point - I never wanna go over that. With stock fans, normal or reversed polarity, I'd often go over that. It's not about going from 220 to 210 faster (though it does) - it's about keeping it AT OR BELOW 220.

FYI - I also have a custom map that probably makes my bike run hotter anyway...