Bonnet scoops & fans. What do you think of then now?

[10G]

I've had a look at some threads on non OE bonnet scoops, lots of them go back 2-4 years. I'm wondering what people think of them now 2-4 years later.

I can understand how a larger scoop will let in more air, but I'm keen to hear if people have noticed any real world difference?

And IC mounted fans. Does anyone know if they hinder air flow through the IC? My thinking is if they run slower than air being forced into the IC by the scoop, they may be more of a hinderance than a help?

Thanks for any help.

[the evil twin]

Never changed from OE to Aftermarket scoop so cannot comment on changes.
Only Patrol I had which had a bigger scoop already had it fitted when I bought it.

I/C fans - I did a lot of research and monitoring on my CRD, before I put it on, while I had it on and after I took it off.
I fitted a 9 inch, top of the wozza, highest flow I could find to a stock 3.0CRD I/C
Showed absolutely no improvement over about 40 KPH but was an improvement under 40 if the vehicle was slogging thru sand etc.

If the ram air speed exceeds the flow of the fan then the fan will free wheel but given the impediment to airflow of the I/C core that doesn't happen IMHO.

Bottom line is I found they are OK if you do a lot of low and slow stuff (high engine load low speed), don't do squat at cruise (low engine load high speed) and may be slightly detrimental if you do a fair bit of towing (high engine load and high speed)

[Hodge]

The tiny stock nissan scoop can definitely be improved with a larger version to cram more air in when driving.

As for the fan. I've found pretty much the same results as evil mentioned.
Cruising / driving at higher speeds, the air pushed in through the scoop well exceeds fans air push power, so the fan does sweet f*** all.
I fitted a manual on / off switch for the fan on my cross country cooler and i've tested it and played around with to see whether it does anything.
What I found is exactly what evil said. At low speeds or when you stop quickly after the motor has worked hard, the fan definitely gets rid of the heat soak faster then when the fan was off.
The cross country intercooler and the scoop I have are a very large unit. Some might argue if the cooler is that big and good why bother with the fan, but it definitely does help at stop/slow/crawl speeds when the temps are getting up there.

At the end of the day, the more airflow through the cooler, the better, whether it be pushed in by a larger scoop and/or a fan.
Thats my take on it.

[10G]

Thanks for the info folks, I appreciate it.

I've found over the past 6 months I loose heaps of power when the weather heats up, from around 30 degrees & up, really noticeable from 35+ and I'm trying to work out what I can do to try and fix that and cooler air going in seems like a good place to start. I was in Alice Springs in July on a day of 35+ and the Patrol was noticeably down on power. I run around pretty much as sea level and in the low to mid 20s most of the year so it was pretty noticeable.

If I can find a cheapish scoop & fan I may try it out.

As no one uses them that I've seen, I'm guessing water cooled ICs are either very expensive, impractical, not available or don't work???

[PeeBee]

Do a search under 'how to get your inlet temps lower than 20Deg'. There is a great write up by a guy around Central QLD who built a system running off the a/c - very clever and thinking about it for myself for later inland touring.

[10G]

Do a search under 'how to get your inlet temps lower than 20Deg'. There is a great write up by a guy around Central QLD who built a system running off the a/c - very clever and thinking about it for myself for later inland touring.

Can't find anything PeeBee. I spent oooooooooo at least 5 minutes looking.

[PeeBee]

OK, took me 15 minutes to find so well hidden.

http://www.nissanpatrol.com.au/forum...light=moranbah

[jff45]

I have to agree with Hodge, the fan is necessary to get rid of heatsoak and to keep intake air temps down in traffic.
I control mine with a Jaycar 50C temp switch and it often comes on now with the current weather. It goes out after running for 5 minutes or so above 60 kph which tells me that my intake temps are at least under 50 degrees at that point.
The fact that it cools down after running for a short period in air tells me that the fan itself is not a big obstruction to air flow.

[10G]

Just had a read of the ARE web site page on the 3.0 CRD intercoolers. They say that there is a certain point at which air being scooped in is unable to go through the IC so additional air just diverts around the scoop, like pouring water in an already full bucket.

With that in mind, fitting a fan under the IC to pull air through may be a better idea?

[MB]

Had an oldest school mate cross back over into Victorian homelands late last year for a short catchup visit. His now ‘Top End’ (FNQ humid hot) TD4.2Ti GU had say a 10 inch + fan elevated up under his decent elevated TM-IC for stop/start feral hunting. Was quite amazed at how well that fan forced heat down/through the engine bay when stationary or plodding along our slow Vic tracks.


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