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MPG's Challenge
https://www.slantsix.org/forum/viewtopic.php?t=28382		 Page 7 of 10
Author:  Doc [ Mon Apr 28, 2008 1:56 pm ]
Post subject: 
The only downside to the flex fan is: they can become a flat "wall" when they flatten-out at higher RPMs and this can hurt airflow thru the radiator at freeway speeds. (high speed overheating)

Keeping the flex fan diameter on the small side and spacing it back from the radiator core can reduce this effect but doing that can also impact the car's standing idle cooling ability. It becomes a "trade-off" deal so you have to fuss around with fan sizes and spacings to get the best results.
DD
Author:  Dart270 [ Mon Apr 28, 2008 3:00 pm ]
Post subject: 
Elec fan is best choice. All new cars have thermostatically controlled elec fan(s). With a good radiator, it doesn't need to run much at all, and never on the hwy.

Lou
Author:  CrAlt [ Mon Apr 28, 2008 3:42 pm ]
Post subject: 
Im going to try and get a clutch fan to fit. I have 3 smaller ones here i need to try.

The electric fan idea would be nice but im already pushing the limit of my stock mopar alt with the MSD, stereo, GPS, sirius radio and what ever else i plug in.


Is there a differance between the 170cui in cams and the 225? I was reading in the archive and it said that the 71+ 225 cam was the "best".

Would a sock replacemnt cam from that time be best for my planned millage master 170?
Author:  SlantSixDan [ Mon Apr 28, 2008 6:07 pm ]
Post subject: 
Quote:
The cylinder head combustion chamber with grooves cut into it is an idea.
So is sticking a fork into a plugged-in, turned-on toaster to retrieve a stuck piece of bread.

So is spending $4.50 in colour photocopying to make a perfect replica of a 25¢-off coupon for cat food.

Thing is, there are two kinds of ideas: the good kind, and the the bad/dumb kind. All three of these are the same kind.
Author:  SlantSixDan [ Mon Apr 28, 2008 6:10 pm ]
Post subject: 
Quote:
Anyone got an opinion on Flex fan versus Electric fan?
Clutch or electric, not flex.
Quote:
it flattens out...should have little or no drag?
Plenty of drag and lots of noise. See here.
Author:  kipamore [ Mon Apr 28, 2008 7:27 pm ]
Post subject: 
Would a sock replacemnt cam from that time be best for my planned millage master 170?[/quote]


Tell me more about the 170. What are you going to do to it, what's it going in, what's you mpg goal? Don't know why, but I get very excited about mileage projects.

Kip on Truckin'
Author:  CrAlt [ Mon Apr 28, 2008 7:38 pm ]
Post subject: 
Its going in a 72 dart 4door.

Hopefully i'll be getting a lower millage 170 from a member here. If that is in good shape im going to just rering/rebearing it. I already have a supersix setup as well as a ported/oversize valve head thats been milled 60.

904trans (still gota figger that one out.. 64engine + 72 904..)
2.76's

Still looking for belly pan ideas..

It was raining like crap here all day so all i got done to the beast was put in a vacuum gauge as well as a brand new, POS, subpro tach. (way off.. and yes its set to 6cyl).

Bumped the timing 17idle/ 51 total. Seems to be all in around 2.1K. This is a MP disto so maybe its already got the lighter springs. Was set at 7idle and 41total.

With the vacuum gauge do i want to shoot for lowest RPM's and highest vacuum or just the highest vacuum? If my car seems to get higher vac at say 70 do i stay there or kick it down to 60? I still have tons of experimenting to do with that..

My goal is 25ish the more i think of it... it gets 18-22now with the 225.
Author:  kipamore [ Mon Apr 28, 2008 10:02 pm ]
Post subject: 
Sounds very doable. 25mpg is a low expectation, IMHO. I'm thinkin' more like 30 highway, maybe more.

I don't know all that much about it, but as I understand it the idea is to keep the from getting under the car to reduce drag. I think a front air dam kind of thing may be more effective than the belly pan. As for ideas, how about a canvas belly pan. Easy to fab/test/throw out when it doesn't work. How bout a front spoiler dam thingy made from truck mud flaps. Easy to test.

I can think of a few things that might get you up to 25 already:

Lower the front end
Rock hard overinflated tires
Block off unused parts of the front grille
Weight reduction: back seat, lighter buckets in front, ect.

What rpm are we turning at 65? I don't know what the slippage is like on the 904 but it's non-lockup so it couldn't help. Thoughts about swapping in a manual or a 5 speed?

This is fun.
Kip on Truckin
Author:  MichaelS [ Tue Apr 29, 2008 6:56 am ]
Post subject: 
Thanks for the input on the flex fans. I thought they were a good idea, now I don't. After the new radiator install I'll be looking for an Electric fan. One thing at a time.
Author:  Pat Dawson [ Tue Apr 29, 2008 7:59 am ]
Post subject: 
[quote="Doc"]The only downside to the flex fan is: they can become a flat "wall" when they flatten-out at higher RPMs and this can hurt airflow thru the radiator at freeway speeds. (high speed overheating)

Never thought of that but it sounds plausible. I'll keep an eye on my gauge this summer when cruising highway speeds.

As to the comment about the noise - This fan is small and I don't hear any noise - especially now that I have the convertible top down. But I know what you mean. I have a "10000 rpm" big flex fan that keeps things cool on a big engine but had a terribly loud roar. Had to get rid of that one.
Author:  Rug_Trucker [ Tue Apr 29, 2008 8:31 am ]
Post subject: 
I had onon my 70 Bee. It iddn't over heat on the highway or around town in SWFL or the Oklahoma 104* summer.

Electric is the way to go.

My nephew gave me a new one that he never installed on his Fiero.

It is rated to 198cid :lol:
Author:  Pat Dawson [ Tue Apr 29, 2008 11:07 am ]
Post subject: 
Electric fans work but it's yet another "system" that, to me, a simple device can be used to get the job done. I have an old big block Mercury that uses the stock factory flex fan and matching shroud from a 1978 Lincoln that has never given me a problem. Electric fans became a necessity with front wheel drive sidewinder engines.
Author:  Aggressive Ted [ Tue Apr 29, 2008 11:50 am ]
Post subject:  Electric Fan installation
I just switched from the stock MOPAR clutch fan sold by Summit Racing to an electric fan. The electric fan rarely comes on maybe once a day. The engine warms up much faster in the morning and the number one cylinder spark plug is running the same light cinnamon color as the rest of the plugs now. It used to run much colder and the plug was always a few shades darker.

I have a very simple schematic for a fool proof set up using a temp switch that screws in the radiator or block and a common relay. The whole thing cost about $100 with fan, everything is brand new. :D

The system is very efficient and is very quiet. If any of you would like the schematic and pictures, send me your email. I would highly recommend the modification.
Author:  ValiantOne [ Wed Apr 30, 2008 11:39 am ]
Post subject: 
This is a really cool thread :D Just got done reading the whole thing.

One thing that popped into my head would be a clutch actuated mechanical belt driven water pump.

The thought of elec. water pumps scares the crap outta me.

So why not use the tried and tested mechanical pump with a smaller a/c type clutch on it. I was thinking that the pump could remain in the "on" position when the circuit is receiving current. That way if the circuit ever broke or shorted the pump would just run continuously.

I wonder if the thermostat could be completely eliminated in a system like that?

Thoughts?

C
Author:  SlantSixDan [ Wed Apr 30, 2008 11:48 am ]
Post subject: 
You need constant coolant flow through the engine, otherwise you get highly localised boiling in the cylinder head with resultant destructive ping...regardless of the temp up at the (relatively cool) front of the system.
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