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Raging Opel-holic
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Discussion Starter #1
I've read that the fan can be removed from the engine and replaced with an electric one to gain some HP as well as reduce noise under the hood. Has anyone done this? Is there a "preferred" kit to use or can a system from a newer car be made to work? I have a Miata that could donate a fan and temp sensor if the range is good. What temperatures should the GT's fan come on and kick off at? Would the fan be removed from the pulley or would I need to get a new pulley? I appreciate any advice or experience with this.

Phil
 

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Removing the fan is good:D . We remove them from all of our race cars, and I don't own a street car that has a "engine driven" fan. At speed the fan doesn't do much more than use up HP. The air being forced through the grill will do all the cooling you need as long as your radiator is in good shape. Unfortunately, the original (new) GT radiator starts out marginal (fan or no fan) if you live in hot climates. (A trip through the Mojave Desert from LA to Las Vegas has "hurt" more than one "fun-run" by a group of Opel enthusiasts.)

A fan is REQUIRED for other than "at speed"... like around town driving. There just isn't any air being "forced" through the radiator. In all likelyhood, an electric fan will provide better cooling than the original fan. I don't know of any "kits" specifically for the Opel. I use a perma-cool 16" fan http://www.perma-cool.com/Catalog/Cat_page18.html. I prefer to blow air through the radiator from the front (but pulling it from the back works too) because it is easiest to mount that way. Just make an "X" for the fan to mount to and bolt the "X" (with fan mounted) in front of the radiator. Take a look at the perma-cool dual fan set-up (http://www.perma-cool.com/Catalog/Cat_page18-1.html) to get an idea of how to do it with a single fan... just don't block as much of the radiator as they do.

You don't have to do anything special to the pulley except you may need shorter bolts. Just remove the fan, and bolt the pulley back on.

Opel engines like to run around 180 degrees. So, anything that kicks the fan on at a little above that will be fine. I had a Fiero that didn't kick the fan on until 200+ degrees. For the Opel that would be bad. Perma-cool sells an "adjustable" kit that you could set for around 185 - 190 degrees. (You should have an 180 degree thermostat.)

Some "weasel words"... I started out by saying that a stock Opel GT radiator is marginal. I have only used electric fans on an Opel GT with a new heavy duty radiator (OGTS) or new aluminum racing radiator. Although I think an electric fan will work better than the stock fan, you do it at your own risk on a stock... old radiator.:D
 

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pusher vs. puller

A fan in front of the radiator typically works 15-35% less efficiently than one behind the radiator, but in the GT you really have no choice. The fan TGSI suggested should work great, but if you order from Summit or Jegs or such, look for the type with only a "ring" around the fan and not a shroud that makes it square. The square ones will need to run almost all the time on a stock radiator.
There is a couple of other things you can do to help your radiator get a little more air too. On F-body Camaros, amd almost every other GM car too, there is a littly hard plastic air dam mounted way behind the bumper to the bottom of the radiator support. This piece should hang down as close to the ground as possible and go as far across the front of the engone bay as possible too. It creates a low pressure area behind it in the engine bay and a high pressure area in front of the radiator, both of which make the air flow through the radiator increase! Convienently enough, the high pressure area is also right neat the front of the wheels, causing the airflow through the wheels to increase too, which could cool your brakes better if you have removed some of the splash shield.
Another option for the raditor is to have one custom made Fluidyne will make a custom aluminum radiator for typically around $300-400, and to any dimension you need. Depending on how far you're willing to go, aa cross-flow radiator with side tanks set to be on either side of the opening in front of the radiator support hole so the whole area is "fins" gets @20% more surface area. Moving the radiator to in front of the radiator support also lets you put an electric fan behind the radiator, which helps too.
Btw, a late 80's Cavalier 2.8 radiator and fan fit the bill for that kind of mod, but remember to measure for yourself before you buy a radiator and start cutting.;)
 

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Kick a little asphalt
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For anyone interested, I have a brand new electric fan for sale. It is a Spal fan that I bought from Pegasus Racing. It is highly efficient and fits the Opel radiator perfectly. I bought two of them for my projects. I am currently using one on my 2.4 Manta and it works flawlessly. I was going to use the other one on one of my other projects, but at this point I don't have the time or money to work on it. So, if anyone is interested, send me a private message or an email. Thanks.

Duane
 

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Thanks again for the SPAL fan, Duane. I've been running it for about a month now, and would have to recommend these fans to anyone with an Opel. One thing I really like about the pusher fan in front of the radiator is the access you now have to the front of the engine . . . without the shroud & belt-driven fan in the way, you can easily turn the engine by hand--which is often useful--& it's much easier to see those timing marks I made on the crankpulley & timing cover. Definitely nicer, & quieter, than the stock set-up. Y'all were absolutely right about this!
 

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Kick a little asphalt
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I'm glad you are happy with it. I figured you would be. It really is a great modification, and simple too. ENJOY IT!

Duane
 

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A semi-interesting note on the fan installation: I used an electric fan wiring kit from Perma-Cool, their P/N 18905. E-mailed the company in California after seeing the kit on their website, & received a quote of $77.30. When I called their 800 number to order the kit, their guy on the phone suggested that I do myself a favor & order the kit from Jeg's--THEIR price on the 18905 kit is $49.95! Very strange, I thought . . . rarely do companies intentionally send business elsewhere, in order to save the customer money . . . just doesn't happen. Glad they did, though, so do yourself the same favor if you're in the market for a high quality wiring kit for your fan.
 

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What model of Spal fan was used for a GT installation? Size? Straight or curved blade? I'm guessing a "pusher"? Still happy with it?

As far as the PermaCool hookup kit, it looks like there are two kinds of thermal sensors available. It seems the "probe kit" was used. Just how/where is coolant temp messured using this probe?

If someone has installed a PermaCool fan as a pusher, which one (size)? The GT radiator opening in the nose area is only 12" by 15". I just don't see how a 16" fan can fit as mentioned early in the thread.

Just looking to pick and buy the right electric fan. Thanks.
 

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Solo II is fun in a GT!
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no electrics for me

Tried the spal. Didn't like it. It got too hot even running all the time with a switch (no temp control switch here). Had the local Rad. Shop do a 3 core Rad. for me. And I am running the stock fan with out the shroud.

This has worked for me for the last two years for Solo2. A side note: your pullys must lineup so that you will not have belt squeel. I had to place washers between the water pump and pully to line up the pullys. Must be my short nosed Discount Parts house water pump. OGTS pump for me next time.

okieopel
Oklahoma Opel Preservation Society
O.O.P.S.
 

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Spal fan

Jimsky, I've had nothing but good things to say about that fan since installing it last summer--I still think it's GREAT. The 2.0 GT that it's on is still the DD around here (thanks to the continuing drought in Colorado . . . watch for news stories this summer about this entire state on fire), & when I think about it, the fan hasn't kicked on since about last October. It's a 13", straight-bladed pusher--can't see how anybody could make a puller fan fit in a GT without relocating the radiator. The pusher configuration works well enough. This Spal's pushing air into a stock GT radiator that's had a four-row element installed by a local rad shop, I'm running a Robertshaw 160 degree thermostat, & the engine coolant passages are CLEAN as they can be . . . the result is what you'd almost have to call undercooling. I believe the temp guage in the dash to be accurate, & it generally shows the coolant temperature to be about 176 degrees--that's the 7 o'clock position, the third of the five longer white marks on the guage. The big valve head on that car is a '74 (a cylinder head waiting to crack), so losing a little power due to running a bit cool suits me fine.
 

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Solo II is fun in a GT!
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Spal pusher

I was running a recently rodded stock 2 core with the Spal curved blade pusher. The Oklahoma summer was just too hot. I wish I could get and electric work, because I hate the noise and could use the extra pony and a half.

But until Gill sells them... I will continue to run this set up in FSP Solo2.
 

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Kick a little asphalt
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There are probably a couple of variables contributing to your unsatisfactory results. First of all, a stock two row radiator is marginal at best even if it is in good condition. Second, having a radiator rodded is not the best way to alleviate cooling problems. After all, the core is 30 + years old. And third, you must consider a fans CFM rating before making a choice for your application. I would guess that the combination of a core that needs to be replaced and a fan with a low CFM rating are the cause for your disappointment. I know the subject of Opel owners being "frugal" has been discussed before, but there are certain things you just can't skimp on. It is not worth ruining a good engine to save a few bucks on a cooling system. The Spal fans are among the best in the industry. However, no matter what brand you choose, you must know that the fan will move enough air for your application before buying it. A fan that moves more air will be more efficient as it will cool the motor faster and run less. A low CFM fan will run much longer before bringing the motor back to temp, if it can do it at all. My fan has a high amperage draw, but if you look at the pitch of the blades you will see why. I have seen some fans with virtually no pitch to the blades. These fans draw less but will not move much air. A good fan is not cheap. My advice would be to recore your radiator (3 row), purchase a quality fan that meets your needs and be sure to install a proper thermo switch and a relay to handle the load. I believe you will be pleased with the results.

Duane
 

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Solo II is fun in a GT!
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351 Posts
Duane- I suspect that you are right. Old Radiator and a skinny fan (no matter the $79 price tag on sale) ain't going to cut it. New radiator is the only way to go.
As for we Opelers being cheap... you would hate to see my VISA bill.
 

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Kick a little asphalt
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I know exactly what you mean. I have stupid money in my Manta. But like I always say, have you ever seen a Brinks truck in a funeral procession?

Duane
 
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