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Post by gitrdun on Jul 17, 2013 8:27:51 GMT -5
I am going to install a small hood scoop on the rear deck over the engine to let the heat out. My question is would it be better to have the opening facing forward like a conventional scoop or would it be better to face it rearward? I dont know if it would "scoop" air down into the engine compartment when driving or if it would work better facing rearward and give the hot air and escape hole.
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Post by Big-birds-ride on Jul 17, 2013 12:40:56 GMT -5
Hopefully, your vw engine has some sheet metal or other separator between the lower engine and exhaust heat and the upper engine. That really makes a difference on engine running temperature. If you have the separation, I would opt for not putting the hood scope on at all. If you do, I would say put the opening forward so that cooler air will flow into the engine area.
If you put the opening facing rear, it seems that it would have more of a draw of the hotter air from the exhaust system below bringing hotter air into the engine compartment. Most of the heat in my experience comes from the exhaust system which really requires a good separation from the upper engine area. Like looking into an old vw engine compartment.
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Post by gitrdun on Jul 17, 2013 12:57:10 GMT -5
The only separation i have is the stock tin covers that go over the heads. Other than that there is nothing and it seems to get much hotter under the rear deck than i think it should. Also im not crazy about having the gas tank maybe 2" away from the opening of the cooling fan, thats gotta restrict the flow.
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Post by Wyn on Jul 17, 2013 13:40:33 GMT -5
On my twoe I have so much opening space around the engine I would not know where to start. I have a Type III engine mounted in my twoe The only way to cut the heat is to wrap the exhaust system. My son suggested to use the Bernie Bergmann porsche fan system which is reported to increase air flow through the engine by 4 times. From what I have researched on it the people who use it say it works good. People who don't use it say it does not cool properly. My engine is fuel injected so the Bergmann fan shroud would not fit. Just another option to think about. Wyn  |
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Post by Dan MacMillan on Jul 17, 2013 18:48:24 GMT -5
It does not matter if you install a scoop or a better fan, without the hoy cold separation it will run hot. Beetle engines are easy to divide as the tin is basically a rectangle. Cut your filler slightly smaller and drop it down over the engine with a foam strip under the filler and over the stock tin.
On my GT2 the fuel tank is where the engine would normally sit. It is above the trans and the exh is along one side. I recently found out that doing a 3 to 4 hour cruise below 40mph creates enough heat to boil the fuel in the tank.
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Post by gitrdun on Jul 17, 2013 21:21:31 GMT -5
Im not sure what you mean by "filler". Also i probably should have noted i have a GT1. Im not sure if the stock separator tins would really separate the heat on the GT since its all open under the rear deck and fenders.
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Post by Wyn on Jul 18, 2013 8:08:26 GMT -5
If you put a vent over your engine cover it should face forward. You should also put baffles or make a small ductwork to directly force this air into you fan inlet. Like on an aircraft the air flows directly into the cylinder tins and the carburetor is open to the outside air flow. It does not matter what the temp is in the engine compartment with very little venting.
The main problem is to keep the air that enter the fan inlet remain as cool as posible. Look back at the VWs there is a number of vents in the engine cover and vents over top of the engine cover in the car body which are close to the fan inlet. With the type III it uses a closed air duct system to the fan inlet directly from the outside air through vents under the rear windows.
With our brads both the GT and GT-2 there is no adequate venting to keep this tempeture air down. The twoe does have a engine cover vent but this vent is restrictive of the air flow through this cover.
Wyn
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Post by horen2tas on Jul 18, 2013 8:49:49 GMT -5
[  I used stainless steel marine vents and turned them facing forward my next project is to separate the upper & lower |
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Post by gitrdun on Jul 18, 2013 13:40:43 GMT -5
Nice rear cover, throw some LED's in there and that would really look trick at night. I found a small triangle shaped scoop at Autozone i think i am going to use.
I dont think there is any way to connect the fan inlet to ductwork as the gas tank is directly in front of the inlet and only a couple inches at most of distance between the two.
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Post by Wyn on Jul 18, 2013 15:33:51 GMT -5
Find yourself a nice transAM scoop cut it down and mount it on your GT. Make up a ductwork to direct the fresh air into the fan inlet. Use craft paper and cover it with fiber glass makes one hell of a nice ductwork. Alot of home built aircraft use this technic very light weight and eazy to fab up. Wyn  |
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Post by horen2tas on Jul 18, 2013 17:36:25 GMT -5
Nice rear cover, throw some LED's in there and that would really look trick at night. PO already installed pink/red neon |
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Post by mj on Jul 18, 2013 18:21:55 GMT -5
As others have written, separating the upper from the lower engine is really important. For mine which has a 4:1 header, first I wrapped the pipes in carbon/fiberglass tape, then separated the upper from the lower. I can run wide full-open, stop, and place my hand on any part of the upper and it is cool. Here. Not pretty, but highly effective. (This is a GTII which has a functional air scoop facing forward. Functional if the builder modifies it as directed in the manual. Cool air coming in goes to the carbs. Rain is deflected out and drains out the bottom of the lid, not into the engine.)  |
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Post by gitrdun on Jul 18, 2013 19:19:46 GMT -5
Wyn - Where did you find that pic of my car? I dont remember having uploaded that but obviously i did.
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Post by mj on Jul 23, 2013 12:43:21 GMT -5
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Post by Dan MacMillan on Jul 23, 2013 21:13:36 GMT -5
highly effective but still needs the separation. |
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Post by Wyn on Jul 23, 2013 22:37:19 GMT -5
Wyn - Where did you find that pic of my car? I dont remember having uploaded that but obviously i did.   |
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Post by mercer77 on Jul 27, 2013 7:06:54 GMT -5
This is one I put on my 2nd Bradley. PO had a large hole cut there with some kind of cheap metal homemade scoop.  I cut the back of the scoop to match the curve near the rear. |
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Post by gitrdun on Jul 27, 2013 19:49:13 GMT -5
Thats the same scoop i just picked up at Autozone. Looks pretty good IMO.
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Post by airsick74 on Aug 2, 2013 12:29:49 GMT -5
I am also thinking about the hood scoop. I have engine cover off and have engine compartment opened up like a baja. I want to put the cover back on and all tins back in place, but worried about heat issues. I drove my baja in Arizona day in and day out all year round. let me know how this works for you.
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Post by cocacoladodge on Aug 4, 2013 12:46:00 GMT -5
i like the idea that was done on the 1969 Bradley GT currently in the new topics section, it appears he made an acess cover with a airscoop on that. yeah I know he has it for sale, I put the pitures upfor him, but it is a good idea in my opinon. then you have room to make a ducting system to cool it better.
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Post by Gary Hammond on Aug 4, 2013 15:05:25 GMT -5
My cheap, metal, homemade, removable for access, scoop installed over a large opening with oil cooler underneath. Works for me! I also have return cabin air ducted into the intake of the center mounted cooling fan. It helps draw in fresh air in summer as well as heated air in the winter. I don't have any separation between the hot side and cold side because the GT is so wide open it really doesn't matter. But I have wrapped the entire exhaust system which helps a lot! The fuel tank location makes it impractical to use baffling for separation of the heat zones unlike in the GTII's.  Gary Hammond,   |
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Post by gitrdun on Aug 8, 2013 20:02:14 GMT -5
I ordered a head temp gauge so once i have it in i can check the running temp before putting the scoop on then compare it after.
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Eric A
Full Member
It's an obsession not an investment!
Posts: 223
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Post by Eric A on Aug 12, 2013 19:55:24 GMT -5
It is fairly easy to separate the engine on a GTII but close to impossible on a GT. I did change to the oil cooler that sits behind the fan shroud rather then enclosed in it and it helped quite a bit. If you still have issues you might be better off with a remote oil cooler rather then a scoop. Just my 2 cents.
Eric A
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Post by Big-birds-ride on Aug 13, 2013 11:51:43 GMT -5
Guess I am lucky having a Corvair engine mounted up to my VW transaxle in my GT 1. The Corvair engine has not overheated once on me and the temp guage does not go above 180 degrees except on really hot days it might creep a little towards 190 degrees. With all the sheet metal on, the corvair fan cools the engine pretty well.
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