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Davidsquared Samba Member
Joined: August 10, 2022 Posts: 19 Location: ON
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Posted: Mon Jan 23, 2023 4:43 pm Post subject: impact of no heater on CHT? |
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Hi, the 68 Ghia cabrio I bought has straight pipes to the muffler. The heater system has been removed. The alu heater hose in the engine comparement end at the floor and are not connected to anything.
This car will never intentionally see bad weather, its my fun summer car. I do intent to drive it however, I am not precious with things. I do not have a engine temp guage on it, I plan on adding one.
The engine operating perameters were designed with an intact heater and I assume to some degree removing it will have an impact on how the aircooled engine sheds heat. Has anyone determined how significant (or not) this is? Take CHT readings with and then with the heater gear removed in similar weather and driving conditions?
Before I start doing long highway runs I would like to understand how its managing over heathing.
THanks
David |
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jeffrey8164 Samba Member
Joined: January 06, 2018 Posts: 3818 Location: Georgia
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Posted: Tue Jan 24, 2023 7:08 am Post subject: Re: impact of no heater on CHT? |
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Just get some block off plugs to go into the fan shroud outlets. That will stop the bleeding so to speak.
https://www2.cip1.com/acc-c10-5439/ _________________ Volkswagen!
Turning owners into mechanics since 1938.
“Let he that is without oil throw the first rod”
(Compression 8.7:1) |
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runamoc Samba Member
Joined: June 19, 2006 Posts: 5601 Location: 37.5N 77.1W
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Posted: Tue Jan 24, 2023 7:24 am Post subject: Re: impact of no heater on CHT? |
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check out this forum discussion
https://www.thesamba.com/vw/forum/viewtopic.php?t=755518 _________________ Daily driver: '69 Baja owned 44 yrs - Plan B: '81 Rabbit Diesel LS Deluxe - Plan C: '72 Ghia
Yard Art: 2 Sandrails
Outback: '69 Ghia - '68,'69,'70,'72 Beetle - '84 Scirocco, GTI - Pair of '02 Golfs-
VW Wiring = It's just wires |
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Era Vulgaris Samba Member
Joined: August 22, 2012 Posts: 1678 Location: Raleigh, NC
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Posted: Tue Jan 24, 2023 7:48 am Post subject: Re: impact of no heater on CHT? |
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Do not use fan shroud block off plugs. Jake Raby has proven with actual data, that fan shroud block off plugs create turbulence inside the fan shroud, which disrupts airflow and increases head temps.
It's just like with a river, if it has an offshoot that gets blocked, the eddies back up into the flow of the main river and disrupt the current.
Even if you had heater boxes installed, that air would leave the fan shroud anyway, pass through the heater boxes, and then get dumped out under the car (or into the cabin if heat is on). It's not "lost" air just because you don't have heater boxes.
https://www.thesamba.com/vw/forum/viewtopic.php?t=153387
You can leave the fresh air hoses as they are, or if you want to get rid of them get a fan shroud that doesn't have fresh air outlets. But don't fully block the outlets on a fan shroud that has them.
Running j-tube exhaust pipes won't increase your head temps. What will increase your head temps is having heater boxes installed with no fresh air running through them. What will increase your head temps is not having all of your cooling tin in place. Familiarize yourself with all the pieces, and make sure it's all there. What will increase your head temps is running low rpms under high load situations (ie highway speeds and/or uphill grades). What will increase your head temps is incorrect carb and timing adjustments. _________________ Currently own:
66 Karmann Ghia, L390 Gulf Blue, under construction, here: www.thesamba.com/vw/forum/viewtopic.php?t=760505&highlight=
99 Mazda MX-5 10AE, Sapphire Blue Mica, 6 speed, LSD
Previously owned:
98 Porsche Boxster, silver, 2.5L -- 67 Karmann Ghia, Black, 1500sp -- 98 BMW Z3, Atlanta Blue Metallic, 2.8L I6 -- 75 Porsche 914, Laguna Blue, 2270cc -- 72 Porsche 914, Signal Orange, 1.7 FI -- 74 Karmann Ghia, Black, 1600dp -- 74 Triumph TR6 with O.D., sapphire blue |
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kingkarmann Samba Member
Joined: November 05, 2003 Posts: 4111
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Posted: Tue Jan 24, 2023 8:58 am Post subject: Re: impact of no heater on CHT? |
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I have successfully ran my 67 coupe for 17 seasons using "J-Pipes" with no issues.
They make a rear tin without the holes for fresh air exchangers/outlets.
There are a couple of options for the shroud.
1. Shave the fan shroud outlets and weld sheet metal over the opening. I did this for mine.
2. Purchase a shroud from a 73 Thing. That year did not have fresh air tubes.
As an afterthought I suppose you could leave the fresh air system in place. I don't believe it would have any negative effects.
_________________ "Depression is a malfunction of the instrument we use to determine reality.”
Mike Gerson
What is your "Bespoke Reality"? |
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jeffrey8164 Samba Member
Joined: January 06, 2018 Posts: 3818 Location: Georgia
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Posted: Wed Jan 25, 2023 5:21 pm Post subject: Re: impact of no heater on CHT? |
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Me too, but only 12 seasons.
_________________ Volkswagen!
Turning owners into mechanics since 1938.
“Let he that is without oil throw the first rod”
(Compression 8.7:1)
Last edited by jeffrey8164 on Wed Jan 25, 2023 5:30 pm; edited 1 time in total |
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jeffrey8164 Samba Member
Joined: January 06, 2018 Posts: 3818 Location: Georgia
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Posted: Wed Jan 25, 2023 5:30 pm Post subject: Re: impact of no heater on CHT? |
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Era Vulgaris wrote: |
Do not use fan shroud block off plugs.
Even if you had heater boxes installed, that air would leave the fan shroud anyway, pass through the heater boxes, and then get dumped out under the car (or into the cabin if heat is on). |
There are valves that close when you pull a cable to stop that air flow. I've never seen another air outlet on a heater box so unless all your connections are leaking... I don't believe that more air directed to the engine is in any way a bad thing. If your worried about "turbulence", it's relatively easy to remove the outlets from the shroud. That will get rid of the scoop on the inside which would be the only thing to 'get in the way' _________________ Volkswagen!
Turning owners into mechanics since 1938.
“Let he that is without oil throw the first rod”
(Compression 8.7:1) |
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