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View Full Version : Anyone with an RPM air gap for a SBC.



Autometer
11-23-2004, 11:02 PM
Do you guys ever use the water ports on the back of the intake? I've seen people run lines back up to the front of the intake. How much does it help with cooling?

Norwoodx55
12-01-2004, 08:37 PM
Autometer, I talked to an Edelbrock tech. about this, and he said they had better results connecting the 2 rear ports with 8AN hose. I made a hose like he suggested and saw no diff. in the cooling. As for connecting front to rear, I haven't heard how well that works.
Brett

Zefhix
12-01-2004, 11:35 PM
Autometer, I talked to an Edelbrock tech. about this, and he said they had better results connecting the 2 rear ports with 8AN hose. I made a hose like he suggested and saw no diff. in the cooling. As for connecting front to rear, I haven't heard how well that works.
Brett

I was told once that the majority of the heat created by an engine is at the rear so I would just assume that running a line from front to back to be benificial. Besides, late model cooling sytems are reverse flow for that exact reason. :)

Norwoodx55
12-02-2004, 07:03 PM
Keith, the Edelbrock tech said something about water and or air pockets "dead heading" at the back of the heads. He said to make the line a little on the long side, loop it behind the distributor, and make sure that the loop is lower than the hose fittings.(using 120* fittings) At any rate it didn't do anything for me other than lighten my wallet by about $65. As for the reverse cooling thing, I thought it was to cool the chambers(heads in general) before the block/cylinders. I dunno, I only go by what I read or hear, :bsjerk: and that usually bites me in the arse. I tend to learn everything the hard way.
Brett

Zefhix
12-02-2004, 07:17 PM
Keith, the Edelbrock tech said something about water and or air pockets "dead heading" at the back of the heads. He said to make the line a little on the long side, loop it behind the distributor, and make sure that the loop is lower than the hose fittings.(using 120* fittings) At any rate it didn't do anything for me other than lighten my wallet by about $65. As for the reverse cooling thing, I thought it was to cool the chambers(heads in general) before the block/cylinders. I dunno, I only go by what I read or hear, :bsjerk: and that usually bites me in the arse. I tend to learn everything the hard way.
Brett

Sure, I hear ya' I've never done the mod myslef just by what I've heard, too. Hopefully someone with experience can fill us all in :)

Fuelie Fan
12-03-2004, 09:04 AM
----take with grain of salt as this is just my mind experiment-----

Unless your cooling system is already being overwhelmed, I would doubt you would see a difference in coolant temp at the thermostat. It's job, after all, is to try an maintain a consistent temperature at that location. However, this doesn't mean it's making no difference at all. Just becuase the thermostat is at 180 or 195 doesn't mean the entire engine is. If you had a second temperature sensor at the rear of the engine, perhaps then you would see the difference as a local drop in temps? I have two temp sensors, one for my gauge and one for my ecu. The gauge is in the head on the pass side near the rear, and the ecu's is under the thermostat. It is not uncommon for the gauge to read 20 degrees higher at times. Technically though, I guess this isn't scientific since they are two completely different devices, and maybe wouldn't read the same even if they were in the same place!

I don't think I added anything to this thread, did I?

gmachinz
12-04-2004, 08:30 PM
Hey-but it looks cool..... :smoke:

Autometer
12-06-2004, 11:10 PM
Thanks for the info guys. :)

touring67
01-07-2005, 01:06 AM
Okay, here's the reasoning I was told and it seems quite logical to me as well. Since the coolant is flowing into the manifold at the front and it takes some time to get around to the back the coolant is already getting quite hot and the same drop in temperature will not be realized at the back of the head resulting in some hotter chambers near the back. If the back of the manifold is plumbed back to the front, or vice versa, there will be greater equalization of coolant temps and the heads will have a better heat distribution. Since there is usually only one coolant temp sensor this is hard to detect or notice. I personally have an Air Gap but haven't tried it nor do I think it is necessary. IF I was running lots of compression and running the ragged edge of pump gas I would probably do it to ward of detonation caused by the heads being hotter in some spots. Does it work? Possibly, but it could be negligible and I wouldn't do it for a street motor. Hopefully that came out in a way that it made some sense..

69Rathead
01-07-2005, 06:29 PM
This Forum is the ****! I just bought an Air Gap myself and was contemplating IF and How I was going to hook up the bypass lines. Thanks to you guys I am going to plug them off an not debate over it anymore! I don't think I'll get anything out of it on my engine (SB 350 with a mild cam and headers) and I'd rather save the $ for something else. I sure am glad I found this Forum and can depend on you Motorheads to bring up and answer any questions before I could ever ask and or even think them up! :worship: