[Matt 78Z]

Tony got into a short discussion of reverse cooling using a GM electric pump. I am very interested in more discussion regarding how to set this up. I run high compression and already know the benefits of reverse cooling, its also just so logical its a wonder why the engine designers didn't do this in the first place, oh yeah its logical thats why! Anyway, help me out here. Also in a post today you talk about pulling air from the windshield cowl area, I already drive with my hood released hanging by the hook and have noticed this helps seat of the pants acceleration and also temperatures drop slightly. Have you done or seen something to make this even better?


Thanks
Matt, just trying to keep a straight head bolted on this pos!

 

[jerja]

General Motors did the reverse cooling on a production vehicle in the late 50's or early 60's. They had problems with too much heat on the bottom end with bearing failures. I don't recall the car make.

 

[Tony D]

Aaaaaahhh...

I don't recall that. I do know during the first major redesign of the small-block Chevrolet, the engineers reversed the flow of the coolant, so I don't think the "bearing failure" story is valid.

The pump is not electric, it is belt driven, and In my application, I am trying to mount it where the stock AIR pump went, but power steering bracket, A/C compressor, wherever, just so long as you can get a belt to it.

In the simplest terms, remove the thermostat, and the stock water pump. Build a blockoff plate for the old pump location with a provision for mounting the thermostat there. You will find that the radiator size is excessive and you can probably get by with something from a four cylinder.
We cooled a 600+HP TransAm with a radiator from a Toyota!

As far as ducting from the cowl area, this is truly what "cowl induction" is: taking the high pressure air from the base of the winshield and using it to pressurize the intake system of the vehicle. Maybe not the easiest but it is the best cold-air induction system available.

 

[Matt 78Z]

Re: Aaaaaahhh...

Thanks Tony, yeah I've know of cowl induction for a while growing up with my dad being a hot rodder- thats why I always run with my hood cracked.

Have you completed the reverse cooling on your Z or is it in the works. And I'm glad that the pump is belt drive I don't like electric pumps on a street car, so that makes it easier. I also have no accesories except alternator so I could mount it about anywhere. I'm kinda lost on the block off plate/thermostat mounting thing. Do you mean physically mount the thermostat on a block off plate that replaces the water pump?

Matt

 

[Tony D]

YEP!

You use the old water pump for a template. Bore a hole in the center and use one of theose neat chevy O-ring seal positionable necks to hold the thermostat in place and direct the hose to the rad. Tricky part is counterboring the plate to accept the 54MM stock thermostat. Just an aside, if you don't mind making stuff smaller, you really can get by with a smaller thermostat (physical diameter) as you really don't need all that flow with the reverse system. In a stock system, they speed up the flow based on keeping the coolant from boiling at hotspots in the head. That is NOT and issue when reverse flowing, so flow can really be slowed, which picks up more heat. As everything is flowing slower, with more residence time, the radiator can be smaller and reject all the heat, no problem.

You can get as fancy as you want--like swapping sides on the rad for in and out, as mounting the pump over by the A/C spot will make for easier plumbing if the lower outlet is on the same side. Same with the upper inlet connection. A crossflow would probably work well (better).

Mine is in work, but heavily stalled, as I may have to start my own business (or be relocated if I take a different job)---which really bites, as winter is the perfect time for projects.

 

[Matt 78Z]

Re: YEP!

You didn't lose your job did you after that email to your boss? Hope not, thanks for the info its definetly something for me to consider although I'm planning on a V8 swap before long but either way I want to use the reverse cooling method. I have a large AFCO aluminum radiator it is actually the exact same size most of the nascar teams are running - I got it from one of them and man it works great. You think it would be too much for the reverse or would I be able to keep it at temp with a good thermostat? This is for a street car mostly although it will see more track time in the future my street driving is extremely harsh sometimes.

Matt

 

[Tony D]

YEP!

I just remembered we used a bigger bypass line to allow flow and trimmed the impeller diameter on the pum to let the engine warm up to operating temp (ideally 220 degrees. It's really wierd to say that, but the Pontiac we r-flowed seemed to run best at 220 degrees outlet.