Ok I will do that. Thx

 

Thank you for taking the time to share your knowledge, very helpful information. Now I know where to start.

 

Has anyone a list of firms who make these water pump adapter flanges when switching to a electric pump?

I know:

- Pro Jay ($80 or $100 with temp sensor port)
- meziere ($111)
- some uk company, but they don't offer them with threads
- xtreme rotaries made a real nice flange, unfortunately they are out of business

I'm sure there should be more options available...

 

Adam at RX7 Specialties sells the billet Xtreme Rotaries adapters.

 

i am getting ready to delete the AST and install one of these, can anyone enlighten me on where to plumb the two top nipples to?

 

The rights to products were sold to Xtreme Auto Parts when the business stopped selling to the public. The adapter is still available here: Billet Water Pump Adapter

 

Have you asked Himni? I would think it hooks up like an AST. The neck nipple would go to the overflow tank, the bottom threaded opening would go to the radiator and the brass barb would be closed off

 

so i should block off the lower nipple on the radiator as well? i think that is where my current AST is plumbed to

 

neck nipple to overflow
brass nipple to radiator
threaded port for the level sensor

*I THINK* you better ask himni to be sure

 

That sounds right. Post the correct hookup when you verify with Himni. They look nice. Too bad they are sold out

 

the design engineers worked to control at the best temperatures for emissions and power, removing a thermostat would cause you to run colder than optimal performance; maybe unless you were doing some special high performance racing.
Then Oil coolers would be better, I hear.

 

I rocked one from these guys instead of Himni (whom I've heard isn't reliable):

https://tgsexhausts.co.uk/product-ca...d3/rx7-engine/

It has a single top nipple that goes to your overflow bottle.

 

To add some anecdotal data to this super helpful thread, I've taken my car on track recently.

Car: '94 RX7 Type R (JDM with twin oil coolers), 47k km (29k miles)
Temp monitoring: SPA digital gauge with sensor in throttle body hose and peak recall function.
Mods: 3" cat back exhaust
Cooling system: stock, 1.1 bar (16 psi) cap. A radiator upgrade is being planned.

Ambient temperature of the day: 5 to 15 c (41 to 59 f)
Average coolant temp: 90 to 95 c (194 to 203 f)
Peak coolant temp: 101c (214 f)

 

As the owner of three BMWs with electric water pumps, One was replaced at 76k miles, another at 53k miles and the third I just replaced at 35k miles. Go over to the BMW forum and you won't find anyone singing the praises of electric water pumps.

 

BMW EWPs may just be crap. Think the pros outweigh the cons where the flow is independent of engine speed (to include off).

 

it looks like those dont have a barb to go to the radiator, only the overflow. what did you do with the small 3/8 hose that usually goes from the AST to the radiator? block it off?

 

I just blocked it off.

 

Fixed that for you