1987 mazda rx7 fc n/a streetport

So i just recently installed a new koyo aluminum radiator, and decided to install a new thermostat as well while I was at it (170F since its what they had at the autoparts store). Fired it up today for the first time since installing it, and it runs noticeably cooler, but now the idle fluctuates.

What could be the cause of this?

Edit: Revs freely and feels the same as it did before when under load. Idle is at 750, and it is on the factory air box. (Soon to be replaced once the cai gets here in the mail).

 

I'm a moron.

I forgot to connect a vacumm line.

Problem solved.

Sorry. lol.

 

What vacuum lines connect to the radiator?

 

You should be using a OEM thermostat.

 

+1

Rotary >Pistons

 

What is the downside of using a 170F thermostat compared to the 180F oem one?

I will totally go out and get the oem one as long as somebody tells me why it is important to use the oem one. What is the downfall to an aftermarket one?

Edit: Nevermind. I just did some searching and discovered that aftermarket ones are prone to failing and result in a 20-30% cooling loss. Anyways, thanks for the help guys.