Following many posts I have read I would like to discuss the following

Ever since I got the FD I have been worried about coolant temperatures - to this fact I have done all usual reliability mods

In all posts I have read about water temps the discussion focuses around operating temps, ie. when the car is running, but what about the water temps when you turn off the engine ?

I have started keeping track of these, and I must say they go way beyond what Racing Beat calls norm op temps (185F)

I therefore believe most damage to the engine o-rings occurs when the engine is off after a spirited run

Has any one compiled any data on temps after engine turned off ??

Possible Solutions:
- Fan mod (medium effect)
- Open hood / vented hood (excellent)

 

Heat soak is a problem in many cars -- especially this one. VW and a few other companies have used aux. electric water pumps that turn on for a set amount of time after the car is off. It also turns on the fans while the pump operates.

 

This is very interesting
I did not know they had designed such a system

 

Yep, I believe that is a new add-on for the 2002+ VW/Audi 1.8T's. Mine doesn't have it...

One of these days I think I am going to convert to an electric water pump... it just seems like it would be so much better (esp being able to run the water pump on a separate timer with the fans to cool the turbos down).

 

someone on the forum has looked into this i am sure the link master mahjik will find it. (i tremble before his search might).

 

Here's the one about the aux electric pump you guys are looking for:

Auxilary electric water pump

 

This is a really interesting link!

 

Keep in mind the fans don't turn on until 221F, so I would consider the acceptable range 180F (thermostat opening) to 221F. At cruising you should stay under 200F or so, but if you're idling you'll see the temps oscillate as the fans cycle on and off. This is normal. Heat soak after shutdown will see very high temps but then this is also normal (not necessarily good but normal).

 

My personnal opinion is the best solution is to get a vented hood for the summer - this is what I plan on doing to be honest

 

the primary source of engine-destroying heat is the 22 pound OEM cast iron turbo manifold bolted to the block.

cast iron is one of the most heat retaining materials on the planet. combined with the fact that the rotary runs approximately 500 additional exhaust temperature vs a piston engine and you have a thermal recipe for diaster.

junk the stock turbo system and you eliminate the oven bolted to the block.... a block that is significantly aluminum ( rotor housings) a substance that absorbs heat.

howard coleman

 

barring removing the turbos, running the fans will help cool things down especially with the hood open. running a vented hood will help keep everything underhood a little bit cooler too.

however, i don't know how much of a net affect this will have on the life of the coolant seals due to the situation of the cast iron manifold retaining heat as Howard described. i'm sure i'll still get enough mileage out of my motor with the twins

 

pomanferrari, did the auxilary electric water pump, with EVANS coolant.
HE did a very good write up on DIY and results and etc.

 

Yep, my VW Touareg uses this. As a side benefit, you can activate it in cold weather to keep the interior cabin space warm without running the engine. This is activated with a seperate switch so that in the summer you're not pumping heat into the interior.

 

I have electric tempereture controls I could see to work with this. They can detect the temps at a certain place (you choose) and can switch an electric pump (and fan) on and off. All from one control.

 

There is a simple solution. Do a fan mod. Turn on your fans several minutes before you reach your destination, and don't boost during that time. The fans will reduce your coolant temps to 180 degrees. They will also circulate air to help cool the turbos. This will result in lower temps of everything in the engine bay at shutdown, and therefore much lower heatsoak temps.

 

junk the stock turbo system and you eliminate the oven bolted to the block.... a block that is significantly aluminum ( rotor housings) a substance that absorbs heat.

howard coleman[/QUOTE]

what do you you recommend in place of the stock twins?

and does anyone if there is a DIY site for a fan mod

 

Fan mod DIY site

http://www.scuderiaciriani.com/rx7/fan_mod.html