Hey everyone! I was wondering what your experience was in using Hypertech's low temp fan switch and thermo on the stock V6. I've got the parts, but was wondering what pros and cons people here have found with using these products. I'd really appreciate anyone with experience in using them's thoughts adn opinions. Thanks a ton in advance!

------------------
My Fro's...

88 Yellow CJB #182 of 1252 formula
88 Red Duke

I believe the PO of my Formula installed one as I found the box in the trunk. The car stays cool but the Fan runs constantly when its up to operating temp.

it may wreck your fuel milage. if the motor doesnt reach a certain temp, the ECM will not go into "closed loop" mode, and will run in super rich mode, and get about 17MPG.

I don't like them. They require you to cut and splice the wiring to the fan switch (unless that's been changed).
160° is also borderline too cold to run the engine efficiently, and as was mentioned the fan will run all the time.

I recommend Rodney Dickman products. I have his 180° thermostat and matching fan switch. He also sells a fan switch to go with the stock 195° thermostat that lowers the fan cuton temp from the stock 235° to something more reasonable. They use OEM connectors and are plug-and-play.
With the 180° t-stat and fan switch, my car never gets over 200° even sitting in traffic and the fan only comes on when sitting still, and even then it cycles on and off rather than running all the time.

Highly recommended!

Both are easy to swap. Document a base line for MPG and then swap them. See what you feel for performance and mileage. The general consensus is they won't affect seat of the pants feel but they will drop your mileage. It would be interesting to see what you find out.

A turn of the thermostat cap, a little wrenching, and a wrap of teflon tape and you have them swapped, or swapped back.

Thanks for all the feedback guys! I appreciate it greatly!

I don't drive the car like a daily driver, so the mileage isn't that important to me. However, I don't know that I want the fan on constantly either. I more want to protect the motor. The factory specs for cooling seem totally rediculous to me. Does Rodney's set up hurt mileage? Can the ECM be programmed to go into closed loop at a lower temp? Does the Hypertech performance chip help with this if used with the fan switch and thermostat? Seems crazy that they would sell a product that would case such issues.....

Has anyone ever contacted Hypertech to ask them?

quote Originally posted by zefferk: Thanks for all the feedback guys! I appreciate it greatly! I don't drive the car like a daily driver, so the mileage isn't that important to me. However, I don't know that I want the fan on constantly either. I more want to protect the motor. The factory specs for cooling seem totally rediculous to me. Does Rodney's set up hurt mileage? Can the ECM be programmed to go into closed loop at a lower temp? Does the Hypertech performance chip help with this if used with the fan switch and thermostat? Seems crazy that they would sell a product that would case such issues..... Has anyone ever contacted Hypertech to ask them?

If I remember correctly they sell a chip that goes hand in hand with the low temp t-stat. I had both in my old 87 z24 and was happy with it. this was many years ago and I think it was a stage 2 chip

[This message has been edited by 86 toy (edited 08-26-2011).]

The stock settings for the themostat and cooling fan are set to help economy and reduce emmisions, as well as protect the engine from damage - not ridiculous numbers, rather carefully engineered settings to achieve goals set out by an experienced engineering team.

As to the HyperTech stuff, phonedawgz is right on the money, try it out for yourself.

By the way, I can't tell you how many of these chips I have pulled out of Fieros and put the stock PROM back in for people,,,,,,,,,,,,,,

These is a reason people don't keep them in their cars. Decide for yourself.

I'm not trying to get better performance from my car, just want to do what is best to protect it from heat. I was just curious if the chip would change the closed loop settings, thus giving the good effects of lower heat on the engine without the loss of fuel efficiency and/or performance. If it is better to keep the whole system stock that is what I'll do. I was only wanting to see if when properly using these devices you could get a better outcome. I know the engineers set the car up the way they did for very specific reasons, however the fiero has always had a known heat issue (probably more for the engine location and lack of airflow. It would seem to me that some extra cooling couldn't hurt. It appears only the ECM throws a monkey wrench into the equation. Without the closed loop setting being set so high, it seems as though we could lower our temps without issue...

Just saying...

I'm going to contact Hypertech to see what their reason was to even develop this product if it is harmful. I'm sure they'll say it isn't, but if the engine can never go to closed loop then if is pointless....

I wouldn't waste the $$ on the chip. Just think of it this way, what can a performance chip reliably change on an engine w/o a knock sensor?

Just get a 180 thermostat and a 195 fan switch. 180 is plenty warm for the engine to remain in close loop while having the fan kick on at 195 will help ensure your engine rarely goes above 200 degrees without having the fan run all the time.

The hypertech fan switches are junk as well, I have used 3 of them and they all have failed within 2 years. The newer ECMs (like the 7730) allow you to control the fan with temp settings in the ECM and allows you to eliminate the fan switch all together.

quote Originally posted by fieroguru: I wouldn't waste the $$ on the chip. Just think of it this way, what can a performance chip reliably change on an engine w/o a knock sensor? Just get a 180 thermostat and a 195 fan switch. 180 is plenty warm for the engine to remain in close loop while having the fan kick on at 195 will help ensure your engine rarely goes above 200 degrees without having the fan run all the time. The hypertech fan switches are junk as well, I have used 3 of them and they all have failed within 2 years. The newer ECMs (like the 7730) allow you to control the fan with temp settings in the ECM and allows you to eliminate the fan switch all together.

How easy is it to convert to the 7730 ECM and at what cost?

The Hypertech Thermomaster set up. Hmm, I had the full package (chip, 160° thermostat, and 160° fan switch) on my 88 V6 for many years. This summer I swapped the PROM chip back to the OE one, and added a Stant 180° Thermostat, and a Hypertech 195° fan switch. My experience with it was pretty much what the current consensus on this is - it richened up the air/fuel ratio across the board. At idle and low RPM the engine ran noticably rich - the tailpipes were covered with soot. The only benefit I found is that the car ran very cool, and had good power at highway speeds. My car would run at 130-140° driving around, and in stop and go traffic (Woodward Dream Cruise) it never got over 180-190°. The performance gains are seemingly negligable, but I pulled out of this stuff out of my car so that it would not run so rich.

As much as I like tuning cars, I hate to say this, but Stay stock on the Fiero. They really pushed as much out of that motor as they could. Leave it on stock temp, switch, ecu, etc.

If you want to help the car, a Truleo intake, or exhaust can't hurt.

Not to start an arguement here, but I feel I must comment................

The underhood temps on a Fiero (once the Cat is removed) really are not any higher than other front engined cars of the era.

With the cat, it gets pretty warm in stop and go traffic, but cooling system modifications will have no effect on that.

Once the car is moving, the airflow through the engine compartment is pretty good due to the vents and the low pressure area behind the rear window, when in stop and go traffic the stock cooling/fan system controls the engine temps very well - when the fan kicks on the coolant temp drops quickly.

Notice that the Fiero does not use an insulating blanket under the rear deck - but most other cars have one.

Anyone have any issues with the paint blistering on their rear deck lid?

My point is that I believe that the Fiero under hood temps are pretty reasonable - especially for the age of the design.

What problem(s) are you trying to solve by changing the thermostat? If it ain't broke, don't fix it.

If your car overheats, a lower temperature thermostat won't fix it. At best, it will only delay the overheating by a few minutes. The sole function of the thermostat is to set the lower limit of the operating temperature of the engine. The cooling effectiveness of a fully-open 195 degree thermostat is identical to that of a fully-open 160 degree thermostat; once the coolant temperature exceeds 195 degrees there is no difference.

If you're looking for some performance improvement (in a normally-aspirated engine), you're looking in the wrong place. The engine design (running clearances, etc.) is optimized for the expected coolant temperature (195 degree thermostat) and recommended oil viscosity. And, as others have stated, your fuel mileage will be worse when running a lower coolant temperature, but only your own experimentation will tell you how much worse.

There is an additional problem with running the engine too cool. During engine operation some unburned fuel and water produced by combustion get past the rings and down into the crankcase. A healthy PCV system will remove most of it, but some will get trapped in the oil. When the oil gets hot enough, most of that trapped fuel and water will "boil off," but a low-temperature thermostat may never allow the engine to get hot enough to boil off these volatile contaminants. Of course, the problem is worst in winter. My '69 Porsche 911S used to accumulate more than a quart of fuel and water in the oil driving in town in the winter, and the oil level would sometimes drop dramatically during the first hour of a highway trip as the accumulated fuel and water boiled off.

quote Originally posted by olejoedad: ... cooling system modifications will have no effect on [engine compartment temperatures].

Correct.

[This message has been edited by Marvin McInnis (edited 08-27-2011).]

go with the 185 hypertec and 180 stat ran one on my 88 for one season worked great