anniesball

I am curious what the reasoning for the TRD cooler thermostat usage in S/C applications.

I have a '02 4runner that I am considering S/Cing.

I have seen numerous posts from people who state that the 2 step colder plugs and cooler TRD thermostat have all but resolved thier pining problems.

My question is, does the engine benefit from the cooler opening temperature of the thermostate? Instead is it that the cooler thermostat will allow the Engine ECU to deliver a richer mixture due to colder coolant?

If the latter is the case, why not alter the resitance of the temp sensor to "fool" the ECU?

Dr. Zhivago

It's funny that you bring this up...

I have been running my truck (NA) with a 1K Ohm Potentiometer wired in series between the ECT Sensor and my ECU. This is an old trick. I had this same mod on my Supra. I wasn't going to post about this just yet as I was gathering data from my Beta test pool. I have had this mod on my truck for about 5 weeks now. I will have to put out a write up now because we're going to get a bunch of questions about this.

Anyway, using my BR-2, I set it to monitor Fuel Trim. According to the BR-2, with this mod, I can send 1-2% more Fuel to the engine, depending on how much you tweak the ECT Circuit. This results in a noticeable performance increase. It's stronger on the bottom and thru the midrange and it pulls more smoothly above 4K RPM's.

mpulver (Mark) is the other forum member who has participated in this mod. He just got his hooked up today and he already noticed the difference. You don't even have to reset the ECU. It also doesn't affect Fuel Economy.

It's really simple. We'll be posting a link to a write up shortly. Full details will be provided.

Peace.
Dr. Z

dukestr

That's why I love this forum
Will be waiting for the write-up Dr. Z! ...

midiwall

I have only one thing to say at this time...
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Thank you Dr. Z!
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(the first cut of the page is coming soon)

oly884

I doubt it, but what about doing that to a 3.0 L V-6? It's a long shot, but I want to find how to get as many ponies out of it for as cheap as possible. There is a lot of things that I've tried, but no prevail.

Dr. Zhivago

This mod will work on the 3.0 as well. It can be applied to almost any modern EFI engine. I don't have a write up planned for that engine, but we could probably fit it in.

Stay tuned.
Dr. Z

Jay

There has to be some increase in full consumption. Thats how your gaining the extra power. Perhaps just not much to consider.

Ive always been trained to look at the thermostat when diagnosing excessive fuel consumption complaints. A stuck open thermostat will cause a richer mixture due to the coolant temp being lower than normal. Which is exactly what your fooling the engine to think. I know you know all this.

I only disagree with the statement that you dont use any more fuel.

Dr. Zhivago

Always with the nay-saying.

Okay, in all fairness, let me rephrase my Fuel Economy statement thusly: The mod doesn't APPEAR to affect fuel consumption negatively. I've tried to gather some good data by running the mod thru one full tank and then running the next tank with it off. I did this a few times and there was no difference in fuel consumption between the tankful with the mod turned on versus a stock setup.

Since the mod also Advances the initial idle timing a few degrees, I think that this might help offset the additional fuel. According to the BR-2, Maximum Advance is unaffected by the mod.

Anyway, I will be posting the write up ASAP. It will probably appear in the next couple of days.

Peace.
Dr. Z

PS Jay is my hero.

PhxTRDRunner

You guys crack me up




I still consider myself a nOOb, thus will stay out of the big dawg's way :eek:

tomus1000

Sooooo, what is better? A resistor or a colder thermostat?

I know that this is a little premature since Dr. Z plans on doing a writeup, but I wanted to keep the post alive for a little while linger.

Dashunde

Would'nt those of us who have very hot summers want to do both during those months?

Dr. Zhivago

I think if you're running NA, then do the ECT Mod. If you're running S/C'd, do the thermostat but test it with the ECT Mod first. I ran a colder thermo on my old Supra and it helped a lot with both performance and fuel consumption. Plus it allowed me to run more boost without detonation.

I installed the TRD Low temp Thermo on my truck, but took it out because of poor fuel economy. It sure gave a lot of extra kick tho. I may put it back in when I get my SMT-5 since I can tune the engine around the lower temp thermo.

With a forced induction engine, the lower temp will allow you to run more boost with less ignition retard which helps both performance and fuel economy.

For what it's worth, and even though the ECT Mod has not been tested on the S/C'd trucks yet, it may be just the ticket for some owners. We'll have to wait and see. I promise to have a write-up posted this week.

Peace.
Dr. Z

ravencr

I can't wait to hear all about it, Dr. Z!

Dr. Zhivago

The write-up has been posted! Go here to see it.

Peace!
Dr. Z