I would like to play it safe on my 1998 4runner w/supercharger and richen up my fuel/air mixture w/o any major fuel mods. I have read about a 170 degree thermostat change or putting a potentiometer in series with the ECT sensor to fool the ECU on mixture. Any advice or experience with either of these mods would be appreciated.

 

I'd really love a side by side post of the 170F napa thermostat and stock. I'll admit to having the 170F, and not having thought of this till after the swap. Point being: 170F will open prior to the stock 180F thermostat. But unless it allows for more flow, both thermostats when open will cool similarly. (Perhaps its a type R thermostat. HA)

That's assuming that steady state temp for our coolant is above 180F - so the thermostats aren't opening and closing frequently as we drive.

Anyways, its cheap. Might as well. Ditto cold plugs.

Of course these are both parts of the URD kit so when you get around to buying that later you'll end up with extra plugs and an extra thermostat. Or at least I did.

as always, YMMV.

(Oh, i think if you look hard you may find a 160F thermostat somewhere. That may be the TRD thermostat. But I don't think its made anymore.)

 

I didn't take a pic but I did put them both in a pot of water together on the stove and yes the Napa 170 does open up with a bigger hole than the stocker did. Bigger hole should flow more right?

 

absolutely - and there went my theory. So to the OP - try the thermostat. Nut I'm sure most here will hedge there bets and tell you that doing the full fuel kit at sea level is best. (note I wouldn't tell you that if you lived in colorado).

 

Your engine is still WAY out of the capability of both the stock fuel pump and stock injectors. Adding either of these mods will do very little.

Your best bet as far as cheap and easy go is to do the free FMU mod. The mod will simply force the maximum amount of fuel available to the engine when in boost. My mpg dropped by 2 when I did this mod, but I still pinged and had high EGT's and dangerous AFR's.

There is simply no getting around what the stock 238cc injectors can do: very little on a SC'd 3.4.

 

I know this is an old post ..

and I have searched ... but what the heck is the part number for the Napa 170* thermo


.

 

I just went in there and asked for the options on the 3.4 and the 170 was one of the options. Then they'll ask if you want the gasket too. I got that as well. It was like $15 out the door.

 

ohh ok .. thanks .

 

Not trying to hijack but the OP brings up an interesting point, I never switched out my low-temp (supercharger) thermostat when I did the fuel upgrades. Anyone have any experience with reverting back to the original thermostat from the supercharged one? I can't imagine how running a little warmer would make a big difference, but again, these motors were designed and engineered to run in a very specific temp range.

 

I guess the OP was thinking the cooler t-stat would cause the engine to run richer. That is just not the case, once it goes to closed loop the ECU will adjust it to 14.7. Running a 10 degree cooler t-stat doesn't keep it out of closed loop, in fact I can't even get out of my garage before I go to closed loop, and that's way before my 160* t-stat opens up.

 

If your going to run a 170F thermostat you need to avoid short trips where the engine doesn't get a chance to fully warm up.

Lower temp thermostats cause the engine to not evaporate condensation out of the oil nearly as quickly as it does with a 180F stat. Because of this if you take allot of short trips the water will never evap out and you will end up sludge and corrosion inside your engine.

If you do have to take small trips, be sure to twice a week get up on the highway and drive for 15-20 minutes so the engine can get a chance to evaporate the water and push it out via the crank case ventilation.


FOG

 

found the thermo today from napa .. It's a - GATES part , # 33867
just incase some one else is looking


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