Y2K2LS1

I was ready to purchase a 160 stat, or tear into my stock stat and modify it, but I thought I would do a search on what temps are preferred for n2o use. Couldn't find any previous discussions about it, so I thought I'd post here.

I've been reading some threads that talk about leaving your t-stat alone and running stock temperatures, and that has led to more power. Then some others say to run cooler = more power. So throw nitrous into the mix, add alot of cylinder pressure, and what becomes the optimal engine temp for nitrous? Whats going on inside the cylinder head during nitrous use? Are things cooling down (n2o is cold) or does the added oxygen and cylinder pressure create a hotter head, and the need for cooler coolant?

What do you guys run? How does it affect your timing? Feel free to comment on this one.

Debian Dog

I run the stock stat

N2O is gonna drop you intake temp (if shooting a dry shot thru the MAF pulling timing) pretty fast and you ex temps will rise as will the motor temps.

IMHO. I doubt a 160 stat really matters much after the hose has been on more than a 1/10 of a second

white2001s10

iTrader: (4)

Do anything you can to keep coolant temps LOW.
Much more heat is produced in the chambers during nitrous use.
It's also a great idea to run colder spark plugs.

Y2K2LS1

That is what I was thinking, lower intake temps but higher cumbustion chamber temps. I'm trying to stay away from detonation. This will be for a 200+ shot, large cam, stock piston. Also wanting to make max power though!

white2001s10

iTrader: (4)

I'd suggest removing the tstat completely and blocking off the coolant bypass passage,
and run Autolite AR472 sparkplugs.
If you don't already have a fan over-ride switch then wire one up so you can control your coolant temp before making a bottle pass. You don't want to be heat soaked when you spray that much.

Debian Dog

By the time you finish waiting in line and your burn out... your engine temp is the same as mine (unless you have an after market radiator)

I would be more concerned with pulling some timing and running a cooler plug to avoid detonation. Whether or not you motor is running 212 or 215 is the least of your concerns.

Y2K2LS1

I have tuning software so I can control everything. I'm still running the stock stat, and temps can reach 225 before a run. I'll be running TR6's and 100 unleaded on anything up to 200. >200 C12 and some autolites If its not a big deal, than I'll just get an aftermarket stat or modify my own to bring the temps down. I just thought there was a target temp that heavy n20 users shoot for.

TigerFan187

iTrader: (1)

In my situation which is not spraying my wet kit that often a HYP 160 stat and TR6's work for me. I use that stat for reasons other than n20. If you spray maybe a few times a week with a somewhat small shot(maybe like 150) I would definitly say 160 stat but if you are spraying like 200+ shot all the time I would defintly ask some of the guys in the n20 section who are big sprayers!

white2001s10

iTrader: (4)

If you are unable to keep a temp of 160* or lower, it sounds like you have poor control over your coolant temp. In the 200hp and up range of nitrous, it's very important to have perfect control over the coolant temp.
Making a pass on the bottle can easily add 20 to 40* or more to your current coolant temp, so you don't want to start out high.

You don't want to start with a cold engine. You want to keep your oil hot and near operating temperature, but you do want to keep your coolant down around 160*F and cooler before making a pass.

It's true that many people ignore the importance of controlling the coolant temp, and make up for it by running a much more conservative tune that creates less heat in the chambers.

BluMachine

A lower t-stat is useless in warmer weather without lower fan set points in the PCM or manual control with aftermarket switch. I like to have oil temp above 150-160 and coolant temp below 185.

Y2K2LS1

160? Thats cooler than I thought I'd need. I see 205-225 on my stock stat with stock fan settings. I was thinking with a 160 stat, I could bring temps to 185-205 and I should be alright. But 160 coolant seems low. Have you verified with any logging software that your coolant temp goes up 20-40* on a big shot?

My goal is to reduce the temperature of the heads to a point that will decrease the chance of detonation, keep the functionality of the components to a maximum (with respect to material properties, expansion/contraction) and make good power.

Most people attribute an engine warming up to coolant temp, where oil temp is probably more critical and takes longer to come up to temp. I guess if oil temp is where it needs to be, than 160* coolant in the heads might not be a bad thing? For those of us that do not have oil temp guages, is 3-5 minutes good enough to get the oil up to temp between cool downs at the track? (not a complete cold start).

white2001s10

iTrader: (4)

You can run 200*F during normal driving as long as you cool it down before making the bottle pass... that's not a problem. That's why it's better to just use a fan override switch rather than changing the temps with Edit. That will allow the engine to warm up quicker, and run closer to normal operating temp for most of the time. The warmer temps keep moisture out of the oil and are generally better for oil & engine life.

I and others have logged many nitrous passes using both the CTS/ECT sensors and I also use a thermocouple wire as it responds much quicker than the sensor. With a conservative tune (very rich & low timing), the temps don't rise so much or so quick, but when you put the hurt on it they do. I've seen 40*F+ temp gains in less than 10 seconds of bottle use with less than a 200 shot and an aggressive tune. I wouldn't have posted it if I hadn't seen it myself many times.

I've not had to worry about oil temps while racing. If you drive to the track the oil and metal will have plenty of heat in them, and will not lose too much between rounds. Vehicles I've had that came factory with oil cooler, I remove it and run a lower coolant temp. I don't tow with my vehicles so it's never a problem.

You're on the right track about keeping the head temps under control on the bottle.

Y2K2LS1

Can you tell me a little more about this? Are you measuring the temp of the cylinder head itself? Or do you mean an EGT guage? How is it rigged?

white2001s10

iTrader: (4)

You can put a thermocouple anywhere... coolant, metal, or air. I've had them in different places from the intake air duct to the exhaust port.
For coolant temp I normally put them on the backside of the tstat in path of coolant flow. They are very quick to respond, are very accurate over a huge range of temps, and you get a digital readout.

Shuck

I run the stock stat and have had no problems at all.