When to measure temps

[rossb]

When am I supposed to measure the temps off my motor? I have a Motorsaver on my S-25 and my outside temps are hot & humid in the mid 80s. My HSN is 5 turns out, which is 1/2 a turn RICHER than the factory break-in settings. My LSN is 3.5 turns out, which is 1/2 a turn richer than the factory break-in settings. The truck runs very good without hesitation and it blows plenty of smoke. It does not have enough power to wheelie off the line with the 15/49 gearing.

After running around on and off the throttle with the body on I get temps in the mid 200s. If I run WOT back & forth across a very big parking lot a few times and then immediately take a temp reading I am somewhere in the 300-310 range. I can richen it up further, but it seems to run good as is and it blows smoke. I did try to richen the HSN even more than the 5 turns and I think it was losing performance. Should I be reading temps after running on & off the gas, or should I read it after a long extended wide open blast?

 

[kwong2001]

First off, when you're tuning, tune when the truck has half a tank of gas. That way, when it's full, it'll be slightly rich, then as the tank goes through, it'll lean out a bit.

But as for reading temps, run the car normally and check it as fast as possible, the longer you let the engine idle, the more it'll cool off and the reading won't be accurate.

 

[olds97_lss]

I'd think you should check it periodically as you run it. If your just sitting in a parking lot going WOT from when end to the other all day long, then you will be putting hella strain on the engine and everything else. But if your farting around in a park and actually "driving", just check it every so often to make sure your within the limits.

The engine temps will obviously fluctuate as you have figured out, but it's the average temp you want to keep around 240. If you check your temps 4 times in an hour of normal driving around and your average is at 180, lean it, if it's at 270, richen it.

Basically, holding it WOT for 5 minutes and checking the temp is kind of retarded, just like letting it sit and idle for 10 minutes and checking the temp is. I mean when are you ever going to peg the throttle for 5 minutes straight or let it sit and idle for 10 minutes straight?

 

[rossb]

Basically, holding it WOT for 5 minutes and checking the temp is kind of retarded

I ran it 4 times back and forth (8 trips total) wide open across a big lot. The lot takes about 5 seconds to get from one end to the other at top speed. That is about 40 seconds total of wide open blasting with about 10 seconds of idle time mixed in while turning around after each trip.

 

[FastEddy]

You will tune differently for each situation you are in.
The average running temp isn't what your looking for, its the spikes or the highest temp the engine reached during a given time. If your running WOT richen that puppy up. When you read 300 as a temp once the truck gets back to you I will guarantee you it was a minimum of 5-10 degrees higher at the spike.

Lean engines run great but don't last long. You will sacrifice in performance running rich but your mill will last much much longer. Did you know an engine runs its best just before it blows?

 

[rossb]

I probably need to richen up the HSN. It seems strange that I am running richer than the stock break-in settings on both needles (which are already supposed to be rich) and I am still a bit on the lean side even though my outside air is very thin (hot & humid). Thin air should require a leaner needle setting, not a richer one.

FWIW, I experimented with richening up the HSN to the point where the truck bogged at high RPM and it was about 6 turns out (1.5 turns richer than the break-in setting and pretty much flush with its surrounding metal). Does a Motorsaver filter really flow that much more air than the stock filter?

My LSN is set pretty good. It idles well, the pinch test causes it to stumble and stall after about 3 seconds. It pulls away wide open from a dead stop nice and clean after idling for 1-10 seconds. If I let it idle more than 10 seconds it stumbles for a few seconds when pulling away wide open from a dead stop.

 

[FastEddy]

Tuning is usually done 1/8 to 1/16th of a turn.
Try 1/16 leaner on the bottom and 1/8th richer on the top and see what that get you.

Brake in settings are just a guide to know where to start. Huge differences in setting are common. There are a lot of factors that will effect the settings. Some of them include weather, altitude, air filter, fuel lines and routing, engine condition, and the list goes on.

Yes a Motor Saver can make that much of a difference.