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MalcolmV8 wrote:Chris, could you explain the t-stat a bit more. You said you were going to be running a 192 but could tolerate more DCR on a 180 but not wanting to drop to a 180 with hot summers. Wouldn't a lower t-stat be desirable in super hot summers? I know I run a 170 in the Cobra in the summer.

The higher the T-stat, the better the combustion and slightly better fuel economy. The higher the Tstat temp, the better emissions usually is too. Part of the increase in fuel economy is also hotter engine oil is less viscous so you get less pumping losses from the oil pump with hotter oil. The difference between 180° and 192° is probably not as big or as noticeable as the jump between 160° and 180°. If I did drop down to 180° or had to run 160°, I'd probably drop down to a 5w20 weight engine oil to maintain my fuel economy. The actual weight of the oil at running temp would be about the same as 5w30 with the engine in the 190s.

What's the fuel economy difference between 5w20 and 10w30? is it a big enough difference one can tell without special equipment. Will a person get noticeable results?

TBO, I don't know. I do know that 5w20 has been allowed since the late 90s and almost all the new super-high fuel economy vehicles are using it from the factory so they can claim high MPGs even though the 1st JiffyLube the thing gets taken to get 5w30, at least around here, since none of the oil changing places have 5w20 on tap. But it is enough of a difference that mfgs are designing for it. I believe even the 2000 and 2001 Explorer 5.0L were approved by Ford for it. Although since it wasn't popular or didn't exist prior to then, it didn't get mentioned in any of the earlier Explorer manuals.

Yeah I've always wondered. I know my Cobra was rated for 5w20 but SVT techs made it known that the motor should really get 10w30 and that the 5w20 was for fuel economy ratings. I always wondered just how much does it really affect mpg.

I thought I had posted this chart before that shows wear vs temp. After looking at it again, just more reason to run a block heater in the Winter. When I left Roush with the new motor the guy stressed to always run 5W-50 becasue of the tolerances and possibly the increased heat from the blower. The weight of the oil is not 50 weight all the time, just changes with the temp, right? Always a confusing topic.
Dave

The 1st number is the weight of the oil at freezing (32°F).
The other is the weight at boiling (212°F).

So yeah the weight changes with temp. However this does NOT mean the oil gets thicker when it gets hotter. It just means that it emulates the viscosity of a different straight-weight oil. But all the grades of oil change in viscosity by a steep curve. The only oil that I know of that is anywhere near a flat change in actual viscosity is 5w50, but even it is getting thinner as the temp goes up...it's just getting thinner a lot slower than a 5w30 or 5w20 would.

Well, I got Dyno2003 installed and I got to play around with some of the settings. Very interesting findings with just a few minutes of messing with it.

For starters, I entered all that info I talked about earlier that represented the Explorer 302 in stock form. Here is what it looked like in table form: All-n-all, those are believable numbers...perhaps a little high, but definitely in the ballpark which gives me some confidence that the numbers have some credibility, not just for comparison purposes, but for expectations on the 331.

Here's my 331 modeled:
Keep in mind the GT40p flow values are still stock values and don't represent the porting, 3-angle valve job, and valve back-cutting that was done. But I have to admit, I was a little disappointed that this doesn't have me in at least the 300s for HP. But I'm more focused on the low end torque, not the HP and I am close to 300 in the sims. So I'm not upset. Just compare those torque numbers to the stock Explorer run and you'll see it is quite an increase in performance.

With a little tinkering around, I was able to discover that this configuration would benefit heavily by having the cam retarded -3°. There's an added benefit that retarding the cam will lower my DCR down to 8.25 which puts me well within the "safe" range for pump gas. Check it out: With very minor sacrifice of torque on the low end, this 1 change got me above 300hp simulated.

I'm just impressed that in about 10 minutes of tinkering, it's already convinced me to retard the cam.

Next I'm going to play around the head CC and quench distance and see what else I can do to optimize the setup.

Pretty nice app. I should tinker with it sometime. Even if you don't hit 300hp the torque is way up there and is what you're after so it looks like you should be happy. It actually looks like quite the torque monster.