Whats the ideal engine temp for a slightly modified 302?

[HISSIN50]

Stangbear, good points. that was what i was getting at too. i dont have a lot of money to dump into any one car, so i go for bang for the buck, for repairs as well as mods. of course, we would all love fresh blocks, cooling system components, etc, but we make stuff we have work (some of us have more money to make that happen than others. you should have seen the things i did in college to keep cars running. LOL). were it more feasable to have the items you mention, you bet i would do just as you prescribe. just not possible for all of us. BTW, we're very cool. ive learned a lot from you.

i just try to keep things running decently, erroring on the side of caution. which brings me into a comment on RX 7 Speed. in reading your response here and to another cooling thread, you know more than i do about the temp stuff. realistically i, and some others here, are trying to keep the stangs healthy and on the road. for me, this means running as cool as reasonably possible, so if there is some error or the stang decides to run funky, i have some fudge factor.

i am curious about your comments. i think i know a decent amount, but not 1/10 of much as some in here. i am in camaro forums (g/f' car) a bit, and a lot of people run 160* stats and get fan switches accordingly (i.e., on at 180, off at 170. stock is 180 stat, and fan on at ~220. thats not a typo).
if heat is better, why do they do this? Lingenfelter is one supplier, and i think his R&D is right up there with the best.
i would think that running cooler would allow one to ward off detonation and dial in more timing, thus creating more power.

(im not trying to be a pain. i just dont understand this very well, i guess). im just in here to try to help where i can and learn where i dont know. any thoughts on all of this? i know there have been widely debated threads on this subject before. seemed like everyone agreed to disagree.

 

[stangbear427]

As Michael Yount once said- "mutual respect community". Which is a good theory, when it works- like we seem to. I know what you're saying. My first fox (a '79) had more duct tape holding things together than I ever would want to admit, we've all been there at some point, and still are to some degree (again, no pun intended). Thanks for the encouragement- sometimes I feel like all I do in here is argue, and that isn't what I'm here for.
I really couldn't tell you what the story is with those F-bodies. New cars seem to run hotter than our 10-20 year old ones were supposed to, and one of my best friends has a '93 TA (LT1 6spd) and it runs at 220*-240*, which Pontiac assured me is perfectly normal. If mine spent enough time up there, I'd be walking home. Now, in the example you used, it could very well be the same reason you run a cooler one- where you live- and those cars run hotter to begin with. As for Lingenfelter, now you're getting into an important destinction that needs to be made. This thread is about the ideal temp on a "slightly modified" 302. Naturally, the same wouldn't apply to a 600HP 393 stroker. Lingenfelter doesn't put out cars that I would consider to be remotely stock, and a different set of rules apply. The fact that he carries them doesn't necessarily imply that he encourages their use on stock GM 350's, any more then we can infer from Steve Saleen advertising his new twin screw for 4.6's that we should be able to bolt one onto our stock '96 GT and proceed to pound it and not have it grenade its guts. So, I think your assumption about why one would want to run cooler is correct- but it is a case sensitive situation. Not quite as cut and dry as the old "more air+more fuel+more spark=more power". Just like AC- when you get into highly modified or high HP applications, all bets are off for conventional wisdom and it's up to the specialists to determine what is best for each engine, which is why things like the Tweecer are getting so popular. Someone who knows what they are doing can remap the cars whole reasoning process, because stock settings aren't good anymore. I better stop before I confuse myself. Hope it helped

 

[HISSIN50]

Stangbear, thanks for the reply. i agree with you in the principles.
as for the f-bods, i was actually goin for RX-Speed to reply. he keeps tossing that out and i dont get it. i know that cars today, including the f-bods, run hot for emissions, or the lack thereof. as did the VR6 VW motors (VW flat out said it was for that and that, ahem, some would greatly benefit from coolin them down via the aftermarket).

as for Lingenfelter and the fan switch, there are many companies that sell that product. i see your point now; i didnt phrase that too well and it was a poor example. your analogy with his products and Saleen' stuff is right on. my bad. with the coolin fan switches, he and many others sell them for the V6 motors as well. dont think he mods those too much. and i would bet your friend may well run one of these or a manual switch (latter is very very common, as you know). same for the 160 stat (very common). my understanding is that the puter uses the HEGO (lambda) sensors for mapping, unlike our 302's (ECT, etc).
these are not things im interested in as a matter of following. as mentioned, i want tractability. to me, that means cooler temps, especially since its so darn hot here. i was just really curious why high temps are desired. seems to me that people would idle their motors for 1/2 hour before staging if that was the best. see where im comin from? just curious (esp from the Wankle man, as he repeatedly says this).
i have seen it argued many ways, and never heard a final verdict. im always open to new/more reasoning pro one way or the other. just a knowledge thing. im not gonna decide to run 'em hotter any time soon. i always enjoy threads like this, as these types often have a ton of info to be learned. and when someone, like RX, says something, i like to present an argument (like the idleing for half an hour before staging. i sure as heck would not do it) and see what they say about it. im always the skeptic.

now i gotta go check on the thread where the guy says he runs friction modifier in his T5 (i think i know why he does it, but wanna see what others thought). LOL. good stuff, S.B.

 

[rx7speed]

part of the reason a f-body goes with the cooler therm is one problem with running the motor warmer is it does tend to heat up the motor bay
so when you are just sitting there at a light your bay is getting all nice and toasty which the filter will just draw in all that nice hot air
another thing is heat soak into the intake manifold

but some newer cars are overcomming that with using a composite (sp?) intake that doesn't soak up much heat as well as moving the filters further from the motor or shielding them from the heat

this way that can run the motor a lot hotter



also when you speak of boosted motors things are alittle different there as well

a lot of times ppl run extra safe on a boosted motor because the damage from failure could be a lot greater
like lets say for instance a motor running 9:1 compression is pulling in 120% of it's volume in air/fuel it's REAL compression ratio is along the lines of 10.8:1
and this is feasable on a boosted motor

while a 11:1 compression motor that is N/A motor which prolly will pull around 85% of it's displacement of a/f in would only have a real (aka dynamic) compression of 9.35

so on two motors with the same displacement on top of just having a higher pressure level from just compression alone on the boosted motor there is more air/fuel being drawn in which in itself cna build pressure and if brought out of hand can cause detonation which could become deadly for the motor

so boosted guys tend to take it safe by running the motor cooler as well as retarding the timing just a tad and running a little rich which also helps cool the intake charge and cause a cooler burn in the cyl

all of these reduce the chance of detonation which on a N/A motor is bad but boosted it is a lot worse


there are always some if's and so forth though
like depending on your pistons be them cast, forged, hyperuteric or whatever they are called can figure out how tolerant the motor is of heat
the last option are very resistant to expansion from heat while cast can be bad at that
or is running a hotter motor going to heat the engine bay up or the intake manifold
all kinds of things can throw a variable in there

that is why I say generally




a few other reason a f-body or some other cars might put the lower temp therm in there is with the computer
computers in stock form work great for a stock car but once you start adding mods the airflow is a little different then what the computer says it is
REALLY noticable on a manifold air pressure car
these things thing ok at such rpm and such load and such a temp motor it is getting this much air
add a cam or change the heads you just made a bid difference on air flow and it doesn't really know how much anymore and tends to at times run a little lean possibly
by putting that cooler therm in there it has a chance of running a little richer to help out but still at that point tuning would be a better option

now on a mass air flow sensor car it isn't as bad being that they can really read how much air is going into the car though still some variation can take place from your mods
but still the heat soak and such apply to these as well on the intake manifoold

so if you could move your filter away from the motor and shield the intake tract you would be set





another advantage of running a hotter motor is scavenging pumping losses and blowdown

when the motor is running warmer yeah you retain more heat which builds more pressure but since you are building more pressure in there when the xhuast valve opens up the exhuast is much hotter so when it leaves the port it will be moving at a greater velocity and be less prone ot heat loss from the exhusat system
when that exhuast pulse is moving faster it is able to creat a stronger low pressure zone behind it which will help pull the next exhuast pulse out further helping pull in more air/fuel mixture

all of these help reduce the pumping loss of getting that nasty exhuast out of the motor


as far as wear on the motor I honestly don't know for sure
I can only take guesses

 

[rx7speed]

hehe just read my post and I think it is time to go to sleep
hissin I think your name is I will check this later man but right now sleep really calls my name as I have been up for quite some time now


but yeah reason you don't run the motor for 30 min is heat soak in the motor bay tand the intake


it's kind of one of those do this and you are hurt
do that and you are hurt

in an ideal world our motors would be able to run at 1500* while our intake and motor bay might be at -1000*

so guess it comes down to how well can you shield the intake from heat and which way in the long run builds more power

run too hot your intake gets warm
run too cold and your combustion proces isn't the greatest and you can get a incomplete burn

 

[stangbear427]

...i was just really curious why high temps are desired. seems to me that people would idle their motors for 1/2 hour before staging if that was the best. see where im comin from? just curious (esp from the Wankle man, as he repeatedly says this).
i have seen it argued many ways, and never heard a final verdict. im always open to new/more reasoning pro one way or the other...

OK, I'm just going to pick one thing out and reply here. I think RX has this pretty much covered, although I agree with him about it being past his bed time. That was a little tough to follow. Regardless, he made the points. From my side of the fence, there are a few things that may simplify my perspective on this too. When you start your engine on a cold day (do you have those?) you may notice on an aftermarket oil pressure gauge that you have about 20psi less pressure when it's all warmed up. In the high stress environment that racing places on the engine, that extra pressure is good to have. It's there because the oil is thicker when it's cold, making the engine tighter, among other reasons. Also, the heat soak that RX mentioned is the big fear with drag racers driving any brand car- hence icing the intakes, heat taping the headers, etc. A stone cold engine will not run efficiently, or very safely, and it wreaks havoc on the internals over time, but it will run hard. This is why you'll see dedicated dragsters that don't even run a fan at all- the engine is never allowed to warm up. This begs the statement that you would never want to, or be able to, drive this car to work everyday. Which is why for the purpose of this thread, we want ice cold fuel, ice cold air, and a fully warmed up engine in our daily drivers here in fantasy land. At the track, another world entirely with different priorities and demands, The benefits of a cold engine outweight the disadvantages- but you wouldn't want to drive it that way everyday. Although some people do- better them then me. My gas milage is bad enough as it is...