Heckeng Posted November 1, 2006 Share Posted November 1, 2006 I have noticed some interesting things with how my car runs, and how the engine and transmission go through the initial heat cycle, and I am curious if any of you have had similar occurances, and if anybody actually knows why these things happen! When I first start my car, of course it is cold, it usually isn't the most responsive until the engine gets above 150 deg F or so. Still, even once it's fully up to temp engine coolant-wise (185 deg f) it will run like crap, and bog etc if I get on it. I had recently installed a transmission temp gauge and noticed the other day that once it's needle starts to move >100F or so, the car changes. It starts to run like it should, crisp throttle response, no bog, just runs really well. So, my question is whether cold trans fluid will cause a converter to stall lower since it is thicker, and that could be interacting with my engine and if it's not stalling high enough, that is what causes it to bog. IF this is true, I assume while at the track, I should NOT try to keep everything as cool as possible right? If this is NOT true, somebody put me on the right track! Quote Link to comment Share on other sites More sharing options...
Sam (Bones) Posted November 1, 2006 Share Posted November 1, 2006 I can't say for sure, I don't like to hammer on mine until it's at least close to operating temp just think about starting up cold engine with thick oil, the rear axle lube cold, and the trans starting it up and flooring it, just think about how much horsepower you would loose to just the oils that's why it's called operating temp the engine is tuned to run at its best at a certain temp cooler will lean it out hotter will richen it all the metal parts in the engine, trans, and rear axle are machined to tolorances and the expansion of the heat is also figured in hear too well, that's my take on it anyway Quote Link to comment Share on other sites More sharing options...
502ci Posted November 1, 2006 Share Posted November 1, 2006 Everytime I first get in and start it up the tranny acts like it`s a slug till it warms up (3,000 stall) I`ve yet to install a tranny guage so I`m not exactly sure at what temp. it starts to act normal. It actually freaked me out when I first drove it. As far as the motor, I can tell mine wouldn`t want to be floored until it is at operating temp. (never tried it) but I can say it would fall on it`s face. Once warmed up everything runs perfect, crisp response at all times... Are you saying your car reaches operating temp.(motor) quicker than the tranny will reach 100 degrees? Quote Link to comment Share on other sites More sharing options...
Heckeng Posted November 1, 2006 Author Share Posted November 1, 2006 Let me throw in my disclaimers now, I don't start my car up and floor it all the way to work! I will goose it occasionally though just to see how it acts if it's above say 150 or so. Engine is the first to reach operating temp, and transmission actually takes alot longer, maybe 5-10 minutes longer. So, even if the engine is ~180, it will still run doggy for 5 more minutes or so at least. Quote Link to comment Share on other sites More sharing options...
Sam (Bones) Posted November 2, 2006 Share Posted November 2, 2006 the water temp is 180, but has the intake fully warmed up, it may take a little longer for the complete engine to reach operating temp, are you running a little on the lean side to begin with? if you are, your engine will like it warmer Quote Link to comment Share on other sites More sharing options...
502ci Posted November 2, 2006 Share Posted November 2, 2006 I didn`t know the tranny took that much longer to reach its temp. , that will be on my list this Winter...tranny gauge... I didn`t think you floored it until it was warmed up..I knew what you meant... Quote Link to comment Share on other sites More sharing options...
Sam (Bones) Posted November 2, 2006 Share Posted November 2, 2006 neither did I, I was saying, "IF" anyone did that, how much HP would be lost to thick oils Quote Link to comment Share on other sites More sharing options...
Sam (Bones) Posted November 2, 2006 Share Posted November 2, 2006 wait a minute here, you're an engineer, you toying with us??? Quote Link to comment Share on other sites More sharing options...
Heckeng Posted November 2, 2006 Author Share Posted November 2, 2006 No not toying with anyone , Sam you have a good memory with the occupation thing! The intake should be up to temp, considering that it's aluminum and an excelent heat conductor. I run very close to 12-12.5 a/f ratio under wot, and have verified that with my friends LM1 A/F meter. I am just asking the question because since I'd never had a trans temp gauge before, I never made the connection between how long it takes to get the thing to run "good" and the trans temp. Quote Link to comment Share on other sites More sharing options...
wallaby Posted November 2, 2006 Share Posted November 2, 2006 Your theory makes sense. If you've ever tried to pour gear oil in the winter, you know it acts a lot differently in the summer! I would imagine ATF to get thinner as it warms, but it's pretty thin to begin with so it's hard to tell. Maybe synthetic is more temperature stable? I guess you'd prefer it to be thin when it's cold instead of thick when warm. A ggod point was made about intake temperature. Fuel atomizes poorly when intakes are cold and the problem is worse at slow engine speeds. Fuel tends to stick to the inside surfaces of a cold manifold instead of staying vaporized. As for trans temp, I believe that most of the heat generated in an auto trans is from converter slipage. If your fluid is thick when cold it reduces the slippage and even further slows the warm-up period. Are you running an exterior cooler on your trans, or do you still have the radiator tank style? When the thermostat opens in the morning the hot water will help to warm the trans if you have the radiator type cooler....not such a bad design on a cold day. Quote Link to comment Share on other sites More sharing options...
Heckeng Posted November 2, 2006 Author Share Posted November 2, 2006 Wallaby, good point on the cooling methods. I run a B&M stacked plate trans cooler, but don't have the trans fluid running through anything with the engine coolant any more. That would definitely help in the cold, and may be why some people notice it more than others. Quote Link to comment Share on other sites More sharing options...
502ci Posted November 2, 2006 Share Posted November 2, 2006 This is true, when I think about it I used to have my lines running to the radiator then to a tranny cooler with a fan. I installed a new Be Cool radiator without tranny provisions and had the lines going directly to the tranny cooler and this is about the time I noticed an increase in initial warm up time on the tranny. Quote Link to comment Share on other sites More sharing options...
kc8oye Posted February 18, 2007 Share Posted February 18, 2007 one other thing to keep in mind.. *IF* you have a Qjet... while the choke is on.. the QJET should keep the secondaries LOCKED out.. so they can't function... if that lock isn't working.. it will very definatly bog and stumble when it's cold. it will also be a slug from not having the benfits of the secondaries working... I'm also inclined to believe you have choke problems.. becuase my qjet even with my sickly engine.. and my TH350.. I can start the car with one pump on the pedal and turn the key.. and give it just a minute or so.. then drive away, and it drives JUST fine.. no bogs.. tho if I drive away right away, it will stumble just a bit on the 1-2 shift cuz my trans shifts HARD and fast. cuz my carb is so lean right now.. it actlly drives far better on the choke Quote Link to comment Share on other sites More sharing options...
Heckeng Posted February 18, 2007 Author Share Posted February 18, 2007 That's kind of funny KC8OYE, you have hit upon something simple that everybody else had overlooked My choke is definitely having issues, mainly issues of being MIA! I have no choke at all! I had assumed that the engine temp was high enough that the engine did not need a choke any more, but like Sam said, maybe the entire engine isn't as warm as the point where the water temp was measured from and it actually WOULD like some choke! Carb-wise, it was a 750 mechanical sec Demon Carb, so the secondaries were definitely working, but you don't even have to get into them to feel the bog. I really think it's probably the cold tranny fluid. Maybe this year I'll figure it out! Quote Link to comment Share on other sites More sharing options...
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