Re:tacoma to tundra?
[quote author=CC_Turtles link=board=20;threadid=1996;start=msg14041#msg1404 1 date=1086408085]
Hi All,
I have been debating upgrading from tacoma to tundra... but i really don't want to spend the money right now and the gas mileage for the tacoma is pretty good..
my tacoma is a v6, 190 Hp, 3.4L, 220lb torque and we pull a 2720sl. my truck pulls great on flat roads - but when we get to any mountains - like Mammoth, Ca. i have to shift into 2nd gear to stay at 40-4mph. i have read the past info on torque (per ray the torque should be a min of 300) and hp but am still confused :P
does driving in 2nd gear for that short time hurt my truck? if it is fine driving in 2nd gear - i can handle the slower speeds - most of the roads are flat in southern california...however, i don't want to cause a premature death! i am planning on adding a tranmission cooler within the month.... also i could add a supercharger - could that add torque?
thanks for any infomation!!
Teresa
[/quote]
Teresa...
The main concern about driving in 2nd gear is the transmission generates a lot of heat...mainly because the torque converter is unlocked and experiencing a fair amount of slippage. That slippage is improving your available torque (a good thing) but is generating much heat (a very bad thing). Heat is what really kills and/or tremendously shortens the life of automatic transmissions.
So if I were in your shoes, I would be minimizing 2nd gear operations (or only be doing them with cool (70 degree and lower) temperatures) until you get a sizable, good quality transmission cooler installed. The best kind are the "stacked plate" types...much more effective than the fin and tube types. I'd also spend the money to get one with a thermostated bypass valve so the cooler doesn't overcool the transmission fluid when you're not towing. Expect to spend around $100 or so for a sizable, top quality cooler plus probably another $50 or so to get it properly installed.
As for a supercharger, I'd not recommend one for your V6. The aftermarket superchargers for Toyota engines are made by Toyota Racing Development (TRD) and, IMO, are designed for short (10 to 15 second) bursts of power like a quick pass or an on-ramp acceleration.
Here's why: Because they replace the intake manifold, the TRD superchargers have no place in the plumbing for an intercooler. Intercoolers are very important because the act of compressing the air significantly heats it; an intercooler is like a radiator that reduces the temperature of the compressed air. So, to somewhat reduce the temperature, the TRD superchargers use additional fuel injectors to reduce the plenum temperature by fuel evaporation. Pouring all that extra raw fuel into the engine is horrible for fuel economy and even worse for engine life. The damage is mitigated by the fact that the TRD system only goes into boost mode at fairly high throttle openings...which aren't common in normal driving but are common when towing. Soooo, for short bursts (measured in a few seconds), the damage from the excessive intake heat (e.g. burned valves) and vast amounts of extra fuel is tolerable...but for sustained boost operations measured in minutes (as would be the case when towing up a long hill), the potential for engine damage is very, very high.
Furthermore, the rest of your drivetrain was not engineered to handle the extra power from a supercharged engine on a sustained basis. Again, quick bursts are ok, but long periods of high power operation are very bad news. For instance, if you don't also beef up your transmission with heavy duty clutches and install a modified valve body (to increase clamping pressures and reduce shift duration), you're almost guaranteed to have transmission problems within a few thousand miles of adding a supercharger.
Because of my high altitude mountain towing, I deeply investigated supercharging the V8 in my Tundra. However, after finding out the issues mentioned above, I've completely decided against supercharging my truck.
The Tundra V8 is a wonderful tow vehicle for my 2720SL...even at 11,000 feet on a 7 percent grade (thousands of feet higher and even steeper than the grades on US 395 around Mammoth), I can hold about 60 mph in 2nd gear. But I do have to use 2nd gear on 6% (and steeper) grades when I'm over 6000 feet. Even though I do have a good transmission cooler, I want to reduce the number of downshifts to 2nd. So I'm soon going to be installing exhaust headers and a low restriction muffler that together should increase my torque by about 10 to 15 percent. If the headers/muffler option meet my expectations, I'll post my results and suggest that you might want to go this route for a bit more towing torque on mountain grades.
|
Linear Mode
