Toyota Tundra Forums banner
1 - 13 of 13 Posts

·
Registered
Joined
·
179 Posts
Discussion Starter · #1 ·
I hope one of the experts in this forum can answer this question.

Lets say I get pissed off because my 4.6 liter doesnt get any better mpg than the 5.7 liter.....

I know that the lexus version makes 380 hp from the same basic set up. Is it possible to add a couple of tweaks to the tundra 4.6 to bump it up close to the lexus 4.6 output?

Is this possible.. what are the main differences between the 2 eingines that make a 70 hp difference.
 

·
Premium Member
Joined
·
164 Posts
The biggest difference is direct injection, which means different heads. Anything is possible with enough money invested.
 

·
Registered
Joined
·
315 Posts
You can bet the bank cams and injection/timing are different.

~JH
 

·
Registered
Joined
·
179 Posts
Discussion Starter · #6 ·
You can bet the bank cams and injection/timing are different.

~JH
Yep.. I'll bet that the lexus engine makes that HP at a high rpm also.. not very conducive to a truck application I guess. I'm just gettin a little frustrated that I cant do any better than 15 /19 no matter how much I baby it. I 'm trying to reserve judgement until after break in period...
 

·
Registered
Joined
·
820 Posts
You could try Unichip. I was looking at getting the smaller V8 back in 08, but the 5.7 got better MPG by 1. So, I opted to get the 5.7 and would do it again love the power.
 

·
Registered
Joined
·
1,251 Posts
Then again there is no substitute for displacement and when mileage is close to the same.

I drove the 4.7 and then the 5.7 back in 07, I bought the .7 with a 5 in front of it.
 

·
Registered
Joined
·
179 Posts
Discussion Starter · #10 ·
I rode in a 4.7 Tundra and the 4.6 has got a good bit more pep to it. I'm not complaining about the power of the 4.6 its plenty powerful to motivate the truck. I really dont mind the mpg too much either( it gets better mpg than my bone stock 2002 5.3 liter Z71..sold in 2006). What I dont like is not being able to obtain the rated mpg while maintaining conservative driving habits.

EG=I have a TDI jetta advertised 41 mpg highway (traded in for Tundra).. I got 45 mpg with no problem.

EG= I have a yaris sedan advertised 36 mpg highway.. I get 39 mpg no problem.

Now I know that a truck is a different beast altogether and I didnt buy it for its fuel efficiency. The thing that irks me is that its not getting the advertised mpg.. thats all.. other than that this truck is f%$&ing awesome, purrs like a kitten and looks great and does not lack in the gut department. I talked to a few people around town that have the 5.7 ( they all have aftermarket tires..rims and such) they tell me they get at best 12/15 mpg and thats to be expected from that beast of an engine. I guess whats gettin my thong riding high is the misleading mpg rating. Like I said before though .. I will wait for the first oil change for a good mpg forecast. I have no desire to own the 5.7 liter. I test drove it extensively did my research and the 4.6 was a better fit for me( I'm not a truck racer). I just want the truth no smoke when I'm buying things, there wasnt alot of data out there for real world mpg ratings for the 4.6.. so I had to go on faith.
 

·
Registered
Joined
·
1,403 Posts
Usually, but not always, I have found that the MPG's on Toyota's improve slightly after several thousand miles.
You might pick up another MPG later. Most modern engines are built with really tight tolerances these days, and take
a while to loosen up. Like I said, this is possible, but is not always the case. Just enjoy you new truck for what
it is. It will never be a Corolla or Prius.
 

·
Registered
Joined
·
918 Posts
These trucks are capable of astonishing mpg for such large and powerful vehicles. It's easier to get rated on sedans because there is not as many factors fighting you. With a truck you have to deal with aerodynamic drag, driveline drag, curb weight. It is still possible to see rated mpg but because of these factors you'll have to drive more conservatively than you would in a passenger car.

I don't know how your friends with the 5.7 drive or what type of mileage exactly you're getting but I have seen about a 3 mpg spread purely based on driving style. 18.7 with the cruise at 60-63 mph. 17.6 at 70-75 mpg. 15.7 at over 80 mph. I sincerely believe 19 highway would be doable if I had the patience for 55 mph and no heavy throttle. This was mainly highway of course, I've seen between low 13s and high 14s in purely city driving depending on how hard I push it. You said you normally do 70 mph on the highway. Drop it by 15 and get back to me.

My personal favorite self-coined saying: Not much utility in choosing the base motor over the optional one in a 6000 pound 4x4 in hopes if a meaningful mpg advantage. I liken it to choosing lights over regular cigs to do less lung damage.

Oh and signcutter Im curious about the significance of your screen name.
 

·
Registered
Joined
·
179 Posts
Discussion Starter · #13 ·
These trucks are capable of astonishing mpg for such large and powerful vehicles. It's easier to get rated on sedans because there is not as many factors fighting you. With a truck you have to deal with aerodynamic drag, driveline drag, curb weight. It is still possible to see rated mpg but because of these factors you'll have to drive more conservatively than you would in a passenger car.

I don't know how your friends with the 5.7 drive or what type of mileage exactly you're getting but I have seen about a 3 mpg spread purely based on driving style. 18.7 with the cruise at 60-63 mph. 17.6 at 70-75 mpg. 15.7 at over 80 mph. I sincerely believe 19 highway would be doable if I had the patience for 55 mph and no heavy throttle. This was mainly highway of course, I've seen between low 13s and high 14s in purely city driving depending on how hard I push it. You said you normally do 70 mph on the highway. Drop it by 15 and get back to me.

My personal favorite self-coined saying: Not much utility in choosing the base motor over the optional one in a 6000 pound 4x4 in hopes if a meaningful mpg advantage. I liken it to choosing lights over regular cigs to do less lung damage.

Oh and signcutter Im curious about the significance of your screen name.
I agree with your thoughts on a base motor over an optional more powerful one on a fullsize 4x4. I was leaning heavily toward the 5.7 liter when I was initially investigating the Tundra. Once I test drove both the engines several times and priced out the option, I went with the 4.6 because of the price difference and the quiet smooth operation of the engine. The 5.7 certainly offered faster acceleration.. (but a truck that pulls 13s in the quarter mile..15s will do just fine lol) and a greater towing capacity but those are two things I would never utilize in this truck. So in the end a couple of mpg better and a few thousand less at purchase pushed it over the edge for me.

(Plus if I got the 5.7 liter .. there is no way in hell I could have stopped myself from putting a SC in it.)

As far as the screen name goes. It refers to tracking quarry, its one of the requirements of my dayjob. +45 -46 usually
 
1 - 13 of 13 Posts
Top