2.7 dyno charts

Tires/wheels make a difference, more weight lower rear wheel HP.

 

Yes... good point, worthy.

There would be some parasitic loss with heavier wheels because of their inertial weight. I'm running relatively lightweight low rolling resistance passenger car tires on alloy wheels. They're rated to carry maximum weight at 51psi and I run them at 40psi. That would also account for a small portion of the gains.

 

Thanks for the great intake pics,

Depending on what happens and if I keep my 2012 RC 4x4 MT, I really want a slightly louder muffler and that header,

Probably going to do a drop in high flow filter though, money will decide, Lol...

As it always does!

 

That's an unknown because there are a combination of small mods. There is likely a small multiplication factor in the intake and header working together since they're both directly related to the operation of the engine.

I'll guess... but bear in mind that this only conjecture of what I think are reasonably proportioned numbers. The truth is likely pretty close:

Intake +6hp
Header +14hp
No AC/PS +3hp
Light tires/wheels +3hp

 

I tell you... the sound from that really long Injen intake tube on acceleration is BETTER than any loud exhaust. It's fucking unreal!



...and it's way cheaper than the other intakes.

 

Subd.

 

For what its worth, I put on some all terrain tires that are 14lb heavier per tire (duratrac 235/85r16 E rating) than the stock after I had regeared to 4.56. I also did the DT header after a few weeks. I could tell the heavier tires, in part, cancelled out the gains from the gears and header. This is why I didn't go up to a 33" for now, that would be about 26lb heavier than stock tire.

 

That's good info thanks,
If I don't trade I'll be getting tired about winter time, and am looking at the Duratracks C rated, not 10, but I want the slightly larger size. I'll bet I notice a difference,

 

I forgot to add my stock size is the 245 not the 265, that makes the bigger differences.

 

I've hardly put any miles on the truck since the dyno runs, but today my wife and I took a day trip up into the canyons which included a mix of city traffic, 70mph freeway, and winding mountain roads. Filled up on the way back. 26.5 is the best mileage the truck has gotten, and that beat the previous best by 2mpg. I'm really pleased how this combination of mods have worked together not only to improve efficiency, but drivability as well.

The little 2.7 is running like a clock.

 

Sounds like a good day of riding around, and good mileage results. Another question: You didn't happen to weigh one of your original steel wheels with the factory tire, and then weigh one of your new 16" wheels with tire, did you? Just curious to see how much, if any, unsprung weight you eliminated.

 

I can also add that my truck is used as a daily driver utility work truck and is always fully loaded with about 600 to 800 pounds of tools and materials. That makes the 26.5mpg even better. Because I work locally in my community, I only average about 100 miles a week which is almost all start/stop short hop driving. This is one reason why the mileage went up immediately upon taking a longer drive.

Sorry, I didn't think to weigh the tires because at the time the new ones were installed, the tire shop bought the old ones for $88. I only know the difference in size:

245/75/16 truck tread

235/60/16 passenger car tread

However I did weigh the rims and the difference was 6 pounds 4 ounces per wheel for a total reduction of 25 pounds of rotating weight.

I can say this... the truck handles nicely with high end Yokohama K580 passenger car tires on it. They're low rolling resistance and excellent handling properties made it feasible to remove the power steering.

I did some sampling of tire weights at tirerack.com and came up with an average weight difference of about 9 pounds between those two sizes.

This yields the total (25lbs + 36lbs) rim and tire weight reduction to about 61 pounds of rotating weight... and that's considerable.

There's an old car rule that one pound of rotating weight is worth 10 pounds of static weight, so that is the equivalent of removing about 600 pounds of weight from the truck. But all of that advantage and more is canceled out because the truck is always driven fully loaded. Still, I'm happy with the mileage I'm getting even loaded down, and am looking to improve it with future mods.

 

Thanks. I guess the total savings would be a little less than that going from the factory 215-70-15 wheels and tires to what you have now. I like the looks of the wheel/tire combo you selected.

 

Are you calculating your mpg using an 11% adjustment for the smaller tires?

Of the mods you've done so far my guess is the passenger tires are making the most difference in improved mpg.

 

The diameter of the 235/60/16 tires I'm running now is less than 1% different than the 215/70/15 stock tires that the truck came with from the factory. I checked a tire diameter chart first so as to get the closest equivalent to stock diameter that was available while still using larger wider 16X7 rims.

You might consider an LCE header. I had one on my 1996 gen 1 Taco for a decade, and it ran great.

 

Yes, I don't think it would be worth the cost except for the cool factor of going to wider 16X7 alloy rims and wider 235/60/16 tires which are the same diameter as the stock tires that you're running now. That particular tire and rim combination preserves the accuracy of the speedometer and odometer.

 

Gotcha, I thought the 245s were stock.

I'll pass on the headers. $450+ is hard to pay back.

 

The big tires came with the 2012 5 lug which was used with 10,000 miles on it. I would have never picked them as I never go off road and was happy to get some money for them from the tire shop when they installed the new ones.

 

I believe it wont hurt to ask.... will it be possible to get almost or the same power as a 3.4 v6 if more bolt ons were added to the 2.7? The only thing i know from the 3.4 is that it has 190hp/220ft. lbs torque, but how much will it put to the wheels on a dyno test is another story, i dont know how much, but with only the header and intake, no ac no ps in my opinion thats is considerable gain in the 2.7...so, will it be possible?

 

That's a very interesting question...
The old rule is that there's no substitute for displacement.

However, from the difference between the rated 159hp/180ftlbs and the 119hp/133ftlbs bone stock dyno chart...

...the total combined parasitic losses from the drivetrain and belt driven accessories is around 40hp/47ftlbs.

If you extrapolate the same losses to the 3.4's specifications you would end up with:

3.4:

150hp/173ftlbs

My 2.7:

145hp/158ftlbs

Difference 5hp/15ftlbs

Notice how the torque difference is much greater than the horsepower difference?

That's displacement.