MPG Mods

Dan is running slightly smaller 2 1/4" exhaust pipe than the stock metric 2 3/8" diameter pipe. The LCE header has larger diameter runners and so is a lot more free flowing than the stock exhaust manifold...




...but the runners are also 20% longer which lowers the torque peak by 650 rpms on the dyno, for better low rpm pull.

I also used the same 2 1/4" exhaust pipe on mine to compensate for the header and retain the low end power.

Greg

 

Lovely.

 

I do wonder what my experience with that would be but I don't have the money to test drive mufflers just to see what they'll do. Dan, could you post pictures of your exact exhaust setup? Did just changing out the muffler give those boosts?

I thought he said it was larger and less restrictive? As for the torque peak lowering, could you show a dyno or explain the old and new torque peak?

I have never seen you post before, do you know of a setup that would accommodate a v6 in the 1500-2500 range? That's where I spend all my time. Specifically at 60MPH and about 1800 RPMs.

 

The header is larger and less restrictive, and his exhaust system is way shorter than stock.

Sure. I'm the one who did the dyno tests. The 3,800 rpm torque peak for the 2.7 is already known as it is specified by the factory.

The blue line on the dyno chart is with the LCE header. Its torque peak is 158.35 ftlbs @ 3,150 rpms.

URD makes a set of long tube headers for the 4.0 which I believe would produce similar results as with the 2.7








You can see the similar design approach for the two. Both have longer runners than stock manifolds, and both have equal length runners the stock manifolds lack.

Same here. My 2.7 turns 2,000 rpms @60 mph so I don't care about high end horsepower, only low end torque.

Greg

 

It appears that my Besttop Super Top has dropped two mpgs from my truck! I've been getting 15-16 when I was getting 17-18... Bummer!

 

Couple pics below, I'll try to get some better ones this weekend. Just changing the muffler gave me about a 1 MPG increase.


Yes, it's hung with a chain. For now. I'm going to do something more permanent. Eventually. And I'll get it welded properly.

I only said it was less restrictive. As Greg said, I actually went with a slightly smaller diameter pipe. The muffler is less restrictive than stock, that's probably why I gained a little.

And it sounds like this (thanks for the video, Greg!)
http://youtu.be/ii_JX8-Hgxs

 

A lot less restrictive than stock.

Flowmaster claims that the anti reversion features built into their mufflers cause the exhaust gasses to leave the muffler faster than they enter. This dyno chart bears that out.

RED is the stock muffler
BLUE is the Magnaflow muffler
GREEN is the Flowmaster muffler







The Flowmaster muffler flowed good enough over stock to actually lower the torque peak by 100 rpms. Now this might not seem like much... but remember just changing a muffler made that improvement with no other alterations.


Greg

 

28.5 MPG was worst since I changed the muffler. Worst ever was 24 when truck was new.

Remember, though, I'm getting getting good mileage cuz my Tacoma is the smallest/lightest you can get, I've got the smallest engine and a manual transmission, and I spend most of my miles commuting on freeways and highways. On freeways I try to average 65 MPH (and stay below 70). On the highways, the speed limit varies from 45-55 which is great for MPG!

When I got 34.6 MPG, I was trying to stay around 55 MPH on the freeway (not easy to do), shifted at 2K RPM, and coasted as much as possible.

 

55 on the freeway isn't that hard You should do some aero mods. Trucks love them because stock drag is terrible.

 

I've considered doing a type of grille block, but instead of putting panels in front of the grille, behind it. This probably wouldn't work too well on a stock-depth grille, but what about one like this, that is flush?

 

Haha, yeah, easy to go 55, but I'll shut down the freeway in some spots. I try to be nice about it. When I'm on a 6-lane highway, I putt along at 55 MPH in the right lane. If there is a 1 or 2 lane interchange, I'll speed up so I don't make cars pile up behind me. I keep thinking I need a sign on my tailgate, "Sorry, hypermiling".

Check out what this guy is doing for aero mods: http://ecomodder.com/forum/showthread.php/amocat-2005-tacoma-29663.html

 

Yeah. I love aeroheads work and have posted about it on here before. Here is my thread ~ 97 4x4 3.4L V6 DLX Tacoma Project ~. I've been busy lately so I haven't been working on it much.

 

A great way to improve mileage is to buy a cold air intake.

 

Could anybody offer opinion on my previous question?

 

good, better, best

fixed

 

Thats my truck...

 

Are you saying it will decrease drag, but not by as much as a frontal block?

I hope you don't mind! its a good looking truck

 

No worries I find random pictures of my truck all over the internet. I just saw a picture of my truck on the TW main page so I thought Id comment.

 

It serves 2 purposes, which I would say are equally important for mileage. It helps the engine come up to operating temperature much faster (be careful about over blocking) and decreases drag. A block in front of the grill will provide smoother airflow and decrease drag more than if you put it behind the grill yes.

 

Living where I live, over blocking is probably inevitable. Its very hot in Southeast Texas. Is there a way I can find out how much block is too much block? Is there an alternate way of cooling the radiator?