I just put new exhaust on my truck and was having a few issues. I was wondering if there were adjustments to the engine that needed to be made in order to get the most out of the new set up.

This is a 22re which is bored out .20 over and has the EB 268 cam. Otherwise the engine is basically stock. The exhaust is the stock manifold and down pipe past the 02 sensor, from there it has a magnaflow hi flow cat and 2.25 inch piping with a performance muffler( this is a kit from LC). I was previously
running the stock setup since rebuilding the engine last november.

The two issues I am facing are a more noticeable stutter/rattle especially when at a stop light or sign. If I shift into neutral the rattle is less (automatic tranny). Could this be a idle issue?? Also, so far gas mileage seems to be slighty worse although I haven't calculated it exactly. I know "winter" gas produces worst mpg but are we using "winter", less ethanol fuel yet?

I know alot of you run 2.25 piping so i was wondering what I can do to get the best performance from it.

Thanks!!! JIM

You really shouldn't need to change anything else. You may want to run a better flowing air filter setup to compliment the better flowing exhaust, but there's really nothing you can do with the computer. The computer uses the O2 readings to determine how much fuel is needed(when not at full throttle) so it should adjust as you drive it. I don't get any rattle with my exhaust so you need to check to see if any heat shielding is loose or if any nuts/bolts are loose. Worst case might be the insides of the converter being loose.

You can try using a higher octane gas and see if that helps, also check your timing.

If the muffler is a high flow as well, this is where your mpg loss is. The problem with a completely open exhaust system with Toy engines is the loss of back pressure. These engines need some back pressure to operate at regular driving rpms, otherwise you tend to be deeper into the throttle than with stock systems. This was the case with my 3.0 after installing an open cat and muffler after with headers. I experienced a 2-3 mpg drop, put on a more restrictive 2 chamber turbo muffler and the lost mpg came back. With the turbo muffler I found I didn't have to give it as much gas taking off from a stop, or when cruising down the highway. I would suggest picking up a Raptor turbo muffler from Kragen's($22-24) and see if this changes the loss in mpg, or change to a smaller pipe from your current muffler back.

i changed from the stock exhaust to a magnaflow highflow cat, 2" to the muffler, then 2.25" out and my gas mileage improved by about 2 mpg. i also got a lot more power. it seemed like i gained low end or midrange power the most( i can be going 35 mph w/ the truck in fourth barely touching the gas and it doesnt show any signs of struggling) which should be the opposite of what should have happened but im happy. my peak hp seems to be from 2,500-3000 rpms, which is about 35 mph in third gear then flooring it. i just need to get a connector pipe made for my lce headers so i can put them on since ive had them for about 8 months lol. its hard working full time and being a full time college student.

sorry if my experience doesn't help you much since i have a carbed motor and a 5 speed but i thought i'd give you a little feedback from my situation.

Actually, the cooler weather the last couple of weeks in the northeast have caused higher start up idle and longer warmups which will account for the loss of gas mileage. I can tell my current tank is off compared to the last one. Also, if you're making more power, you tend to use it more at first. Right now you probably have a heavy foot because it's more fun to drive. I wouldn't change anything until you go through several tanks of gas but see if you can isolate where the rattling comes from.

Thanks for the replies!!
I will hold off any changes for now, I do feel more power so my foot is a little bit heavier.
So far, on the second tank it seems my mileage has improved but I did alot more highway miles this past week , i'm usually doing more stop and go , around the town driving.

I need to contact LCE and see if the muffler is hi flow as well. The description doesn't go into much detail, my fault for not finding out when I bought it.

Once again this forum does not dissappoint, thanks again!!

Jim

Just to give you reference, my last tank of gas was 2 mpg less than I got all summer. The last few weeks have been colder than normal so the morning startup was a much higher rpm and lasts longer which wastes gas.