Just bought a new Unl "X". Knowing this thing is underpowered from the get go. I proceeded to do a few things to help. I know that there is not any one thing that is going to do the trick (besides Hemi swap). I wanted to do this in steps/stages to assess each component

1 Added a K&N intake to improve airflow- did not see much change. I did get a cool whistle out of it when i step on it

2 Installed throttle body spacer last night and can see significant difference. Best $90 bucks I have spent so far!!

3 Also installed a MBRP exhaust right after spacer. install took a couple hours. I can see slight change. was expecting a little more throaty sound out of this and was disappointed. I would not advise the MBRP if anyone is looking for a distinctive difference in sound. I did the research anfd listened to sound clips on You Tube. My expereince has been that pipes sound nothing like the clip

4 I also picked up a Superchip and will be doing this install later today. I am a believer in tuners.

I have been on vacation and found time and $ to tinker and research. I have to wander if all the emissions crap is restricting the engine further? More to come..................

 

You'll notice the biggest difference from the Flashpaq. Especially with the CAI and exhaust already added.

Make sure you update it before installing it.

 

OH GOD...!!! Don't say that, they'll run you outta town...!!!.....lol

 

Yep, and they would be mostly correct on a port injected vehicle outside of higher manifold pressure at idle and the blade on the throttle body closed a little more. Step on the gas and that advantage is all gone as it doesn't lead to any better fuel atomization as in a throttle body injected vehicle.

 

Yep, very true. The stock PCM doesn't necessarily take well to intake and exhaust upgrades. What it's looking for and what it's trying to correct for are the stock components values that fit in it's nice little box. That in part is why I abandoned my prior programmer as it was built around stock components. So there are basically power targets if you will and the change of other components will work better with the flashpaq than they did with the stock PCM.

 

wow take us some dyna runs and post up the results how much does that cost u can pm if u want

 

Ok, twin turbo JK that would be nice to see.

 

You are right about the upgrade changes, The PCM does not take change too well, I went back to my stock air filter from a drop in K&n filter, I don't noticed much difference, actually I still don't know witch is better. As far as the flashpaq and a CAI does this make the engine run leaner? I'm trying to avoid this problem but its hard to do on these 3.8's

 

Planman, that's a great post on the subject. I too feel that I have all the power I need out of the 3.8 and the bigger trick is transferring it to the ground. Would I like more, sure but I'm totally unwilling to drop 5 bones or more on it.

One thing I have played around with is various rpms at highway speeds as I am currently under geared and my conclusions were that it isn't rpms that are the big killer in efficiency, but rather rotational weight and aerodynamic factors of a barn on wheels. So while you're seeing over a 30% drop off in mpg from 60mph to 75mph it's much more attributable to spinning the additional weight and getting the barn to move through the air.

My little tests included same speed in 5th and 6th, about a 20% difference in rpm, at the same highway speeds. The difference in mpg is very nominal and far less than the 20% additional rpm the engine is getting twisted at. Bounce up 20% additional speed and that's where the efficiency really drops and again less than 10% differences in mpg in 5th or 6th maintaining the same speed.

Those tests are indeed what convinced me when it's time to do the gears (have been holding out for 37s) that indeed "don't fear the gear" is an appropriate slogan. Also, for those concerned about mpg and having that play a factor in their gear selection, the best way to get better mileage is to slow down and don't think that going easy on the gears is going to buy you much of anything.

 

What would 5.38's due to your economy though? That's pretty low gearing.