Originally Posted by jorban View Post
Thanks man! Yeah, like you said there wasn't anything that unlocked a tons of extra HP. With all of the driving time now I will give you my current thoughts.
Since you are most interested in the higher RPM power I think that the exhaust will be your best friend. This made the biggest difference with my highway cruising. I am now able to accelerate in 5th gear without bogging down instead of having to downshift to 4th to climb even small hills. I also felt that the engine didn't brake as hard when I let off of the gas which does tell me that it is flowing much better. I did do a high flow cat at the same time as the rest of the exhaust so I cannot say how much of a difference it made.
Spectre Cowl Intake:
It is really loud when you start a cold engine. After your jeep warms up there is much less noise. If you do a good clean installation with no sharp edges you will not get any whistling. At WOT the intake growls like a beast! I love that noise. Unless you are at WOT often then this noise won't be an issue at all.
Normally when I start my jeep it seems to have more pep and power when the engine is cold. After it warms us is slightly more sluggish. With this intake that was not really an issue since the air going in was still cold. I only had it on for about 2 days before I got my exhaust so I cannot comment on the power that the intake provides.
63MM Throttle Body:
This was a great idea over all. I think that it tapers down to like 54mm when stock. This is a huge dam when all of the other modifications are designed to increase flow. Your system can only be as good as the most restricting part. That is why I have done all of the little performance mods.
The power from this mod was most noticeable at low speeds and take off, but like I said I eliminated this as the smallest part of my intake.
This is a must do if you want more power and a smoother engine. My engine is just as smooth at start up in 0*F as it is when it is completely warm. When at higher RPMs if you cannot ignite the fuel efficiently then you will be losing a tons of power. The stock injectors are fine, but with the 4 hole injectors my engine didn't want to bog down unless I was really pushing it in too low of a gear. This was one of my favorite upgrades both for the power and the super smooth engine that you get with the better injectors.
A lot of people claimed HP gains be removing the mechanical fan. I do not think that I did. I was not able to tell any noticeable difference. Unless you need the extra cooling power, or the ability to turn them off it is not really necessary. There is a cool factor for having a sweet fan setup though. haha
For higher RPM power I would suggest basically all of the above. It is all about removing the weakest link and when you upgrade one it makes another part the weaker link/limit.
If I had to choose I would do the injectors and the exhaust.
I will be doing a header and down pipe once I get some armor under my rig. So I will be able to comment on the benefit of those as well.