Quick update on what's going on with my Jeep...

Exhaust leak is still not fixed yet. The one confirmed leaking cracked weld, I might just have to pay a local shop to grind it out and re-weld it.

Driveability generally seems nearly perfect when the engine is fully warmed up now. There's been a few specific situations I've run into occasionally that cause the engine to stumble and reduce power around 2200-2500 rpm at freeway speeds while pushing on the throttle a bit to maintain speed up a an incline (like when the freeway passes over another road). This was with the Jeep fully loaded up with the family and a small trailer packed full of camping gear for a week.

I still consistently get some annoying hesitation/stumbling at specific engine speeds for a while after a cold start. I'm hanging on to a small amount of hope that this will improve after I finally get the exhaust leak fixed.


I have two projects I plan to get done before winter:

1) Add an oil catch can to the breather hose side of the PCV system and connect it up to the air filter for a fully closed PCV system. I have the catch can and I have a plan for where/how to mount it. I'm getting a custom bracket/spacer made so I can mount it nicely. After that, I'll be handing it over to a local performance shop to finish the install. The tricky part is the exact details of how to route the hose to the air filter and exactly what fittings to use to connect it to the air filter, etc. The performance shop should have familiarity with what types of fittings are available and have access to suppliers to come up with a solution much more quickly than I could (and possibly cheaper, because I'd probably have to use a trial and error approach, potentially ordering many fittings).

2) Switch to a lighter wastegate spring (which will produce less boost purely based on the spring), but add a boost controller to set the boost level higher than spring pressure alone. This setup will both allow me to get a bit more boost than I have now, and will cause the turbo to spool more quickly because the boost controller will hold the wastegate completely closed until the target boost is reached. With the wastegate alone, the valve starts partially opening about halfway to target boost, slowing down the spool. It will also allow me to turn the boost down to stage 1 levels. This could be useful if I need to let someone drive the Jeep that I don't trust with full power.

You might wonder whether it's safe to just add more boost than I have now. Well, I used to get up to 8.5 psi boost with the Garrett turbo during a 2nd gear full throttle acceleration. Now with the Precision turbo and the same wastegate spring, I only see about 7.5 psi in the same situation. This is most likely due to differences in the turbine side of the turbo (also part of the reason it spools more quickly and at lower rpms; I think I discussed this already earlier in the thread).



Also, Prodigy is now running their Jeep with the Precision turbo and a boost controller setup for 9 psi. Check this out:

https://www.facebook.com/prodigyperf...8717512221883/

They ran a 1/4 mile in 12.76s @ 106.5 mph!

In the comment thread, they say:
9lbs on 93 octane pump gas
Jeep has made 427rwhp and 411rwtq

427rwhp and 411rwtq!!!