i know this from talking to the guys. the UDP is what will get you the most as far as reduced losses. next being the over drive. the lite crank is good if ur going turbo. the alt and WP idk anything about.

How do i remove the battery? i thought it was bad to ever disconnect the postive side.. don't ask why. i swear i heard that at least twice through my life.

 

You can disconnect the positive terminal. No adverse effects.

 

Pyro, this just my opinion but I think NST02020 represents the best bang for the buck. I've had this pulley installed for over a year now and haven't had any issues due to the underdrive. You'll need the belt too (K060750).



DJ, there is no harm in disconnecting the positive battery connection and removing the battery. Just remove the negative side first to be safe.

 

thanks scion. how hard would you rate that UDP install? any special tools needed?

 

It's not too hard but you need an impact wrench. I bought an electric one but you could also rent or borrow one. Just jack the front, remove the PS front wheel, remove a plastic panel and you have good access to it. Getting the belt on without a helper is the hardest part.

 

I tune Subarus. I always refer to SRI as HAI to my customers. The Intake Air temps as measured by the MAF are always near ambient with a CAI as opposed to the SRI which are anywhere between 120-145 in th esummer. Anything over 122 and the Subaru ECU will start to pull timing to avoid detonation. Im sure the Scions does the same.

 

I could check some data logs but I'm sure the Scion ECU starts pulling timing in that IAT range. I'm trying everything I can think of to lower my IATs. TB coolant bypass, intake pipe insulation, turbo blanket, cowl venting... I wish I could re-locate my filter to it's CAI placement but my SMIC is there and there's no space left. At least I get enough air flow from the bumper vent to keep IAT low when moving. The IATs still get pretty high in stop n' go traffic or during extended idling.

 

Not much you can do if the filter element is in the engine compartment. As for an extreme measure, I guess you could make your CAI a 3 piece unit by cutting before and after the MAF housing to isolate it from any heatsoak the rest of the unit is passing along. Just be sure any cuts are 8-10" before and after the MAF to reduce turbulence.

 

When I had my new intake made it was supposed to be a 2 piece for just that reason. Before I knew it my fabrcation guy had welded it up as a 1 piece and I just let it go. Oh well, my IAT is very good as long as I'm moving faster than 25mph. The dyno guy suggested removing the mesh grills from the bumper vents and I may try that to get more air to the IC and intake.

 

@ScionFred: Cool deal. Based on the price point of this underdrive and the expected gains (projected at around 7-10whp), I think I'll invest in it. THanks bud you're always helping me out. You, elwaylite, and CIONIDE. lol Oh and FroZone, too.

@FroZone: I searched ScionLife and read through a DIY thread about installing this, and it didn't look too bad. From what I remember, you jack it up, take off the passenger wheel, and then remove the wheel well liner so you can access the underdrive.

EDIT:
Just did a bit of research on ScionLife. The wheel horsepower gains need to be adjusted down to 3-4whp. The underdrive pulley from Non-Stop Tuning is lightweight, ergo, frees up HP. It doesn't actually add any, so we're looking at a minimal gain. But for the price point, it's worth it in my opinion.

 

You're welcome, bud. I bought my XB in '07 and have had many of the same questions you have and received a lot of help from others along the way. I'm just paying it back.

You're essentially correct about underdrive lightweight pulleys but keep in mind that although you're not adding HP at the crank, you're adding it at the wheels and it can be measured by a chassis dyno or timed acceleration runs. Non-UD lite pulleys don't neccesarily free up any hp but let the engine rev a bit faster.

 

BorlaHey, have you had any noticible drone or is it anything even worrying about?