So will i have issues going with the stillen sc kit if i have test pipes? even with the new tunes?

Mark at Stillen told me to leave my cats on the car or I would be down HP. He would be the man to ask if it causes any other problems.


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Thanks Jason.

You will not have issues with the Supercharger if you have test pipes. We have a lot of customers who have decided to use test pipes or been sold on them from their shop. Because of the way the valve overlap works on the VQ37 you lose some of the boost in the cylinders without the back pressure of the cats. Yes, the test pipes flow better, but because you have less boost in your cylinders, you make less power.

Hey Mark, can you show us an example of this power loss? Same car, same day, difference being with/without cats?

My car with the Stillen S/C made a little more power using Test Pipes. Best thing was less heat too!

Lemme guess, more power with less PSI?

Was a big 3Hp! :roflpuke2:

Since when does less boost equal less power!? That's not how it works.

But less boost pressure? (That's safer)

OK, all jokes aside I love this kit for my Auto Z, that's why I went this route. But let's be honest this kit is very prone to heat soak. With Hp swings from 30+hp to 30-hp real quick. That's why the Frozen Boost Intercoller is a must to help keep intake manifold temps in check! Lets take five pulls for example with Cats on and then five with Test Pipes on and you will see more consistent HP with the Test Pipes. I use the 9lb pulley and Test Pipes with my set up and see almost 10PSI. The heat the Cats give me, I gave into the Test Pipes equalling in less heat and more consistent HP even thought I might have gaven up a little PSI. At the end of the Day it's not always PSI that will get you to the finished line, but to keep the heat in check with consisted numbers that will win the race! Again at the end of the Day with less heat, the Test Pipes proved more consistent HP for my driveability. :tiphat:

If the kit is that prone to heat soak I'd look into meth injection. Heat is bad and if your car can't pull enough timing to combat it you may have a detonation problem on your hands.

Thinking too much about boost pressure can sometimes be misleading.

Airflow. :ugh2:

Maybe tuners need to play with cam timing..

I don't have any Dyno Sheets saved from tests. I know there are a couple posted around the forums. Don't get me wrong, you can still make good power with test pipes. However, you will make more with the stock cats provided everything less it tuned properly. Now we haven't tested this with all the different cat-back exhausts out there and it is possible that some exhausts paired with test pipes would do better than the stock cats, but I can't say for sure.

1. Date of install 2011
2. Model year of car 2009
3. Model of car G37 vs 370Z Z
4. Problems at install Yes, no way to get even torque spec on intake bolts; even with 20 bends in the wrench
5. Late problems - including mileage at which they occurred and nature of problem Leaks, Intake casing + pressure making it difficult to get baseline to tune from
6. Stillen's actions relevant to warranty No action, made me sign waver and pay by money order for replacement parts (PITA) took for ever. Didn't want to discuss my build at all, sale new nothing about the kit; i kept getting refereed to a mechanic to identify replacement parts in the kit, didn't call back, i had to call until i got an answer.
7. Upgrades and modifications to the kit - including modifying the UpRev tune COG's, 928 Impeller, 25mm BOV, 650 Injectors, 1/2 gallon water res, CJM fuel Return, Grounding Kit for fuel pump, AN12 fittings larger feed and return lines
8. Max HP achieved - and how - UpRev tune, increased PSI (smaller diameter pulley), etc. 11 PSI, 510hp, then 12 PSI, blew out rings
9. Additional mods - Exhaust, clutch, etc FI Carbon Fiber, ARC Resonated test pipes, 7AT raise line pressure for quicker shifting10. Current miles on kit Sold it, kept leaking under the manifold.
11. Would like to know the max HP any one has achieved with the Stillen Kit 510 to 490 to 430 Sold
12. Most miles anyone has achieved with the kit.

You had to sign a waiver because the kit was modded?