Calling Stillen SC Owners with upgraded kits

tsui_san

Saw in your sig that you're running 9lb pulley on 91 oct. I'm currently running the kit with the 8lb pulley but want to upgrade. I've been recommended only to run that setup either with 93oct or meth inject to prevent detonation. What's your experience been with the 9lb pulley on 91oct? Any reliability issues or other quirks?

Also interested in an impeller upgrade also...surprised you haven't blown your motor yet.

future370zzz

Haven't come up with any reliability issues yet (knock on wood). I let the car and SC warm up properly before stomping on it. Only quirk is the power and torque levels are bumped up compared to the standard kit.

I prevent detonation with this setup by not stomping on it when's it 90 degrees out. It's a shame that this car doesn't have a knock sensor that can be used to monitor it.

The tune from Rob at z car garage is conservative to prevent detonation, can't stop it. He runs it on the dyno and tunes it aggressively until it starts detonating and pulls back the tune a couple notches. There is always risk with aftermarket setups. I installed a temp probe near the Stillen manifold and saw changes of up to 30 degrees within 5 seconds of boosting/stomping. The temps stabilize within 10-20 seconds of normal driving.

The goal for me is to bump the area under the curve for more usable power for my driving (street driving, stop and go) and to sustain that power level and keep the engine as safe as possible. The impeller upgrade and 9psi bump up the power from the standard kit and the test pipes lower the peak boost (seeing 9.8 psi on the dyno and 10.8 on my boost gauge - thinking that it would be 2 psi more if I threw the stock cats back on - problem is increased heat and potential for detonation). The future air to air intercooler addition and vented hood would delay heat soak and generally lower engine temps (air charge temps).

The blown motors I have heard about seem to be from running at the drag strip or running the motor hard for an extended period of time on high boost (12 to 13 seconds haha and repeated boosted runs).

I don't know what the standards are for a boosted car in terms of how long you can stomp on the car until it blows. Maybe your tuner is expecting you to stomp on it all the time so the practical thing to do with impeller and 9psi kit is to use 93 or meth so you can run hard all the time and at the same time pick up safe power/torque that doesn't make the upgrade a disappointment. For my setup, I feel my power numbers are low but I believe that they are safe and right now safety is higher on my list. I wasn't expecting much from the craptastic 91 octane so I wasn't disappointed by the number. The car feels great though.

Z car did mention that a mix of 93 would be a good safeguard against bad 91 gas and when it gets really hot. 7 gallons of 93 mixed with 91 remaining give me 92 octane. This is my extra safeguard against detonation in addition to

My goal was not to make the most power on crappy 91 octane but with either 100 octane or e85 if I get the itch for more power. I already have enough problems trying to keep the tires from spinning with the current power level (in 1st mostly but the quaife has helped make the most of the power).

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tsui_san

I agree with you on the safety point - that's why I'm still on the 8lb pulley albeit with a custom tune. Another priority for me is CARB legality...I don't want to run around looking for a shady shop who will pass me for $300. I'm way too old to and don't have a lot of time to do that anymore. As such I am running the kit with my stock cats. If I didn't care about CARB I would've just gone TT.

Got my kit installed/tuned at Borelli Motorsports (close to Z Car) by a guy named Aaron (former lead tuner at Stillen). He knows my car is a daily as well and perhaps he was just being overly conservative about needing 93+/methanol injection to go with a 9lb pulley. Not surprisingly Stillen recommended this as well and rebuilding the engine with an impeller upgrade. Wondering if it's safe or even worth it with my setup to try the 9lb pulley and then just detune a bit like you did (more boost but less timing = minimal gains?)

future370zzz

Yeah, California sucks for aftermarket mods. I see where you are coming from with CARB.

Don't know what your numbers are with the 8psi kit but if you're close to 400whp the car will still be fun to drive.

The stock cats will push the psi up which will bring up the engine temps and may cause the engine to blow if you push it too hard with the 9psi pulley and impeller upgrade. It has happen to a few. Just have to be ready to re-build the motor if you go with the power upgrades.

1 psi could pickup maybe 10-20whp/trq. Would need the pulley, install and re-tune. Could cost you $1K. Maybe ask Aaron how much power you could pickup from increasing to 9psi pulley. You will not be running at 9psi every minute you drive. Just have to be diligent about not mashing on it all the time but that can be a challenge.

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tsui_san

Thanks for the feedback, very helpful. I do recall talking to Rob about adding the 9lb pulley and him mentioning only to do that with test pipes (he was probably referring to you haha). My power numbers are much better than stock (382hp/289wtq, previously 276hp/216tq) which is not "great" by this board's standards but it definitely is pretty fun when some punk Mustang/Lexus/M3 starts tailing me on 280/101...they learn quickly that it's pretty hard to keep up. I'd love to increase the power but definitely not at the expense of flexibility (e.g. mashing the pedal whenever I want), safety, and CARB. If there were more race gas available in the Bay Area (only 4 stations in South Bay/East Bay combined) I'd get the pulley in a heartbeat...it's a damn shame with these smog laws.