Nissan 370Z Forum - View Single Post - STILLEN 370Z Supercharger System

Phimosis · 09-05-2010, 02:13 AM

I've put over 200 miles on the new tune and have a pretty good feel for what the car is all about now, so I'll summarize:

The car runs perfectly. let me say it again. THE CAR RUNS PERFECTLY!

It starts like stock, whether hot or cold. It idles smooth. It doesn't smell rich when you get on the throttle at low rpms (like it did previously). It doesn't bog at throttle tip in (like it did with the last tune). The gains come earlier (mostly because of the 9 psi pulley). By 3,000 rpm it pulls noticeably harder than stock. It makes 300+ lb/feet of torque from 4,200 rpm up. It makes a really sexy turbine sound from idle to about 2,500 rpm that turns heads in parking lots.

Because I did the clutch/flywheel at the same time, the synchro rev match downshifts are awe inspiring. The rev match is blindingly fast and accompanied by the sound of the turbine spooling up and the boost augmented bark of the exhaust. I was rolling down Rodeo drive this morning where poseur types take their exotic cars out for their saturday morning drive to troll for model/actress types. I did the usual 3-2 downshift as i'm rolling by Louis Vuitton and the number of heads that turned to see what kind of car it was, was too many to count. Maybe 10? Brought a smile to my face. Ok, I'm a poseur too. So what?

If you analyze my dyno graphs, you may be surprised that I'm raving about this new tune, when I have to run a race gas mix and I went from the 8 lb pulley to the 9l b pulley and it didn't make any more power (421.96 hp vs 422.4 hp). The reason I am happy is because of the gains in the mid-range. On the old tune, it didn't make decent power until 5,000 rpm, then the power came on explosively. The dyno chart doesn't reflect that, but it was very noticeable while driving. In a few race situations, its seemed like minutes, not seconds waiting for boost to build. You can't get full throttle at 5,000 rpm to the ground exiting the corner in second gear, so you exit in third gear at 3,800 rpm, then a corvette starts passing you..... and you're going crap.....come on, get to 5,000 rpm....come on! It was frustrating to say the least.

So the million dollar question, is why isn't the peak power higher? Well, kyle was nice enough to introduce me to their lead engineer and he went over the tuning with me. Basically, they are pulling timing from the top end to prevent detonation since its running at 9 psi of boost rather than 8. Retarding timing kills hp, but saves pistons.

To be honest, I don't mind that this tune doesn't make more peak power. At 7,000 rpm under full throttle, the game is on. It doesnt need any more "on" unless its accompanied by similar gains in the mid range. If you loook at the slope of the line from the 8 lb pulley, it was linear, all the way to 7,100 rpm, then it trails off. If the trace of the 9 lb pulley dyno run followed that linearity to 7,100 rpm, it would be making over 450 whp, but you'd only get getting those extra 30 hp for a few seconds at a time because it's only a 500 rpm window where you would have the extra power.

The only peculiarity I have seen that makes that car not respond like the stock engine is that on throttle tip-in, the torque output fluctuates slightly for the first second or two. Like maybe 5-10 hp worth of fluctuation, similar to turning the AC on or off. It's not abrupt like turning the AC on though. It's like a sine wave of 2-3 fluctuations. It's not even annoying. I just noticed that it does it, so I thought I'd report it. At least it doesn't bog when you open the throttle. That WAS annoying.

Today I posted my praise. Tomorrow, I'll post my criticism. <-- not plural. I only have one bad thing to say.

09-05-2010, 02:13 AM	#1613 (permalink)
Phimosis Enthusiast Member Join Date: May 2009 Location: Oildale, CA Posts: 412 Drives: 2013 911 4S Rep Power: 416	Driving impressions: I've put over 200 miles on the new tune and have a pretty good feel for what the car is all about now, so I'll summarize: The car runs perfectly. let me say it again. THE CAR RUNS PERFECTLY! It starts like stock, whether hot or cold. It idles smooth. It doesn't smell rich when you get on the throttle at low rpms (like it did previously). It doesn't bog at throttle tip in (like it did with the last tune). The gains come earlier (mostly because of the 9 psi pulley). By 3,000 rpm it pulls noticeably harder than stock. It makes 300+ lb/feet of torque from 4,200 rpm up. It makes a really sexy turbine sound from idle to about 2,500 rpm that turns heads in parking lots. Because I did the clutch/flywheel at the same time, the synchro rev match downshifts are awe inspiring. The rev match is blindingly fast and accompanied by the sound of the turbine spooling up and the boost augmented bark of the exhaust. I was rolling down Rodeo drive this morning where poseur types take their exotic cars out for their saturday morning drive to troll for model/actress types. I did the usual 3-2 downshift as i'm rolling by Louis Vuitton and the number of heads that turned to see what kind of car it was, was too many to count. Maybe 10? Brought a smile to my face. Ok, I'm a poseur too. So what? If you analyze my dyno graphs, you may be surprised that I'm raving about this new tune, when I have to run a race gas mix and I went from the 8 lb pulley to the 9l b pulley and it didn't make any more power (421.96 hp vs 422.4 hp). The reason I am happy is because of the gains in the mid-range. On the old tune, it didn't make decent power until 5,000 rpm, then the power came on explosively. The dyno chart doesn't reflect that, but it was very noticeable while driving. In a few race situations, its seemed like minutes, not seconds waiting for boost to build. You can't get full throttle at 5,000 rpm to the ground exiting the corner in second gear, so you exit in third gear at 3,800 rpm, then a corvette starts passing you..... and you're going crap.....come on, get to 5,000 rpm....come on! It was frustrating to say the least. So the million dollar question, is why isn't the peak power higher? Well, kyle was nice enough to introduce me to their lead engineer and he went over the tuning with me. Basically, they are pulling timing from the top end to prevent detonation since its running at 9 psi of boost rather than 8. Retarding timing kills hp, but saves pistons. To be honest, I don't mind that this tune doesn't make more peak power. At 7,000 rpm under full throttle, the game is on. It doesnt need any more "on" unless its accompanied by similar gains in the mid range. If you loook at the slope of the line from the 8 lb pulley, it was linear, all the way to 7,100 rpm, then it trails off. If the trace of the 9 lb pulley dyno run followed that linearity to 7,100 rpm, it would be making over 450 whp, but you'd only get getting those extra 30 hp for a few seconds at a time because it's only a 500 rpm window where you would have the extra power. The only peculiarity I have seen that makes that car not respond like the stock engine is that on throttle tip-in, the torque output fluctuates slightly for the first second or two. Like maybe 5-10 hp worth of fluctuation, similar to turning the AC on or off. It's not abrupt like turning the AC on though. It's like a sine wave of 2-3 fluctuations. It's not even annoying. I just noticed that it does it, so I thought I'd report it. At least it doesn't bog when you open the throttle. That WAS annoying. Today I posted my praise. Tomorrow, I'll post my criticism. <-- not plural. I only have one bad thing to say.