This is a little off-topic but is there any "rule" of when you could add a SC or a Turbo?

Say my car is at 70k miles and I add a SC or Turbo, everything is still fine?

 

Like I said, the only time you will see 1000-2500 rpms is on a launch, and at wide open throttle you will only be there for a split second in first gear, the rest of the run will be spent at 4000+rpms as you work through the gears. That low end power is almost inconsequential, and can even hurt you if you're building boost too early. On a turbocharged setup, without slicks, first gear is almost unusable anyway. No reason to make it worse.

Torque below 2000rpms is barely usable torque in most situations. My setup makes 300 ft/lbs at 2800-2900 rpms and 400ft/lbs at 3200 rpms, which is where you'll actually be using it even with a conservative launch. I'm not really sure what you mean by "S shape". This is why many ST guys are running excellent ET's at average power levels.

Top end torque isn't as consequential as power, especially in the higher gears generally, TT setups make better top end power on the stock motor, but I think with tuning you could pull more out of the ST setup. I'm waiting to see some bigger power numbers out of the ST kits and how these larger turbos perform at high boost levels. Hopefully Turbonetics will release their stage 2 kit soon...

 

And who might this be? I hit 500rwhp with my procharger but it was with a 75 shot of nitrous. I have not seen a single dyno chart displaying 500rwhp on a supercharged Z/G35 and there is no way (atleast not right now) there are any supercharged Z's pushing 600rwhp

 

I agree except for why exactly is 1st gear on a turbo not as usable as it is on a SC? It's because of the torque spinning out the tires is it not? As long as you don't cross your traction threshold and have traction, you're fine. I can report that the vortech with making boost below 2500 rpms maintains traction. The torque isn't really THAT high to cross your traction threshold - unless you have crap tires or something If anything it helps your launch and having too much midrange torque hurts your launch unless you have drag radials or slicks

I can only report that my car makes 296 torque at 2800-2900 rpms with my vortech setup However I have 3.9 gears which gives a 10% more gear torque

You don't think that 100 ft/lbs torque surge over 300 rpms has anything to do with 1st gear not being as usable? A normal street tire I'd think would have a hard time dealing with torque accelleration of that magnitude

i agree with the comments with the ST and TT, except this statement because torque directly reflects your hp. If you have a lot more torque at 6000 rpms than another car, we can be sure it will have more hp as well. The torque is how hard the engine works, the hp factors in how often it works


DSport G35 comes to mind, he hit 508whp at 7200 rpm and has an engine capable of going to 8000 rpms, but his belt the way it's setup (not stock) breaks beyond 7200 rpms. He's working with vortech to find a working solution
https://my350z.com/forum/showthread....t=7000+vortech

 

I'm not going to quote all that, but this is why learning to launch is SO important. You never really see 0-2500rpms anyway unless you roll off the line with no throttle whatsoever. On any setup, dropping the clutch at 3000+ rpms will give you traction issues. This is why you either a) feather the clutch extensively on street tires, or b) get some drag radials or slicks and learn to heat them up. If you shift at redline on a prep'd track, 2nd gear shouldn't be that much of an issue when it comes to traction unless you've got big power and in that case you should be running some good slicks.

From there on out you should never really be below 4k RPMS if you're shifting aggressively. This is why I don't really understand why people complain about turbo lag. As long as it isn't excessive, like some Supras I've seen, you can be at full boost almost instantly if you know how to shift.

I should have just said that I believe that a better top end can be achieved on a ST setup by tuning, and of course, running more boost. Single Turbos aren't the most efficient at low boost levels, at least not nearly as efficient as Twin Turbos. This is why I said I'm still wanting to see someone a high boost setup on a properly matched single turbo.

One good thing about most of the TT setups, and the ST setups to a lesser extent, is you can achieve a very linear powerband via tuning. They definitely offer a better range of flexibility than a supercharger.

 

Yeah, provided everything is installed correctly, and there are no major problems with your car.

 

yeah but that's for racing situations, do people really race from stoplight to stoplight like that with dumping the clutch at 3000rpms on a daily basis?

IF we're talking about racing, then the turbo has a real advantage with lauching with drag radials and using all that midrange power at launch. If we're talking about driving on the street in daily traffic on street tires just trying to go fast (not race) at a stoplight then I think the SC would have the advantage with having an easier time controlling the launch and ultimately going WOT sooner than you would on a turbo. Without race tires, you're opening the possiblity of screwing up your launch because of how much you'll have to feather the clutch - or spin tires

All I know is with my setup, I launch at around 2000-2500 rpms and pretty quickly ease into WOT so that around 3500-4000 rpms I'm flooring it and make full use of my 1st gear and that's with a 3.9 final drive even. From there on out I'm in my high boost range. If I had a turbo that made peak torque at 4000 rpms, I'd only just barely make use of that on the first couple shifts when the rpms drop to over 4000 rpms, then over 4500 rpms. From 4th gear and up where you're for sure above 5000 rpms the centrifugal really shines because the torque will be flatter and stay high while a ST's torque drops like a rock beyond 5500 rpms

but yeah who knows what possibilities will come from someone REALLY pushing the ST setup. Likewise for the SC setup

the stillen is going to fill the daily driven power range in the best especially with a larger blower. The ST probably has the most fun factor because of going from no boost to full boost so fast and then having high mid torque - which is likely to be used more in daily driving than the high rpm range. The centrifugal is IMO a compromise between a stillen and turbo setup in general because it gives you more power below 2500 rpms, a decent midrange (not turbo levels of mid torque) and a very competitive high end. Yet you don't need an extreme tire setup to make full use of 1st gear

 

Well said Sentry. Very interresting reading!

Tauran, you're talking of drag racing situation. The OP is looking for a daily driven setup. Sub 4k rpms are common and the engine responsivness is important then.

Open an engine design manual if you have one handy. Turbos don't make power from nothing...

 

Sentry your foolish comments regarding the S/C's being better for launching on the street and making more power than turbo's under 2000rpm's (like anybody ever dyno's under that) are simply retarded. You play the S/C's low TQ up like its an advantage, funny thing is your the only who who prolly believes that BS. You act like the ST TQ is not controllable off the line, the truth is-and this applies to a STOCK Z, if you dont know how to launch you will have issues with any kit. And if you think your S/C would outpull any turbo Z from a 4th gear roll at 5000rpm's with similar whp as you, your crazy. Id like to see you put your awesome for launching S/C setup on a track and put up some times, until then it all "theory"....

 

ok we have a misunderstanding I think

I never said I think my SC setup is better than a turbo setup - especially on the track where race tires might be used. Actually I think I said on the track with racing tires a turbo would be better because of its ability to make use of the high mid torque to launch harder - especially if both setups were running the same whp.

launching on the drag strip you're right no one cares about below 2500 rpms. On the street though I can tell you I really can feel the power difference below 2500 rpms. I'm not making it up and most of the dynos I've seen support that as well as boost charts. IMO below 2500 is worthless on the track, but in daily driving situations gives a little more ***** to the car when you're driving at low speeds/rpms.

third point, if you have really sticky race tires you'll have an easier time launching. Yeah there's some skill involved, not sure I ever said there wasn't. But I will stand by what I said in that a centrifugal is EASIER to launch on normal street tires (not drag radials) than a ST daily from stoplight to stoplight because it has less peak torque and it's slower boost buildup. Can someone's awesome skillz compensate for the ST's surge of power with slipping the clutch a little more? Yes I'm sure that's possible

4th point, where I said the centrifugal really shines in 4th-6th gear at WOT was relative to itself in the other gears. This should be obviously true seeing that a SC makes more boost at 5000 rpms than it would at 4000 rpms. The lowest rpms in each gear gradually go up and up each gear. Plug the numbers into http://www.f-body.org/gears/ for reference

I consider my 440whp/370tq vortech setup equally hard on the stock engine as a 400whp/400tq turbo simply because I'm much less likely to hit 6500 rpms daily basis though I might hit 4000 rpms much more often. Yet when I go WOT to redline the power is there in that range yet I get a decent boost on the low end and a moderate boost in the midrange

besides, midrange torque doesn't convert to midrange hp very efficiently. You can add 21% more torque at 4000 rpms and only get 14% more hp at 4000 rpms. Where in the upper range at 5250 rpms if you added 21% more torque, you'll get 21% more hp - and as the Z revs higher that efficency increases. So if you added 20% more torque at 6600 rpms, you'd get something like 25% more hp. If torque was truely the king of racing and was all that mattered, we'd all be using turbo diesal engines reving to a 3000 rpms redline.

A ferrari F430 only has 343 ft/lbs of torque. If you can explain why it's as fast as it is with only 343 crank torque and why it can beat the snot out of a C5 corvette with 375 tq and 150 lbs less weight then you'll understand how important hp/rpms and gearing actually are compared to torque

 

If a compression check turns out good then yes.

 

This doesn't really make much sense to me either. Sorry, but if you're anywhere under 2000rpms at any time during a race, whether it be on the street or on the track, you're most likely going to lose. The only advantage the SC would have at launching on the street is that it's actually making less power in prime launch/midrange rpms. It really has nothing to do with the power between 0-2000 rpms.

FWIW, I can launch my car on the street at 2500-3000 rpms just fine with minimal spinning/wheel hop. You just have to know how to modulate the throttle/clutch. And yes, my stock clutch is still holding.

 

enough about racing, I've been mostly talking about daily driving and not being boy street racer at each and every stoplight. I'm talking about normal take offs the additional power below 2500 is nice and it's noticable. There is a difference between doing a hard launch and driving normally right?

I almost don't know how to explain it. After adding my vortech, the car darts out of the parking lot faster from a stop. It "darts" faster and feels quite a bit more responsive at those lower speeds/rpms

I gained 40 tq at 2500 compared to before with all my NA mods. You guys might say that means absolutely nothing, but I'm going to politely disagree and say I enjoy the additional power and it's noticable in daily driving situations. My dynos started at 2000 on a dynodynamics load dyno so I consider there to be minimal dyno errors at 2500 on my runs. But for what it's worth, at 2200 rpms I gained 30 tq from before.

If anyone here has EVER driven a stillen SC or a corvette or any V8 car, you'll understand what that low end torque increase feels like compared to a stock V6 350Z. Is it "useful" for racing? No. Is it nice for daily driving? IMHO hell yeah it is

if anyone can add a JWT popcharger to their Z and say they can feel the 5 tq it gains them up top, you can bet they'll feel 30-40 tq at extreme low rpms

 

A "stock" 350z is fast enough for daily driving. I could really care less how much torque my car has off the line unless it's in any racing situation. If I want a peppy take-off I could always just roll off the line, shift into second, and then punch it. Come to think of it, my car would still be easier to start off the line because cause I never actually boost when I'm driving normally. If I wanted to, I could drive my car all day, or week, and never hit boost if I chose not to.

I'm trying to think of a situation where I'd want to get off the line and risk spinning my tires when I wasn't "racing", showing off, or trying to launch the car just to run it hard....... .. uhh... Basically, if this isn't in a "racing" situation then this debate really makes no sense whatsoever.

 

i see what you're saying and agree with you about it in a WOT racing situation.

I'm not really meaning in any sort of racing situation though, just how responsive the car is at daily driven rpms. Yes a stock 350Z has more than enough daily driven power. With my setup I actually drive around 2000-3500 rpms 90% of the time, but I don't launch the car hard from stoplight to stoplight. My idle is at 1000 rpms so I tend to "launch" from stops at something like 1500-2000 rpms when I'm driving normal.

I guess it's more along the lines of if you drove a pickup truck with a 150 hp 4 cylinder engine, then drove the same pickup truck with a 330 hp V8 and drove it around town never going above 2000-2500 rpms. Something is wrong if you can't feel the difference in how much more responsive the V8 truck is.

or like when you drive around town just cruising in a viper vs a geo metro. You can just feel how much more power you have at your disposal if you wanted to use it in the viper.

2500 rpms and below isn't useful for racing at all, but the throttle response is enjoyable. It doesn't drive around town like a stock Z then become a beast when you floor it. Its normal driving is much stronger and when you go WOT it won't be as dramatic as a ST/TT, but it's top end is strong

 

I dunno what turbo kit you have driven but my car doesnt feel sluggish in the .8 seconds it takes me to go off the line to 2500rpm's....I really think your arguing a silly point here. BTW-how much boost are you making at 2300rpm's? The reason your car "darts" off the line is your gearing.

 

I've had my gearing and bolt on parts forever now. When I added the vortech the low end has become considerably stronger and we'll leave it at that. Obviously some people don't agree with me or my dyno charts.

I've been saying it's a moot point all along, but still noticable. It's not like I came into this thread bragging about how awesome my low end torque is and that's the main reason someone should get a SC

at 2300 rpms I'm making 1.8 lbs of boost and there's a lot of reactiveness probably because the SC is directly linked to the belt. There's something else at work though cause I don't see how 1.8 psi could be equal to 35tq. Maybe 2.5 psi would

What boost are the turbos making at 2300 rpms?

 

I agree on the fact that 1.8lbs shouldnt be making the power it is over stock, but you also have a nice set-up including cams/gears that surely help everywhere. You know its sad, I dont remember what my car used to build for boost at 2300rpm's, its been too long. Hopefully somebody else can chime in and we'll know....

 

On the ST kits, I'd say 0 boost at 2300 rpms. It comes on soon after that. But then again, this serves no purpose as any time you're intentionaly boosting you will never see anything below 2300 rpms anyway.

Some of the twin turbo kits (PE, JWT, maybe APS) will see boost that low, but not much.

I still maintain that this debate is worthless and has no place in the actual performance of the setup.

 

yeah I suppose my cams and headers might be contributing to the torque curve being higher there

I do know that an APS ST that was dynoed around the same time when my car was at the same shop I go to was making about 1 psi at 2300 rpms. He was making about 30whp less than me. Anything below 2900 rpms and I'm making about 30 more torque than him though in the midrange he's making about 30-70 more torque than me, but then at 5700 and higher I'm making about 25 more torque. If I remember right he had the APS ST, APS plenum, and APS exhaust