Speedracer

Let's face it....this debate can go on until the end of time. However, one really needs to take a honest look at how you will use your car, and how much time you want to spend tuning it. For some, having the car on the dyno a third of the time and tweaking it for maximum performance is actually part of the fun of it all. Other's need a daily driver. All that considered, here's my take....

In all reality, the practical limits for a useable street car in terms of power, unless you spend you life in rural Montana, is in the range of about 450 crank hp. I have owned and driven a car with this much power as a daily driver, and more than that in real world driving conditions, traffic, rain, etc, is just plain dangerous. You build up speed so much faster than almost anything else on the road, that the level of attention you need with a car like this is significant. A friend of mine, recently got rid of his 6 month old Viper in favor of a Porsche 911, becuase the Viper was barely driveable on anything other than a flat open road. The 911 provided a much more overall enjoyable driving experience. So, in my opinion, there is a state where there is just too much power for a street car.

With regards to the Z, both SC and TT, with minimal tuning will get you close to this range of power. For track/drag/show cars a TT set-up will ultimately allow higher reliable power and a better distribution of torque across the power band. For real world street cars, however, an SC set-up is both easier, and will supply more than enough beef. The key component for both really lies in the engine management, and ease thereof.

So..for the track/drag/show scene....go TT. For a real street car, the set-up that provides the best and most reliable engine management is the one to go with, either SC or TT. Just my opinion.

Sharif@Forged

iTrader: (92)

hmm....so what exactly is your recommendation? I saw about three different conclusions in your post......still waiting for the real answer. (said with a sarcast ****-faced grin)

SKiDaZZLe

um... i only saw this:
what was he comparing the TT setup to again....?

SQUILL

That pretty much sums it up. Superchargers are great however for the 3.5L engine turbos are superior.

Everybody keeps making the tuning argument however if you leave the Greddy Kit stock (4.6psi) for example you need not do any further tuning and still wind up with a better power curve throughout the entire power band than the superchargers at their stock 7psi settings.

Speedracer

if you haven't already taken the plunge. I think the engine management for the Z will be better figured out soon. I am personally waiting to see what the JWT set-up with integrated ECU reprogramming is like, as well as the upcoming HKS supercharger. It is also interesting to see that NISMO of all people has released 8.5:1 compression pistons for sale (hint, hint). Wonder what that could be all about. Anyway, since I own a new roadster and live in the northeast, i'm going to just enjoy my car in stock form over the summer and fall. I don't want to waste open air driving weather with the car in the shop and on the dyno. Around December or so, when some more of the dust has settled, I'll see who has the best ECU tuning and go with that system, be it SC or TT. In the two previous cars I owned, I did SC, then TT upgrade and was one of the first when the kits came out. Inevitably the software was improved within 6 months to a year. Also, brand specific companies tend to do more R&D than "general" tuning companies. I'm really leaning towards the JWT TT for this reason. Honda/Acura has Jackson and Comptech, BMW has Dinan, Audi has MTM, APR....you know what I mean.

UsafaRice

JGTC race motors? Supply and demand?

Remember that you "can" turn down the boost on the turbos with an electrically controlled wastegate. It's a lot harder to swap the pulleys on a S/C at a stoplight!

But you do bring up a good argument.

knuguy

I enjoyed reading how the SC fans have the "lag" on the brain, meanwhile the Vortech is the same compressor type as a turbo and is stuck being RPM dependant. Then you have the roots type, but it eventually runs out of steam.......go turbo, more torque (the one thing people keep eluding, Greddy puts down 50ft/lbs more then any SC out there) better power..........the end

SQUILL

ahhhhh thank god somebody else gets it !!!!!!!! this is what ive been saying but these s/c guys just dont get it. Im not thying to say that their supercgargers suck im just saying that turbos are simply better! They say they have no lag!!! i say where is the benifit under 3500 rpms with SC??? and then after 3500 rpms still how is the s/c better???

97modman

With all respect to the SC's and Turbos. I think there both great power adders..

Unfortunately i do not have a Z yet, but i am working on it..probably hold out till winter to get a good deal on one.. but also in the back of my mind i keep thinking that nissan had this top secret single turbo 360hp Z that no one knew about and it will be on sale in '05..

But in any case i have not seen anyone post about the supercharger actually robbing almost 10% of power due to more drag on the crank, this is also why the Turbo is superior to the SC..Free power if you want to call it..

My biggest problem with the Z car is that i like the old turboed Z's and Nissan not putting one out kind've stunned me.. i wasn't crazy about the V6 turbos but i learned to like them..
I do like the inline 6's, I think it distributes power better than the V's and there is alot more clearance to work with in the I6..But to that is my opinion..
I think i will have to do some research to see if the RB26DETT will fit in the 350..it will require modification no doubt.. but just the thought of a engine like that in a car like the Z makes me smile...


sorry so long..

knuguy

A better question is where's the torque???? Oh thats right the SC is robbing you of it, where as the beloved turbo makes "free" power (no parasitic drag on the motor). Underdrive pulleys and SC's go together real well too

SQUILL

Parasitic loss is just a fact of life with superchargers if you do a litle research on any supercharger for any engine you will see...its really not posted that much because its common knowledge.

the rb26dett will fit in the 350 z there is one or two out there right now i believe top secret just did such a swap.

why you would want to throw an insanly heaver motor in the 350z is beyond me un less you are going for wow factor

as time progresses you will see that the VQ35DE is a real power player i nnow of one car with forged internals with the greddy kit that put down 597 rwhp @ 14 psi...as soon as the fuel system in this car is redone it will be capable of running 25 psi...700 hp???

uberfaybk

i think new internals will be more worth it than an entire engine swap...

97modman

Just found out that installing the RB26 is a real chore and can get to be costly.. i guess the wow factor would have been nice.. Just still use to the my old single turbo Supra i guess..

Do they make Single Turbo Kits for 350Z's??, i would rather go for one nice sized single like a T-62 with a .68 a/r instead of 2 turbos..less weight and heat...

what do you guys think??

Speedracer

but they are also a more complex install and harder to tune on an otherwise NA motor. I guess my real message was that turbo is the best, but for street power, an SC will do just fine, and I would opt for a nicely tuned SC before a poorly tuned turbo. On the other hand, a well tuned turbo set up goes home with the prom queen.

UsafaRice

Well modman, Nissan's not releasing a turbo Z because Ghosn has decided he wants to build and sell cars instead of building them and not selling them. Chevy put the LS1 in Camaros and Ford sold their piceces of crap cheaper and killed the Camaro.

Look at Nissan (300ZX), Mazda (RX7), Mitsubishi(VR4), and Toyota(Supra) and notice one thing. All of these cars cost as much or more than a C5 Corvette in the late 90s. While I will always drive Z cars regardless of whatever, a lot of people were making a hard decision and opting for more power and more of a status symbol in the Corvette.

Nissan almost died in the late 90s and their new management is smart. For example, the Altima beats the Accord and the Camry in space and power, and just look at the Z's sales!

If Nissan put turbo(s) in a Z, it would drive the price of a fully loaded track model to the low or mid $40Ks. While some people would still buy them, a lot would be looking at BMWs and Benzs.

But Nissan does recognize the desire for the powerful car. They will probably be bringing in a 300-400 HP AWD version of the G35 (Skyline V35) to America in a few years. First, they are going to sell all the Zs they can, then sell the Skyline to all these people from California with lots of money (j/k)

Me, I can't afford a $50K car when I could put that extra $20K into either 1) another car/truck or two, 2) a nice used Z32 TT, or even 3) a full blown 4.3L twin turbo, 9.6 CR, high flow head, 7,500-8,000 RPM racing motor for this Z!

So, that's long, but it's economics.

D'oh

When S/C people talk about lag, they are not talking about the RPM @ which the turbo's spool. Instead, they are talking about the delay between off-throttle and on-throttle.

Even with small turbos, this delay can be quite noticeable in certain situations.

For instance, I drove the Mazdaspeed Miata @ the Rev it Up event earlier this year, and even though the turbo is providing full boost @ low RPMS (I think 2500 or so), you still notice quite a delay when entering a corner under heavy braking and then stepping on the gas. Since the S/C is always spinning, you don't have that delay. When you are going through a tight course, and are only on the gas for a split second before hitting the brakes again, that slight lag can really put the turbo's at a disadvantage.

In fact, in many reviews of the Audi TT (which has full torque at soemthing like 2000 RPM) the magazines often bring up the feeling of turbo lag. Whether or not the lag affects you will depend on the kind of driving, but for an AutoX or Road Course I think a S/C (preferably a roots type) would be a very good choice because it doesn't have the lag.

Still, the turbo's definitely have the advantage of flexibility.

It really is a tough choice!

-D'oh!

SQUILL

The real fact alot of people dont consider is that Lag is only noticable because so much power comes on so quick.

The power under 2500 rpms is not that much higher than stock anyway with either system.

But after 2500 rpms the turbo is kicking in hard delivering a lot more TQ and HP than the s/c as it is only delivering 2-3lbs of boost.

what you wind up with is the TT car accelarting much harder sooner than the S/C as by 3000 rpms the turbo is killing the S/C in power output.

Even though the turbo may feel like there is lag it it still making more power than the S/C after 2000 rpms.

D'oh

That may be true (although a roots type S/C has a power delivery very similar to a turbo - and very different than a centrifugal S/C). However, for track or AutoX use, the issue isn't necessarily the amount of torque, but that there is a delay between the time you are get on the throttle and the time you feel the torque (this is when the turbo's are spooling back up). Often you get on the throttle at the beginning of a corner, and get a surge of power in the middle, when you might not want it. It doesn't matter so much what the RPMs are, because even at high RPMs the turbo's will spin down if you are off the gas. Because a S/C doesn't need to spin back up, the response it quicker and the car is easier to control. Obviously you can eventually adapt to the power characteristics of the turbo, but if you are more interested in road courses a S/C might be better since it won't have the lag and you won't have to adjust to that. Also, if you are at a road course you will be above 4000 RPM pretty much all the time anyway, so even if you have a centrifugal S/C you will still be getting most of its available boost. At an AutoX you don't shift as much, and are more likely to be coming out of corners @ say 3000 RPM in second, so the centrifugal S/C may not be as good in that situation. A roots type would still be great though.

For drag racing a centrifugal S/C will probably not be so good because of the lower RPM's at the launch, but maybe a high stall TC or a high RPM clutch slip would help. A turbo or roots S/C is probably better though (although any of these will spin the stock tires, so you need some big sticky ones to take advantage of the turbo's low end power off the launch).

I completely agree that for most types of street driving the lag isn't an issue and the turbo's have the advantage of flexibility and efficiency over the S/C.

Everything is IMO of course.

-D'oh!

SQUILL

Well the only way to tell is when some TT cars start running the tracks ...i think they will run better than a supercharced car out on the track however I wont be able to prove this untill i get my turbo kit and get it out to the track.

little_rod

SQUILL, I like turbos, but they are not the best for every situation. On a tight autox course, any lag hurts you. I know you think turbos are similar to magic pixie dust, lol, just please get the lube out of your homemade turbo.........................