Thats what ive concluded too. Ive been hoping for a electromagnetic clutch of some type for a centrifugal SC kit for a while.

Im supprised to see that no one here has mentioned that the ATI SC has a slight deficit in torque as compare to a TT setup with simular boost. Because a SC always leaches off the engine, like running the AC, you will always be at a slight torque disadvantage. Its not much of a lost. I mean I can still live with it.

 

It is not my intention to ask whether the SC or TT setup is better, what I am trying to find out is :

1) Given the large price differential ($2600) will people be
interested in the GReddy kit. And I'm not talking about just
saying that they would be interested, but when time comes
down to putting an down extra $2600 to buy the kit.
Remember this is almost 10% of the price of the car. Not just
the cost of the kit, but just the difference between the SC &
TT. At $7600 that is 20%+ of the price of the car.

2) I know the pros & cons of the SC vs. TT setup but if the ATI SC
is set safely at 7 psi with a maximum of say 15 psi and the
GReddy TT is set at 7 psi for safety, witha 20 psi limit does it
really matter what the top end of these products are ? Isn't it
the engine that is the weak spot of car. If 7-9 psi is the limit
of the engine before breakdown occurs then who cares if it can
go to 20 psi. I fully support the answer of building up the
engine to get more boost, but in normal setups if none of the
drivers is going over 9-10 psi, why on earth would you pay an
extra $2600 ?

3) It's not like one of the kits produces 125 whp, and the other
makes 200 whp. The ATI has put out a dyno proven 370-380
whp, while GReddy claims 370 hp +, so they can't justify hp
difference as the cause in the substantial price premium. I
know the TT setup has a different hp/torque curve, but is it
worth it ? Will the acceleration #'s bear this out ? For the same
price of the TT setup w/ IC, you can get the SC, I/H/E, pulley
upgrade, AFC, etc. Is it worth it for the TT ? If 500 hp & about
$10,000+ is your target then it sounds like the TT upgrade is
your cup of tea.

 

Fanman, you need to reread my above posts. 7psi for an SC is different than 7psi for a turbo. The turbo will put out 7psi from like 3000 rpm to the redline, while the SC will only put out 7psi at the redline. At 3000 rpm, the SC will be putting out ALOT less boost.

You have to see that putting out 7psi from 3K to 6K for a turbo is just a lot more power than just 7psi at the redline. Power is not just measured by peak, there is a power curve. Having more area under the power curve will give you better acceleration numbers.

 

[QUOTE]Originally posted by 350zdanny
[B]Ok that is not true. ATI released a product to market that has blown engines. Greddy has blown engines in R&D. There is a difference I actually agree with you, but if you had structured your point correctly, you would have simply stated taht 90%+ blown engines result from poor tuning or installation. As hard as ATI and Greddy try to find qualified tuners, mistakes will be made, and people will fiddle with their kits. So in that sense I agree that poorly tuned FI blows engines, not Greddy or ATI specifically.

I think I structured my point well. I first said that the ATI kit is the only form of FI you can buy at this point in time. Then I proceeded to explain that the PE kit has blown engines. (2 that I am aware of) This thread specificly compares two products, one that has been used by multiple users for months, and another that has been on one car and thats it. I don't think it is necessary to state the location of the product in the product life cycle. However, that was my first point that you missed. IE the part about ATI being the only from of FI you can buy... The only part I should have expanded upon was the point that ATI has sold in excess of 100 kits. Only 2 cars have had significant issues. The PE kit has blown two engines and has not gone through 100's of cars like the ATI kit. Lets see 100 kits to 0. Wow they both have two blown engines. I would dare to bet when or *if* the PE kit comes out, there will be multiple blown engines. Many more so than with the ATI kit. Please refer to the heating and spiking issues that will back this point. I'm sorry (Danny) about my *structure* but you have no room to critique. What kind of response is OK that is not true....I actually agree with you. Plus you quote small fragments from multiple users. It is hard to follow what you are trying to say. Maybe *you* should work on your structure.

[QUOTE]Originally posted by 350zdanny You're exxagerating the reality of turbo lag here. You're talking about a large turbo if it doesn't begin to spool until 4k rpm. With a redline of 6600 rpm, do you think that turbo application is feasible on a street Z? Thats why most kit manufacturers are using 2 smaller turbos. Indeed the boost does turn on instantly with a S/C, but a small turbo can hit MAX boost just as fast as the S/C.

Please, we are talking about a Z that will hit 500-550rwhp, as OCG35 mentioned, not 370 rwhp with two baby turbos. Give me some examples of small turbos that can hit this number and turn on before 3.8K rpm. Then tell me that they hit full boost before 4.2Krpm. Its not going to happen, especially with this car. I have had two small turbos (modified stock supra twins) produced 410rwhp at 4.5Krpm and the turbo came on at 3.2rpm. I have had one medium sized turbo SP63, produced 515rwhp at 4.8Krpm and started at 4.0Krpm. I have a s/c (ATI procharger) producing 368 rwhp at 6.8Krpm. Granted it doesn't put out nearly the amount of boost I am used to, but it does boost instantaneously. That has to count for something. In a street race that may be the difference between a win or a loss. I have given you my opinion after personal experience, having had all three types of FI. What have you had and how do you base your opinions?

 

Rod,

I understand the difference in hp/torque, but what I am saying is that with a dyno proven 380 whp from a ATI SC'ed 350Z is that greater (acceleration wise) than a 370 hp TT'ed (330 whp) 350Z ? If you have a TT 350Z is it as fast as a SC, I/H/E, high flow cats, AFC, w/ pulley 350Z because that is what you can get for the same price. If you are willing to drop way more money than that is a good reasoning for the TT setup, but for $7600 which would you get ?

 

Well, on a stock Z, the procharger has been dynoed at around 350 rwhp. As for your question, we don't really know the answer til the TT comes out, and we have acceleration times and power curves for it. But you just can't go by which one has the most peak hp, cause the TT will have more area under the power curve. That is all I am saying.

Some people have had good/bad experiences with either system so that will affect their opinion. If it were me (after all, that is what you asked), and I had $7600 cash burning a hole in my pocket, I would get the turbo. The reason I say this is cause if I had $7600 in my pocket, I would know that ain't the last amount of money I will make during my time with my car. 6 months, a year, whatever, I could strengthen the engine and simply turn up the boost from my driver's seat.

Now, if I had $4600, then I would look at the SC. Then upgrade with later money. It is a money thing to me, but that is just me. Now, there are ALOT more other reasons other people choose one or the other.

 

Please don't live by 1/4 mile times. Look at the mph and you can see the difference in POWER the kit has made.

Someone can actually run a 14.0 1/4 mile time with the Gredy kit, but does that mean the kit is a POS? not unless he ran 100mph in the 1/4.

ET's are about the driver and traction, and I would not live by magazine 1/4 mile times either.

 

If the Greddy TT kit feels anything like the STi feels, then I would go for the TT. The STi claims 300 crank hp from a 2.5L engine and when I rode in one it felt like a big NA engine and not like a boosted 4 banger. All things being equal, that would equate to a 420 crank hp 350Z.

Does the Greddy kit include a turbo exhaust system?

 

I doubt it. I'm sure you retain the cats too. It's prob up to the owner to swap out the exhaust and cats.

 

The only difference between 7psi and 7psi, is what temp each one is at. The cooler (more effecient) boost, will net more power. No matter what it is from.

Not 100% fact, but I will let this one slide. Tire size, gearing, tranny, TQ converter, etc. Just to many factors play into that one.

As for my comment regarding "Holding your breath for the Greddy", and saying that the ATI is out and about. Is because I have heard about this mythical greddy kit comming out for over a year! If we were talking about a woman here, that would be called a c*ck tease. I don't think anyone likes that, now do they.

I say congrats to the guys at PE, and Cheston for actually making a kit in a good amount of time, and sharing real world results. And not just putting it into the Magazine and getting everyones hopes up.

So there shouldn't really be this debate about TT vs SC. Cause there is no Turbo kit you can buy today! Just keep waiting, while the SC guys have all been playing with their cars for a year, and now are starting to build the motors or buy wheels and stereos with the money they saved.

We don't need another Thread on the Turbo vs blower power differences. They are as played out as the Domestic vs Import threads.


EA

 

I've heard that the supercharger makes boost exponentially and linearly. Which is it? does it make more boost in a straight line, or is the boost increasing at an increasing rate? Or vice versa? What rpm is the first psi of boost registered?

 

A little fuel for the fire...non-IC V2 SC vs. IC T4/T04E single BB turbo on a 3.0L VQ. Also, the turbo was not even tuned and had bad spark plugs, so I'd expect even better. However, look at the TORQUE!!! Big difference IMO and only going to be BETTER with twins hitting full boost at ~3Krpm.


I read the Greddy kit cost ~$6K INCLUDING the IC. Where did you see PLUS? Also, what does the ATI kit include for the fuel management? I know the GReddy includes 440cc injectors and an eManage for fuel, which is around $1K in extras. What does the ATI kit use for fuel?

 

LOL, thank you IceY2K1Max for proving my point. I am not saying the boost is different SVT, just saying the two systems get the boost on entirely different curves.

 

It was in Road & Track, the IC will be a seperate $1600. If the IC comes with the kit, then it makes much more sense, but the article specifically pointed out that it is an extra cost.

 

What the supercharger does depends on the supercharger. The ATI unit is centrifugal, and is VERY similar to a turbocharger, except the compressor is driven by a belt rather than an exhaust turbine. That being said, all centrifugal type compressors (ATI and turbo) build boost exponentially when compared to a linear increase in compressor speed. With the ATI compressor, speed DOES increase in a linear fashion - speed of the compressor is directly proportional to engine RPM. So when you tune the ATI to 7psi or whatever, and since it's exponential, you'll see the majority of the boost at the top end. This is shown by the video of the ATI 350Z racing the E46 M3, M3 had it for a sec until revs got up - then whoosh. Turbos are always better, but produce more heat, and are much more complex (read dangerous). Turbo compressor speed is not directly proportional to engine RPM, it spins up as fast as it can go until it hits max boost, then a wastegate vents the exhaust turbine so it won't go any faster - this usually means a properly sized turbo hits max boost at 3K rpm, vs max boost at redline (as Rod and others pointed out). There are other types of SC's, screw type, roots type, rotex, etc. Screw and Roots are positive displacement, instead of compressing the air to force it into the engine, it 'gulps' the air in measured quantities and 'stuffs' it in - their speed is also directly proportional to engine RPM, but their 'gulping' action produces instant boost, almost max across the RPM range. Problem with these is they produce ALOT of heat, no where near as efficient as a centrifugal compressor (i.e. can't produce as much ultimate power). I thing there are hybrids, i.e. centrifugal compressor superchargers with variable belt systems to compensate for the exponential nature of the compressor (i.e. spins up quickly, then less quickly as rpms reach max), and I think Rotex makes them, but not sure how reliable they are - don't see them in many kits. Hope this all makes sense.

 

Mercedes "Kompressor" engines which use a roots style supercharger have had in the past a blower clutch, which is reasonably inexpensive and could be bolted to the procharger on the Z with little effort.

A series of switches (say at 20% throttle to engage, and boost regulator to disengage for safety) would make a nice automatic setup.

Mercedes has recently stopped using these clutches (My '01 SLK does not have it anymore) but I know you can get them on several MB parts web sites. I did add an overdrive pulley to my SLK to kick the boost from 8 to 12 PSI @ 5K rpm before the bypass valve cuts me off.

Roark

 

No hard feelings little rod, I do follow what your saying. I don't want to start an argument, when we are both in 100% agreement with eachother. I was just making a point so people don't think 7psi from a turbo is better then 7psi from a blower.

What did that dyno graph prove? It's a NONE intercooled Vortech, vs a Intercooler Turbo? And not even the same boost numbers. Thats not even an apples to oranges comparison...that was like....... apple to bananas. Believe me when I say I know the difference between turbo curves, and blower curves. ( I currently own cars that have Turbo, ATI, and even a Roots blower, and work on everything from 10 sec. Single T'ed Supras, to EVOVIII's) Chances are that there was some sort of timing retard on the SC to make up for the lack of the intercooler. So that also throws the curve around. Also a ATI's impeller is hardly related to a Vortech V2. Just throwing out a few factors that make the comparison even more silly.

Last year when I was at SEMA, I asked Greddy, when they thought the kit to be out. They stated "About 3 weeks" Well this years SEMA is just weeks away... maybe this year I will hear "About 2 more weeks"

That is what my point was, is that there are no turbo kits (except the ones on the companies cars) And it's been teased about for a year now...maybe this year people can finally put them on their Christmas list.

I don't want to ruffle anymore feathers, it will be cool to see what Turbo kit's are coming out, and the power they are going to make. Sounds like they are all in about the same price range, same parts, and about at the same stage of completion. I think the market is going to be flooded very fast, and that might drive down the prices of some of the kits offered. I was just stating that the ATI kit has some distinct advantages. ( You can BUY it today with no promise of a release date, No tapping the oil pan of a new car, comes with a warranty, comes with a intercooler, has proven power number by members of this site, it's cost effective, etc. )

I don't want anyone thinking I am mad, so cheers
EA

 

from driving my car while the TTs were in the car, i felt no lag that is typical of most turbo cars... ihi ball bearing turbos (in the pe kit) felt great, and if i recall, produced nearly full boost at 2800, and for sure full boost at 3k..

just stating that the ATI kit is out now really shouldnt affect certain advantages or disadvantages.. ppl just need to be a bit more patient.. i'm sure these retail companies are just as enthusiastic as potential owners b/c the sooner they come out. thats money in the bank to recoop R&D costs...

i hear alot of word about Greddy's quality and waiting for that kit because it has greddy on it.. i'm sure any builder that is good at what they do can build a fantastic kit just as good if not better.. take SkiDazzle's custom turbo kit.. looks damn good from the images i've seen... and i'm equally as happy with the PE kit and the processes that i've seen it go thru... i'm really impressed with what it can do in the long run... and the way the piping was done.. which is probably the hardest part in a turbo kit...

 

SkiDazzle's kit is going to run him up toward 20k including install and tune to put out the same power as both PE and Greddy. Way too much money for me!

 

I lost you here. Most of the boost at high RPM = Linear. Exponential would mean as the RPM doubles, from say 1500 to 3000, boost quadruples. That is the pattern of most turbos, isn't it? Correct me if I'm wrong. I just don't think the ATI can have a linear relationship with RPM AND have an exponential boost pattern.

Whosyourdaddy -

I'm sorry if I ruffled your feathers a bit. My argument wasn't the best either, but don't lose your cool over something like this. That's what blows about this board. Some of our best, most productive members were hotheads and it got them muscled out of the community. Sorry if I offended you.

My experience stems from a 1993 Mazda RX-7. aka the car that is the bastardization of all the best and worst aspects of a FI vehicle. My BNR ball bearing twins could build sick boost south of 3000 rpm (10 lbs) and if I wasn't a *****, I probably could have touched 400 whp with just 1.3 liters of displacement. As it was I hit 338, which is a healthy 7.98 lbs per whp. I was happy with full boost at around 3500 rpm depending on the setting. Take care.

Dan