TougeFiend

I read up on the thread for the either/or elsewhere here, but I'm looking for opinions and info from AT owners specifically. I'm looking at either the Greddy kit (for cost reasons, w/ Greddy Emanage Ultimate upgrade) or splurge a big and get the Pettit Racing Stage II. My goal is to improve the low end performance of the car, and I'm not a huge horsepower guy. Also, are exhausts like the RB, Legamax and the like that aren't 3" in dia. still good for FI applications? I'm also planning on a highflow cat as well. Any opinions and info would be much appreciated.

Phil's 8

iTrader: (3)

I decided to go s/c because of my past experience. I also wanted quick low end response. My company trucks are equipped with turbos and you could take a nap waiting for them to spool up. My boat has a s/c and has quick response out of the hole. So I went with the s/c. Not very scientific.I got what I wanted very quick low end response.

You can pick up a Greddy much cheaper than the s/c. Which ever way you go make sure that you have someone to tune it and plenty of cooling capacity.

I'll let someone else have their say on the exhaust.

mysql101

With the SC, you'll make more power than the greddy under 4k rpm. With the turbo, you'll make more power than the pettit over 4k rpm.

It really depends on what you're looking for and how you drive.

I think I'd opt for the SC if I had an AT.

MazdaManiac

iTrader: (3)

With a properly sized turbo, you will make more power than an SC everywhere in the RPM band (low and high) and throttle response will be as good or better than the SC since you won't be chasing a sudden, non-demand increase of air with fuel-added tuning.
With an SC, you will have a really neat looking device under the hood that makes some pretty cool noises, which is really what most people want, anyway.

TougeFiend

I think for me, the immediate low end response is what I'm looking for. I understand about the properly sized turbo part as I have owned a stock turbo'ed vehicle in the past (WRX). But I feel that in looking for the right turbo, I might end up spending more money on doing that then buying a SC kit that's good to go. You gotta admit though that a turbo kit looks equally as blingy under the hood and makes noises (i.e. bov), unless you coat the pipes and do a recirc option with the bov.......hmmmmmmmm

Brettus

iTrader: (2)

Comparing Pettit SC to Greddy (which will be best turbo for low down power) there is very little difference - especially if you look at a 6PSI greddy vs 6PSI Pettit so don't think that argument holds any water in this instance.

edit : on second thougthts I think the pettit puts out more power at the same psi
Greddy @6psi is around 240-250 from memory
Pettit @6psi is more like 260
would be interesting to compare the charts ......

MazdaManiac

iTrader: (3)

My system is all but invisible. You have to know what you are looking for to even understand what is going on under the hood.
Even an open BOV can be quite subtle. I have an HKS SSQBOV and it barely says anything.

Precisely. And at higher RPM, the turbo will walk away easily. That is the point. The turbo is good everywhere in the RPM band - the argument that it is somehow "peaky" is ridiculous and out of date.

First of all, we should use A/T numbers since that is what we are talking about here. I don't have those numbers however, other than to note there have been quite a few dynos that put the A/T with FI still struggling to keep up with an N/A MT.
Second, just go to the comparison thread and look at the area under the curve. That is the ONLY thing that counts in evaluating a kit for a street application.

mysql101

Rather than get into yet another argument with Brettus, I can provide a summary so that everyone reading this thread can understand what he'll be saying.

Brettus is a SC fanboy who claims everyone else is a turbo fanboy and that he's not biased towards SC, but every post he makes is about how SC > turbo because turbos generate heat and destroy reliability. Yet he has has nothing to back up his statements other than anyone who questions said statements is a turbo fanboy. He'll also shrug off or ignore anything that refutes his statements.

Yeah, I think that about sums it up.

mysql101

As long as your RPM is above 3,000, you should be able to get full or close to full boost at any time. That's why I said I might go for SC if I were AT because .. quite frankly, there isn't as much control as you'd have with a MT,

But then again, I've never driven an AT RX-8. So if you stomp on the gas and your RPMs go over 3k, then you'd be golden.

It would be hard for you to spend more on the turbo system than the SC though, even if you upgraded half of the parts in the greddy kit, including the turbo. And by then there would be no comparison. But then that brings me back to the AT part of the equation. I'm not sure I'd want a ton of power going through that torque converter.

DOMINION

Greddy turbo, Na I would go for the

http://www.mazsport.net/shop/index.p...33&prevstart=0

If I had the cash!

MazdaManiac

iTrader: (3)

Yeah, I know. He isn't a big fan of data, either. But at least he is cordial.

We aren't going to bring money into the equation because it is a red herring.
Ultimately, building it yourself (if you are so qualified) is the best option, regardless of the choice.

Brettus

iTrader: (2)

This is very funny
The only reason I didn't continue that argument we had the other day was that neither of us really had the info to back up our statements so it was somewhat pointless to carry on . You have your opinion - I have mine . I didn't ignore what you said - I just didn't agree with it . If you really want to carry on the discussion in the other thread I'm up for it ?
edit : you must be one of those people that thinks they won the argument just because they got the last word in ....

As far as this discussion goes - I agree with MM area under the chart is what counts . But lets compare apples with apples - Put up a chart of a 6PSI Greddy vs 6PSI Pettit !
Results we get for the MT should roughly translate (as far as one vs the other)for the AT so I think that MT results are relevant for the purposes of this discussion.

sosonic

Word, put a Greddy 6PSI vs Pettit 6PSI chart up. Then that would be a better comparison. I don't see how its fair to show a Greddy at 10psi to 11psi vs a Pettit 6psi system, then claim victory.

RX-8 Auto torque converters limit launches from a dead stop to between 2,500 to 3,000 rpms. A twinscrew supercharger is at full boost at around 2,500 rpms and boost can start from idle. That matches up nicely. My opinion is the RX-8 needs what it can get at the low end, in day to day. Once you are hitting 6,000 rpm, the RX-8 feels good, even without FI.

DOMINION

I'm not qualified thats why you'r going to build my 8 right?

MazdaManiac

iTrader: (3)

Why do I always get the sneaking suspicion that people that say stuff like this have never driven a properly turbo'ed RX-8?

If you are paying, I am building.

Atilla

iTrader: (1)

Sounds good - see you in about 2 years...haha.

sosonic

I have drove a Re-Amemiya Greddy turbo RX-8 (hmmm... I think they know what they are doing), a Blitz supercharged RX-8 ( I might be able to get my hands on a dyno chart from a Blitz SC one day), and rode in a Re-Amemiya NOS experiment car (not owned by Re-Amemiya, but they were helping him hook it up and play with using NOS).

Me, I would go with a positive displacement supercharger... but that's just me, my opinion, and my situation. If everyone else wants to go with turbo, no problem.

Also, compared at the same PSI, the Greddy and Pettit chart would look mighty interesting and I dare say everybody would have a whole new outlook on it. The other way is just drag it out at nearly the same PSI and see what happens. At some point, there will be 10psi Pettit kits, so we will see what happens at that point as far as the chart, track, or street goes.

I have nothing against turbo, I just lean towards the SC in this case. Another interesting point is I don't recall anybody wanting to give up their Pettit supercharger... but more time will tell... SC or Turbo, they both would be fun to drive, both would have their issues, and if done right both will cost a decent amount of money.

MazdaManiac

iTrader: (3)

1) I wouldn't compare the GReddy to the Pettit directly. One is half the price of the other. I am suggesting that the best SC system be compared to the best turbo system. That is an entirely different race.

2) No one wants to "give up" their Pettit SC because there are only a handful of them. If there were a similar number of installs to the GReddy, you would hear just as many dumb posts about "where does this rotor go?" and "why wont the BOV fit in my glovebox?" and just as many "lightly used" systems in the for sale section.

3) The Amemiya turbo is just a regular GReddy system. There are only two wires different. If you want to know how that goes in the states, I can introduce you to people that didn't pay the Amemiya price tag for yet a better install.
Amemiya is just like Kalvin Klein - 10x the price, but in the end, the same cheap Georgia cotton as Levis.

4) I can show you the math for why a positive displacement system is a bad choice, but I've already made that demonstration and, by his absence, so has Hymee.

mysql101

The chart is actually incorrect. It's really 9 psi for the greddy. There's other incorrect data on there (for other systems) that also needs to eventually be updated.

As MM said, it's not like a 6 psi greddy vs 6 psi pettit would be fair either, one kit costs half as much as the other. But it does go to show that not only does the turbo system cost half as much, but for the price of a $300 boost controller, you can double your gains with the push of a button and easily trump the SC.

We can either do as MM said, and look at top of the line SC vs top of the line turbo, OR we can even the score and put the same $$ into both and see where we end up.

Consider that a GReddy kit + upgraded turbo at 6 psi would beat the Pettit at 6 psi hands down and still be $2000 cheaper. Now you see why there's really no comparison.

Brettus

iTrader: (2)

Yes it is . However if you read the OPs original preferences he was talking about having power available at low rpm - Not necessarily a drag strip beast . The best turbo system for peak power does not do too well at low rpm as can be seen from the chart comparison thread.
edit - actually the PTP turbo does look damn good . Did not spot that one earlier - would be interested to know why it fares so much better at low rpm than Mazsport or SFR

That is why we are comparing the Pettit to the Greddy - because both do well at low rpm .
Which does better ? Not a lot in it if you are comparing at the same PSI .

Brettus

iTrader: (2)

where is your "supporting data" for this claim ?

TougeFiend

The one thing that I like about an SC is that it holds consistent boost, it will always have 6psi regardless. That was the big problem with the WRX, no matter which way you tuned it, you would reach peak boost inconsistently and sometimes at unpreferable rpm's (though, that might be just the matter of the laggy *** boxer engine w/ its variable exhaust pulses that push the turbo, not the turbo system...and this is on an A/T WRX btw ). The idea of having 6psi no matter what with a SC is more tempting than trying to tune for a consistent 6 psi on a turbo system. Of course, I have no experience with the Greddy system, I'll have to wait for SSX to take a full look at both systems I think. All the info and opinion's that you guys have provided is awesome, keep it coming.

tajabaho1

back to the topic, I really think that, once you put money into play.....I'd actually consider the turbo man, its 3k, pettit is 6k, even at stock, EVEN IF pettit is what.....20 whp more than greddy at stock, upgrading your turbo to 10-11 psi would not cost you as much as a pettit supercharger kit

its not to say I hate superchargers, I actually love them, but I am, case and point more towards supercharging my car than to turbo it(mostly cus I had bad experiences with turbo cars) but I'm not buying a damn pettit supercharger for 6k to get the same as a greddy turbo upgraded for like 5k, hell no

which is why I'm waiting out, its not like money just fall out of the sky (well for me it came in the mail)

btw, MM, would you build a stable turbo for the AT rx-8 with say, 260 WHP?
how much would that cost?

quick_dry

mazdamaniac: why is a positive displacement system a bad choice and is that something rotary specific, or a claim in general?

I agree that a turbo is probably a better choice than a centrifugal SC, without a CVT/gearbox for it they're just a turbo that drags on your engine and can't get max boost until redline.

sosonic

Hahahahah.... We may disagree about a thing or 2, but I damn sure agree with that. Re-Amemiya is like Pro "designer" tuner expensive...


About the price difference...

One of the major factors is using the Int-X. A Greddy kit using the Int-X would also go up in price. If the Cobb AccessPort ever comes about... The superchargers may be able to use them to flash the ECU and the price would be cheaper. Tuning may get cheaper as result of that too...

If they ever get their act together, install prices for the supercharger should fall over time. Especially if they ever come out with a video. A Pettit supercharger install video would mean they could not keep enough of those superchargers on the shelf... Though other issues may arise... However, it would still be easier to install the superchargers than turbo.... Though I do agree you get what you pay for it and installs can be screwed up regardless of the system.

Yeah, I expect the Greddy to be cheaper... But there is a case to be made if the Greddy is really cheaper over time. There is also lots of little things being bought, tuned, and lots of little things that happen over time.

I'm also a fan of constant and consistent boost... I like to know what's coming, when, and how much of it.