Huey52

iTrader: (2)

I didn't say factory or aftermarket, I said manufacturer, which encompasses both. You actually affirmed my point. Concur therefore that Turbo's are the more cost effective solution.

Yes, they are both viable, and there are risks and rewards with either solution.

In practice s/c's are more reliable, attention to the needs of FI in general being equal.

I personally prefer a linear response.

Uh oh, I posted again.

dillsrotary

I prefer Windows XP than..... whoops wrong thread.

1.3L

This setup will probably give you the best results on your RX8:

Atilla

iTrader: (1)

^hell yes.

Huey52

iTrader: (2)

Just as a point of clarification, that's a Super-Duper-Charger (s/d/c).

Jedi54

iTrader: (7)

My Axial Flow Supercharger will PWN all the rest of you!!!

dozer

iTrader: (3)

Atilla

iTrader: (1)

Hey, nice engine bay YOU LIAR!

Jedi54

iTrader: (7)

I am incapable of lying.

dozer

iTrader: (3)

1.3L

Wow, very impressive! Question: does your supercharger installation keep the trick factory, 3-stage induction system? You know, the valves and ports that open up at various points as RPM climbs?

Thx,

-1.3L

blackenedwings

I don't actually think that the manufacturer reason for using turbochargers over superchargers is due to overall cost effectiveness, but more cost per output. Because turbos are not parasitic and incur no loss since they are using recycled "waste" energy they can produce power more easily. I know that is a simplification, but in a well configured (ie. factory) setup a turbocharger will be configured to be nearly as responsive as a supercharger would be and as reliable. Nothing makes either form of FI more reliable than the other. The biggest reason "in practice" turbos appear more unreliable is they can be tweaked more easily by people who don't know what they are doing. Modifying your boost controller to crank your TD06 turbo to 17 PSI to really pwn that Civic in the next lane is something you can do with a turbo. Short of changing out the belt for a supercharger you cannot make the same sorts of changes. Also because a turbo is very dependant on being properly sized for the motor, an improperly sized turbo causes a lot of reliability and engine safety problems. None of those issues affect factory turbo setups so a manufacturer has a choice of biggest bang for the buck. The manufacturer only has a couple of options, either displacement with a larger engine, or a power adder like a super/turbocharger.

Most large displacement cars, with torque profiles more suitable for a supercharger already have plenty of displacement to meet the need for a production car. In most cases of top of the line models of those same vehicles they choose superchargers which match those engine characteristics. The ZR1 Corvette is supercharged because the displacement alone of its naturally aspirated motor isn't enough to reach the target numbers GM had. Supercharging makes perfect sense for that car, and if you look at the 'Vette community you will find a lot of superchargers and few turbo 'Vettes. Superchargers are also good with automatic transmissions as the added stress of the additional power comes in with a smooth curve.

Turbochargers work especially well with small engines which can run through the first couple thousand RPM quickly, spooling the turbo and bringing full boost online. The additional bonus torque helps cars which have a generally low torque curve. The main reason most of the turbo 8 owners went with a turbocharger was for the added torque to address one of the weaknesses of the car. It doesn't mean thats the only consideration, but it is certainly something to think about.

The main thing to think about in my opinion that makes a supercharger really worth considering for the RX-8 is what kits for both forms of FI are available. Both Pettit and Hymee reputably make amazing kits. I've seen the Pettit system in person and its very well put together. There are no equally nice complete turbo kits available for the RX-8 currently. The SC solutions use OEM ECU flash software which is very reliable, and have a high quality kit built from the ground up. Most of us turbo guys have had to piece bits together from half a dozen kits (ie, my Frankenturbo) to make a viable FI build. For those that want to put that time and effort in, they can get a great setup, but it takes a hell of a lot more work than swiping your credit card and buying a Pettit system.

RIWWP

iTrader: (2)

Not a counterpoint, just a comment...even if it is kinda laughable. Manufacturer choices to go with superchargers more than most people recognize. Granted, it hardly applies here, but on the 'large' end, most big rigs are supercharged. And on the 'small' end, Toyota's TRD line used to have a few tiny turbos for it's 4-bangers, but now actually goes with superchargers...The Corolla for example

neXib

I have read it, and it makes somewhat sense. But so does many other things until you get the bigger picture and other opinions.

Bastage

iTrader: (1)

Send them an email if you want a bigger picture. Or bolt on a Greddy turbo and run more than 6 psi and validate it for yourself.

Like I said, pretty objective paper; not an opinion.

neXib

If I wanted to prove a point I'd get a good turbo, not a crappy Greddy. My point is just that for every problem there's a solution, and I'm not so sure you have to completely modify the engine to make things work, even if it doesn't out of the box with a Greddy boosted up :P

blackenedwings

Yes, an unmodified TD06 is WAY too small to handle the flow needed for the Renesis generating tons of backpressure at higher boost resulting in tons of heat which equals engine damage. It was a hack-job by GReddy to release the kit in the first place. As I said, the reliability issues people are referring to are often directly related to an inapropriately sized turbocharger for the application, a factor that simply doesn't apply to the supercharger kits. That doesn't make the application more reliable or turbochargers themselves bad. If you strapped a 48 psi pulley to your motor it would pop like a grape instantly, but in your case you just call up Pettit and ask for the proper sized pulley and you get it.

The truth is, the benefit of going with a supercharger is there are better products available. With a turbocharger you really need to know what you are doing and be willing to do the legwork to put together a kit. Hopefully with some of the work with the SFR kit using the AccessPORT now, and continued updates from Esmeril there will be a turbo product as well put together and supported as the Pettit kit.

DailyDriver2k5

BAHHAHAHAHHAHAHAHHAHAAHAHA! I spit up my vitamin water all over my white shirt and suit! Damn I have a big meeting to go into in 10 Min! Damn Now I am going to get fired because of your stupid A$$!!!!! LOL!

Red Rex

iTrader: (1)

Ehhh **** it. I don't have anything else going on today so I'll hop on this bandwagon again, especially since this is now a constructive debate thread instead of an all out flame war like I thought it would be.

Its common knowledge that the GReddy turbo sucks. Bad wastegate (I think?), horrible tuning software, and overzealous oil lines are the key problems. Anymore? And since Mazsport went under and MazdaManiac won't be building anymore of his turbos indefinitely, what else can you do with the GReddy kit? Fluid Motorsports offers an upgrade but I haven't found any feedback for it. Then there's the Esmeril turbo kit (nice but over-kill IMO) and....what else?

I know the Pettit kit is tried and true and just about everyone loves/respects it. And the Hymee supercharger is supposed to be uber awesome but I'm still not certain on the bhp/whp figures. Not a huge issue for me, I'm more concerned with the powerband than peak figures, but the info seems sketchy.

GReddy turbo - Fluid Motorsports upgrade
Esmeril turbo
Pettit Supercharger
Hymee Supercharger

What other options?

blackenedwings

No reason we can't have a reasonable discourse... especially since this is an issue a lot of people are concerned about.

The stock GReddy turbo (TD06) has a lot of problems with it including bad flow, undersized wastegate, oil only cooling, journal bearing shaft... etc. It was a cheap poorly sized turbo for the application that GReddy threw together with a bunch of crap and called a turbo kit. Because they were the first to market however, it sold, and people started blowing motors left and right. The lousy piggyback ECU made a bad situation even worse. I wouldn't even consider going FI with EManage.

With the advent of the AccessPORT and some of the other available turbos there are other options now that are more properly suited to the car. Some of them use the GReddy manifold and piping, others do not. Those that do not are generally speaking not able to use the AccessPORT for tuning, although SFR is attempting to change that. The available kits that I know of are:

SFR, PTP, Esmeril, Pettit, and Hymee. There are also two available upgrades for the GReddy turbo, one from Fluid Motorsports and the other from Bryan@BNR. Bryan's seems far superior as he includes the center cartrige for water cooling among other changes which should increase the reliability of the turbo significantly. I believe Fluid's modification is generally porting and results in much less change to the stock turbo. (someone with this mod done can correct me if I'm wrong here)

If someone had little knowledge about FI and wanted to get a "no hassle" kit for their RX-8 I would recommend the Pettit system. I haven't seen the Hymee setup so I just can't speak for it. The Pettit setup is very nice, and the customer service seems wonderful. For someone that is a little more savy and willing to do a lot more legwork I personally believe a properly sized turbocharger will outperform a supercharger with this car. The gains in torque are significant.

Red Rex

iTrader: (1)

Ugh!

A hassle free supercharger sounds very nice, and its not like I'll be tracking the thing every weekend so 0-150 mph figures don't mean much to me. But extra torque is always nice

Silly question, but how does a Pettit RX8 drive? I know superchargers are supposed to provide modest boost across the whole powerband and blah blah blah but that only tells me how a supercharger works. Does it still noticeably run out of steam in 3rd gear? How is driving in the city? On the highway? How much more power do you get in 6th gear at ~70 mph? Is there still a need to drop to 5th or 4th for good passing power? How much low end power do you gain? Are you still going to get passed by a Camry driving normal off the line unless you shift at 4,500 RPM?

These would be the biggest questions for me. If I choose to go FI I wouldn't do it to make the ultimate race car. I would want to build the greatest street car, which means more fun at all times at any time. Peak figures don't impress me much. We all picked the wrong car if we wanted to make dyno queens. The drive it what matters to me.

Red Rex

iTrader: (1)

BTW is the Pettit kit intercooled??

Took a quick glance at a pic and all I see are what looks to be upgraded oil coolers? And no piping leading down to the front of the car

EDIT: Took a better look and the Stage II Pettit system is intercooled, not the base model.

RIWWP

iTrader: (2)

^ This is why I would choose S/C over T/C. I have the patience to do the research and build a kit properly, and I understand that when built and tuned properly a turbo is just as reliable as the S/C. I have two motivations driving my opinion (which I am hardly going to be forcing on anyone) to S/C instead of T/C.

Motivation number one for me is I simply want to keep it as simple as possible, but something simple that works. I don't think anyone here would disagree that a proper turbo setup is more complicated than a proper S/C setup. Yes, when both are done properly, both are just as reliable. The extra complications needed to get a turbo working properly is a level of risk that I am not comfortable with, even with research. As it is, even the simpler complications of a S/C is more of a risk than I can take financially right now, hence why I am not FI yet. The T/C has additional complications that I don't see a direct benefit to immersing myself and my cash in. A bigger power spike later in the band is not a benefit in my eyes.

Motivator number 2 is part of what makes the 8 so much fun is it's flat curve, and a S/C preserves that curve, just moves it higher up the charts. The Hymee engine dyno chart shows an almost exactly even lift to the curve at every point in the band, and that is very very appealing to me.

Turbo can have higher highs than S/C. I get that. But do I need it? No. Do I even want it? No, not at the cost of the disruption of the curve the N/A has.

I would hardly call top of 3rd gear running out of breath, although I would also be interested in what exactly changes about driving dynamics with a S/C. I suspect very very little, hence the appeal.

Edit:
Not sure if Pettit kit is. Hymee lists an intercooler on the "included parts" list when ordering, so it is used. I can't see Pettit not having one.

Edit2:
How do we have 61% of people preferring turbocharger and 50% of people prefering supercharger? gg 111% of people reponding!
I think the poll's calculation is a bit off

DarkLord7854

People choosing to vote for both options throws poll off

kersh4w

iTrader: (3)

i voted for both options.

fail @ poll making.