shelleys_man_06

Check out MazdaManiac's thread on the e-manage . Sorry about the rudeness. The post sounded like some nonsense from the RX7 Club webpage. Yes, there are some new and much better turbochargers other than Mitsubishi/Greddy's T-Series. I won't deny it. I wouldn't mind trying out, for example, a GT3540 dual ball bearning turbo over its journal bearing equivalent. GT Technology makes Buchi's device much more efficient. I just don't like the talk about dyno sheets. My philosophy is to put your money where your mouth is, and take your car to the track. BTW, aren't there ball bearing cartridge options for T-Series turbochargers? Welcome to the club, friend .

shelleys_man_06

If ball bearing turbochargers are the supposed future, then why are there still journal bearing options? Is there a limit for friction bearings before they are compromised?

shelleys_man_06

In addition, the e-manage and the PowerFC are not analagous. The e-manage is a piggy-back and the PFC is a complete stand-alone device. Also, the PowerFC is a vehicle-dependent EMS.

shelleys_man_06

Also, you can say that you can retard the spark timing, control the fuel supply, etc., but it's much harder in practice. This engine is quite new, so figuring out how it behaves under certain conditions is going to take some time. And, unfortunately, we are confined to PCM tuning until we can turn up the ****.

cretinx

Yes I'm aware the e-manage and the PowerFC are totally different units, just two options I've always liked to use in the past (Celica GT-S). I hate my current setup (S-AFC on my Eclipse GSX) and have been pondering Haltech, but it seems like I'll be selling this overweight pig to get the RX-8 and shut up the kids at NewCelica.Org with a nice 400hp turbo setup.

So yes, we need to crack this ECU. Well, more specifically, someone who isn't me needs to crack this ECU. I'd relish an AEM plug and play standalone, simply because its so easy to use.

As far as turbos, dual ball bearings are expensive, and aren't needed in every application. With this motor displacing 2.6L and revving to 9500rpm it should spool up even a large journal bearing turbo in an acceptable amount of time. However, I love instant response, the IHI VF23, for example, hits like a supercharger when equipped on the Celica, however, this is a bad thing with FWD where you want some time to get traction before melting the front tires. I know the RX-8 could handle a dual ball bearing - I've practiced launching a few at 7500 rpm with no wheel spin, the car just flies off like it was in a slingshot.

Anyways, I'm still torn between rebuilding an RX-7 from a $6000 shell or just getting a new RX-8, crossing my fingers, and hoping the aftermarket develops (and these bizarre dyno readings get sorted out).

shelleys_man_06

You could design your own turbo kit, although it's going to cost tons of money. Ever since you made that post, I've been doing some research on the latest GT technology turbochargers. I know this is a pretty big turbocharger, but I am interested in experimenting with a hybrid GT3540R. The target is 360+ rwhp. I'm sure you've read about this in other threads. It's my side project...

I wouldn't recommend any stand-alone EMS without understanding how this car works. Plugging in rong (I spelled like that on purpose) values for fuel/timing maps can cause serious damage. I wouldn't risk it. Piggy-back devices aren't so bad. They're not as flexible such as a stand-alone, but they're relatively simple to tune. We all don't want 800 hp, so there probably won't be much demand for stand-alone EMS's. I personally don't like the idea of having to build your own fuel map from scratch. I prefer to build on one that already exists. The e-manage and the Canzoomer unit do it quite well for the RX-8.

Also, turbo lag doesn't seem to be an issue today, even with journal bearing turbochargers. There are so many turbo options one could choose from. And yes, dual ball-bearing catridges are not always needed. Besides, both ball-bearing and journal bearing turbochargers can fail. The cartidge option is dependent on the application. Actually, journal bearings can perform just as well as ball-bearings.

A reason that the Celica GT-S had traction problems was probably the differential. Of course, if you have something like a VF23, you're going to get some wheelspin. Minimalizing it would probably involve a 1.5 or full 2-way LSD. I am assuming this ZZT23# had no LSD.

cretinx

Yes, the ZZT didn't have an LSD (though mine had a quaife up front, along with a light flywheel and ACT XT clutch). I did a custom turbo on my Celica and I've seen it work a lot of times before. In fact, a custom turbo is usually CHEAPER with regards to parts etc because you don't have to pay retail markup. You can get mostly everything in good quality on eBay. The only part I wouldn't skimp on is the turbo itself, but intercoolers, piping, blow off valves, wastegates, oil lines etc are pretty simple. The labor would involve custom exhaust manifolds and downpipes, tapping the oil lines and generally install of things which often makes it worth getting a kit because everything fits . . . . . and then the tuning. That is a huge headache.

I agree the eManage with the Profec E-01 is an AWESOME combination because its simple and the Profec E-01 can actually have boost levels dependent on RPM so you get smooth boost. I also know the S-AFC can be hacked so that your fuel loads are boost dependent (my friend who worked at Inline Pro for 7 years can explain more . . . ).

So yes, a custom turbo would be awesome on these cars, but I think I'd wait to see what the pros are putting out first. Turbo sizing is gonna be an issue. I'd decide what boost level you want to run first, and then pick the proper turbo that's within that efficiency circle, so pull out your compressor maps!

shelleys_man_06

It's not all about compressor maps. Remember that the turbine has to provide enough power to run the compressor. Depending on your sign convention, the compressor should produce a large fraction of the work provided by the turbine. I expect excellent back-work ratios of 40% or higher. The compressor map looks so appealing because it has regions, surge lines, etc. People disregard the turbine map because it's just a logarithmic slope. Turbine efficiency is just as important.

Isn't the Greddy Profec an fuzzy logic boost controller? I can't remember, and I'm too lazy to visit the site. If I had to go through all that trouble, then I would consider getting a stand-alone EMS. The Electromotive TEC-3 has all of these options, eliminating the need to buy more electronics. But, that is still pretty extreme. I think the RX-8's stock computer can handle some pretty big power gains, as long as we have the right ancilliary electronics, and correct tuning methods.

cretinx

The Profec B had the fuzzy logic. The Profec E-01 has boost dependent on RPM, and can be linked up to the e-Manage to make the fuel maps boost dependent as well (and since boost is dependent on RPM with the Profec E-01 they would then also be RPM dependent).

The hack into the S-AFC involves getting a GReddy electronic boost gauge and hooking the S-AFC up to that, making the fuel maps dependent on boost instead of RPM and throttle position.

I'm also willing to bet the stock computer can handle 5-6 psi with a piggy back fuel computer. What really concerns me are the initial low horsepower figures - I can't seem to figure out a straight reason why and most of the posts on that subject don't really help.

shelleys_man_06

I am about as clueless as you when it comes to how much the computer can take. You may be right. No one as of yet has utilized the S-AFC in the RX-8. Well, at least no one i know of. I think I wrote a response to someone who inquired installing/using the S-AFC. Try a search. It's somewhere there.

As for the RX-8's skewed power and torque figures, I myself have no idea why the 13B-MSP is 238 hp, instead of the proposed 247. My theory is the addition of emissions controls. It's too late to complain now. The car has been out for about a year, and I don't think Mazda is going to be making any apologies. I guess, except Japan, we are forced to work from the adjusted rating (I think it's much lower ). As stated in other threads, there aren't many options as of yet. But, I would be glad to keep everyone posted about my GT3540R project .

cretinx

Yes, keep us posted about the GT3540R, that's one twisted little turbo.

As far as boost is concerned, from what I've been told (by the professionals) the car gets pretty nasty with about 4 psi. 6 psi from a supercharger and some JIC Magic coilovers seem like a perfect combination.

shelleys_man_06

I just like the characteristics of the turbo. From what I hear from the FD3S boys, this turbo is unbelievably insane. Tomorrow, I'm going to the library to check out Corky Bell's turbocharger book. I need to do more research about this before I buy or even plan anything. For the suspension, I plan on waiting on what kind of options there are. It's still too early for me to do anything. I'll wait for someone smarter than me (there's lots of them here) to modify their car. Then, the leeching and usage of information will begin.

bureau13

Actually, the Profect B did not have fuzzy logic...its just a basic electronic boost controller. It was the unit of choice, at least in the GReddy family, for the twin turbo setup on the FD, BECAUSE it didn't use the fuzzy logic learning system. That was in the Profec aka Profec A.

jds

davefzr

Hey dudes.. Watch for Pettit racing to come out with FI

Motortrend magazine....

Omicron

Exactly. There is NO reason this cannot be done, WHEN (not if) the ECU is cracked. No matter what the naysayers say.

The bottom line is that 6-8 PSI boost is safe, and will result in 250-300 WHP. With this kind of power and ball bearings to reduce lag, this 3000 Lb car scream.

Would I spend $6000 plus for this kind of Porche/WRX-STi/Evo/350Z beating performance? HELL yes. :D If you want a cheap solution, sell your RX-8 and buy a Neon SRT-4.

davefzr

Look up Yes they did it.

WTF no turbo

Petit blew the tranny on the first pass in cali doing the magazine article. It starting to look more and more depressing for performance adds for this car everyday.Im taking off exhaust,wheels and some other aftermarket stuff in the next couple weeks.Putting it back to stock and going to use this as my comuter.Its a nice car but im starting to realize it will never be tuner friendly.On a happier note i should pick up my new fd next wekend,

shelleys_man_06

Dude, that's loser talk. J/K. Then what really was the whole point in you buying the RX-8? I think some of us feel duped because there aren't that many aftermarket options like the Z33 or the V35, or even the SRT-4. The RX-8 is a pretty advanced car, so maybe we're just too stupid to figure it out. J/K again. I'm going to wait and see what develops . GT3540R away!!

davefzr

that totally sucks!!!

They should have just taken it easy and not tried to push it... I got an invite.. well an invite to sneak in to california speedway to see it.. but I didnt go....

Rrrrrrrrrrrrrrrrr.......................

I wonder what they are planning now... Rrrrrrrrrrrrrrrrrrrrrrrrr..........

zoom44

sorry to back track here but this is really my first read thru of this particular thread. i am not an old rotary head. i'm fairly new and my knowledge of porting is only what i have been able to sponge up in the last couple of years. there was some talk before about porting the renesis. to my knowledge except perhaps someone mentioned in this thread noone has done any porting. my question is this while it is normal to do a port job on older 13b variations when turboing or upgrading the turbos do you think it will really be necessary for the 13b-msp? the ports on this engine are already something like 30% larger than previously and if we're talking just around 7 psi would porting really be necessary? and if so why?

shelleys_man_06

Porting the rotary engine is like changing camshaft profiles on a piston engine. Bigger ports allow more air to come in, as well as change the port timing. High-boost turbochargers need something like that. I am sure that the stock ports will suffice under a low-boost setting. For something like 7 psi, the stock ports will not be compromised. I don't think it would be a good idea to port a rotary engine for-low boost. What if the turbo doesn't supply the pressure required from the port? It would be like opening your mouth and not having enough oxygen coming in. You don't want to make the straw too big. Having too big a port can lead to a loss in volumetric efficiency, which can lead to a loss of power. I don't know the dimension or shape of the ports on the 13B-MSP. If what you say is true, and your application is 7 psi, then the stock ports are fine.

shelleys_man_06

Actually, I am glad you caught me. I just borrowed Corky Bell's book on turbocharging from my school's library.

zoom44

thanks your seems to mirror my thoughts. as to the dimesion and shape of the renesis ports there are some pics diagrams and sizes around here somewhere i'll dig em up for you.

zoom44

ok first here are some stats for you on the timing. grabbed these from one of buger's posts:

Primary intake .....opens 32° ATDC .....closes 40° ABDC
Secondary intake opens 32° ATDC .....closes 30° ABDC
Tertiary intake ..........opens 45° ATDC .....closes 80° ABDC
Exhaust ..............opens 50° BBDC .....closes 23° BTDC

The intake port timings are exactly the same while the exhaust port opens 25 degrees later (increased thermal efficiency) and closes 71 degrees earlier

also i was wrong earlier. the exhaust port size is 30% larger. the intake port size is 100% bigger than on previous 13b's!!

alsoread thru the original thread it's amazing what we were talking about 2 years ago. some of the same things as today. especially pages 3 and 4.

here is one view of the ports

meh i can't find the damn port specs!!! wakeech or rotarygod has them.

shelleys_man_06

rotarygod lives near me. If I ever meet him I will ask for the port specs .