Thanks, Dave!

I should also say that my point wasn't for him to draw too much from my experience. My setup is still very new and is still being tested - bad things could still happen (knock on wood that they don't . My point was more just that people in general have gotten good response to boost on the 4-port and that despite its inherent disadvantage to the 6-port, it is possible to have a lot of fun with this motor.

 

mdw1000-im glad to hear/see your experimenting and i'd like to know too how everything goes,goodluck on the journey bro.BTW,like that you tried the FEED 4.777 ring gear,wondering how that is..i was looking at that too

So it seems guys, that this is my conclusion to the 4port/4 speed A/T power potential.The 6 port and the 4 port were originally designed as N/A motors,the 6 port having the advantage.Without forced induction,the only way to get more air into a motor is gonna be intake design and we're on the short end of that stick, being negative 2 intake ports.If you asked me,"what's your theories on a N/A build of a 4port,i'd say(horsepower wise)the 6 will always make more than the 4 port because no matter how much fuel we have,we'll never be able to match the air getting sucked in.the trannies im not gonna go into anymore for now cause thats alot longer debate.The 4 port has more potential to find and im not completely satisfided with the amount of experimentation done yet.So,with more F/I experimentation,we all will hopefully see a happy ending.Without having to sell your kidney to pay for a 20bT swap...



~R

 

The 4.77 gear is a noticeable change. Not huge, but noticeable. You will probably get more bang for your buck with FI if budget is an issue. I had written up reviews of it in some old threads, but I can't seem to find them now.

Keep in mind that your gas mileage will be slightly worse, and your potential top speed is a little lower. But considering how insanely tall our 4th gear is, I wouldn't worry about that.

 

I'll try to find out more,you got me putting the ring gear in the back of my head as"things to buy"when it comes to this Rx8 i got..Oh yeah,this threads done unless someone has something important to add

~R

 

I'll disregard the rest of the post AND what you originally typed to just clear up this specific point and hopefully push you along the right path. The port timing is different between the two motors. While the exhaust port area is the same the timing is different which will create a different flow profile.

 

Talk to Paul at Mazmart about the ring gear. Mazda has their own version of it now (the 09 MTs use it). He and Rick Engman can build you a high quality differential.

 

To add to mac's point, keep in mind that an AT will always have more driveline loss than an MT. So even if you were to get the rpms to 9000 on a 6-port AT, you'd still have less whp than an MT.

Now if Mazda would give us a SMG or DSG, things get more interesting. But technically it is no longer an automatic at that point because you've removed the torque converter. It is a manual that can shift automatically or at least has an automatic clutch.

 

mac-your point is dually noted

mdw1000-you are right,also,the drive shaft is steel on our A/T's and carbon on the M/T's i believe,but yeah,a little more work for us to do in the end...

~R

 

dually?

 

yeah,that was suppose to be duelly ,not dually,but if you like big trucks...

~R

 

One thing though, wouldn't it be much easier to streetport a 4port and gain more power than a 6port Due to the lack of aux port and the other one (which I can't remember)? Also, when you go forced induction on the 4port you will gain more torque than you would on a 6port.

 

You can do some port work. In comparison to a 13b-rew streetport the renesis dosent have as much material to work with. Remove to much and you're in the water jacket. Even if you do port the motor it total port area wouldn't equal the 6ports port area.

I'm not saying it can't be done. You can do it but your planning and engineering need to be well thought out.

 

I thought the max was 300 for the tranny but Mazsport screwed me over so I never got to find out.

Off Topic...

Check out the top 2 STOCK Corvette C6 runs...
#1) 11.71 @ 119.94 - AndrewZPSU - 08 M6
#2) 11.80 @ 118.82 - Gmrulz - 08 A6 Z51, Npp
http://forums.corvetteforum.com/c6-t...lenge-200.html

5 of the top 6 are automatics - and the list is pretty long.

Add some bolt ons:
#1) 10.62 @ 126.98 - Dennis50NJ - 05 Z51 A4 - CAI, CB, conv, ewp, fast, hdrs, 3.73, ptb/int, tune, DR
#3) 11.25 @ 125.07 - Jbsblownc5 - 08 M6 Z51 - CAI, CB, Hdrs, ported int, 3.73, torco & meth inj, tune DR

The fastest with just bolt-ons is an automatic. By more than half a second.

Add a blower:
#1) 9.73 @ 143.17 - Doug@ECS - 05 A4 F55 -Novi 2200, alky, Cam, conv, hdrs, RPM trans, 3.4 gears, tune DR
#2) 9.93 @ 136.88 - Tekhombre - 05 M6 - SC, Cartek cus fuel sys, H&C, hf cats, HD rad, tune

The fastest with a blower is an automatic.

The day has already come where automatics hold their own - and do better than - manuals. I was seriously getting tired of hearing all the crap about, OMG YOU HAVE AN AUTOMATIC?? I can't count the number of times on the vette forum that people wish they had got the automatic because, YES, it is faster.

 

You are comparing apples to oranges. The auto trans is not a limiting factor when hooked to the LS motor. It is a limiting factor when you hook it to the Renesis.

There are factors you are not considering that make the playing field not level when comparing the MT and AT in an RX8:


04-05 AT is a 4 port engine vs 6 port engine.
AT is limited to ~7500rpm redline with the factory tq converter.
AT has more driveline losses than MT
04-05 AT is a 4-speed gearbox with REALLY REALLY tall gearing, meaning significantly slower 0-60.

 

subscribing for more info

 

What type of information

 

for anything i can do once I get a new engine from Mazda

 

The number one thing holding autos back is probably a lower number of people running enough boost on them to blow them up.

1. The number of ports is somewhat irrelevant. The flow area and timing generally just establishes your engine's natural preference for torque versus hp. See the ford 5.0 for what can be done on a lower flow area engine. Granted, you are not going to build a rotary torque monster, all things being relative.
2. Autos dominate bracket racing. C6 autos and Rx8 autos are not the same beast but faster and more reliable shifts hold true. Number of gears is irrelevant if people later on change the gearing. 4 gears is enough for a quarter mile (if that's what you're looking at).
3. The line of what can and can't be done moves progressively over time. The MTs are certainly making more power now than 2 years ago.
4. Compression ratio is merely an inconvenience. The new 335xi has a 3.0 twin turboed engine with 10.2:1 compression.

So go out, blow up some engines and some trannies and see what works. Maybe the ceiling is generally 80% of what you see in an MT but if the MT barrier keeps moving north, so does the AT.

 

If you are more specific you will get good answers from those that have tried the various mods. If you stay general you will get dumb answers and maybe flamed.

If you want to do what this threads name suggests then go FI or Nos - don't screw around with bolt ons as they do little or nothing. If you don't go overboard you can end up with a fine daily driver that is very reliable and has enough added power to satisfy you. Of course if you want the screaming flame shooting dragon racer you can do that to but I hope you are mechanically inclined or have a boodle of cash.

 

RJ, I cheer you on. We need more like minded A/T owners out there. The only limits we have are ourselves and pysics, neither of which are controled by the opinions of others!

I am just begining my journey on moding my 6 port A/T but so far at about 2-3lb boost I am hitting about 200 RWHP. I am just about to push for hitting 300 but plan to add meth injection to insure I don't pop the engine.

While our engines are not exactly the same I look forward to hearing any results you achieve and the specifics of how you did it.

On a side note, when looking at FI I decided to go with turbo over Super Charger. I was originally leaning towards SC but had a discussion with Charles R. Hill (BHR) which led me to Turbo instead. The basic jist of it was that with the A/T your tq doesn't engage until higher RPMs and the spool point for the turbo isn't much higher than that. You can launch the car at just below the boost point so you really are not losing much off the line from a SC and don't hurt the top end as much as an SC would. This would not be true if it was a M/T but obviously we don't care about that ;-)

 

When I was first thinking about going FI, I would hear that you can't FI an a/t then I would hear that I would detonate the tranny if I tried to boost more than a few psi. All I can say is if I would have listened to the nay sayers I would have missed out on a great performing vehicle. There are some that say the turbo is the only way to go and others that prefer the supercharger. My style of driving suited superchargers as does my past experience. For dollar cost of the equipment and what you gain in enjoyment and performance it's a waste of money trying for added performance by using bolt-ons. Bolt-ons have their place but usually to enhance the FI performance or change the sound.

 

Hey everyone,Sorry ive been MIA for the past week cause of work,but yeah,ive been thinking about everything discussed about in this thread and feel confident to journey into this realm with you guys,to say if im gonna go S/C or Turbo is still undecided,both have there ups and downs.But anyways,still subscribed.

~R

 

Did you by any chance dyno before the turbo? 8.5 psi on the Greddy snail netted 202whp. Now if you are see that at 2-3 psi thats very cool. You don't have the Greddy do you? (duh ,just read sig)

F the naysayers! If I listened to them I couldn't heckle Phil like I do.
You still haven't figured this out? Tubo IS the only way....

It entirely depends on what YOU, not the others here that post want from YOUR 8. For Phil the SC works great for his requirements and the turbo works great for me (now if I can just figure out that boost controller)...

I don't see a reason for rehashing +/- of either one. I have no problem anwsering questions if they are honest "hey Idk this". Stupid ones, dumb looks are still free.

 

ok here is a general question.... if tuned properly (for both S/C and Turbo) is it possible that the engine will last almost as long as it was stock? Basically, how long would the engine last if you put a properly tuned FI onto the car.

 

^^ too many variables to even give you a decent S.W.A.G.
(Sophisticated Wild *** Guess)