Rev Limit on Auto
 

The RX-8 Auto engine should be able to handle 9k to 10k revs like the manual/T. The limiting factor would be the transmission. Also, when going from 0-60 or the quarter mile, the RX-8 auto hits the rev limit way too fast and this prevents it from getting its full performance.

With an Automatic Transmission Cooler and different transmission fluid, do you guys think it would be safe to remove the rev limiter/inhibitor on the RX-8 Auto?



I'm interested in your opinion.

Thats odd, I remember a thread about this before. It must have been cleaned up or something.

Anyways:

The 4 port auto is a different engine than the 6 port manual, I'd say the limiting factor would be the port configuration in addition to the transmission.

If you wanted a safe 9-10K you would need an entirely different transmission.

Depends what model year you have, I think the new rx8s have 6 port autos

the 4 port autos might run outta breath that high, and if the torque converter saw 10k itd be wicked dead.

the new 6 port autos would have the ability, they make 212hp at 7500 and the manuals make 212hp at 7500 rpm.....its the same engine now cept that the revs are kept low. if they revved it to 9k like the manual, itd make the same power.

theres a reason mazda doesnt want it revving that high, i believe its mainly to save the torque converter. other guesses from other ppl aim for mazda wanting the manual to be the peak in performance and excitement or whatev......

personally, no company should sell any auto sports car. that defeats the purpose. its like gettin an suv in rwd only or a truck with no towing capacity.

suvs are to get u thru anything
trucks are for towing crap
sports cars are for fun......autos are not

I'll be sure to share you auto sentiment with my friends who drive beemer smgs, funny how I watch them destroy other "manuals" on our drives through the twisties, sure looks like they're having fun too. :rolleyes:

I would be more happy with the auto if you could just rev it up more that 2200 rpm or so on take off. If I could powerbrake and rev up even to just 3-3.5K that would be nice. I think that alone would give it a lot more pull at least in the 0-60 range.

Well I'm going to try it. I think the RX-8 auto should be able to handle 9k, plus the ATF cooler and performance transmission fluid should help. At the very least, the attempt to increase the rev limit should help.

The question then becomes how to go about increasing the rev limit. I wonder what some Mazda mechs would think about this and if they would help.

As for the wise crack against autos. Dude, RX-8 autos can be run in "manual mode" too (not excactly the same as M/T, but still fun). I've also done 0-60s in auto and in "manual mode". The manual mode does make a big difference, because I can control when it shifts after hitting the red line and rev limit.

Its just a whole lot more fun to be able to switch from Auto to Manual mode (and back the other way) when driving in the city, getting kissed by your girlfriend (i mean upstairs and downstairs), or when watching videos on the DVD player and navi system. Lastly, if it was not for the RX-8 Auto, there might not be any more new RX-8s being produced. Not everybody is a "stick jockey". Also, the weird "auto hate" and "auto de-tune via Mazda", really makes little sense. Giving people choices, makes way more sense and increases sales. As for the Mazda "de-tune" on Autos, that is really madness because there are a number of solutions that could be thought of and I'm no Mazda tech.

I think the RX-8 autos can be modified to bring them much, much closer to M/T level performance and beyond ( if you add supercharger or turbo ).

JTtheDude, totally agree with you. If you "semi-race" the autos, you can easily see that the rev limit is one of the major issues with slowing it down. The RX-8's "power" comes from the high revs and the ability to easily and quickly rev that high. If you could launch at 3K to 4K and had a higher overall rev limit, you might be able to see a 6 second auto (with mods) and low 7s should be a very safe bet.

Right now RX-8 autos that I have been in, with the passport G-Timer and no mods, see 8 to 9 second 0-60s (high, but low enough that you can improve and get into 7s or perhaps 6s). Adding CAI, ATF cooler, new transmission fluid, 2nd oil cooler, tuning, flashing ECU, and perhaps getting that rev limiter higher should get the RX-8 autos into the sweet spot. Those combination of mods are also, NOT as expense as a supercharger or turbo (though I will eventually go supercharger anyway).

Hey man, I rev up to 8100 rpm for 2 secs delay shift from 2nd gear to 3rd.

The car was choking.

Funny thing about the Auto, is that I saw better times launching between 1500 rpm to 1750 rpm than at near its limit of 2200 rpm. Just coming near that rev limit seems to bog down starts.

I'm not clear what the 2200 rpm or so launch rev limit is all about. Obviously, 1st gear can handle more. I heard some weird sounding stuff as to the reason. But none of these reasons seem to apply to the M/T guys for some reason.

I'm not sure what the 2200 rpm rev limit is all about, so if anybody wants to provide a reason, feel free.

As for going up towards 7000 rpm, its a bit tricky. If you go to manual and shift just before the beep of the rev limiter than you can get better times. I really think thats the trick, you have to get more out of 1st and 2nd gear (on a 4 speed). By doing things to protect your transmission ( ATF cooler, ATF, etc... ) and raising the rev limit here to 8000 k than you should see an improvement in times.

The trick here is that there is a point where the extra rpms give you diminishing returns. You have to find that " auto sweet spot". It appears the rev limiter is cutting in before the "sweet spot" for additional power and below what the auto transmission can handle ( to be on the too safe side).

The cool thing about the 4speed auto is that you only have to shift once in 0-60 and just about leave it at that for the 1/4 mile (it comes close to needing that 2nd shift though and you may or may not have to depending on how much "street space" you have ahead of you). With the rev limit raised to 8000 rpm, you should only have to shift once.

Of course adding a supercharger will do wonders, but its nice to get the non-turbo and non-supercharger RX-8 up to their full potential.

It appears thats the rev limiter kicking in and its limit depends on what gear you are in. Thats what I mean about raising the rev limit, but to a just tolerable point for the auto transmission. I'm thinking the auto transmission, if taken care of, could handle a bit more.

If the RX-8 had smg it would be different. Don't try tell me the manual mode is the same thing, is no way close.

:)

http://media.putfile.com/Cj-RX8-184mph

https://www.rx8club.com/rx-8-multimedia-photo-gallery-6/184mph-rx-8-a-98135/

That's the torque converter. Stall speed is too low to brake launch much higher. The torque produced by the engine (remember the converter is a torque multiplier) overpowers the brakes. With a higher stall speed converter, the launch point could be raised. The converter would have to be modified or a new one built. The bonus of this is better converter efficiency, and custom building one would allow for making it more efficient at high rpms. Less slip in the converter would put more power to the ground. Custom TCs tend to be expensive though.


Raising the rev limit really won't do much. You could probably raise it to 8k and get a little better average power, and you'd land higher in the power band in the next gear (which would probably be the biggest benefit). But the engine is not going to get much more air above 7500 without addressing the intake ports, and then you're going to lose some low end. But the intake ports should have a lot of room for work, and combined with a supercharger/turbo would make some impressive power I bet. $$$$$ though.

Thanks...

Even rasing the rev limit a little bit and in the 8000 range would be a big benifit to the RX-8 Auto. From 0-60 to 1/4 mile, the RX-8 is still accelearating comfortably before being "stalled" by the rev-limit. Putting the range in 8000 should also allow you to hit the "auto sweet spot" for the maximum power per rev that the auto could get in 1st and 2nd gear while doing a 0-60 or 1/4 mile.

It also seems there might be a market for an RX-8 auto torque converter. Even with the upcoming new supercharger releases, a new RX-8 auto torque converter would be something many guys may want. It would of course depend on the price and benefit. Nevertheless, rasing the rev-limit will improve 0-60 and 1/4 mile times on the RX-8 Auto; this as an inhibiting factor is very obvious when you run the RX-8 Autos.

I was checking this website, http://www.specriteconverters.com/race_series.asp , and their racing torque converters don't seem all that expensive (starting at $700 dollars). They have 3,000 to 6,000 RPM stall. That would be more than enough to launch an RX-Auto at 4,000 RPM.

It would seem that somebody making a supercharger kit for the RX-8 Auto, might want to include an torque converter option. The key would be to have people building and having experience building custom torque converters for the RX-8.

If anybody has information on building torque converters for the RX-8, feel free to give info.

I had the rev-limit/speed-limit cut on my RX-8 Auto. Its now in the 8,500 RPM range. Re-amemiya can do 8,500 RPM or raise it to 9,000 RPM for you (for the Autos). It is advised to change your transmission oil and get an Automatic Transmission Fluid Cooler.

The change does appear to give me a 1/2 second improvement from 0-60 and of course lets me have lots more fun going really fast.

Re-amemiya has a test project going to customize torque converters. They said its very hard and will take a while. They don't expect the project to be finish until sometime around March of next year.

Off topic, but Re-amemiya has this cool test NOS kit project too. I don't know when that will be finished or if they are making it available yet.

Anyway, the torque converter is a huge "bottleneck" on the RX-8 autos, so somebody making customized torque converters for the RX-8 would be great.

I want to max everything out (rev limit, air intake, 2nd oil cooler, ATF cooler, customized torque converter, etc...) and see where that will take me, before going SUPERCHARGER (though I'm 100% going to do it and just looking for the right kit).

Automatic transmission threads in Automatic transmission forums are just that. MT vs AT has no place here. Go troll somewhere else please.

4 port will not run out of air. The updated greddy turbo kit has a plate to block off the extra ports - making the 6 port engine 4 port. People have done this on the 7's too.

so is there a supercharger or turbo kit for auto tranny rx8's???

blitz supercharger has just come out for the auto too. look for that thread. Hymee is making one, Pettit is making one for the AT (i think), and there are a few other options coming soon. search and you shall find.

Another "rev-related mod" seems to be the pulley. It seems from various threads on this site that the Agency pulley is worth it ( http://www.rx7store.net/product_p/ag...r%20pulley.htm ). The Unorthodox Pulley ( http://www.rx7store.net/product_p/unorthodoxrx8.htm ) has less underdrive, which may prevent problems with the battery and running a lot of electronics, but its unknown if you can get the same results as the Agency pulley.

The benefit would be revving to higher rpms faster and a 5 to 10 HP increase. The main concern with it, is whether or not there are issues with the AC at idle, running an amp with this mod, or any long term problems.

If it can be substantiated that this mod works well in the RX-8, it should help with 0-60 times and faster starts. At the cost of only $145 dollars, this mod looks like a good choice.

Hey I thought I would post since ive posted a couple times on ATs. Well im not saying i know everything or pretend I know everything I just post stuff that i know and ive seen other then that I really dont pull shit outta my ass. Ok back on topic I rev to 9k with my AT but the only problem with that i really shifts bad since the torque converter slows it and its really hard shift so I really dont recommend it. I fell 8k is a good limit on the AT it shifts smooth and u fell the AT really pull. Ive got the interceptor-x, AEM cold Air, Mazdaspeed exhaust which sucks in my opionion, RP supercat, and Unorthdox pulleys. Ive even switched my oil to 5w-30 royal purple which makes the engine run smoother that just what I feel IDK u might feel something diffrent. Sorry im getting off topic but on the rev I think u would need to do some major transmission upgrades to get 9k which i really dont feel are worth it since u can work on other stuff and get power that way instead of droping money on just revving but I will admit I like revving higher. This is just my 2 cents thats all.

kowzan5, was that unorthdox pulley worth it? Did you have any cel light isses?

I'm going back and forth between getting the Agency pulley or the Unorthdox pullery.

Also, it looks like you need an ATF cooler and new AT Fluid (Red line is good). Thats recommended with the rev-limit increase

I raised my limit to 8,500k. I backed off on the 9,000k because that was pushing it. But if I get a new torque converter, than I will probably raise back. I do feel the increased performance with the 8,500k rev limit.

I would love to see what a customized torque converter can do for the RX-8 Auto, I'm so surprised that they are not more common and people don't have kits for it.

Well on the CEL light no issues it went on and off the first day and then stayed off. If they are worth it well I would say ya I felt a little more power nothing like the interceptor though I fell alot from that. But on pulleys ya if you really want to go up to 9k I would recommend them like I said I felt it pull a little harder. Im sure an ATF cooler would Help hell I cant hurt and cooling is the best mod for lengthing the life on any car. I was planning on changing my Transmission Fluid to Royal Purple but its looks like a pain to change the fluid so im holding out on it for now. Good luck on getting to 9k keep us posted sound intresting.

Could somebody in the US check out the availablility of any automatic transmission or torque convertor upgrades from this company: -

www.levelten.com

[QUOTE=sosonic]I had the rev-limit/speed-limit cut on my RX-8 Auto. Its now in the 8,500 RPM range.

I have reread this thread several times and still seem to be missing something. How did you have your rev-limit/speed limit cut on your AT? By changing a pully? I am interested in how you accomplished this.

Hi, I had mine re-mapped by Re-Amemiya. The rev-limit/speed limit was cut and I can easily rev it up to 8500rpm. I was told that it could be rev pass 9000rpm but I have not tried that yet. I am also very interested in the Agency Power pulley, have anyone else done this on an AUTO 8 and have you had any issues???
Cheers!!!

Re-Amemiya did mine also.

The pulley would be separate mod. The pulley should help you rev to high rpms faster (since it is lighter than stock), which is arguably not a true HP increase, but will make you faster in the 0-60 and 1/4 mile and show up as an HP increase when tested. People are claiming its an 10 HP to 15 HP increase. I've not done the pulley yet and I'm looking into it.

I'm also really more interested in what a customized torque converter could do for me, but we have to find a vendor who can do it for the RX-8 and re-amemiya will not finish testing their customized torque converter until next year.

Hi Sosonic, does your car run cooler, rev up higher before changing gears and generally feel more eager after the Re-Amemiya ECU re-mapping?

The rev limit is now higher, 8500rpm ++ but I do not know at what RPM it cuts off and my speed limiter of 180+km/h ( Mine is JDM model ) has been removed after the re-mapping

It was money well spent as I could definately see an improvement in the temperature ( about 5 degrees cooler for water and oil temp based on my Defi gauges and the centre console no longer feels hot like it used to )

I,m looking forward to the Pulley Mod once I am sure I will not face any cel or other issues.
Anyone else who has the AP Pulley on an Auto 8 please comment

I don't have temp gauge, yet (working on car navi/stereo upgrade), except for the stock. So I can't get exact reading on temp. On the re-amemiya paper that they give you, it shows that the ECU flash also turns the fans on sooner/at a lower temp to cool the engine. The car does run faster.

I have the same issues as you do about the Pulley mod. Cel and other issues concern me, I'm going to keep asking around and consult some local mechs about it. Its down to either Agency or Unorthodox, just want to be 95% comfortable with which I choose. But, its a kind of cheap mod (well least not the most expensive).

Do keep us updated if you do either pulley, I will do likewise & cheers to all who responded in this thread.... :fingersx:

I really feel for you guys with 04/05 automatics who are still dreaming of making this car faster, cause I remember the struggle back when I had mine. By the way, if you want to launch past 2200 RPM, you can try putting the car into neutral, revving it up to the desired RPM you want to launch from, and then quickly shifting into drive (a neutral slam). Whenever I tried this I was never sure if it worked too well, plus it has the potential of causing some damage your torque converter. Then again, if you guys are trying to increase your rev limiters past 7500 these days, it's pretty clear that you don't care too much about the health of your tranny anyway. Good luck guys.

The high revs won't hurt the tranny as long as you take care of the extra heat. Won't hurt the TC either, it just won't be as efficient above 7500 (again take care of the heat). Neutral slams will hurt the tranny and possibly the rear end.

I'm pretty sure Re-Amemiya knows what they are doing when they raise the Rev- limit. When they re-mapped the ECU, they must have taken into account that with a higher Rev-limit, the tranny and other stuff will run hotter too. Those who had their ECU done by Amemiya will know that the car runs much cooler because the fan cuts in earlier to cool things up. :ylsuper:

Yeah, neutral slams are a good way to force you to buy a new tranny way sooner than expected. Much more interested in customized torque converter... I want the car to consistently be able to handle high rev launches, without buying a new tranny every 6 months.

The low power renn uses a differn't e-shaft, main bearings (non multi window), and rotor bearings. Infact the bearings are identical to the ones for the 86-91 rx7's which had a maximum redline in the 89+ NA's of 8000 rpm. I wouldnt take that motor above 8500 rpm. The motor is not build to take 9000-9500 rpm like the high power.

I have installed a Agency Power crank pulley on my 04' Jdm Rx8 AT 2 weeks ago...

No CEL or any other negative issues...couldn't tell the difference in air-con temp either.

Power-wise, it revs noticeably faster from 3K onwards. That's all.

Faster revs = better acceleration.

Hi, I noticed that you are in Singapore too! Did you have the pulley upgrade done by a local workshop and how much did it cost you? In SGD...Singapore dollars so as not to confuse the others over in the states..... :rock:

I had the pulley installed by Monster Garage. The installation process was a breeze for them. Cost SGD30, but that was because I bought the Autoexe underbrace kit at the same time.

So far, after doing so many mods on my AT...the most effective one would be the Knight Sport Final Gear 4.777. I highly recommend installing the pulleys with this gear. Awesome results! :Eyecrazy:

[QUOTE=sosonic]Off topic, but Re-amemiya has this cool test NOS kit project too. I don't know when that will be finished or if they are making it available yet.
[QUOTE]

Dont think they will manufacture it for the AT cause I have checked with them before.

Did you buy the AP pulley from them? Or did you bring it in from the USA and $$$$ ???
Thanks :D:

Nice and thanks for the info. Feel a little better about the Agency Power Pulley, but anybody else feel free to tell their stories about it. Would be nice to see a Dyno number of the Agency Pulley too.

I'm still on pause mode, since I'm seeing what type of numbers these new super chargers (Axial Flow and Hymee) will put out and how much they cost. Also, I'm studying on the customized torque converter issue and seeing what kind of price and HP numbers I could get. If the SC or torque converter is some crazy price or the numbers are not to my liking than I will go with Agency Pulley and MS/AEM or RB Cold Air Intake, and save up (eventually going SC and/or customized torque converter later on).

The customized torque converter still intrigues me very much, as I'm hearing you can get a decent HP gain and performance from it. Maybe 20 HP. Torque converter, Pulley, and CAI might give some really decent performance and HP numbers for an NA RX-8. Want to compare that with the price and HP numbers for the new superchargers and then decide.

a custom tourque converter is an interesting idea. so the point of it is that it idles higher so that you are already at a higher rpm when you go?

would this mean that you would get noticably worse gas milage? or is there some way that it can be shut off and on?

Not really.

The stall speed of a converter determines what rpm the car will take off at (when you floor it from a stop). If the car does not have enough power, you'll not reach stall speed without brake boosting. There are actually 2 stall speeds, but I'd rather refer you here: http://auto.howstuffworks.com/torque-converter.htm ; than mangle the explanation.

I'm not 100% sure what the stall on the 8's converter is, but by all accounts the tranny is from the FD, so makes me wonder if the FD's converter is the same as ours. In which case, upgrades should be easy to find.

Edit: turns out HSW doesn't really explain stall speed, but I can't remember where I saw a good explanation.

oh well. if the converter is the same as the FDs than that would be awesome and give us many more options.

has anyone even looked into this?

I thought it WAS the same torque converter. Can't remember where I read this, unfortunately. Same tranny, same converter to save money.

Could the interceptor-X be used to raise the rev limit also? Getting it with the pulley, intake, along with other "simple" bolt on and getting it tuned seems like the best bet.

I have the a 2006 6spd auto though with the sports package and would love to rev it just a bit higher and faster.

I'm in the Dallas, TX area, anyone know where I can get my ecu reflashed and rev limit cut in this area? Are you guys having to send off your ecu to be reflashed? How much does it cost to do this? How long is the downtime to get it done? I've searched and the only info I can come up with is it's possible to cut the rev limit, I can't find out who will do it, is there somewhere to go that's better than others? I need help. I want it done but I can't find out anything on where and how. If you have any info that would be awesome.

I talked to mazsport and you could use an interceptor-x to increase your rev limit along with all the other goodies it can do however it cost $1500 which is a lot more then a rev limit cut ecu reflash. The other posters said they sent their ECU to RE-Amemyia which is in Japan as far as i know. you could be without an ECU for up to couple of weeks depending on your shipping methods, how much is 1-2 day global to japan? lol. Also their products are are pretty high, so along with the shipping cost dont know what the total cost is. If one of the guys could post how much it all cost that would be awesome.

The price of the re-map is 50,400 YEN? which is US$424?
Just guessing since i dont understand japanese

http://www.re-amemiya.co.jp/rx_8/rx_8_cpu_redom.html

Hey fellow AT 8 owners. Ok I was looking at this thread and I see that people took off the speed limiter. The max mine goes is 125mph because of the speed limiter. Is there a way to get rid of the limiter without taking off the rev limiter? I dont have the money right now to replace the tranny so I dont want to mess with its rev limit at this time. But I always race and I know my car can go way past the 125mph limit. Any ideas?

Well, it could be done.. I just don't know how.. lol..

I have heard of some companies that can do it, there is a chip that modifies it but it takes of the rev limiter as well. All in all if I have to rob from peter to pay paul then so be it. I would just rather not.