veilsidev1

whats up,
so yea, i installed a REVi system a few months back and had been running fine, no problems. The check engine light turned on almost as soon as i installed it, i checked it out and everything was ok, i figured the MAF sensor was just getting used to the new intake. I went to the dealership for a flash upgrade and asked the question, they said the same thing, so i did not worry about it. About 4 months later, my 2nd gear started grinding, first when downshifting from third, then anytime i tried to put it in with rpms below 5k . I stopped using second gear unless necessary until i brought it in to the dealership to fix a few other problems. They called me today and told me the reason my second gear was grinding was because of the intake and the change in MAF. He said some bs and said some difficult terms to try and convince me, i couldnt really argue because i was driving so we said we would talk later. Im not really buying it. He said i should put the stock system back in and it should fix it, but i dont see how it can be related at all. They are already plannin on charging me about $50 for "figuring out" what the problem was, but i doubt it was that at all. Does anyone have any input, has this happend to anyone?. And if so how does it happen?. Is there anyway i can argue with facts against this and actually get them to fix the problem without bringing the REVi into it. Thanks

ZoomZoomH

iTrader: (1)

they're absolutely lying

how the hell can an INTAKE affect the TRANSMISSION, it makes absolutely NO SENSE

Xyntax

Nope. Try a more honest dealership if you can find one. Drive the extra mile if you have to.

They are trying to dodge responsibilities.

lurch519

ok, the only way an intake could possibly be the cause would be if you were driving the car harder. next time you talk to them, let them know about the magnusson moss act, that they cannot deny warranty unless they can prove the aftermarket part was the direct cause of the failure. technically the intake could be considered the problem with the engine or emissions system, but not the transmission. speak to a lawyer if you have to.

Ericok

Personally, I think your synchronizer is shot - that's why it can shift clean at high rpm and not low. In older, non-syncromesh transmissions you had to "blip" the throttle to change gears cleanly. Gets the oil and everything spun up for the shift. Good news: The part's not that expensive. Bad news: you have to disassemble the transmission to change it.

Technically, in a syncromesh transmission you never actually "grind the gears" (except for reverse - unless you're driving a Lamborghini for which some models have syncro reverse). The gears are always engaged and spin loosly on the mainshaft along with what passes for the cluster gear. When shifting, you're coupling the synchronizer teeth on the loose gear with the one fixed to the mainshaft. To do that, the synchronizer has to but up against the "real" gear and spin it up to shaft speed so it can engage. Once that happens, they're locked together and power can be transmitted from the engine to the rear wheels. The grinding you hear are the synchronizers grinding not the gears. A broken synchronizer can't get the real gear up to full speed so the synchronizer teeth grind against the coupler. Synchronizers are usually made from brass so their tolerance for abuse is VERY limited.

sburkett

Ericok is mostly right. It's really hard to describe without pictures, I recall that there is a really good diagram on howstuffworks.com if you're reallyinterested.

You can never grind gears, including reverse, they are always fully meshed. Except in a theoretical failure mode that I have never seen, you can never grind synchros, either. There is a hub locked to the mainshaft between every two adjacent gears. When you shift, you move a ring that locks one gear to that hub onto teeth attached to the next gear (called dogs) that lock the new gear to the mainshaft. The synchros are between the slider and the dogs and spin freely. As the shift progresses, the synchro is forced onto a cone that is part of the gear/dog component. The resulting friction speeds up or slows down the gear to match the mainshaft speed, and when the speeds match, the teeth on the slider engage the dogs,the desired gear is locked to the mainshaft, and the car is "in gear".

A bad synchro (probably your problem) does not make enough friction to spin the gear up to speed fast enough to prevent the slider teeth from bumping up against the mismatched rotation of the dogs. Slider teeth on dogs is virtually always the grinding sound. Regarding reverse, there is rarely a synchro there, primarily to force you to only shift to reverse when the main shaft is not moving. I've never had an RX-8 gearbox apart, but I thought I read somewhere that reverse is synchronized too. If so, it is a departure, as there was no reverse synchro on the earlier Mazda boxes.

Steven

veilsidev1

thanks guys. Yea i kinda knew they were BS ing, but i couldnt really prove or argue with him because i dont really know alot about this. Im going to go talk to him. Can anyone give me something to tell him or argue against, so that he think that i know what im talking about???. What should i tell him to disprove him. Thanksss

ps1726

The tranny is a a mechanical component totally independent of the ECU , and of any electronic system, it is only actuated by sheer human force , so there is no point in telling
you that an increase in air flow, or a measly 3-5 Hp gain will strip synchros or gears inside it,
thats 100% BS.

MyRxBad

iTrader: (1)

Check the other tech issues thread for 2nd gear problems. It's a common problem in some Rx-8's.

veilsidev1

watup guys, so yea i talked to the dealership's service representative, and tried telling him what u guys told me. That how could the intake have anything to do with it, that the MAF was barely affected, hp gains were minimal, and that even then this had nothing to do with the gearbox, and what was wrong with the car was the syncrhonizer.

Well, he gave me this explanation that the gear was not griding, and that what i was experiencing was a spark knock. He said the intake was making the fuel run richer and this was the cause of the knock. He said i should replace the stick intake and use 93 octance fuel (i use 87), and that it should go away.

Are these guys right?, could this actually be true? And if so are these really ways i can fix it. Or what else can i do. But yea, i really dont see myself taking my REVi off :p

Glyphon

spark knock is causing 2nd to grind?

get a 2nd opinion.

bureau13

Well, that depends in part whether or not its really knocking or if it really is a grinding gear. It is certainly possible that you're knocking, but the REVi will not cause that in a properly running car. It doesn't make it THAT much leaner (NOT richer...that would certainly not cause detonation!) but theoretically if something put your car on the hairy edge, I suppose the REVi could push it over. The problem with the REVi is that, using parts from the stock intake, putting it back may not be possible. I would suggest trying another dealer and possibly trying to determine for yourself what the noise really is. If it IS possible to put it back to stock, you could do that, and probably your noise will still be there.

jds

veilsidev1

its actually really more of a grind than a noise. As in its difficult to get it in at high rpms or with a simple downshift. And uea, i kinda destroyed my factory intake when installing this one . But i am planning to go to another dealership to see whats up. And is the thing with the fuel octane true?. What if i clean the MAF sensor

ZoomZoomH

iTrader: (1)

try 93 octance at next fillup

RX8PDX

We ran a test in High School once, it was mechanics class.

It was for one of the students old chevy truck.

Calculated how much it cost to fill tank with 87, then 91 (highest we have around here).

The actually drove the truck with both, and recorded mileage.

The 91 got better mileage, and made up for the extra cost for the 91.

SilverrbRX8

wow reading all this really bothers me...i just added the REVI myself along with the ram air kit and the car has been smoother through accel and smoother at high rpms but nothing unusual.....YET. from whats happening to you at the dealer and what ive been through in the past i think they are blaming the problem on the changes you have made to the car so that they dont have to cover it on warranty. so as much as u hate it u should put the stock unit back on and take it to another dealer and NEVERRRR tell them that you had a aftermarket unit on and they should be honest with you since they are none the wiser about what the other dealer saw on the car. keep us updated on what happens because my car has the same intake system and it wasnt cheap !

Tim Benton

What was the verdict on this? Did you try a few tank fulls of the highest octane you can buy to see if the 87 you were using was making the car knock and retard timing?

Tim

SyLRX-8

I run 94 Octane ( Sunoco Gold, up here in Canada ) and have not had any issues with cold starts ( Gets down to minus 40 C here in Canada ). I tried racing Octane Boost additive from Lucas oil company which is proven safe for Rotary engines and man!!!! did the car run like a charm, unbelievable smoothness, smooth starts and response but shortly half way through one tank of gas, my engine light came on. The dealer just said that they had to reprogram the CPU with an update but did not mention the Octane factor. At 11$ canadian a bottle of Octane additive for one tank of gas, it is quite expensive, although I will try it again and see if the engine light comes back on. I am planning on installing a REV-i air duct and air box system, but would like to get feed back on the increase of performance or HP and/or what to expect from it from any of you guys that have one.

Does it void manufacturers warranty ???

Anyways for the issue versus the REV-i and the way your 2nd gear shifts, the tech is out to lunch, the intake has nothing to do mechanically with the transmission and a slight increase in HP should not either. If the Stock RX-8 trany can't take it, it means its garbage. I always noticed went misshifting a manual trany that it always happens with the second gear.

Thanks for any comments in advance.

SLYRX-8

arghx7

Did you try changing your transmission gear oil to synthetic?