Brettus

iTrader: (2)

Fixed it for ya OD

olddragger

iTrader: (3)

LOL--you did dint ya!

Brettus

iTrader: (2)

For Mark - here is what you were after .
*NA with lots of aftermarket boltons to maximise power/ torque
*The highest powered supercharger ever to post a dyno on this site
*A quick(ish) spooling greddy turbo with a mild compressor upgrade.

OD: if this does not give you some idea on what you are missing (torque wise) I don't know what will.

Mark: note over double the stock torque from 3200rpm right through to about 7000 then not quite double from there on.

TeamRX8

iTrader: (25)

I'm just going to let this sit and age for the time being, to be re-visited at a later date

Brettus

iTrader: (2)

I can't wait . Even if you do make something good - I'll be able to quote your own statement :
to discredit whatever you do .
You can't win now !

:

olddragger

iTrader: (3)

I am happy with my pettit setup. Its a nice little build, 300rwhp with lost boost numbers and a powerband that is close to oem. I also dont have to mess with the hot side of the engine. Parasidic lost --yep its there but thats ok with me. I have enough power for what I want to do with the car.
Besides have you heard of the advances being made with superchargers? Newer models are becoming more efficent with water cooling, tighter toleraces, different porting, different lobe ratios, gear drive pressure equalization, better bearings ( microblue or ceramic), intake side discoveries, better gears etc. Its nice more companies are looking at the twin screw design and are doing research. Heck one company is even testing magnesium rotors (lighter).
A SC will never be as efficent as a proper turbo, but the overall system is simpler and more reliable. So I will take that over a 1-2 second difference on the track anyday.

slvrstreak

iTrader: (3)

these are my thoughts exactly
well worth a few lost HP for me

Brettus

iTrader: (2)

I was not trying to put down SCs OD - just trying to get you to see the torque differences as you seem to think a renesis cannot make torque . Having double the factory torque available from 3000rpm , I can assure you , totally transforms this car for everyday street use . I only wish i could get mine to spool another 1000rpms earlier which would be awesome for those very slow right angle 2nd gear corner exits .

olddragger

iTrader: (3)

No offense taken Brett--none. Its just that i dont consider Tq to a part of the rotary engine at all. I grew up with the big block recips---over 400 wheel Tq was common.
You could those cars 1/2 throttle at 2krpms in high gear and have a hard time holding on!
i used up a LOT of rear tires and I was dangerous to be around in the rain

Brettus

iTrader: (2)

I see your point OD . It's all relative I guess . I would consider the amount of torque available from a V8 a total waste of time in a lightweight chassis like the the RX8.
Especially when you can get the same tire shredding effect with a few extra revs if you really wanted to.

olddragger

iTrader: (3)

we are a sum of our experiences....................................... ........wait; i just had another experience --damn i just changed again---when will it stopppppppppp
Its all good

MarkAngelo

Brett,

I hope I can double the torque of my engine once we begin tuning.. Definitely looking forward to feeling the difference of this machine with twice the torque... and a bit over 300whp..

Regards,
Mark

slvrstreak

iTrader: (3)

good luck

olddragger

iTrader: (3)

power transforms this car--thats for sure. some suspension/drivetrain/aero weaknessess becomes more apparent after the power/speeds get higher.

MarkAngelo

Thanks for bringing that up.

I think I understand what we can do to the suspension, but what do you mean by aero and drivetrain weaknesses... Will you please elaborate on this.. I'd like to figure this out so that I can budget accordingly... I'm not trying to build a race car.. just want a nice, fun car to drive around on the daily that I can occasionally take to the track and have a good time.

Thanks,

Mark

bse50

The transmission is weak and the oe body sees a lot of lift above 200km\h but it's already noticeable over 160km\h. Good suspension potentiometers and a datalogger will show you how much. This is on a lowered car though, not sure about how it behaves stock.
Nothing to worry about for a daily driver that's seldom driven on a track anyway.

olddragger

iTrader: (3)

Bingo.
I have noticed in over 4k track miles in this car, that the car hits a aero wall at around 100mph. At over 120mph the car in its oem form starts getting a little light (lift), but is kinda ok, At over 130mph the car is definity light and your inputs have to be really dialed back--even braking. at over 140mph I start to get a little concerned. Hood movement, car really light, i have blown out the wheel well liner etc. I dont like over 140mph with the oem body ( no aero)
Be careful with the S1 trans, be careful launching during a drag race ( if you are in that sort of thing) as some can have pretty bad wheel hop and watch the temps in the diff if you have long track sessions. typical 20 min track sessions are usually no problems.
Watch the alternator voltage also if it gets too hot as that can affect your fuel pump etc. Our cars are starting to get some age and miles on them, which means you have to be more careful about these things.
For example I noticed on my 85K mile car that my alternator voltage on a 90+ ambient temp day and hot underhood temps had only a 13.1--13.2V out put. It should be 13.6 to 14V. That doesnt sound like much but that 1/2 volt difference means a LOT to the fuel pump. Heat influences everything. A new alternator fixed me right up.

cavemancan

O_o OMGWTFBBQ!!!!!!

Do you know how long I've been looking for a solution to this??? I thought I was having fuel starvation issues during the tight left handers but I also started getting a check engine light mentioning a voltage problem but only when racing. I thought it might be the fuel pump so I bought a Walbro. Now your telling me I need an alternator (I have 115k miles)? This makes soooooo much more sense!

OD...I also saw this on the Mazda Speed Motorsports parts site:

olddragger

iTrader: (3)

glad to be of some possible help.
Years ago i was measuring the voltage available at the fuel pump. This was when the fuel starvation issues 1st started showing up. In seeing what I saw I became interested in the Kenne Bell Boost a pump. I havent gotten one yet because the S2 model fuel pump fixed me up. But in trying to educate myself concerning fuel delivery I discovered how important a small amount of voltage is to fuel pump operation. Check out their site and read about it--lots of good info and I think it is very pertinent to us guys on track and those that have went FI.

MarkAngelo

Brett,

What's the advantage of increasing dwell by 10% on stock coils...?

Thanks,
Mark

MarkAngelo

Thanks for the details..

Lots to look out for... Good info about the alternator.. something the top mount turbo guys should watch out for as well. I don't plan to drive the car above 100mph at extended periods of time, or while driving around curvy roads, but this is good info about how the car feels..

I'm thinking of doing Auto Cross and time attack with the FI 6spd RX8..
I just hope the suspension parts, such as the bushings, etc and tranny don't give out on me while I'm on the track.. When you track a car, do you have to change out suspension parts often? Like bushings, etc..

Just a note regarding the voltage... It's not just the fuel pump that is sensitive to slight voltage drop, the ignition system's performance is affected, right?

Thanks again,

olddragger

iTrader: (3)

everything is influenced by voltage, I didnt measure anything during that time concerning the ignition.
I am running the msd 8247 coils on oem dwell.
The bushings, wheel bearings, u joints etc seem to hold up pretty good.
The steering shaft knuckle does need some cleaning/ lubrication after so many years.

Brettus

iTrader: (2)

Decreased that to 5% plus limited max rpm to 8300 so coils never see 9000 rpm.

I was having misfires when I increased the boost level one day so did that one change and fixed it . Was told it would make no diff. and only serve to heat up the coils . I ignored that and just went with it - worked great. Coils had 80,000 kms on them and were still going strong before i swapped them out .

MarkAngelo

Thanks Brett,

I had misfires with my 21psi eclipse and had to upgrade my ignition system to solve the issue.. I guess I was blowing out my spark, because the spark was too weak for the boost and the RPMs...

I was told I'll encounter misfires at high rpm boost with the renesis on stock coils, so I was going to save for some upgrade coils... like the BHR or LS1 / modified corvette Z06 coils... This is good news, as I am trying to save all my pennies right now as I am finishing up with school.. If I run into the misfire issue, I'll just back my max rpm down closer to 8k (since we max out torque and begin a steep drop at 7.5k anyway) as well as increase my dwell across the board 5% to see if it makes a difference.

Cool. I'm even more excited about getting mine done..

The only thing that I noticed on the previous FI setup was that the APV was stuck open... The motor was removed and the APV was set to open... I'm not sure if my APV is in working condition, but I hope it won't affect my low end too much to leave it open.. The kit I have started off as a Mazsport low mount and I think they suggested to leave the APV stuck open..

Thanks again,
Mark

MarkAngelo

Thanks for the heads up regarding the steering knuckle.. I noticed the steering shaft in the engine bay is oxidized and can use a bit of lubrication. I'm surprised they never lubed this during the engine replacement..