Rote8

The Miata ring and pinion fit the RX8 differential; or did you swap the entire differential in the RX8?

bse50

The miata ring and pinion doesn't fit, the whole diff. does.

Harlan

iTrader: (3)

BSE is right, just checked, I have a 7" ring so it won't work without swapping internals or full diff. Oopsie. Need to find a replacement that's actually compatible. Glad I didn't find that out the hard way.

Also for your amusement:
https://www.youtube.com/watch?v=Bwa-...&feature=g-upl

Mawnee

Harlan

iTrader: (3)

Ok, I need a ring and pinion from a stock 93-97 rx7 automatic. Should be pretty easy to find. What I have is compatible with earlier RX7s but I doubt anyone would want it. Time to sell.

Brettus

iTrader: (2)

why not just get a 4.1 from an RX8 auto ....sheeesh

Harlan

iTrader: (3)

I may be missing something but aren't all auto 8s 4.3 rear ends?

TeamRX8

iTrader: (25)

up until this thread was posted you seemed like a halfway smart guy ...

Harlan

iTrader: (3)

Wow Team, that's almost a compliment. Everyone makes a mistake while learning, I just rush into things further beyond the comfort zone than most and can make more mistakes because of it. I'm not ashamed of that, I just keep fallback plans for when I make a mistake. My first engine swap was on my 8. Did it myself with little help, and surprisingly no problems. Had a plan to do twin rear mounted turbo's, got a used pair of garrets, one of them didn't survive rebuild, so I shifted gears and changed plans. Ok, I didn't do enough research and got the wrong differential based on bad information. No big deal. The scope of this build may change rapidly depending on what works or what doesn't, but I have no regrets. I will know more tomorrow than I did yesterday, and again the day after. And if I fail everyone including myself can have a good time through the journey.

Harlan

iTrader: (3)

Alright I've pretty much resolve the smoking transistor problem with my coil mod. Need to redo the circuit board so it's not such a mess, and need to wire my car, but the hardware issues and most of the coding are now done.
https://www.youtube.com/watch?v=ExK3...Y&feature=plcp

bse50

The problem is that you start with a tabula rasa to learn instead of picking up where others left.
So many complicated coil mods, weird turbo setups, lack of some fundamental research (pre-turbo water injection etc), custom boost controller that may or may not work...
There are proven setups that reach your goals in a direct fashion and without many complications. It's like climbing mount everest on your hands while you could walk there instead.

The external parts of a turbo build is well documented and is a straigh forward deal if one knows what he's doing. The challenges are inside our engine. Go with a simple turbo build and have fun with the internals instead....

olddragger

iTrader: (3)

I really like this :
"I will know more tomorrow than I did yesterday, and again the day after. And if I fail everyone including myself can have a good time through the journey."

Like this one too:
It's like climbing mount everest on your hands while you could walk there instead.

Sometimes the journey is more important than the destination. Thats my excuse anyway. lol.

Pre turbo water injection can be done and has been done. It is much different than the usual set up.
We supercharged guys have pre injected for a long time. Some precautions do have to be followed.
Got to admit all--this is going to be interesting.
__________________

jay_tibo

My 2 cents would be to go 1 step at a time and have better focus. If your hell bent on the rear mount then get the turbo setup without fancy stuff to start off with (water injection, boost controller, rear diff....) and before running water injection there are some small water to air intercoolers that would do the job very well. Were the rear mount will get you is it's real on or off power not really a smooth transition, I've seen drag cars made like this. I would get the basic setup first then go from there, fab should be easy so thats a bonus, and I do agree with others get a used turbo off a car T28's and T3 are easy to come by for $150 - $300 (check out 240SX sites they typically like to upgrade the stock SR turbo's and sell off the old ones pretty cheap) .

Good luck!! Cheers

TeamRX8

iTrader: (25)

there's no better way to start off an experiment than by purchasing parts of questionable specs and tolerances

Harlan

iTrader: (3)

Mini Update:
Almost all the components are here now. Wastegate looks beautiful. Turbo is mechanically sound and only needs some minor modifications. 3Bar Map sensor works great and tracks linearly with voltage right up to 28lbs. Boost control solenoid working well with PWM. And I have one of the glasspack repacked with SS wool waiting to get a new acetylene regulator to weld it back together. I'll post more when I put everything together for the boost controller and test it with compressed air.

Also I've found that Howard Coleman on the RX7 forum is using bosch fuel injectors for his water injection. Wish that info had been around 2 years ago, I would have skipped a lot of experimentation and went right to what I'm trying now. I'm gonna uncap a yellow injector and that should let me flow about 1000cc, and if the spray pastern is nice enough I may do the same for my existing injectors instead of going bigger.

Brettus

iTrader: (2)

NYET ! on the air filter setup PM Bumblebbee why that is a badski idea .....................

Harlan

iTrader: (3)

Not my air filter setup, just placing the components I have. Will be adding the maf tube, water injector and shield to surround the filter. Sent Bumblebee a msg.

Brettus

iTrader: (2)

/\ nothing wrong with learning from what others have done . A lot of the mistakes you are about to make have already been made and overcome ....

Harlan

iTrader: (3)

Thanks for the advice Brettus. I'm willing to take suggestions from others, and really do appreciate the input. I'm just tired of hearing "OMG you'll blow up your engine." or "You need to have a ball bearing Garrett chosen by professionals or your build will suck."

I've msged oltman about stock knock detection but he seems to have disappeared. I'm gonna try feeding the stock ecu some tones and figure out if I really need to do my own knock retard scheme or can just use an amplifier or frequency multiplier and let the ecu do the job.

Yellow injector is uncapped. Took about 30 seconds when I did it the easy way. (The hard way was still going after an hour.) Will test spray pasterns today.

Also testing higher spark frequencies and putting the boost controller together.

Edit: tested uncapped spray paterns/flow
Capped: 620cc/min (water flow, not at stock fuel pressure.)
Uncapped: 890cc/min (again, water flow.)
About a 43% increase in water flow which should correspond to a similar increase in fuel flow. Pattern isn't bad. Stock has 4 holes which flow pretty straight. Uncapped flows in a circular pattern which focuses down and crosses itself then flows straight. I personally wouldn't use either for Primaries since they directly effect fuel economy. But as P2/S they should do just fine.
Also corresponds to the increase here: KGParts.com - Modified RX8 Fuel Injectors

Well... can't find injectors much larger than stock that have more than 4 holes. Guess it's just hard to flow that much finely. Oh well, back to plan A.

Tried to experiment/learn about FFTs on the arduino for knock detection. Boy does that stuff go deep fast. Hopefully I'll have something to work with soon that will be better than my original plan.

Brettus

iTrader: (2)

Interested in this WI idea using injectors . Wonder about the tendency to clog ?

Harlan

iTrader: (3)

Clogging isn't the biggest problem. The spring isn't stainless so the injectors themselves will be wear items. I already have plans to use a check routine. The pump will stop, the system will wait for a minute for a low pressure switch to come in, then the injector will fire for a predetermined amount of time and the pressure switch will have a band of time it is allowed to come in at. Should both check for leaks and injector flow rate. If it fails the self check it will lock boost at 4psi and retard timing.

Brettus

iTrader: (2)

How long do you expect them to last ?

Harlan

iTrader: (3)

I don't know. Howard Coleman on the RX7club is using bosch injectors and seems to like them. If I have get a new injectors yearly but it gives me the performance I want then it's a good deal. Just started a thread on the 7club. Hopefully someone there doing similar will chime in.

dannobre

iTrader: (3)

Distilled water with a 1micron filter will be Ok for the clogging... corrosion may be problem though

olddragger

iTrader: (3)

true--even the water meth nozzles will "clog" after a certain period of time. Deposits from the fittings/plastic tank/pump,lines all come into play. Water is pretty corrosive stuff.
harlan so the injectors are going to control the volume not the pump? Correct?now here is a vid showing the spray pattern for the rx8 yellow FI ( capped)

Mazda RX8 fuel injector 450cc flow rate Denso 4450 - YouTube

here is a vid with different w/m nozzles
http://www.google.com/url?sa=t&rct=j...C97tyVqw1eq5DQ

It would seem to me that you really want the better atomization spray?