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Thread: My RX-7 build thread:

  1. #1
    Boost Junkie breckboarder55's Avatar
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    My RX-7 build thread:

    Can an administrator move this to the projects section... Please
    , Thanks!



    I bought this car about the time I turned 17 before my Junior year in High School. Picked it up for a wapping $4250.

    Its a 1987 Mazda RX-7 Turbo II, it had 68k miles on it, 5k on the motor, and 15k on the turbo.

    It also had hail damage, the rear deck had been hit with a hammer, and the side had been backed into by a lifted truck... So the exterior was horrible, the interior dirty, and mechanically it was in excellent shape.

    Unfortunately my computer crashed a couple months back and I lost most of the original pictures of it... So the only ones I have through my swap and what not, were the ones I had posted on various forums.

    The day after I got it: (don't hate, the young age of 16)


    Off topic story:
    I wasn't aware of how quick the car quick the car was when I bought, but the third day I owned I happened to pull up next to a 350Z. He must of thought I was a piece of junk (allthough I have to agree, it did look like one) because he got on it when he pulled along next to me. I followed suit and managed to pull about 2 cars on him by 80 mph. Ended up finding out his car had intake/exhaust, nice guy.

    As a reward for buying my own car, and a birthday present my parents had the car painted/ body work done.



    The car came with some mods, it was running about 10 psi through ported intake manifolds, and a stock motor. 550cc injectors squirting the fuel with the help of a 230 lph third gen rx pump. Helping keep the air/fuel in check it had an HKS F-CON V-pro engine management system on it. Ported wastegate to keep the creep at bay, and breathed through a cheap ass muffler shop 3in turbo back exhaust, with a highflow cat, and a Hooker max-flow muffler. Had a Greedy BOV, and a Koyo radiator and electric fan to keep things cool. It had Tokico Illumina adjustable shocks, with eibach springs, along with some cusco camber plates. It also had a FCD (fuel cud defender), along with an HKS megaflow intake. Other stuff like a ported TB, and manifolds, plugs, and wires yada yada...

    Probably around 2700 pounds and 230-240 hp, through a five speed with 4.10s.


    So I ended up painting it Mazda Winning blue, from the RX-8. Had the lights and markers smoked.



    Had to put some junk yard probe wheels on... (long story) They will be gone this summer. (years later) I was always more concerned with being fast, over looks.

    back end with a friends SRT-4 (ended up putting like 3xxhp and 400 ft/lbs on a 50 trim)



    Along the way the alternator went out, and replaced it with a 3rd gen rx alternator.

    One day while driving on the feeder the brakes failed. (very scary if it has never happened to you) The brake master cylinder went out. Replaced it, along with the rotors, and put in some portorfield race pads. Also added stainless steel brake lines.

    Drove it for a while until my funds caught up... This thing would dump all the fuel when you let off and the secondary injectors let off and it would shoot great fire balls... It was allot of fun. Looking back I don't know how I didn't kill myself...

    Fast forward six months: One day, while driving down the road. The motor just went on me... Pop! Apex seal was gone... I limped it home on one rotor, terrified that my baby had died. I had no idea of internal engine work, and the only things I had done so far was a new alternator, basic maintenance and brakes.

    Well after a couple of weeks of sitting in the garage decided to tow it up to Gotham Racing in Ft. Worth. One of the widely known rotary company's in the country and arguably one of the greatest rotary tuners in the world.
    They built me a new motor and we made some major changes.

    New Motor:
    Series 4 13bt block
    2 new mazda reman (series 5 housings)
    Gotham Stage 3 race port for intake/exhaust ports of the housings
    (for those that don't know, this is kind of the cam and stroke of the rotary world, huge power increase)
    milled the rotors, one new to fit 3mm apex seals, along with apex springs from a third gen RX (i guess you could compare to forged pistons?)
    Teflon coolant seals
    new gaskets, ported Eccentric shaft pellet (remember this)

    It took them 4 months to finish the motor because they were in the middle of a shop move.

    Also while up there they took out the HKS F-CONN and replaced it with a Haltech E6K standalone engine management. Also added some MSD ignition amps. Time for big fuel! 720cc primary injectors and 1600cc, let me repeat that 1600CC secondaries. Swapped out the 230lph for a 285 (iirc) Nippondenso unit.

    Brought it home for a while, breaking in the motor. Mean while make a friend that is getting out of RX-7s because he is getting married. Makes me a hell of a deal on a T-70BB turbo (0 miles on rebuild), an HKS cast manifold, a 4in down pipe, 3in. intercooler piping, a big spearco intercooler, an hks bov, 4in K&N filter/Boost Logic intake, and an HKS Waste Gate. All for 1600! The IC piping alone would have ran about 850, lord knows the turbo would be expensive! So I jump on it.

    While waiting for school to end (since it was my DD). The radiator fan goes out one day... Order a new one and summit didn't tell me it was on back order until I checked in on it a week later. Perfect time to start my swap!

    I went from this:

    to this:
    Last edited by breckboarder55; 09-26-2008 at 08:35 PM.
    SHUT UP AND WHEEL

  2. #2
    Boost Junkie breckboarder55's Avatar
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    So I start the swap and it quickly became apparent that the person I bought the set up from left out some details… In order for the IC piping to fit I had to delete the Power steering, and A/C. So I do it… I also order some flanges for the oil and coolant lines from Turbonetics. (great product, but service sucks! It took months!) I had to use my dremel to cut down the flange adapters to hook up the oil in and one coolant line because they were to thick to bolt to the studs on the engine block. I also had to use a cheap 30 dollar sears map gas torch to cut through the radiator supports because the IC mounted V-mount style, but directly in front of the radiator. The torch was slow and I did start a small fire with it… No damage was done though.

    My intercooler is on top, the bottom is a stock srt-4 unit.:


    Along the way I relocated the battery to the hatch and used this trick little box, along with a kill switch:


    Added an oil pedestal to hook up some oil temp and pressure gauges:


    The RX came with molded metal lines which meant I had to do some running to Smileys Racing to have some stainless lines ran. This specific one was a *****… The factory hook up was welded to the metal line so I had to rig up a banjo fitting with two crush washers for the oil in. The washers were a weird size and no one had them with the correct fit, so I had a machine shop punch them to the correct diameter. :




    Lowered the oil cooler due to some clearance issues with the intercooler. Its pretty hard to see the IC through the bumper:



    Intake:
    SHUT UP AND WHEEL

  3. #3
    Boost Junkie breckboarder55's Avatar
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    Test fitting the turbo:

    Found out I would have to get a different flange to get the oil drain to flow properly

    Finished the swap, some messy wiring…:




    I also added an Apexi AVC-R boost controller: before I put it in



    Close up of the turbo:


    Drove around with just the 4in. downpipe for a while, on a break-in tune… Caused the revs to bounce 2k rpms when cold. It would crack every time the rpms dropped too…

    Had a waste gate dump Pipe made: (note the unhooked up vacuume line)


    Than a 4in. mandrel bent exhaust with a 4in borla XR-1 muffler… It is pretty much a strait exhaust.



    Extremely loud, neighbors threaten to call the cops. One even claimed it knocked a picture from off the wall… Couldn’t hear the stereo it was so loud…. So that came out, along with the sound deadening…

    Will throw this in sometime:

    and for when I get a wideband:
    SHUT UP AND WHEEL

  4. #4
    Boost Junkie breckboarder55's Avatar
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    Drove it around for a while, got it tuned for a DD. Took it easy on the tune trying to get the basic ACT clutch and heavy duty pressure plate to last… That was only good for 330 ft/lbs… Was in the low to mid 400 neighborhood, on just under 1bar of boost. So safe to say 430-450whp. Similar setups have done more on Higher boost.

    As soon as the motor was broken in I did three pulls and the clutch took a ****… Was two weeks before graduation. Luckily my grandpa thought it would be nice and buy me a spec Stage 3+ clutch for graduation… The beast was up and running again…

    How the interior looks now with a variety of Autometer cobalt gauges, and the VC-R mounted.:

    Gauges include boost, oil pres, oil temp, coolant, and EGT. Still need a wideband!

    How the motor looks now, changed the fan set up… Puppy runs 185 all day long, and rotarys run hot!





    some friends:


    note the plate holder:


    So drive it around some more and than start having some oil pressure problems just as the clutch was getting broken in… Eventually it got worse and worse, and I decided to stop driving it when the pressure got low enough… Meanwhile trying to recoup financially, I researched what could be wrong. From what I read/was told it was most likely from a fairly common problem of the O-ring for the pellet that sprays oil into the eccentric shaft, (like a crank) to than cool the pistons and lube the seals… That means, no pressure blown motor… Real fast. So I work and I have all the parts to fix it, but hear stories of people messing up the rest of the motor trying to fix it, and a rotary specialist (atkins) told me you would need an impact wrench. A tool I don’t have in my arsenal. So it hasn’t been driven in a couple of months, since I have decided to use my money else where. I think I will have enough time to attempt it myself over winter break. If not maybe I will have produced enough money to have it done pro.

    So my future plans are:
    1.get it running
    2. Re-tune, pump and race gas. I would like to see 500, more on race gas…
    3. Methanol Injection
    4. C02 spray (just to give the IC a little extra help in the TX heat)
    5. Wheels and tires (17x9 Zigen FN01-rcs rear and 17x8 front)
    6. Cage
    7.2 step and From there on…

    Obviously this is a long term project, but I have gotten quite a bit done all things considered.
    The majority of this project was paid for by me. I have gotten small loans from the parents when I needed it(things breaking and I spent all my money on mods). I also did all of the mods except for the engine build, the standalone wiring, the clutch, and the suspension(came on the car).
    Im sure I’ve left out on some stuff along the way, its been over 4 years in the making!
    Last edited by breckboarder55; 09-26-2008 at 08:44 PM.
    SHUT UP AND WHEEL

  5. #5
    Once was lost... BMFScout's Avatar
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    cool car
    Boats and hoes

    Stumble in to the liquor store
    With a dollar-fifty for a bottle of wine,
    I know just what I'm lookin for
    Thunderbird will do just fine.

  6. #6
    ill be your pickup man
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    Good looking car, the Probe wheels definetely kill it though. Awesome and fairly legit build thread/update though. Keep the pics and updates coming.
    92 YJ
    04 F-150 4x4
    11 F-250 4x4

  7. #7
    Registered User robertf03's Avatar
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    interesting

    there were a few guys in the efi tuning class I took that were into rotary engines. they feared predetonation in ways piston people can't understand. I assume that is what took out the apex seals?

    A friend of mine in highschool had a convertible with a swapped over turbo hood, never got around to the turbo install though.
    ...

  8. #8
    Boost Junkie breckboarder55's Avatar
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    Quote Originally Posted by robertf03 View Post
    interesting

    there were a few guys in the efi tuning class I took that were into rotary engines. they feared predetonation in ways piston people can't understand. I assume that is what took out the apex seals?

    A friend of mine in highschool had a convertible with a swapped over turbo hood, never got around to the turbo install though.
    Did you take the EFI class here? Sounds cool, I would like to take one aswell.

    Thanks for the complement's.

    I hate the probe wheels too, but at the time it was a must for the situation.

    There probably won't be any updates on this until I'm home for thanksgiving or more likely winter break... Makes me sad being away from it.
    SHUT UP AND WHEEL

  9. #9
    Hazaa Fredo's Avatar
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    Nice car, you've done a ton of work man....reminds me of a car I know. Do a lot of work to it and it rewards you by kicking you in the testicles.

    Not to try and start a fight or anything, but I'm just curious where your horsepower/torque figures are coming from. Have you actually had this car on a dyno, or are you just estimating your figures based on other similar builds?
    "You know, this car is so fast, that giving Corvette owners this car, is kinda like giving an AK-47 to a pysch ward."

    -Ron Fellows (Corvette C6R Team Driver)

  10. #10
    Dead or alive... mudtoy67's Avatar
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    Cool car!
    BDR

  11. #11
    Buckaroo Bonzai!!! Reckless's Avatar
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    Quote Originally Posted by breckborder55
    As soon as the motor was broken in I did three pulls and the clutch took a ****…
    Pulls on a dyno? If so, that answers your question fred

  12. #12
    Hazaa Fredo's Avatar
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    Ah, missed that. I was scanning the build instead of reading word for word. That's a stout f'n rotary motor then.
    "You know, this car is so fast, that giving Corvette owners this car, is kinda like giving an AK-47 to a pysch ward."

    -Ron Fellows (Corvette C6R Team Driver)

  13. #13
    Boost Junkie breckboarder55's Avatar
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    I'm comparing it to other builds. (an estimate) Seen the exact setup motor and turbo wise go upper 400's with about 18 pounds. I'm not saying its spot on, buts its definitely near my estimate. No traction first, second, and third... Its cool to roll on to the throttle in third and when you hit boost, it spins. All the way through at just under tripple digit speeds.

    Never got a good dyno pull though... =( Thats why its an estimate.


    The power is all in the porting, and its as big of a port you want in a street car. Lots of people have similar power on similar boost.


    Rotary's have a huge split between tq/power in most cases.
    Last edited by breckboarder55; 09-27-2008 at 05:06 PM.
    SHUT UP AND WHEEL

  14. #14
    Teaching America's youth RCcola55's Avatar
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    camaro vs. rx7 showdown fred
    Ryan Clarke
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  15. #15
    D-FENS agjohn02's Avatar
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    you need to swap this drivetrain into a mazda pick-up with a divorced t-case and put toyota axles under it.

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