RX7Club.com - Mazda RX7 Forum - my new project... with pics

RX7Club.com - Mazda RX7 Forum (https://www.rx7club.com/)

- Build Threads (https://www.rx7club.com/build-threads-293/)

- - my new project... with pics (https://www.rx7club.com/build-threads-293/my-new-project-pics-966618/)

my new project... with pics

a quick background. ive had my 82 GS model Rx-7 for 5 years now and its gone through many modifications and projects. I bought it almost stock with a full racing beat exhaust and 102000 miles on it. over the years its recieved 2 MSD6AL's, a 45mm sidedraft weber style carburator, aeromotive FPR, GSL rearend swap, Ford taurus Efan swap, S5 alternator and many more small things here and there. last year i started down the road to go full blow through turbo on the 12a and built and modified the fuel system to support it, but ultimately decided to not finish and go a different route.

3 months ago i concluded that i needed to do something with my NA FC i scored for $300 a few years back and my 82 GS that was pretty much set up for EFI, so i combined the 2 and am actually gonna finish a big project this time

installed and after much adjusting of the CAS and the TPS its running

http://i71.photobucket.com/albums/i1...x/DSC_0854.jpg
http://i71.photobucket.com/albums/i1...x/DSC_0853.jpg
http://i71.photobucket.com/albums/i1...x/DSC_0852.jpg

and heres a short vid of it running with a few revs. ive been letting it idle for about an hour at this point making sure it doesnt over heat or piss fluids out. i need to replace the TPS which is causing the iffy/lack of the ability to idle, plus the BAC (idle control valve) has been removed, along the the 6 port sleeves and actuators (im using GOOPY PERFORMANCE 6 port sleeve replacment inserts)

pardon the choppyness of the video as photobucket apparently murders the frame rate when it uploads videos :( but atleast the audio is there ;)
http://i71.photobucket.com/albums/i1...h_DSC_0851.jpg

lastly, i would like to thank the great guys at Weaver auto parts for letting me use there machine shop and blast cabinet, plus getting me great deals on many of my needed parts, and finally a HUGE thanks to Jonathan at GOOPY PERFORMANCE, the best customer service hands down. im using their 2mm oversized apex seals, which allow you to bring worn out seal slots back to proper clearance, and um using their 6 port replacement inserts (similar to pinapple inserts, but are designed to be used in the housing with no sleeves at all) johnathan from GOOPY always answers the phone (with enthusiasm :) ) remembers who you are, will answer any tech question or help you trouble shoot problems, give advice, and he even did a follow up call after i ordered parts to make sure i was satisfied with his products and asked how my build was going. once again, great guy and i recommend everyone check out their products and services :)

Killer work man, cant wait to see her on the road^^

The purpose of the modified FB/SA instrument cluster?

^Probably to get the 130mph speedo on his 82 cluster. Not sure why he didn't go with an 83 cluster since then it would match, maybe he had the SA cluster laying around :)

Project is looking good, car looks clean too!

very nice project! i need to get a 1st gen one day! good job man
:icon_tup:

Quote:

Originally Posted by Directfreak (Post 10759429)

The purpose of the modified FB/SA instrument cluster?

i dunno, but the SA looks so much nicer!

this thread says awesomeness all over

the reason behind the SA speedo is the availiability as I have a 79 roller and I can't stand the s2's wimpy 85mph that I would top out in the middle of 3rd gear. I wish I could find a decent s3 parts car for cheap so I could have a color matched speedo, but im working with what I already have. plus ide like aquire some S3 struts/spindles and a large axle rearend. That would make the 5 bolt/ fc brake swap go much easier.

i was almost going to do my motor swap with the fc front subframe, but decided it would be less hasle and money to just use an -SE oilpan and retain the fb subframe. I still have the fc entire front subframe; struts, brakes, control arms and all if I choose to go that route later.

The car is pretty fun I must say, it leaves something to be desired for low speed/low throttle driving. Pretty similar to in town drivability of the 12a w/ a Weber. But what can I expect. All emmisions removed, no BAC, modded throttle body and the irons and housings are moderately ported with open aux ports. The touchy bottom end and idle are easily made up for by WOT power after 4k. Unfortunately I am advised by Jonathan from goopy to keep it under 6k for the first 500 miles. I've gotta fight myself to shift at 6 rather than winding it out. She definitely comes alive around 4 and keeps pulling harder up to 6 and it feels like there is a lot more waiting up top

Thanks for the compliments guys :) I will try to have more build pics and in car vids up soon

another example of working with what i have readily availiable. last year i bought a brand new clutch masters stage 3 kevlar clutch/pressure placefor my 82 12a, and as some may know, pre-83 rotaries used a 215mm clutch, while all post-83 non turbos used a 225mm clutch. to save money i wanted to reuse my clutch that is still not even broken in yet with less than 1000 miles. luckily for me the FC that donated the motor was an automatic, which supplied me with an appropriate rear counterweight. so you should be able to see where im goin with this ;)

i was able to source out a low mileage lightly used racingbeat light steel flywheel for the old 215mm clutch here on the forum less than a year ago. put them all together and here i am still rocking out the old small diameter clutch on the later model motor

... on a side note, the light steel flywheel is probably magnifying the low end drivability and idle hiccups. the lower load/inertia lets the motor kinda act up. ive even noticed that itll behave noticeably better under even the small load induced by the alternator when the efan kicks on or headlights are up :o

I have heard that this can happen too, but usually more noticeable with a really lightweight aluminum flywheel...the steel should only be somewhat.

Quote:

Originally Posted by Sgt.Stinkfist (Post 10764089)

it leaves something to be desired for low speed/low throttle driving. Pretty similar to in town drivability of the 12a w/ a Weber. But what can I expect. All emmisions removed, no BAC, modded throttle body and the irons and housings are moderately ported with open aux ports.

Quote:

Originally Posted by Sgt.Stinkfist (Post 10764177)

... on a side note, the light steel flywheel is probably magnifying the low end drivability and idle hiccups. the lower load/inertia lets the motor kinda act up.

I've said it before, and I will say it again.

A 6 Port Motor will always have incredibly crappy low-end power without a working set of 6 ports with their sleeves.
The engine was DESIGNED to have them in and provide a shitload of torque (for a rotary).

Removing the sleeves, and/or wiring the ports permanently open is a crime.
It isn't worth the .5% of a Horsepower in the top end to bypass that system.

There is a reason every normally aspirated 13B since 1984 has been a multi-port engine.

If you can't change it back, your best bet is is a stock steel (heavy) flywheel to smooth things out some.

I went into my project knowing that operating aux ports will give me better bottom end and driveability, but for the sake of simplicity, working on a budget and simply that I didnt have any means of operating the actuators, not to gain miniscule amount of top end, I ultimately opted to go sleeveless. There is no going back as im running GOOPY inserts, which are like pineapples sleeve inserts, but slightly larger diameter and designed to replace the sleeves all together and be permanantly fixed inside the port itself. Lastly the light steel flywheel was the cheapest route I could go, considering the other parts i intended to use. The small downsides and quirks I had expected and can accept, especially considering that every aspect is better than the characteristics of my previous engine/setup. torque, power, drivability, response, and fuel economy have all been improved upon.

Many parts of my project were done due to budget and simplicity.

--The exhaust system is comprised of a RB 12A collected header that i already had, that has the collector chopped off and engine flange split in half to fit the 13b block. I welded some flanges on the remaining primaries and ran dual 2" pipes all the way to my preexisting RB dual inlet/roadrace muffler.

--The S4 throttle body has been gutted of all un-neccesary parts. All that remains are the main throttle butterflys and the TPS. I am goin to re-install the dashpot eventually, just to keep ithe engine from almost dying when the throttle is snapped shut. It doesnt stall but it does drop to 400-500rpm, then creeps back up to 1000 and holds solid.

On a side note, my TPS adjuster on the TB wasnt being held as securely as it should, allowing the TPS to go in and out of adjustment. So today at work I did some tinkering and got it snugged up as it should be and re-set the TPS. Now it holds solid and doesnt go out of adjustment. Low end driveability has been drastically improved, I can cruise and maintain speeds with virtually no more bucking/hiccups...even creeping through a parking lot in in 1st or 2nd gear :) the only remaining drivability issue that remains is just the characteristic quick lean bog from the modded TB upon large throttle movements below 3k)

--the engine management has been whittled down to the bare neccesities for engine operation. everything i didnt need was de-pinned from the harness and removed completely. all that remains are the powers and grounds, main sensor inputs and injector&ignition coil outputs. if it didnt directly control or dictate engine operation, its gone.