Wohnson89

iTrader: (3)

I'm just about to hit 45k miles on my street ported na motor, and I was reading up on this thread https://www.rx7club.com/2nd-gen-arch...s-31410/page2/ and was going through figuring out what I could do for a "mini" motor build. Basically some things to add a little hop in the saddle. No looking to hit crazy numbers.

Here is my current setup.
1989 gxl
Engine: street ported 13b na with about 45k on build.
Exhaust: racing beat road race system.
Drivetrain: fd flywheel, exedy stage one clutch, s4 turbo2 from the trans back.

So far this is my list of stuff to do:

Intake manifold port matching (via:https://www.rx7club.com/2nd-gen-arch...actions-79511/)
-replace all manifold gaskets
-ceramic coating intake manifold and polishing.
-replace all the vacuum lines(via:https://www.rx7club.com/2nd-generati...thread-931057/)

If anyone has any of the pictures that were up on this thread that would be great and I will award you 10 internet points for your time.

Atkins 5th & 6th port actuator valve kit
-84-92 Rx7 Atkins Designed Six Port Actuator...
-clean actuators
-replace gaskets and seals

The throttle body is a place I'm not so sure about. I've heard mixed opinions about the throttle body mod. I still occasionally daily drive this car so streetability is important. Not sure if I should go whole hog on this one and weld in the holes where the second butterfly was or just take out the screws and leave the rod.

Currently I am running the plugs recommended for the non ported engine, should I run a different setup on account of the streetport? Have ngk wires going to them.

Exhaust
-Ceramic coat header
-Fabricate test pipe in place of presilencer (and ceramic coat).

Tuning
-Rtek 2.0
-innovative wideband
-coolant temp gauge
-a good tune by someone that knows what they are doing, aka not me.

Anyway, that's the plan. I'm going to do the stuff to the intake first, then the exhaust, then the get a rtek and get it tuned.

Any thoughts or opinions? I'm going to be ordering all the parts today and hopefully I'll get started by next weekend.

j9fd3s

iTrader: (3)

sounds good! i've got a couple of suggestions/thoughts...

for the throttle body, if its a DD i'd keep the thermowax, it'll give you the fast idle, etc. deleting the secondary butterflies don't affect drive ability at all...

for spark plugs, in the FC stock seems to work best. the Rx8 plugs are better, but they seem to want less fuel, so you need the programmable ECU to take advantage.

for the tune, basically the stock tune is something like 12.2AFR @4000rpm, and then goes to 11:1 @8000, and if you just set it so it stays at 12.2 it feels like you pick up like 40hp, which is like 90% of the hp gain.

oh and the tube between the AFM and the engine is too small, its big on the outside, but it isn't on the inside, replace with something.

another low hanging fruit gain is to ditch the turbo trans, it takes like 80hp to spin at 8000rpm, and the ratios are horrible...

Jeff20B

iTrader: (13)

I didn't know that about the turbo trans. Glad I stuck with an NA unit.

Edit: Decided to add more. I didn't know the stock ECU was so rich. Maybe swapping a MegaSquirt in is the right choice.

I picked up a 3.5" tube to replace the teeny rubber/plastic black sorkel. I guess it'll go in first.

Wohnson89

iTrader: (3)

Good info s far! I'll defiantly look into the afm tube and on the turbo trans, I had a na trans in there, but that glass sucker blew one morning on the way to work. I had another s4 na trans lying around, but it got stolen by stupid scrap thieves. The turbo trans was so I could put the tii LSD in the back. (Got a great deal from a salvage here in town.)

Anyway thanks for the info so far, keep it coming!

rotarygod

iTrader: (1)

A few years ago I tested out multiple parts of the intake system with a magnehelic gauge. I found no restriction in this tube. In fact I found no restriction in the afm either. The biggest restriction I found was the stock paper air filter.

Jeff20B

iTrader: (13)

Ah, that's good to know. Thanks rotarygod.

j9fd3s

iTrader: (3)

https://www.rx7club.com/2nd-generati.../#post10601567

maybe with a full exhaust on the car it is restrictive?

Wohnson89

iTrader: (3)

I put some special instructions in my order to atkins rotary, and they came through with flying colors.

Anyway, I got all the parts in today and I believe I might start this weekend.

diabolical1

iTrader: (3)

holy ****! too funny ....

Wohnson89

iTrader: (3)

Well got a little side tracked today, got my new wheels in. Out with the old 350z wheels to the new bbs rs wheels.

out with the old,


In with the new.



The next run of ceramic coating is the week after next, so I'll just wait till then to pull everything apart so I don't have a dead car for 2 weeks.

Casual_John

iTrader: (8)

My advice is 'keep it light', if you want it to 'getup and go'.
Those new rims are nice and light.
The NA drivetrain is lighter than that Tii backend.
Lighten the flywheel, if possible, too.
The RB Road Race exhaust is sweet (looks good and sounds nice) but it ain't light. Pacesetter header and a single muffler is a lighter combination.
But I can tell by the photos that you take pride in the appearance of your car, so you wont want a tinny exhaust or an empty spot in your rear bump.

Wohnson89

iTrader: (3)

Good info is always appreciated! I did get a lighter flywheel installed when I did the turbo II drivetrain swap, got a lightly used fd flywheel, which I like because I have had some weird stuff result from a flywheel being to light on my conquest. My goal is more or less a street car. I most likely won't take this car to anything more than maybe an auto x here and there. I'm not to concerned about weight when it is something like the exhaust or my trans and diff. That being said, I do have a turbo aluminum hood being prepped to paint right now. Probably the best thing I can do right now is not date a fat chick, that saves like 250lbs! Some day down the road I would like to build a track car and just go at it ripping everything non- essential and heavy out and having a bonfire.

Anyway, this has gone slower than I expected to get this stuff started. My conquest, the problem child, needs some attention. I gotta rebuild the turbo and replace the starter on it this coming week. After that *fingers crossed* I will be able to tear down my fc to git er' done.

j9fd3s

iTrader: (3)

a couple other things that really help an NA are weight, and short tires/gearing.

the AL hood is actually a big weight savings, i like to pull the jack and spare too. a cat back looses a bunch of weight. the next step is the AC if you're not using it, and then maybe the PS.

then you're down to removing all those oddball brackets that Mazda puts all over the car.

if you do all of that, you still have a full interior, and you haven't pulled out the interior or stereo (or ac/ps maybe) so its still a street car

the short tires and or gearing, get the engine into its powerband more quickly. going from 205-60-15 to a 205-50-15 makes a huge difference... you could also drop in a different rear gear*, but that is $$

*the Rx8 runs a 225-45-18 and a 4.44

TonyD89

iTrader: (10)

Out of curiosity, does that diff fit into an FC? If not, what about internal swap into a NA or Turbo diff?

j9fd3s

iTrader: (3)

Mazda has two RWD diffs, the M type, P type and the T type

four diffs, the M type, P type, T type, and whatever the newer miata has, and an almost fanatical devotion to the rotary engine....

so the Rx8 uses the P type, which is shared with the FD, turbo FC, 929, mpv, and some trucks, it has an 8" ring gear.

the M type is the one in the Na FC, and is in the 79-92 Rx7 non turbo, 94-2005 miata, some trucks, the kia sportage, and the S2000* i think its a 7" ring gear, and the FC uses an oddball long pinion which makes it unique, as usual

the P type is found in the 90-93 miata, and 88-89 323 GTX, its teeny and useless

the newer miata uses something with a different prefix, and since its a 21st century thing, there's no info on it. the manual just tells you to pull it out and put it back, no specs.

*the S2000 uses a Mazda diff. please note that Mazda only uses the M type diff up to 160hp/2700lbs, and Honda is using it at 240hp/2800lbs.

TonyD89

iTrader: (10)

So I can put the RX8 diff internals into my TII diff. Right? TII stub shafts work also? Can just the gear set be swapped?

Wohnson89

iTrader: (3)

Well this lazy sucker finally got around to doing this build. Car was torn down for way to long because I got really busy (having a life really cuts into car time).

What I ended up doing to the car was a little different than I planned but not by much.

Starting at the block I installed the Atkins port sleeves (they are awesome pieces, I highly recommend them). I port matched all the points I found a mis-match by using the new gaskets as a guide. Carbide rotary cutters are amazing and they went through the cast aluminum like it was butter. I was originally planning to polish all the interiors, but I talked to a tuning and engine building genius friend of mine and he said to never polish intake manifolds on in fuel injected cars because it will tend to "puddle" the gas and pull it out of the air mixture. He suggested to use my glass bead machine to re-do the factory texture once I port matched the manifolds. (kind of like a gold ball effect). After a through cleaning with carb cleaner and lots of rags, I sent the manifolds off to get ceramic coated at a place here in town (Lorac powdercoating), and got them back within a couple of days. Just to achieve a kind of fancy look, I wet sanded the stripes and the lettering off the top of the UIM. Looks spiffy in my opinion.



I went back and forth on how far to modify the throttle body and I settled on keeping the secondary butterflys but removing the thermowax and the cold start system. I cleaned the whole thing with carb cleaner and shined up the metal with some scotch-brite and Never Dull. That and I cleaned off all the old grease from 1989 and sprayed new white lithium grease on all the springs and rotating surfaces.



After resetting the tps car started first try but ran like crap past 3500rpm. I traced the problem back to sticking port actuator rods (I tried to use dry graphite lube on the shafts) and once they were cleaned out everything ran great! I am very happy with how everything turned out! Throttle response is awesome and maybe even a few hp was found somewhere.



The only problem now is that I bought a 05 Mini Cooper S since I tore the engine apart last July, and the steering is so tight and crisp on the Mini that my FC now feels like driving a fast piece of Jello in comparison (crappy steering pump I figure). My plan now is to buy a 17.4:1 steering rack and de-power the steering instead of de-powering the 15.2:1 rack in my car. I had a spare ac/ power steering bracket lying around so made up a bracket that gets rid of the unnecessary power steering bracketry while letting me keep my AC with a shorter tensioner.











That's all for now folks! More to come soon when I get my new rack.

j9fd3s

iTrader: (3)

the other thing that makes a difference in steering feel is toe in, the stock alignment runs a ton of toe in, and feels really lazy and flabby. running closer to zero toe in, it feels much better.

TonyD89

iTrader: (10)

How much do you want for the rack?

Wohnson89

iTrader: (3)

I actually run just a little more aggressive alignment than what the book says. I can't find the print out from my last alignment, but its near zero I'd be willing to bet.

Do you mean you have a good 17.4:1 rack to sell me, or you want to buy my 15.2:1 when I take it off?

NCross

iTrader: (18)

I hope you have a back up car for when that Mini jumps time

My shop has replaced three pre 06 Mini Cooper S cylinder heads this year alone due to timing chain tensioner failure. You'll also want to check out your front subframe bushings and make sure the power steering pump and lines aren't leaking onto the cooling fan. Just words of advice. They are fun cars, but boy do they have issues.

FYI the engines are engineered and built by Chrysler

Wohnson89

iTrader: (3)

Well ****, no one told me that cars had reliability issues, I expected it to run forever with 10k miles between oil changes. I guess I should go buy a Prius because that surely has no problems whatsoever.
Complaining about the reliability of a Mini on a Rx7 forum, that's funny.

Let's give this man a hand ladies and gentlemen. Bringing up an old thread for a useless comment unrelated to the topic at hand.

NCross

iTrader: (18)

I was giving you helpful advice.

You seem to be intelligent enough to figure these things out for yourself though. Good luck.