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Login to post Forums » Grassroots Motorsports » I'm Benjamin Buttoning my RX-7: A build thread.

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Jan. 22, 2012 10:39 a.m. Osterkraut SuperDork

MrJoshua wrote:

Osterkraut wrote:

Greg Voth wrote:

Exhaust looks good. Racing Beat Stainless header from the looks of it.

Where did you get it? Custom built or shop built?

It's a Defined Autoworks system. Some guy on the club was having some financial difficulty, judging by the firesale he was having.

MrJoshua wrote:

Those headers are reaaally long! Hell, that exhaust looks way too long to even FIT under a first gen. That isn't even taking into account that there doesn't appear to be an over axle section-what gives?

Long primary headers need to clock in at 100+ inches for most good power yes. But you're right about the exhaust not fitting an FB: it's from an FC, I'm going to have to use my "excellent" welding and pipe bending skills to make a few changes.

IIRC 100" is right in front of the rear axle for a FB. After that you immediately need the over axle 180 degree section. You will likely only be able to fit a rear muffler on that setup and that single straight through Borla is going to be LOUD! Maybe you could shove one of those Auger style muffler cores into the Borla to make the sound wave bounce into the silencing parts a bit more? Another option is to cut into those pretty headers and add the best/biggest presilencer you can find in each leg. That makes a really nice sounding car, but it would be a shame to cut up those headers.

It's actually not 100" straight because of all the bends. The 02 bungs line up roughly with the end of the transmission, for a sense of scale.

Of course, it's still probably going to be loud as berkeley, even with the resonator and muffler. Worst comes to worst, there's several nice straight sections to hack into those headers. Throwing resonators inside the primary tubing lowers the torque peak, but not by much.
Jan. 26, 2012 10:31 p.m. Osterkraut SuperDork

First change of plans

Well that didn't take long, now did it? Succinctly put, I've decided I don't think I like single exhaust tips on FBs, and have become quite fond of these:

Yeah, yeah, I know they say Racing Beat on them, but the only other ones I've found in that style are these: And I really don't like them as much.

Pictured Racing Beat tips have have a 2" inlet, and a max diameter of 3.7". Hmmm, I wonder, roughly, what that will look like on a muffler? Oh, well then. Looks good to me!

Alternate strategy: find a cheap Racing Beat FD cat-back, it's basically the same look.
Jan. 26, 2012 10:46 p.m. MrJoshua SuperDork

The upside of the racingbeat can is that they usually are HUGE with lots of rotary specific packing so you might not need resonators.
Jan. 26, 2012 10:58 p.m. Osterkraut SuperDork

MrJoshua wrote:

The upside of the racingbeat can is that they usually are HUGE with lots of rotary specific packing so you might not need resonators.

Downside: Looks like a used one runs $400...no thanks, that's most of what the exhaust already cost!
Jan. 27, 2012 8:56 a.m. Curmudgeon SuperDork

For a budget sorta setup, the Dynomax turbo mufflers are available in 2 1/2 and 3" ID's. Caution: there are two different types, the cheapie has 2 1/4" ID tubes with the stubs expanded to fit the advertised pipe diameter. The other more expensive version carries the stub diameter all the way through the muffler. One of those at the end combined with a presilencer should get the racket down considerably.

The fun part: the Dynomax has fiberglass packing. After a couple of hard AX runs, the stanky is amazing. People will walk by and sniff, then get a real worried expression on their faces. It goes away once the packing finishes melting.
Jan. 27, 2012 9:18 a.m. MrJoshua SuperDork

You could get a factory muffler from a big diesel truck and cut it in half.
Jan. 27, 2012 11:29 p.m. Osterkraut SuperDork

Curmudgeon wrote:

For a budget sorta setup, the Dynomax turbo mufflers are available in 2 1/2 and 3" ID's. Caution: there are two different types, the cheapie has 2 1/4" ID tubes with the stubs expanded to fit the advertised pipe diameter. The other more expensive version carries the stub diameter all the way through the muffler. One of those at the end combined with a presilencer should get the racket down considerably.

The fun part: the Dynomax has fiberglass packing. After a couple of hard AX runs, the stanky is amazing. People will walk by and sniff, then get a real worried expression on their faces. It goes away once the packing finishes melting.

Unfortunately, Dynomax doesn't make a 2.5" in, dual 2" out muffler that's any cheaper than the Magnaflow I've picked out (Magnaflows sounded great on my old FC).

Ooo, shiny

Finished the throttle body mod (not shown: JB weld in the holes- pro tip: use the JB Stik subtype), followed it up with a port and a polish. At this point I need to stop grinding on things or else I'm going to need a new Dremel.
Jan. 28, 2012 5:44 a.m. Javelin SuperDork

Osterkraut wrote:

First change of plans

Well that didn't take long, now did it? Succinctly put, I've decided I don't think I like single exhaust tips on FBs, and have become quite fond of these:

Yeah, yeah, I know they say Racing Beat on them, but the only other ones I've found in that style are these: And I really don't like them as much.

Pictured Racing Beat tips have have a 2" inlet, and a max diameter of 3.7". Hmmm, I wonder, roughly, what that will look like on a muffler? Oh, well then. Looks good to me!

Alternate strategy: find a cheap Racing Beat FD cat-back, it's basically the same look.

I ran a stainless steel dual-tip (from a single) on my FB. Affordable and very quality. Take a look at the pics in my garage...
Jan. 28, 2012 7:43 p.m. MrJoshua SuperDork

Have you considered a WRX take off? It should flow plenty for what you want, looks like it might fit the stock hole, and built pretty well.
Feb. 14, 2012 9:46 p.m. Osterkraut SuperDork

The GSL-SE's previous owner was a BP executive Gross.

Clean.

Don't forget when changing front covers, in order to safely remove the eccentric shaft nut, you're going to need to apply forward pressure to the flywheel so a bearing located in the assembly doesn't shift and bork your whole engine.

The GSL-SEx came with two engines, a half-installed good engine in the car, and a bad engine out of the car. The bad engine is donating all the conversion parts (front cover, oil pan, injectors, etc). After that, it'll be broken down and the good parts sold, the bad parts scrapped or turned into rotary-themed trinkets.

Random shot of the 13B sans front cover:

I spent like half an hour cleaning the vacuum spider and pouring over vacuum diagrams, trying to figure out what line went where and which ones I needed to keep. Good thing I test fit it: Well E36 M3. How to fix that?

Well that wasn't too bad.

As an aside, I'm trying out silicone line from McMaster-Carr. It's a tenth of the cost of traditional silicone vacuum line from an autoparts source, so I have high hopes. The thickness is less than your traditional stuff, I'm hoping it won't collapse under vacuum...if it does, I'll just order a thicker spec, and still come out ahead financially.
Feb. 15, 2012 8:18 p.m. Osterkraut SuperDork

There's no turning back now

As you may be aware, the GSL-SE has only two injectors, where as the FC has 4. This leaves two large holes in the middle intake manifold that must be filled somehow. My solution was to fill them with JB Weld; not exactly removable, but manifolds aren't that expensive if I ever want to go standalone and add back the second fuel rail.

In addition, having figured out the vacuum routing, I shaved off and plugged all the unneeded nipples (so to speak).

I also finished the vacuum spider, here's a nice overhead view if you're following along at home:

The five that aren't connected go as follows, from left to right: manifold vacuum source, manifold vacuum source, BACV, fuel pressure regulator, and finally metered air from the throttle body.

And here it is all hooked up:
Feb. 15, 2012 9:33 p.m. SyntheticBlinkerFluid Dork

Ok so I'm confused. Maybe I missed it earlier in the thread, but what exactly are you doing with the fuel injection? You're using an FC intake instead of the FB intake?
Feb. 15, 2012 9:49 p.m. Osterkraut SuperDork

SyntheticBlinkerFluid wrote:

Ok so I'm confused. Maybe I missed it earlier in the thread, but what exactly are you doing with the fuel injection? You're using an FC intake instead of the FB intake?

S5 block and intake. Should make for one quick little FB.
Feb. 16, 2012 9:30 p.m. dean1484 SuperDork

If you are going to use the AFM in the car see here>>>> http://www.ehadesign.com/~dsmith/mas.htm

You will have to highlight the text to the left of the photos of read it. There is a weird glitch on my site that I need to go fix.

IT really helped the throttle response and the old but dyno said it was worth a couple HP.
Feb. 19, 2012 2:18 p.m. Osterkraut SuperDork

dean1484 wrote:

If you are going to use the AFM in the car see here>>>> http://www.ehadesign.com/~dsmith/mas.htm

You will have to highlight the text to the left of the photos of read it. There is a weird glitch on my site that I need to go fix.

IT really helped the throttle response and the old but dyno said it was worth a couple HP.

Noted!

Frankenblock Created

-SE front cover and oil pan installed, S5 waterpump clearanced and installed.

No so good picture of the issue with the waterpump.

Of course, when I say "Frankenblock created," I really should say "Frankenblock twisted even more evilly." It's already got some parts-bin engineering, the turbo rotor housings being probably the most obvious example.
Feb. 23, 2012 6:38 p.m. Osterkraut SuperDork

Dear Lard,

I know we don't talk much, but just this once, can you make exhaust bolts not royally suck?

No? OK, I'll try somebody else.
March 2, 2012 5:49 p.m. Osterkraut SuperDork

Minor, useless update:

Old engine is coming out this weekend. I've decided to take the transmission out with the engine, because
1) It's filthy.
2) There's some rando wires hanging back there that look like they belong in something, and I'm curious if their connections are on top of the trans or if this car used to be automatic. I guess I could open up the FSM, but directions? Never.
March 2, 2012 5:57 p.m. nicksta43 HalfDork

In reply to Osterkraut:

As much as I disagree with your avatar I wish you luck with your project.
March 2, 2012 7:39 p.m. Osterkraut SuperDork

In reply to nicksta43:

Whatchua talking about, Willis?
March 3, 2012 12:02 a.m. nicksta43 HalfDork

Your new avatar creeps me out. If I scroll up and down fast it goes super fast.
March 3, 2012 8:48 a.m. rotard HalfDork

Oh noez, I wonder what exhaust for rotaries is expensive?
March 3, 2012 2:12 p.m. Osterkraut SuperDork

Ze engine, she is out.

Anyone want to spend 3 minutes watching a time-lapse video of me removing the engine?

God, transmission is fiiiiiiiilthy.
March 3, 2012 3:33 p.m. dyintorace SuperDork

What is your avatar??
March 3, 2012 4:44 p.m. Osterkraut SuperDork

dyintorace wrote:

What is your avatar??

http://www.youtube.com/watch?v=0PlwDbSYicM

12:20 in, for the exact bit. Bonus Mandy Moore content.
March 17, 2012 2:55 p.m. Osterkraut UltraDork

I haven't forgotten about you guys! I've been gone all week for work, so I haven't exactly been in the garage much.

In the meantime, I've been busy playing debit card mechanic. Purchased in the past two weeks:
-Sent all 4 of the GSL-SE injectors I have out to be cleaned. Three came back flowing 720cc, but the fourth only made it to 590. Well, I think I found the fuel problem the PO had...
- Used double alternator pulley, and (new) belts for it.
- Tune up stuff; plugs, wires (NGK), fuel filter, and a dizzy cap and rotor (OEM Mazda: gotta get those brass contacts).
- Moog idler arm: my beautiful header comes reaaally close to the arm, plus the chassis has 200k on it: time to upgrade.
- While holed up in a hotel this week, I made a set of poly motor mounts for myself. Didn't have the forethought to take pictures for a writeup, but it wasn't hard. McMaster Carr has everything you need.
- 3 quarts of Redline MT-90 for the trans. There was a nice little pile of metallic sluge stuck to the drain plug when I pulled it. Not enough, I think, to be really worrying, but it certainly won't hurt to fill it back up with the good stuff.
- Exedy Stage 1 clutch kit. I bought this off of Amazon of all places. Go figure.

If anyone's wondering, I'm at $1625 spent right now.

Oh I also painted a bunch of random parts, inspired by the Dirty 911 built. Pulleys, alternator supports, etc.

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