Alex84GSL

My 84 GSL that I spent all summer putting together is sitting on the driveway with a blown apex seal... on the engine that a guy told me had compression tested 110-120 or so.

Yesterday I found a guy with a 88 (I think) non-turbo FC. The body is crap. But the engine seems to turn over well and I talked him to $400 if I can get it off his hands fast.

I want to throw on a carb and a decent exhaust and see what I can get out of this beast in my little FB. Thoughts? What carb would you throw on a 13b? (Also this would be a six-port I think?)

Alex84GSL

No replies? Maybe this is a newb question. I'm going for it, and I have an idea what I need already (intake, exhaust, SE front cover and oil pan and do something with the engine mounts.)

For those who have owned 13b first gens with a carb, what's the best carb?

Directfreak

iTrader: (2)

Get a 48 Weber, 48 Mikuni, or 48 Dell'Orto (my personal favorite).
Don't get a Holley unless you want drag racing or Turbo Blow-through.

You need the carb, Racing Beat sidedraft intake, GSL-SE oil Pan, GSL-SE engine brace (or modified 12A one), 13B Headers would be good too. (You can modify existing 12a one if you have it).

Good Luck.

84stock

iTrader: (5)

I would take an edelbrock over a holley

85rotarypower

I actually had a 88 6 port 13B (non turbo) in my 82 with custom exhaust and a Edelbrock Performer 600cfm carb on a JayTech intake manifold. The Jaytech is hard to find these days, but is a nicely designed manifold. The RB holley manifold will work as well though. The engine performed very well once I got the carb sorted and I had no real issues with leaning out through turns like a Holley will. Overall, the car had enough power to hit a 15.53 @ 89 mph quarter mile run with a real crappy launch and 60' time. With more practice, I've no doubt I could have done low 15's with that setup, and that was stock porting on a 150xxx KM engine that wasn't rebuilt.

If I were to do it again though, I would probably go for a Edelbrock Thunder AVS series carb in the 500cfm configuration. 600cfm is a little bit much for a stock port 13B and the 500 would probably perform better for this reason. They are more geared toward offroaders as far as I know and have better operating angles meaning it should hold up better through corners. Tuning an Edelbrock is very easy too and there is some information from about 4 or 5 years ago on the forums showing a good starting point with your jets and metering rods along with the couple small mods to make the carb run great on a rotary engine. Edelbrock carbs can be had for peanuts too on Ebay as well, probably cheaper than any other carb out there.

On another note, I regret dumping the edelbrock carb in favor of a Mikuni. I kinda got the crap end of the stick on the deal as the carb wasn't as advertised and was actually a 50phh2 with odd venturi size instead of the 45PHH that it was supposed to be. I never did get this Mikuni to run right on the engine after many hours of messing around with it and many emails to an expert on these carbs. I found it very hard to tune and always wanted to run rich, even with the smallest jets I could get (probably due to the massive CFM the carb would flow).

PercentSevenC

Weber fanboy here. I'd take a 48 IDA over any other carb for an NA setup. Simple, flows well, and performs well in high-g situations. A 48 DCO or Dellorto 48 DHLA would be my next choices. Not a fan of Holleys or Edelbrocks due to their fuel slosh issues, though my Edelbrock made for a pleasant daily driver (just don't make hard stops or left turns!).

Alex84GSL

Thanks for the help. Basically I'll take whatever of those carbs I can get.

Shopping list grows as I keep searching more articles on here
-RB motor mount
-SE oil pan (and front cover?)
-exhaust system
-carb and intake adapter
-cushion to protect my butt from the acceleration when I finally drive it

-Will I need a different battery?

Directfreak

iTrader: (2)

Same battery, same front cover as a stock 12A.
It's straightforward and not complicated at all.

j9fd3s

iTrader: (3)

me too! i'd be tempted to do a DCOE to keep the 6 ports... but either way, i like the weber

Alex84GSL

Thanks everyone. I'll probably go with an Edelbrock 500 because I have an excellent connection in Calgary (84stock) who is kinda god-fathering me into Rx-7 proficiency! Will an RB Holley intake work for that? Anyone got one kicking around?

PercentSevenC

It will work fine, but may need a spacer for the carb to clear the water pump housing. Make sure you get the "Thunder Series" carb with the adjustable secondaries.

84stock

iTrader: (5)

Mine is a performer. I do agree with the benefit of the thunder series though......as for the spacer both the edelbrock and the holley benefit from an open phenolic spacer.

RotoricanNY

iTrader: (2)

I got an S4 13B with a Dellorto 48DHLA and full RB exhaust on mine and I must say I'm pretty happy with it. Tons faster than the 12A with a stripped down nikki.

PercentSevenC

Yep, mine was a Performer Series, too, but I would've killed to have the adjustable secondaries.

Another word of advice: stay away from the triangular foam air filters they stock at Autozone and the like. They're terrible. If you need a cheap one, just grab one of the round paper element ones.

Alex84GSL

I was reading up on the air valve system on the Performer Edelbrocks, designed so that the secondaries don't open more than they can be useful - seemed like a good thing to me? Can it be converted like the Nikki?

Also GEEZ the vocabulary you guys throw around... phenolic? Please someone tell me what that means

bumpstart

adapters avail in aus to fit either a hitachi and 13b carb manifold,, or the nikki on a 12a manifold to 6 port FC block ( also are avail for t2 blocks )

tweakit

tweakit also do a manifold directly for the weber 48

i have first hand experience with 6p engine with theses three carb setups
,,, and also with the 465 holley on the RB manifold ( onto an adapter ) onto a 6 p engine

the adapter plate ,, the 12a carb,, and the doubled phelonic spacer mod
( and cross port of the manifold at the carb base )
works very well,, carb is easy to tweak the accel pump and simpler to work on than the hitachi

of the two mazda carbs on similar 6 p engines, in similar weight cars ( s2 rx4 sedan V s4 rx2 )
the nikki carb was faster , and had more top end

the rx4 ditched the hitachi for the holley setup,, and possibly went slower
,,a poorly setup holley 465 is still no match for the well setup hitachi or nikki on doubled phelonic spacers

then,, the rx2 evolved to a 6p with 48 ida weber ,, 42 chokes,, 140 -160 A,, 205 - 210 fuel F11's
and was totally transformed ,, especially up top


+ for the weber,, pretty,, simple,, and works very well on the 6 p engine ( sans aux control ) when over 2500 rpm

PercentSevenC

Both Edelbrock carbs have vacuum secondaries. I've never understood why some people prefer mechanical secondaries over properly-working vacuum secondaries. If the vacuum secondaries are set up right, you won't even feel the transition. That's the advantage of the Thunder Series: you can adjust the transition until it's perfect. The only way to adjust the secondaries on the Performer Series is to drill out the weights.

"Phenolic" describes the type of material. It doesn't have to be a phenolic spacer, an aluminum one will do. It just won't be as thermally insulative.

Alex84GSL

Ok thanks
I might not want to insulate my carb temp-wise since I live in Edmonton, Canada, and we get a couple weeks of -40 celsius here in the winters...

84stock

iTrader: (5)

The edelbrock is a mechanical secondary carb, the butterfly above the secondaries open when the desired airflow is present.

84stock

iTrader: (5)

True, but now for 12a to 13b 6 port. And when you factor the price, duty and shipping to Canada you can just buy a new intake and an edelbrock works quite well and is cheap.

Great feedback though, and tweakit does carry a lot of cool stuff.