Jeff20B

iTrader: (13)

Thanks for posting those pictures, Steve. I gotta ask about that 4 port 13B you had with the Yaw carb since I'm thinking about doing a similar engine with a Sterling carb. Wasn't it stock ported and made 170 HP at the eccentric shaft? Or am I remembering it wrong? You put it on an engine dyno, right?

steve84GS TII

I didnt dyno it,but the 170HP claim was pretty accurate, based on Yaw's power numbers and head to head runs against my buddy.

Paul put a stock port 12A at 150 crank HP with his carb/intake,direct-fire ignition and a full exhaust.That was the exact setup I ran, since his products and essays were highly touted back then(and are to this day).
It felt the full bit of 150HP and I swapped all that gear onto the stock port 76' 13B when I pulled it from the wrecking yard.I figured adding 20HP for the increased displacement was fair and it definately had more power and torque than the 12A.My buddy had a 94' Civic that weighed the same as the RX and it had a stock Integra GSR B18, rated at around 170HP.Multiple drag races between us ALWAYS ended in a draw,with nearly identical off the line, and through the gears performance.

Jeff20B

iTrader: (13)

I thought your engine was actually a nitrided R5 from an early '80s HB Cosmo. Either way the ports are the same size going all the way back to the '76 13B and 12A.

I agree with your assessment. 170HP sounds reasonable. I just modified a Hitachi manifold to accept a Nikki so I can eventually use a Sterling.

orion84gsl

iTrader: (5)

I actually didn't know for sure what a GLC was until this thread. I thought it was like a B2000 type pickup or something. Also can anyone tell me if the GLC and REPU were sold in Canada? I'd like to find another old FR Mazda to stick a Rotary in once I finally finish with the FB.

I'm always encouraging you because you do an awesome amount of work with these cars/engines. I'm also the kind of guy to say why not. You've already put the 20B in the GLC, so why not stick it in the S now. I always say "I gotta go WORK on my car", but it's rarely ever work. Hours fly by and I'm always left thinking, "that felt like only a couple hours, not 10".(true, GF came down and yelled at me for taking so long) It especially sucks this winter, because I'm outside and have to count on global warming to give me a decent day to do my work. Hey a though just entered my mind. Since your going to leave the 13B N/A if you put it in the GLC, why not use the SC for the 20B in the FB, you know, later down the road when you get bored and want to kill yourself at higher rate of speed Either way good luck, and don't forget the pics when your done.

Jeff20B

iTrader: (13)

The GLC probably made it to Canada. The REPU did as far as I know.

I think I've settled on the 20B in the S. Why not?

The SC is only a little 5". The 20B would require at least a 9". Atkins does make an SC kit with a manifold and stuff for a 20B, but I don't think I would want to bother with it.

FirebirdSlayer666

iTrader: (3)

I say enjoy it NA until you decide you want more power, then find a nice sized single turbo LOL

steve84GS TII

GLC......Great Little Car.

It was based on the Mizer and it used the same 1.3L iron/aluminum engine.The GLC didnt have a rotary twin like the older Mazda cars,it was simply a small,economial car that came about right when Mazda needed it.The rotaries were being axed due to fuel and smog concerns and the RX-7 hadent come out yet to bring the company back into the limelight.The GLC could be a barebones commute car,or in the case of mine it could be fitted with just about every option you would find on GSL.....except the performance stuff like LSD and rear discs.A fair bit of RX-7 stuff will adapt over to the 78-83 RWD GLC cars too,but when they changed the GLC to front wheel drive in the 80's it basically became another cookie cutter econo-box, which later grew into the 323.

Jeff,Im not 100% sure what my engine was originally from.I pulled it from a 76 RX-4 that was in the wrecking yard.It was a 4-door,all stock car with the factory exhaust and carb....the only mod was an MSD box and some stickers.
Amazingly,it had sat for several months with rain water in the engine.I didnt pull it right away since I figured it was shot,but one day I decided it was worth getting,even just as a core engine.After pumping many cans of carb cleaner and ATF through the ports I installed it into the RX and to my surprise it ran perfectly.No smoke,no leaks and perfectly even compression on all chambers.It ran great for a couple years until I went to the S4 TII engine.I later sold the engine,carb and headers to RSdevil and its still running like a top to this day.

Jeff20B

iTrader: (13)

Thanks for the little bit of history.

I think I saw a picture of your 13B once and it looked like a J-spec nitrided R5 from the early '80s. Did your engine have thermal reactor holes in the rotor housings? Or did it look like somebody installed some plugs in the holes?

steve84GS TII

Must have been someone else.
I didnt even have a camera back when I had that engine.This is the only pic I have of the 13B,and its a digital picture of a film picture I took back in 99'......

Jeff20B

iTrader: (13)

Heh, you even had direct fire back then. No doubt from reading Paul Yaw's site. I recall reading about the MSD stuff in '98 and finally getting one in '00.

I think you or RSdevil posted a picture of the back of the engine and I think I can recall seeing some indicators that it was a nitrided R5. Did it have an oil pressure sender? Or a little BSP plug? Or just a blank undrilled casting?

Jeff20B

iTrader: (13)

Here is the flywheel I'm going to use in the GLC. It is a super light flywheel weighing in at a whispy 8 pounds. It only works with 215mm discs so you can see why it could work in the GLC with a 13B but probably not so well with the torque of a 20B.



It is currently in the white '83 GSL and I was like "holy crap!" when I got a ride in it today. It accelerates like aluminum flywheels but lasts far longer since it's all steel instead of multiple pieces which can fatigue/crack after so many heat cycles.

Since that car will eventually get a turbo the torque will probably double so out will come the super light flywheel and in will go a Racing Beat light steel flywheel weighing in at 13 pounds or so. You have to go to the bigger heavier flywheel in order to use 225mm clutch components. A slight weight penalty for greater torque handling capacity.

I had a funny thought today. Should I try the SC on the 13B that's going into the white '83? You know, before the turbo goes in? It will bump the HP up to maybe around 200, giving the owner a chance to get used to that much power before he goes all out with the turbo, expecting around 300. It currently has a bit over 100 due to the '74 ports and slightly modded Nikki. The super light flywheel and semi-stock exhaust help. It's still gutless though compared to Z-beater's turbo FB. I think the SC would level the playing field a little and give him a chance to learn how to drive more power. Thoughts?

Jeff20B

iTrader: (13)

Here's a better picture of a resurfaced one.



And here it is installed. Those are stock bolts. Not much holding them in.

trochoid

iTrader: (6)

From all of the reading I've done, the REPU was sold in the US only.

Jeff20B

iTrader: (13)

trochoid, what do you think I should do?

trochoid

iTrader: (6)

20B FB.

Then do a primary sp, an Ito port secondary with DCDs on the 13B for the GLC. That would put the 13B near 200 hp. If you want more low end on the 13B, just clean up the primaries. What does the GLC weigh? If it's the same or lighter than an FB, it will walk a stock TII providing you can get the traction.

Jeff20B

iTrader: (13)

20B FB it is.

Man you love those DCDs. I'm still debating how I'll do the 13B.

trochoid

iTrader: (6)

Yep, sure do and you can still buy them new. Fun part is finding the intake mani if one goes that route.

steve84GS TII

Yaw's website and tutorials were responsible for getting me into the real HP.Before that,I had spent a couple years over at Mazspeed.com learning the basics and bolting on parts.I learned about Yaw through that site and I got to talk to him on the phone for an hour or two,VERY nice guy.I still feel bad for bailing on Mazspeed after about 02'.Since its a 1st gen only site,(and kinda old-school purist) I didnt really participate much once my car got really modded out.Funny,Im still on the COTM page after 4 years!!

Your right,I think RSdevil did post some pics after he got it.
That 13B had no oil pressure sending port,I used a Mazdatrix lower banjo bolt to screw in my sender.

Jeff20B

iTrader: (13)

I remember when you started posting on this forum. It was a welcome addition.

I don't hang out at Mazspeed anymore either. It wasn't progressive enough for me. I like to change and mod things in new and interesting ways. Mazspeed didn't really suit that about me. Now their forum is down and what not.

I have an R5 that someone had done that to the banjo bolt to make it work with a set of electric guages. They used a 1st gen mushroom type oil pressure guage sender. It leaked, lol. They probably cut NPT threads in the banjo bolt while the mushroom requires BSP threads.

I ended up getting another banjo bolt, cutting NPT threads in it and installing a compression fitting and nylon tubing for a mechanical oil pressure guage. Man that thing was animated. It would swing from a high of 90psi down to 15psi with engine RPM. It was so sensitive at low RPM you could actually see when the eccentric shaft holes would momentarily line up with the holes in the stationary gears. The effect would be a minute drop in oil pressure right when they'd align, for like a split second. Or maybe I was seeing the pulsations of the oil pump's output itself. Either way I'd never seen that effect before. It was pretty cool.

Now the electric set of guages are going into my baja with a 4 port 13B conversion. I cleaned and painted the waterpump today and installed the temp sender.

As for the GLC's 13B, a friend dropped off a modded Nikki manifold for a 6 port 13B today. It was on the RE-SI engine in his REPU when he got it in '01. It never had much power but I suspect it's because the RE-SI has tiny ports. I' debating trying it in the GLC but there are no aux actuators. It's all flow, all the time. That's bad for low end, but only useable at high RPM. Perhaps I could take a picture so you can see what I'm talking about. I had wanted to build a non ported 4 port 13B for it like stilletoman's car so it will have pleasant driveability and a wide flat torque curve/power band. No need for a peaky engine since the car's limits are a lot less enjoyable to explore than a 1st gen's.

But still I am a little curious how that 6 port manifold would perform with a Sterling and a '74 intermediate instead of the RE-SI, those ports were so small I had trouble poking my thumb in the primaries. '74 spec is like twice as large.

You know, with that much total port timing, a Sterling would be too small. I bet it would need a Holley 650 double pumper at least. Why not get the RB Holley and manifold kit? Hmm, maybe the primaries should be GSL-SE/S4 NA/NO sized instead? They'd be a little bigger than RE-SI spec, but a little smaller than 12A spec.

steve84GS TII

If you make the GLC light enough,it should more than make up for the lack of bottom end.
Its not hard to get a GLC well below 2000lbs.Even with a topend heavy port/induction job,the 13B is still making far more torque than the GLC's little 1.3L 4 banger ever did.......A rev happy, N/A 13B GLC with RX-7 suspension would be a hoot at the Auto-X, or on a mountain pass.

Jeff20B

iTrader: (13)

The engine that's currently in the GLC is a nitrided R5 I built about a year ago. The primaries have a mild streetport and the secondaries have an extended streetport. The exhaust ports were a copy of T2 spec but enlarged about 5mm later closing and maybe 2mm earlier opening. The widths is the same as T2 spec.

The intake consists of a Hitachi jetted to the max (105 or 106 pri, 160 sec, 60 pri air bleeds and 90 sec air bleeds = half decent high end for a Hitachi). The venturis are 22mm which is larger than later Hitachis and all Nikkis, which had 20mm. For comparison, a Sterling carb has 24mm. I think a Yaw does too.

The carb is basically too small for the engine. The large ports hurt low end torque a bit. Even so, the GLC can get up and move thanks to the low weight of the car. An Edelbrock was planned to go in, but we would have needed an RB Holley manifold. If I had an appropriate Holley at the time, I could have gotten away with my aluminum adaptor plate. Edelbrocks are wide and the linkage hits the waterpump. Holleys are narrow their and will fit.

It currently has a Racing Beat light steel flywheel and OEM 225mm clutch components. You honestly don't want a street strip pressure plate as the stock style one actually feels correct for the car (this is due to the older type clutch master and short clutch pedal along with the ribcase tranny's clutch fork pivot point). The clutch disc is also stock and feels ok.

As for the rotational weight and driveability, the RB flywheel feels a little on the heavy side. I'm planning to use the super light flywheel, pictured earlier in this thread, in the GLC next. I also plan to just go with a non ported 13B 4 port for maximum driveability and minimum fuss. Plus I'm setting it up for my dad and I doubt he'd want to fight a jungle cat on a daily basis. Heck its current owner is getting kinda tired of its quirks and likes the super light flywheel and nice wide rev range of the smaller ported 12A in the white '83 GSL. I figure since the GLC is a 4 seater and all four seats will be in use at times, a torquier, better behaved 13B would work out better, even with a super light flywheel. That will keep it fun to drive but it will remain pleasant and driveable in bumper to bumper. Imagine driving an aluminumn flywheel and I suspect that's pretty much how the super light flywhyeel behaves. With the right carb and this flywheel, it will be rev happy and fun.

The front suspension is already done with RB springs and RX-7 struts with vented discs. The current stock struts seem ok. Just the rear remains to be done.

1983GSP

just got done watching directfreaks 1st gen GSLSE on youtube and was throughly impressed. i could just imagine the torque of a 20b in there. i second Trochoid.
20B FB FTW!

Jeff20B

iTrader: (13)

No NOS for me either.

stilettoman

iTrader: (1)

"Imagine driving an aluminumn flywheel and I suspect that's pretty much how the super light flywhyeel behaves. With the right carb and this flywheel, it will be rev happy and fun."

Jeff - I don't know if you have seen this, but I drove over 100,000 miles on the stock clutch disc and pressure plate, still working fine when I sold it. I spent two seasons dragging my ski boat up and down boat ramps and the driveability was fine with the alumnum RB flywheel. Eventually, when the GLC was wrecked, I got it back, everything but the engine and tranny. That same flywheel was run for a while in my son's car and now it has been in my 84GSL for about 30,000 miles. It is a 215, and cannot be resurfaced again - took a little bit off the bolt heads on the last grind. Guess we are getting our money's worth.

Jeff20B

iTrader: (13)

It's very encouraging that you were able to do so much with your aluminum flywheel. It gives me confidance that my super light flywheel will be just as capable, should I choose to tow a little something and what not.

Speaking of towing with a light flywheel, I just aquired an old REPU flywheel so I can measure the step and determine whether the REPU pressure plate is compatible with a Racing Beat light steel flywheel. So far it appears that yes, the step is almost the same as any '83-'92 NA flywheel. The REPU step is actually taller by about .5mm, as if that is going to do anything. I'm now free to drop the tranny, remove the REPU 30 pounder, install a counterweight, '83-'85 225mm disc, and the REPU pressure plate with a set of RB bolts and aluminum spacers for '83-'92 NA light steel flywheels. This swap to a light steel flywheel is in preperation for the 5' SC mentioned earlier in this thread. It's going in the truck after all. I think I'll do this project right after the GLC is running on its new engine.

I got an order from Atkins today for the GLC engine. All that's left is to put in an order at Mazdatrix for a couple parts and I can start building it. Here's to lasting 100,000 miles.