True. I get a lot of interest and compliments on the rx.

 

suspension swap from GSL to SE is not worth it. You're better off buying a GSL-SE with a known good suspension and swapping your heart into that, and seling the GSL

financially speaking.
Fabrications are always the best, if you have the skill. My advice on your GSL though is to upgrade bushings to polyurethane but keep your watts link pilot bushing rubber (the large one that sits ON the differential)

 

We'll guys I guess it doesn't matter to me any more cuz I just picked up two FB a SE and GSL now I have 3 FB. My wife is going to kill me..lol gotta get rid of my FC now :-/

 

Yea I'm looking at energy suspension bushings

 

Bori, bring them over to the OGTA meeting Tuesday evening June 3 in Buford. We'll take a vote which is better, the GSL or the SE.

 

Ha would love too, i've been wanting to go to a meet for a while but every time I say ima go something always comes up.. The SE is going to take a while cuz it's been sitting for a couple of years so I have too go over the engine..:-)

 

Here's what they look like the gsl has a lot of rust but I'm going to strip it.. The SE is in very good shape no rust or dents

 

The "GSL-SE" badge is on the wrong side... odd

 

You know I thought about that also..but I've seen before other GSL SE with it on that side too.

 

time to look for evidence of crash damage!

 

daddy want

Can you pm me details on this set up? I've got an S4 13b here with '74 primary intake ports and stock secondary 6 ports. I want to install a Nikki on it! I also have '74 spec 12A irons to make it into a 4 port, if thats needed...

 

I'd rather just post here for all to see. My car is a GSL-SE with some GSL parts in it, after all.

First there is the coolant seal location of which I'm sure you're aware. So look into that before making any more plans.

Maybe you're not familiar with my setup or read any of my recent posts but my SE has a 4 port R5 (nitrided) 13B with GSL-SE exhaust port timing and 74 intake ports on all four. I had an NO intake manifold (the crappy tiny J-spec hitachi intake manifold, but works brilliantly with a Nikki with a stud pattern drilled and tapped, and flows plenty for NA and turbo). It was later clearanced to fit the S5 turbo and a 7/16" steel spacer plate with FD studs in the exhaust manifold. Gotta get a Moog idler arm to clear the turbo, but it's a good mod anyway.

The exhaust was the RB long primary but I recently swapped to an S5 turbo. Both drove exceptionally well and the car is the best FB I've ever driven. It has other nice mods too such as a competition trans mount and hockey puck motor mounts. Light steel flywheel, stock disc and currently a centerforce pressure plate, all in 215mm and it doesn't slip yet. Stock boost and old hard tires, so you get lots of wheel spin when you open the secondaries. Mallory 4309 fpr and MSD fuel pump (avoid walbro). I suppose stock GSL-SE fuel pumps will work but mine was long gone when I got the car.

The Nikki mods are the standard ones I do. I have a .046 (117 to 118) drill bit which works out perfectly to drill jets and air bleeds. Enlarged venturis; 24.7mm is where my tools stop wanting to cut, and leaves enough venturi shape to still pull a decent vacuum and run fine. Then I do other Sterling inspired mods which I won't go into here.

As for a Nikki on a 6 port, it could work. I'd cut the venturis slightly smaller. I did one carb to 24.5mm and will test it on a buddy's 6 port that has the same 74 ported primary as yours and slightly enlarged secondaries. The intake manifold is either a 79 with a 6 port flange welded to it, or a 6 port 12A with a 6 port flange welded to it. I have both so one or the other will be chosen.

How well will it work? Compared to what? stock EFI? Some other kind of carb? That remains to be seen. The car currently has an Edelbrock 600 on an RB manifold and it works more or less. Some power, of course. It's NA, though. The fuel slosh upon braking/turning is anoying. Its secondaries don't hit as hard as I'd like. However the tip in is nice. So we will see whether the Nikki is better or worse than the Edelbrock for driveability and mileage. He just needs me to install a mallory 4309 to get it down to 2.5psi.

 

Something else to add. The S5 turbo makes the car feel like it still has the long primary. But now when the secondaries open, it add an extra dimension of power.

Think of it this way. You already know how your car runs and drives with the long primary. Plenty of low end torque, sounds good etc. Mine could break them loose in gear on wet road while NA, as I'm sure yours can too. And now with the turbo, it can break them loose in gear on dry road. Stock boost levels too (like 7 psi from the factory).

I'm as happy as can be. I find it difficult to want to change anything about it now. Even at stock boost levels I'm satisfied. In a way I kinda miss the mods/parts swapping/testing though. I also have an FD shortblock waiting for rebuild parts, JW manifold, boost prepped 650 DP Holley, aftermarket ebay TO4B with a P-trim exhaust wheel and divided housing, kinda expensive wastegate and all that jazz. Basically everything I need to totally redo the car for a "proper" blow through setup but I'm left asking why? What defines proper anyway? If it works and I'm happy, why change it?

 

Proper is when you find satisfaction with your work while on a budget lol

 

I was planning to use the 650 AVS on mine, not the ideal size, but the carbs secondaries are fully tuneable. It also has the spring loaded needle and seats and other neat stuff. I think the only difference in size between the 600 you have and the 650 is the secondary barrel size... And I want mine to open late-ish.

BUT if I could have a hogged out nikki on this setup (and maybe im dreaming but functional aux ports) I would do that sooner than any other carb. The 12A I daily is injected, but this next build to replace it I really wanted to go back to carb. And of the 3 nikki's ive "Sterling'd" none of them had any issues at mid ohio, even in the technical bits.

I even pondered the IDA or DCOE for this engine, but I just cant live with it on a daily basis without a manual choke and 4 barrels

Got any videos of the edelbrock in action? I need inspiration...

 

Nope.

Hey, you should look for a 6 port 12A. It's a 12A and can have functional aux ports! Oh the Nikki it came stock with had special mods specifically for the 6 port intake scheme.

Seems perfect, right? However according to people who have driven them, they only had low end torque. Well, I have a 6 port 12A and plan on updating/upgrading it to GSL-SE end plates and a typical Y intermediate plate. The stock ports on these engiens were VERY small. The manifold will require some port matching and quicksteel here and there as it has insanely small runners and a few voids which will mess with the tall runner Y (Mazda's idea to reduce interchangeability).

The carb came stock with 18mm venturis and small boosters. I've since swapped them out for stock 20mm venturis and matching boosters. I'm kinda having second thoughts about having just gone with 20mm though. Should have looked into 22mm or something. Oh well they're in there now and a good 2mm upgrade over stock. The secondaries were stock size but the boosters were bigger with multiple holes in the brass tube. Very weird. It also used a water choke which malfunctioned and kept it running rich all the time. I removed all that crap and swapped on a typical FB air horn to use the manual choke. Also swapped in some stock 92 primary fuel jets as it came with 79s! Never seen jets that small before. The secondaries were 120! So I swapped in some 140s. It also had a set of through holes in the float bowls connecting directly with the secondary slow air bleeds No1 or No2 (the long ones). Not sure what that's about, but must have something to do with the aux ports when they open, letting in more fuel, maybe. Probably why it had 120 stock jets. It also has mechanical secondaries now and a Sterling inspired accel pump mod. Now I just gotta scrape some parts together to build the engine.

 

i don't know about the 6 port 12A, but the 6 port 13B engines have some features that might explain the odd carb jetting.

1. the primary ports are small, and the opening is retarded, this gives less overlap, and better BSFC, better BSFC = less fuel needed for the same power

2. since its primary, secondary and thirdinary, the secondaries probably open sooner, so the primaries don't have to support as high an rpm as they do in a normal 4 port.

3. since power is up, but the primaries are smaller, that means the secondary has to flow a larger %

4. the 6 port timing is way late, so while it helps power way up top, it hurts down low, so BSFC is worse, worse BSFC = more fuel needed for same power.

although this is just an educated guess, ultimately the engine needs to get what it wants, weather it looks weird or not

 

Well after looking at the body I found no signs of crash damage repair ..but what I did find is a bad paint job. I thought the color of the car was dingy cuz of its age and being out in the elements for a long time. That's not the case I can see paint peelings in by sunroof and by the back window.so I guess that's why the SE badge is on the wrong side..

 

I never really embraced the mechanical secondaries on the sterling. The ones I made for myself retained the vac secondaries, which oddly works very well only after the throttle shaft mods. You can bore out the carb for more airflow, but the secondaries dont start coming in super fast and perfect until you do the throttle shaft thinning. I built my first one in steps, and one of the last things I did was make a custom secondary spring. I was pleasantly surprised that thinning the throttle shafts had the desired effect in response from the secondary barrels even before cutting the spring...

The one im driving everyday now is nigh perfect, but id say its still too small for a 13B. Only thing I dont like, is that after jetting it "for what the engine wants -j9" It smells rich all the time. Still, no fire ***** or anything though. But pulling up to a stoplight with the windows down means youre surrounded by a cloud of gas lol.

BUT, with the vac secondary mod, i didnt have to make a huge acc pump (even though it might actually need it regardless) and the engine has no sputters or bogs because the secondaries arent forced fully open at low engine speeds, regardless if I stand on it or not. So that combined with small acc pump = waayyyyyy more power than stock, and the MPG's are still in the twenties.

Sadly I just want better low end torque. Thats why I got the 13b. Pretty sad when my 158 hp 2.0 mx5 is more fun to drive than my FB, ONLY because of how punchy it is down low.... (which is a stealth vote for the OP in the direction of the GSLSE)

 

I've never thinned the throttle shafts and don't feel the need now that my setup has so much down low. I guess we had different goals and took our carbs in different directions with differing results. I also needed to keep my secondaries totally stock for less the worry about under boost. Works perfectly NA too.

As for your too richness, mine was that way rich until I ventured into swapping in smaller primary slow air bleeds. Stock was anywhere from 150 to 190. Actually the carb I was testing was 180, so when I swapped in a set of 150s, it improved but not enough. The only other option was to take my trusty 118 drill bit and drill a set of nickle plated 60s from another carb's secondaries and throw them in the primary holes on this carb. It brought the mixture screw back within its range and leaned out or richened up the idle to where it would idle correctly again (can't recall which direction it was out of calibration but the mixture screw was either all the way out or all the way in until I did the 118 drill mod). Now my engine idles at 11.9 to 12.3 which is what it likes best and doesn't smell rich anymore. Smells normal, if that makes sense.

Again I tuned the idle for what the engine wants, not some number on a wideband. This engine just happens to idle best around 12.2 and still has good driveability when it cools down or heats up under various conditions. Sterling said to tune the idle slightly rich to avoid stalls, but so far my setup seems to like where it's at, and doesn't seem to stall unless it's still cold and I don't pay attention (like pretty much all carbs so it's nice to know my recalibrated idle was successful).

 

If im honest, my carb does have a slight lean surge when going through the gears quickly at lower rev's. I think its the tiny stock acc pump, which is why I hinted at that before. So, leaning anything out seems like a step in the wrong direction, but you might be right. Take fuel away from where it doesnt need it, add some where it does. Makes perfect sense! I just hope its that simple.

 

Hmm, you might try the basic accel pump upgrade to increase fuel. Simply remove the banjo bolt, drill out the tiny jet at the bottom until it's gone. Then drill through the two holes up on the smooth part of the bolt. I use my 118, but you could use a .050 or whatever. Leave the nozzle squirter alone for right now. Just reinstall the modded banjo bolt and observe the results. I bet this will get rid the the lean problem. You see, the nozzle is now the bottleneck and will be basically maxed out where as before the tiny jet at the bottom was your bottleneck. Does that make sense? Remember the 79 Nikkis don't have this tiny jet so it's not like you're modding it beyond anything that ever existed stock.

 

Yeah, that does seem to make some sense, but I will say the 12A 6 port's intake ports are WAY smaller than the 13B. See, the 13B primaries are the same size as an NO intermediate plate. Not big but not super tiny. The 6 port 12A is much narrower, but about the same height (actually maybe slightly taller for a later closing but still shorter than a 12A Y port). The low RPM ports were also super narrow and the aux ports were a tad smaller than a GSL-SE. I know the S4 NA are taller than GSL-SE.

I hope adding a set of GSL-SE end plates and possible swap to a Y intermediate will give this engine all the port area it can handle, without needing to port anything. Hopefully the stock 40 degree closing of the Y primaries won't cause the tiny primary manifold runners to run out of breath. The secondaries will also be asked to flow more than they can. lol

I might try this in a rotary truck to test the whole "low end torque" thing that others who've driven these before have talked about. What better way to test a theory than in a truck, right?