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Hypothetically Speaking...

Turn Two

Freshman Member
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If (hypothetically only) I were to remove the smog pump, air rails, and all the other government mandated boat anchors from the '79 B... What need be done to correct for timing and fuel changes.

The car has a Piranah ignition and has been converted to SU's. I would also scrap the Cat and have an exhaust system fabricated by a local muffler shop ($120). The car is exempt from emissions testing, but I would keep all the removed stuff! (If I, hypothetically, removed it!)

Timing adjustment? Idle Mixture? High Speed mixture?

I am awaiting the alternator rebuild, so I have time to think about these things!
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Michael~
www.turn2art.com
 
Hypothetically speaking? Hmmm? My favorite subject.
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I don’t know for sure, but I’d think that you could start with the settings used for the earlier vehicles.

But playing Devil’s advocate – Technically (not counting off-road use) “any modifications” that change or alter emissions controlled vehicles in the United States (exempt or not) is a violation of the “Clean Air Act”.
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So since you’re car has already been modified (by you or a previous owner) it is already in violation. Should the car ever be taken to a state or location that requires testing it would have to be converted back. You might get lucky and only have to re-install what you currently have. But some states emissions laws (like California) are much stricter than others, so you might be really unlucky & be required to find and re-install the entire Zenith Stromberg carburetor manifold setup.

Good luck,
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Ahhhhhhhh... The People's Republik of California... I remember waaaaaaaaaaaay back in '93... we went to a Rose Bowl to watch our son play against the Huskies and stayed with a friend who had an original RX-7. Even then, he could not change anything under the hood without being shot on the spot. Very scary place, California.
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I will hang on to everything that I remove... just in case NC goes nutzo in the future!

Thanks for the heads-up! I'll be looking over my shoulder.

Michael~
 
Well, I'll freely admit that my Midget (not subject to emissions or inspection) is heavily modified. The engine is built and I'm running dual webers and a mallory unilite system... I'm running a timing of something like 16 degrees BTDC, and I believe the standard spec is something somewhat less (but I don't rememember what the number is). The car will still run at a lower advance, but it's a matter of finding where it runs best. If I retard timing much beyond 10 BTDC, it responds poorly at part throttle in the lower ranges due to somewhat cammy engine (and therefore it isn't 'on' the cam at these engine speeds), but shouldn't be a problem on a strictly stock setup as its tuned for economy and good low rpm operation. When its slightly over advanced, it simply doesn't run with as nice a sound. As to the carbs, i'm not too certain. My carbs need to be fine tuned on a dyno, but i took jetting recommendations from others who'd set it up w/ dual webers and the results are satisfactory, if not yet optimized. The mixture is close, if not exactly right. In the case of SU's, I understand the process is more about the fine tuning, as they don't have scads of jets, although I have never owned those carbs. Hope this helps ...
 
one thing you may want to do before you get a new exaust or if you want to leave the exaust alone is take off the cat then get a lons screwdriver and bust up all the ceramic inside and put it back on so it will be just like a normal pipe and you may just be happy with that
 
With twin SU's you don't have to do anything to the fuel system. I assume that you have a early exhaust manifold. Getting rid of the cat and installing a stock exhaust for the early manifold will help. On the ignition side you need to make sure that the distributor is curved to match the early spec's. Find a shop that can check out the curve on your distributor. Here is a link to a site that has info on ignition curves. Click on spanners and look for ignition.

https://www.mgb-stuff.org.uk/

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[ 03-19-2004: Message edited by: Jim 67B ]</p>
 
I have a queestion for ya Michael?

You say you’re B already has a set of SUs and that it still retains the Catalytic converter.

Normally with the ZS Carb set-up the Cat is connected directly to the intake/exhaust manifold. So it is my understanding that with a Duel SU manifold you need to run a header or one of the early (pre-cat) manifolds.
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I'd like to know how you connected the cat? Not that I would ever want to circumvent the United States Clean Air Act – I’m just curious.
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<blockquote><font size="1" face="Verdana, Arial">quote:</font><hr>Originally posted by Bugeye58:
Bret, FLEE!!! The Smog Police are headed down I-15 right now!!

Jeff
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<hr></blockquote>

I promise you this that the only way they’ll take my MGB when they pry it from “my cold dead hands”!!!…
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May Charlton Heston, forgive me!?!

Anyway, you’ll have to excuse me now, I need to start scanning the heavens for black helicopters.

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