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Discussion Starter #1
In my everlasting quest for better fuel efficiency. It is time to move up to getting a new ignition system to replace the good old optispark, as well as some new spark plug wires. I wanted to see if I can get some suggestions for which system. If you could, I would like specifics as to which company as well as the model number.
 
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Discussion Starter #2
The TBI cars do not have an OptiSpark. They use the good ol' standard small block distributor setup. I'd suggestion just doing an R&R on the distributor and replace the wires and plugs.
 
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Discussion Starter #3
I already have the plugs installed and I am already know which wires to get, now I need to know which distributor and coil to get.
 
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Discussion Starter #4
Unless you are having problems with the distributor itself, I would replace the cap and rotor, and maybe the coil with an upgraded unit from Accel or one of the other quality ignition vendors. It's hard to improve on the old HEI without spending some bucks.
 
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Discussion Starter #5
well, from what I have been hearing, and therefore planning, is to go all MSD ignition system components all around, I don't know how they made their systems better, if they even did, but, every inch of benefit counts
 
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Discussion Starter #6
I'm going to save you some trouble and unneeded costs.

1. as mentioned, 94-96 cars get the optispark. You have the predecessor HEI (high energy ignition).

2. the HEI is an excellent system.

3. MSD boxes, among others, won't help you. You haven't done anything to your engine to demand hotter, or multiple, ignition sparks.

4. Also as perviously mentioned, spend the moey to refurb what you have: new coil, new cap & rotor, new wires. Also get a new sensor pickup for the INSIDE of the distributor. When you put it all back together, get the timing set to the stock spec.

5. You want more fuel economy? Upgrade the exhaust to the 92-93 9C1 ypipe and use a good low restriction aftermarket muffler. Leave the stock air filter but plumb the passenger side of the plastic "toaster" filter box for a second cold air feed. More cold air, slightly better air intake breathing, and a better exhaust, plus the ignition work will help you a LOT. IF you do these items, then you can probably benefit from advancing the base distributor timing by 2 to 4 degrees. It will help power and economy.

6. Have you taken the TBI off, taken it apart, cleaned it, and then rebuilt it with new gaskets? A GM TBI rebuilt kit would help.

7. Replace the fuel filter, check (or replace the air filter), change the oil and filter in the engine, remove and clean the PCV valve. Check the tire air pressure and make sure you have 35 psi in each one. Draining & cleaning the trans pan, adding a new tranny filter, and then refilling with fresh ATF can also help economical performance when the converter isn't locked up.

Most of the above are std maintenance items that are needed for optimum fuel economy. A few of them are cheap performance upgrades that will also help fuel economy.

There's probably a few more things besides these, but these are the basics. HTH. - Ken
 
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Discussion Starter #7
what's the difference in the y pipe from the 92-93 9c1's than the 91 9c1's. just curious cause ive already opened up my exhaust and have a dual air intake system for my 9c1. i also have been considering the msd setup.
 
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Discussion Starter #8
-Dan- Do you have pics of your dual air intake system? I'm interested in knowing what it looks like and what it is involved in doing the Mod.

I have another question too. How difficult is it to install a y-pipe from a 92-93 9c1 on a non 9c1 92 caprice with the 305? and would the dual exhaust off one of those cars work or would i have to go the custom route?
thanks
 
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Discussion Starter #9
<BLOCKQUOTE>quote:</font><HR>Originally posted by Dan 91 9c1:
what's the difference in the y pipe from the 92-93 9c1's than the 91 9c1's. just curious cause ive already opened up my exhaust and have a dual air intake system for my 9c1. i also have been considering the msd setup. ...... 91 9c1 Dual air intake system, gaterback belt, dual flowmaster exhaust,160 t-stat, ss grille, clear corners, more mods to come <HR></BLOCKQUOTE>

92-93 9C1 with LO5 got a larger diameter Ypipe, along with supposedly better cats. The 91 LO5 9C1, along with all the other 89-93 cars, got a smaller diameter Ypipe.

If you've modded the exhaust, and added a decent cold air, then you might alter (advance) the timing a little bit, and do the quarter mod which will raise the fuel pressure slightly. As the engine is breathing a bit better, you need a little bit more fuel and a slightly advanced spark to take full advantage.

The MSD is not likely to add anything. IMO.
 
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Discussion Starter #10
What is the quarter mod? Also, is there a certain brand of ignition system products that is preferred?
 
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Discussion Starter #11
kdrolt thanks for the reply. as far as the quarter mod i tried it and im not sure where the quarter goes. does it go under the sping? if so i had a hard time getting it to stay theyre so i could put the screws back on the regulator. i will try it again soon. im planning on pulling the heads off to send them to the machine shop so i could get them redone. ive got a little bit of a smoke prob right now. i did a compression test and my numbers were pretty high. they varied from 195 to 210psi. i figure i got worn valve seals causing the smoke. does anyone know what type of headers will fit a 91 9c1? i want to get them soon so when i get my heads back i can install the headers. 92 on dubs, i don't have a pic now but i can get one soon. when i do i will post it.
 
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<BLOCKQUOTE>quote:</font><HR>Originally posted by Dan 91 9c1:
... as far as the quarter mod i tried it and im not sure where the quarter goes. does it go under the sping? if so i had a hard time getting it to stay theyre so i could put the screws back on the regulator. i will try it again soon. im planning on pulling the heads off to send them to the machine shop so i could get them redone. ive got a little bit of a smoke prob right now. i did a compression test and my numbers were pretty high. they varied from 195 to 210psi. i figure i got worn valve seals causing the smoke. does anyone know what type of headers will fit a 91 9c1? i want to get them soon so when i get my heads back i can install the headers. 92 on dubs, i don't have a pic now but i can get one soon. when i do i will post it.<HR></BLOCKQUOTE>

AFAIK Hedmann (spelling?) makes full headers that will fit (I've seen them on more than one Caprice before), and I think there are threads on it at both the 9C1 digest at yahooforums, and possibly a file on them at Bob Lane's http://www.9c1.com/technical website (best viewed under IE).

The info on the headers is probably somewhere on this forum (under either the Engine Performance section, or under Caprice). Do a search.

I also thought that the shorty headers people use on the 94-96 LT1 Bcars will also work, but IMO they are no better than the 94-96 stock exhaust manifolds (which are better than most people think).

The quarter mod is a modification that places a quarter (coin) within the fuel pressure regulator (FPR) to raise the spring (compressing it more) and that in turn raises the fuel pressure line feeding the injectors slightly. Many people that do this mod also modify the FPR base screw (a torx I think) so that you can adjust the FPR from under the hood.

Details on making it adjustable are on the Tech Pages at http://www.thirdgen.org and when you have it apart it will be easy to see where the quarter goes (it acts as a shim to put more preload compression on the spring).
I also suggest reading the two tech pages on the so-called Ultimate TBI mods. They will help to increase airflow.

Note: the quarter mod will not help a stock engine but it should help any TBI engine that has minor mods to the exhaust and intake.

Dan91 9C1 - those compression numbers are very good, IMO. When the heads come off it would be worth it to have the valves back cut, which will help flow at low lift, and a mild cleanup of the ports will also help. David Vizard has a really good book on cylinder head work that would help, and if the shop is going to refurb the heads, that would be the right time to have these things done (or do them yourself).

Also, when the heads are off, that would be the perfect time to do a complete rebuild and mod on the TBI unit.

Keep us posted, please. - Ken
 
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