Jordon Nutbrown

I was wanting to find out if you can set the timing. I heard you cant change it because the computer will reset it back to the factory settings


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project89

iTrader: (1)

u can only set the base timming.

what u do is unplug the single connector by the heater box, this stopes the ecm from controling the timing. then u set the timing with a timing light as normal. once ur done u plug the connector back in.


i belive the factory is set to 10* u can change this setting to 12 or 14* if u want what it does is is it add 2 or 4 degress to whatever the computer tells it to give

fasteddi

iTrader: (2)

Use a extention with a swivle end on it and a 15mm socket. Its a pain to unloosen the hold down bolt on the dizzy. Only loosen up the bolt enough to turn the dizzy. Then once you set the timing like project said, retighten up the hold down bolt and recheck the timing to make sure it is still where you want it in relationship to the base timing. 10* is stock on the 91. Also reset the ecm when your done(just disconnect the neg batt terminal for a minuet) With a stocker I wouldnt turn the timing up past 16* since you dont know if youll add to much and cause spark knock.

IIRC turn the dizzy clock wise to advance and CCW to retard the timing. I just woke up so that may be backwards but you see once you start to play with it.

KG427KG427

iTrader: (1)

What should I set it at for best gas mileage ?

I have a 1991 v6 3.1

ItstillaV6

10* will get you excellent fuel economy, however, running 12-14* base timing may help improve it more. It could make it worse. There are a lot of factors, when estimating how to improve fuel economy.

If you are as unfamiliar with ECM controlled HEI setups as I am, there are other things you can do, to improve both your performance and economy. I'll list a few general things, that everyone should do, as they are part of routine maintenance too.

1. Make sure you have the proper size tires/wheels on the vehicle. Make sure to have them spin balanced and the suspension properly aligned. This will keep the tires straight and reduce vibration, during driving. Unbalanced tires tend to vibrate a lot, which wears them out quicker and causes a lot of friction. Inflate then cold between 28-32psi.
2. Keep up on your oil, transmission, and cooling system flush/change intervals. Oil absorbs dirt, and will sludge up inside the engine. Standard 10w-30 should get you by. 5w-30, to me, is black/brown colored water. If the tranny starts going, it can require the engine to work harder. Deteriorated coolant will cause corrosion to start forming inside the engine. If the engine heats up, the ECM will add more fuel to compensate for an overheating engine(trying to prevent detonation).
3. Keep the suspension lubed and in good condition. Also, keep your universals on the driveshaft lubed up. Stock driveshafts have sealed joints, but most repair kits have a grease fitting for regular maintenance. So if your unversals have been replaced, check them.
4. Keep your braking system in excellent condition, upgrade it, if you can. Braking wastes a lot of fuel, from the friction and heat generated, to stop the car. Remember, your brakes are vacuum assisted, off the engine's intake air.
5. If your exhaust is leaking, get it repaired. A Leaking exhaust will flow unbalanced, out of the engine. Ever notice how much more vibration you can feel, right after your muffler falls off?
6. Finally, keep up with your air filter change schedule and tune up intervals. If you have to replace ignition parts, try to get a distributor cap with brass tips. They tend to last a lot longer than aluminum ones. Use 8mm plug wires, over the stock 7mm ones. As far as ignition coil? A stock unit will do just fine, so if you want to go with high performance, that is totally on you. Use the stock replacement plugs, as platinum plugs don't really perform well with our engines.

ItstillaV6

As far as advanced modifications, that will improve economy? Well, I have a couple of those too.

1. Air Cleaner: If you are keeping the stock setup, buy a K & N. However your best bet will be to modify a "Dual Snorkel" setup, off the TPI V8 Camaros. I have a custom setup, on mine that works really well, and you can use all junkyard parts to do it. It won't give you the coolest air charge, so some performance will be lost.

2. Remove your A/C: A/C clutches still engage, even when the A/C is not on. Either way, it adds extra weight to your front wheels(drag wheels). Removing it will free up maybe 2-3 HP and Torque, but will reduce engine load when cruising. Lower front end weight will save on your tires and brakes too.

3. Driveshaft: GM did have an aluminum driveshaft available for 3rd Gens. Go to the home page FAQ section. There is an RPO code for a direct bolt-up aluminum driveshaft, that fits in our car. Less rotational mass, in the driveline, helps the engine rev up faster. So you cut down on fuel consumed during acceleration. NOTE*** You will decelerate faster as well, similar to putting a lightweight flywheel on your engine.
This also drops your vehicle curb weight slightly.

4. Exhaust: If you don't have to pass emissions and inspections, get rid of the catalytic converter. Also throw a general turbo muffler on. Stock 3.1L's probably put out about 200cfm/min of max airflow, so you won't need an expensive dual, crosspiped, 3in Flowmaster setup.

5. In correlation to #4, AIR pump: Remove it, and plug the pipe going into your passenger exhaust manifold. During a cold start this pump adds extra air into the exhaust, to heat the converter up quicker. When the engine is warn, the valve is shut, BUT the impeller and pulley still cause a LOT of drag on the engine. 88-89 2.8L Auto Camaros had an idler set-up. You should be able to get one at a local salvage yard, or I have instructions for how to re-route the serpentine belt without the idler. NOTE*** You will get a little belt chatter, from the crank to alt distance, but it won't snap the belt, cause undercharging, or undercooling. I have driven on mine for over two years, like that.

6. Pulleys: Get underdrive pulleys for whatever engine accessories you have on the engine. I made mine custom, from junkyard parts, but it was a lot of time consuming work and resulted in a snapped PS pump bracket, the first time around. They do sell kits, for our engine, that will be the easiest route to go. Once again this goes back to less rotational mass, and also, it ups the coolant flow, alternator amperage, and PS pump pressure. That helps maintain engine temperature better, reduces power loss from the PS pump and alternator(though alternator don't cost you that much to begin with).

7. Radiator: Get a 2" or better. This may not help with cold start economy, as the engine takes longer to warm up, but it is helpful to keep engine temperature constant and reduce the chances of overheating. My radiator is out of an 86 Camaro, that had a 305 V8. I had to plug the auxiliary heater line, but other than that, it is a direct fit.


A lot of these I have done, with the stock timing(10*), and the stock PROM/ECM.

Currently, I can average just a hair over 25 mpg city/highway(with my cat still on the exhaust), with my best highway economy being well over 35mpg.

As far as performance, I have been able to beat a couple different models of "comparable" vehicles, that have been rated as much as 162 HP. Now, that doesn't mean I'm able to out run them in a 1/2mile or full mile, but in 0-60mph and 1/4 miles, I'm still ahead(barely).

Hope this helps and good luck.

fasteddi

iTrader: (2)

Set to 10* base timing and let it be. Thats what the ecm thinks it is unless you tune it.

KG427KG427

iTrader: (1)

This is going to keep me busy I'm calling GM right now I'm going to start with drive shaft.

What's the point of installing the dual snorkel cai if it doesn't do anything performance wise ? Just looks ?

fasteddi

iTrader: (2)

If you really want good mpgs just get some tuning stuff and tune it. I managed 30+ MPG highway when I tuned mine a year ago when it was close to stock. Its much easier then chasing that white rabbit. ITs alot easier to manage the fuel consumption when you have control over it, the spark, and even the lean cruise mode. And cost less in the long run. IMO though....

KG427KG427

iTrader: (1)

So have you heard of BMR fabrications heard they carry the driveshaft? GM doesn't carry that AL driveshaft.