wgripp

iTrader: (1)

I've had my trans am since 2005. It's a 1991 model with a stock 5.7 TPI. I think I replaced the spark plugs with copper ones a while back, but I'll need to double check. However, the wires, etc. haven't been replaced since before I purchased the car. I've only put about 10,000 miles on the car since owning it. Should I replace these?

If so, is there anything else I should replace besides the ignition coil, distributor cap and rotor, and wires? Would I see increased performance on a stock motor if I upgraded to performance parts? What about a performance distributor?

For wires, I was thinking of getting MSD superconductors.

https://www.msdperformance.com/produ...ts/parts/31833

Any inputs would be greatly appreciated.

Thanks!
Bill

Vader

Instead of replacing the wires they can be tested. An ohmmeter will reveal the continuity and overall resistance. Expect good wires to exhibit about 4-5KΩ per foot of length for common resistor wires, less for wound core wires. If any have failed or are damaged (jackets, insulation breakdown, poor connectors, etc.) they can be replaced with anything you like. However, it's tough to beat the OEM Packard resistance wires with silicone jackets and boots, or a good quality clone of those wires.

Tthere may be no advantage to replacing an intact factory coil. The stock ignition system is generally sufficient to well over 6,000 RPM, which is a range of operation unlikely to be achieved with a basically unmodified TPI system. Bolt-ons don't count, either - It takes substantial head/cam/valve/intake work to get a TPI making any respectable torque above 5,600 most times.

Since the distributor cap and rotor are wear items, replacement is a good idea if they are aged or worn.

If you are picking up parts, be sure you have a supply of silicone dielectric grease to apply to the boots for sealing and lubrication.

KyleF

Basic circuit analysis will tell you a lower resistance wire will get more voltage to the plug.

What Vader is saying is true about RPMs and the HEI is a very good factory system. The factory style wires are a quality unit, but there are better options, but they can be costly and not make a huge improvement.

However, a performance coil, MSD6 Box, a high quality cap/Rotor, and good quality wires can allow you to do a few things. You can open up you gap a little for a bigger spark to help get a more complete burn and with a more complete burn, you can bump fuel pressure a bit a make a bit more power with a bit more fuel. If you were getting into major mods, more voltage at the plug also helps as compression goes up.

What you will most likely see with an upgraded ignition and basic bolt-ons is increased throttle response and a slightly better mpg. The hp gains will actually be minimal, but will add up as you do other things. Just like a set of headers. They create a good bang for the buck mod on a factory motor, but if you had already upgraded the intake and fuel system, going to headers would make a much larger impact. Same on ignition. Though, buying quality components the first time, keeps you from having to buy them again when you go further.

wgripp

iTrader: (1)

Vader, KyleF, thanks for the feedback. I'll have the wires tested.

Another question... It turns out my spark plugs weren't replaced. I've been on the car since AT LEAST 2005. My mechanic says they look good. Would it be worth replacing them, or should I leave them alone?

no new tires

lol, are you serious?

-YES

KyleF

Actually, this depends a lot on how many miles they have put in and how good the motor was running. Plugs are cheap and ward off potential problems. So, I would replace them.