Tired of the light fluctuation in the RS Capri.

[Hemlock]

Is there a way to remedy the light fluctuation on our cars? I have noticed that the more things I add that have lights to my car the more annoying this is getting. Just finished installing and testing the new pillar gauges. When ever I am driving at night I can see the lights dim on the dash and gauges on my car when the RPM drops and if I have the stereo cranked, I can see the lights dim with the bass hits when idling at a light. It has been like this as long as I can remember but only now as I get older has it become more annoying. I am pretty sure the head lights and fog lights dim a little too at idle.

Is this an expensive fix or something I can do for a reasonable cost? Is it a simple fix or does it require a PHD to do? Keep in mind, car electrical is not one of my strong points so I steer clear whenever possible. I am always worried something I wired will burn my car to the ground!

Robert

[BMW Rider]

Bigger alternator.

[mustangxtreme]

If you have not yet converted to a 3g alternator, I would highly recommend it.

[mrriggs]

You either need a bigger alternator or you need to spin it faster (overdrive pulley).

Underdriving an alternator doesn't really free up any power. When you spin it slower, the regulator will put more current through the field to maintain a constant output so it's harder to turn. Likewise, overdriving an alternator doesn't cost any power. Spin it faster and less field current is required so it's easier to spin. You are trading torque for RPM but required power stays pretty much the same.

Overdriving the alternator is the easiest solution to low RPM charging issues. The only downside is if the engine spends a lot of time at redline then you can burn up the alternator bearings. In which case you would need to underdrive the alternator to save the bearings, then upgrade to a larger alternator to maintain full output at low RPM.

[Hemlock]

I am currently running a Powermaster 150 amp 3G alternator. I am also unfortunately running an ASP under drive pulley on it as well. I will need to start looking for a red anodized pulley to replace it I guess. Any other things that can cause this problem?

Robert

[mrriggs]

I'm not familiar with the Powermaster alternator but do know from playing with motorcycle charging systems that aftermarket "high output" alternators often sacrifice low rpm output to increase the maximum output power rating. One trick is to rewind the stator from a "star" configuration to "delta". Output at high rpm goes up and low rpm output goes way down. Again, I have no idea if this is relevant to your alternator or not, just throwing it out there.

If the problem can't be fixed with pulleys then you may want to try a "stock" 3G alternator just to see if it makes any difference.

[KevinK]

You might want to try replacing the head light switch as the dimmer circuit controls the dash light brightness. The rotary contact gets dirty with age.

[stangPlus2Birds]

I got a PA Performance alternator. They have a higher output at idle than factory or many other of the "high output" alternators. That's important if someone wants to run a dual fan or MKVII fan, plus lights, plus rear window defogger, plus wipers, plus AC, all while sitting in afternoon traffic that isn't going anywhere, and it's Hot Hazy Humid and it's raining.

Output Graph in the following article:
http://www.fordmuscle.com/archives/2...nce/index1.php

[Haystack]

Upgrade all the cables. From the factory, 3g cars all had 8 gauge or bigger cables. I added 6 gauge because they were the same price. Also clean and check all grounds. The grounding is just as, if not more important and often overlooked. Last thing I would also do is run a larger battery. The battery should be a start and recharge only thing. But it also acts as a capacitor when you are pulling too much power with subs.

If you don't have at least 6 gauge power and ground cables, I'd start there.

[ashley roachclip]

Do a relay retrofit to the head lights .
Cheap , and you can buy harnesses with the relys that are plug and play .

[cb650]

what is a good kit to buy?

[GliDeThuNDeR]

I have a 20+ year old power hungry amplifier in my car with a 65A alternator. I have an 850CCA battery, and a half farad stiffening cap I bought for like $30. Even with a 550CCA battery, and the cap, there was very slight dimming with the stereo loud. Almost completely gone with the current setup.

[wraithracing]

what is a good kit to buy?

Here is what I would recommend.

https://www.ronfrancis.com/prodinfo.asp?number=HR-58