"My main question is, when I add an air pump for the pneumatics and a full neon fit, will I have have enough amps. And would adding 22's be the same as underdriving the alternator? (that was pretty funny, huh?)"

Now that I would pay to see I say go of it!

Based on my alternator experiences, you'd have to know your specific alternator and what it is capable of at idle and under load. Once they get under RPMs, most alts will do the job. I'd have to troll through all my info (which I am admittedly too lazy to do right now ) but I think the OEM alt is rated at 90 amps and that will be once the car gets moving, or above at least 2,000 RPMs or so. I want to say at idle the unit puts out like 70 amps. We measured it a number of years ago and concluded with all the crap that was on my car at the time, we need more amps particularly at idle and then under heavy load. The Excessive unit for me works like a charm. It puts out around 110 amps at idle and then quickly gets to 200 amps which is more than I'll ever need. We did also eliminate my ignition amp setup as it placed a big load on the car and then also rewired my second fuel pump to come on under load versus on fully at ladle. Both of those changes saved around 30 amps at idle.

Of course I am not an air pump, full neon baller like you

 

So what did you do with the factory alternator wires?

 

T-von I believe i read in a few other threads you were still having electrical issues. Figured this would be a good place to update.

 

 

Lots of ebay sellers claim to sell high-output amps for FD. But honestly you shouldn't need one unless you have a huge stereo system installed or maybe your car is 20b etc.

 

The IRP alternator is the way to go if you do need to upgrade. They spent a lot of time finding the right combination that would put out more amps but still provide good voltage at idle, which is a tricky balance. It's bolt in and go.

Cheaper options will either crap out in short order or drop voltage at idle (or both).

Dale

 

+1 on IRP alternator

 

 

Most aftermarket bullies are under drive. You may want to take pics of your pulley setup and post them up.

Also, it may not just be the alternator pulley, if you have an under drive main pulley that can also under drive the alternator.

I assume you have better voltage when the RPMs are raised up a bit?

Dale

 

I do have the petit power pulley. I suspect that has something to do with it as well. I haven't really monitored voltages until lately and mostly only notice it when I have that drop in idle, I'll pay attention to it now that's for sure.

 

I'll measure the diameter of the stock alt pulley tonight. I'd take the alt to a alternator/starter shop to have it tested/checked - a good shop would open the case and check the brushes as well.
Is your battery relocated to the rear? If your alternator is fine then you wouldn't need a high amp one but rather good grounds. Anyways, first I'd just have the alt tested.

 

 

The outer lip is approx 2.4 inches in diameter.

And the negative from the battery goes to the chassis near the battery area?

 

What should be good voltage at idle and crusing/wot

 

Just finished the diode alternator voltage boost mod. My 120 amp aftermarket alternator now has cold engine high idle voltage of 14.3-14.4 and warm idle voltage of 13.8-13.9. Cruise around 13.8-14.0. They were 0.5 to 0.6 volts lower without the mod. I spliced in a small mini fuse holder in between the sense wire to the voltage regulator and bought the alternator voltage booster from the Australian company HKB Electronics on Ebay. The diode is molded into a mini fuse and works great. This will allow higher idle voltage to all of systems including fuel pump, coils, etc. It did affect my idle AFR slightly dropping from 13.2 to 13.0. The real reason to do this is for anyone with a AGM battery. These must charge cold at 14.2 or higher to keep the battery happy. Our older voltage regulators don't do this typically. This mod fools the regulator to think the battery is more discharged.
Mike

 

 

My IRP alternator is pumping out those same number without the diode mod. Are you underdriving the alternator? Those number looks like my old stock alternator with an underdrive pulley.

 

Nice.

 

It's going to be higher when cold, typically around low 14's cold then high 13's warm.

If you see low 13's/high 12's you need to check things out.

Dale

 

Stock size aftermarket SuperNow aluminum pulley. Without the mod, I was again 0.5-0.6V less. It may be my aftermarket alternator's voltage regulator. It might be the older style regulator which were more for standard lead batteries. IR Performance therefore probably uses the newer type regulator good for AGM batteries. Also, my battery is fully charged on a battery tender. No need for charging. I will check it next time after the car has sat for a few weeks.
Mike

 

Which 180 - 200 amp alternators would be the best choices currently?
I can see a few years ago some guys were using the Excessive Amperage alternator and also the Power Bastards universal alternator with good results.

 

Thread resurrection !!

I've been noticing voltage drop lately on my drives. Start out at about 14.0/ 14.1 at idle and cool motor, after about half hour + of driving and things warm up under hood I can watch voltage steadily drop to low 13 to high 12's. Current alternator is a Bosch reman, maybe 3 years old now. I did purchase the DC Power 180 amp alternator but have not installed it yet. My concerns are, do I need to add or upgrade the wiring from the new alternator to the battery? If adding additional wire what gauge and should it be fuse protected? I know the alternator is only going to produce what power is needed but want to be covered as I don't want any problems in the future.
I did convert to single turbo and have added the following items that are possibly drawing more amp. Walbro 450 rewired, IGN smart coils, Haltech w/wire harness & integrated fuse box, upgraded injectors, small stereo amp to run a sub. Banzai pully set that I believe has a main underdrive (does not seem to affect idle amperage) Battery is also AGM 51R in the stock location. So what are your thoughts, just put in the new 180 Amp alternator with stock wiring, add additional wire to the battery & grounds wires (what gauge) all new wire (1/0 gauge) and and ground ?

Thanks for your help
Mike

 

Assuming the length of wire between the battery and alternator is about 5 feet, my scratch calcs suggest you might see 0.26V loss across a 4-gauge wire when carrying 180A. (assuming 0.292 ohms per 1000 ft, from a wire resistance chart on engineeringtoolbox.com). If swapping to a 2AWG wire the loss will be 0.17V at 180A.

The factory wiring harness has a 120A 'Main' fuse between the alternator and the battery. If you simply replace the original wire with a new 2-4AWG wire that 120A main fuse will still be present. I wouldn't trust that the original housing can handle a higher-capacity fuse, I would start with the 120A fuse and see how that goes.

 

The stock wiring from the battery to the alternator is meh from the factory and is going to have problems when you start putting a big amp draw on.

The starting/charging harness isn't hard to remove with the car all together, that's the harness that goes from the positive battery terminal to the alternator and down to the starter. You can remove it, replace the heavier gauge wires with larger wiring, and you should see a good improvement in voltage.

Also it's normal for alternators to put out more voltage cold then warm, that's part of how they are designed. But if you are in the 12's at idle something is funny.

Dale

 

Triple Resurrection!

@Mike93r1 what all did you end up doing with the DC Power 180 alternator? My OEM alt is toast and I am seriously considering the same unit.

I already have my battery moved to trunk with bigger wires, so I should be good to go... Just curious how the DC unit has worked for you.

I have a 7" double din display, ancient Sony XM-C1000 amp with 2 8" subs, upgraded fuel pump... definitely thinking I would be better off with a stronger alternator vs. a refurb.

Thanks!