OMFG! I give up. It's a free country, believe what ever you wish.

Ok I did some research and your right. I would need to match both fuses equally to carry the added load. So if I couldn't find a 150amp fuse, two 75amp fuses would work but it's not ideal.


Will two 60 amp fuses wired in parallel act as a 120 amp? - Third Generation F-Body Message Boards


Also see post 13.

THX ;) There are a tons of opinions out in the world. I appreciate you trying to help me on the thread. But I never take any one or two examples as fact. Sorry you got frustrated as I found some different explanations that helped me see what you guys were talking about. My mind works in 3 dimensions so if I don't get and explanation that makes since to me, then it makes no sense.

We work with some 200 amp systems on rigs, do to wire size limitation sit is common to double up the wire .. same termination each end. this is no different that a 8 stand conductor being upsized to 16 stands of same size, they just don't share the same jacket insulation.

No sweat. :-)

Yes, of course on high amperage, large wire systems it would make sense. But on a car? I don't see the point. And that is my guess why you almost never see it.

I have a 200 amp alternator on my 20B FD from:

Excessive Amperage

Works great and Nate has really good customer service. Puts out around 120 amps at idle and 200 at WOT. Blew up 2 of the 150 amp ones most use on the forum before going to this. Ultimately tracked this down most likely to too much amps at idle as I had two fuel pumps wired in that ran at high speed. Now run two pumps with the second on coming on under boost.

It's amazing all the problems we create while trying to improve on our vehicles. ;) I have 2 pumps as well. A stock one to feed my swirl pot and a Bosch 044 external to feed the rail. I should be fine with my 150amp (hopefully) since I'm NA and my fuel pumps won't ever see the same loads as your boosted 20b.

So, how exactly does one determine when one needs more amperage via a 'high-output' alternator? There has to be some way to quantify this supposed need vs just being another mod.

Does one monitor or log voltage with full electrical load on a dyno, street or track?

The upgrade is needed when you start adding hi current accessories to the vehicle (double fuel pumps, ignition amplifiers, sub amps, ect). Every typical thing I mentioned in my 1st post gave an general idea of something that's hi current. All those components come with amperage ratings so you calculate from that.

Example: You add a new upgraded fuel pump that needs 10 more amps than stock, then you add water injection. Well that pump is gonna have an amp rating also. It may need 15 amps. Then you change out the radio for a double din unit that needs 5 more amps compared to the factory bose. Just like that you have added 30 more amps that the stock alternator can't handle (IF) everything else is turned on max. I don't condone street racing but, a ton of people do so with their hi powered amplified sound systems blasting. That's a lot of work for a stock alternator under those conditions as sub amps cause the biggest drain in car electrical. Remember alternators only put out just enough current to carry the required loads however like fuel injectors, you don't want them running near max output all the time as they will fail prematurely. So if I did the above upgrades, I would at least install a 140 amp alternator. If I went with a big sub amp that needs 90amps then I would want 200amp unit like what David has.

I tried 2 different 140amp alternators from IRP, my car didn't like them so I returned them and went back to stock. IRP are great to deal with btw.

Maybe someone here can help me figure out why I'm unable to use other than stock alternators.

My battery is relocated to the truck with 0ga wires and 150amp circuit breaker. I have a long ground back to the original location and and a short ground to the chassis about 18 inches from the battery.

When I installed both 140 amp units I got flickering lights everywhere and the PFC commander would show the voltages varying a lot between 12 and 15V. With the stock unit I get a much more solid 13.8 V with small variations with differing loads and no flickering...

When I was having electrical issues with my car, I went to a mechanic that had an electrical load tester. We measured the voltage and amp output of the alternator and then the load on the car. I think we did the load on the car by measuring back at the battery, but it's been awhile since we did this. In any event, the stock alternator I had on the car at the time passed in terms of being good, but when we measured load, it wasn't able to keep up with the demands on the car. We measured load by letting the car idle with nothing on and testing the amps. I want to say we were at above 70 amps with nothing on and that surprised us (see my above comments about the two fuel pumps to know why) and we then started one by one to turn on each accessory component (lights, radio, ac, etc.). So, we got at idle how many amps we would possible encounter if everything was turned on and it exceed 100. This was more than what an OEM alternator is supposed to handle especially at idle so I knew we needed something more robust.

We never did test under WOT but drew some conclusions from the idle tests. We concluded the extra lost under WOT should be around or below 150 amps so I first went with the IRP alternator to handle the load. Went thru two of these and they didn't work so ended up with the Excessive Amperage 200 amp unit which has worked great ever since (around 3 years). Not cheap but worth it at least for me. Ihor at IRP was great BTW.

My battery is in the bin area so close to your location. I too have a 0 gauge wire and a 150 amp breaker. Had the same results with the IRP unit that you had. Never figured it out but the Excessive Amperage unit solved the issue for me.

I think a big factor for me was the second fuel pump coming on at full load at idle. The two fuel pumps alone measured at above 30 amps at idle so it's quite a draw. It could be that once I changed this to have the second fuel pump come on under boost the IRP alternator would have worked just fine.

Another issue with alternators is the size of the pulley you are using. The larger the pulley, the slower the alternator will run at idle, thus leading to potential under powering at idle. If you have flickering at idle but not when you increase RPMs (say go to 2,000 RPMs) then you might solve the issue simply by using a smaller alternator pulley. The flip side of this is a smaller pulley may drive up the RPMs on the alternator too much or more than it can handle so you also need an alternator that can handle a higher level of RPMs under WOT. In short, the Excessive Amperage unit I ordered had above 100 amp capability at idle (wanna say it was around 120) and also the ability to handle high RPMs at WOT. Remember somewhere around 14,000 RPMs but again, it's been awhile. In any event, more than what my size pulley (which is a bit on the small side) would product in terms of RPMs on the alternator.

I just sent Excessive Amps an email and they quoted me $370 for a 200amp alternator, definitely a bit pricy.

Sounds like two faulty 140amp alternators. By the way, it's always better to run as short a ground as possible. My battery is in my storage bin. I have a continuous ground that bolts to the lower seat anchor and then goes under the carpet through the shift tunnel to bolt on the back of the transmission shifter plate for engine ground.

Real world testing....I love it. This info right here is very valuable David. Don't forget about the 2 extra ignition coils for the 20b and didnt you also have an ignition amp? If so, it's crazy how quickly those amps add up on our application. Did you also run 0 gauge on the alternator?

^ Yep, gotta love actual testing :) I did have an ignition amp on the car but not at the time of testing. Back then Kilo Racing had stripped all "non-needed" as they called it electrical components off the car.

I am now back to this setup, but am using the AEM smart coils.

Wow, that debate about proper wiring got out of hand and quick!

Just like when one builds an engine, upgrades have to 'balance' each other. Add more boost and you have to add more fuel. More fuel means you need more spark, etc. the same logic applies to the electrical system as well.

With any alternator upgrade, you need to properly protect the circuit based on its maximum output. Using a S4NA as an example, the alternator output cable runs straight to the battery, while power is fed through the 80A MAIN fuse first, then to everything else. Mazda went slightly higher than the alternator's maximum of 70A to account for situations where the battery has to make up the difference in requested power (headlights & stereo on, defrost & A/C running, etc).

150 Amp circuit breakers aren't expensive, so why risk not having one when dealing with an upgraded alternator. It makes much more sense to use properly sized cables than to cobble wires together to make do, when the correct parts are readily available.

For my battery relocation to the passenger side storage bin in Project OldTree (S4NA gone 20B-REW), the 4awg ground cable for the battery is about 12" long and bolts to an existing hole. As for power delivery, ~12" from the positive terminal to a 150a breaker, then ~13' to reach from the bin to the positive bus bar where everything under the hood gets power from.

During the summer, this arrangement of having one breaker showed its biggest flaw during a short test drive. My original 130A Taurus Alternator's voltage regulator had failed a block away from home, sending the voltmeter to 15.5-16.0v. This tripped the breaker next to the battery, but the car didn't shut off from it as would be desirable to prevent damage. Luckily, nothing was damaged by this failure. However, an upgraded alternator going ape-shit like this is completely unacceptable as is the mode of failure. A better approach would be to have the alternator output cable run through a 150a circuit breaker. That way, should the alternator be called on to deliver 100%, it can. But should there be a failure, it disconnects itself from the rest of the car.

I'm using cheap Xscorpion breakers from Sonic Electronics for about $10 each. The one mounted near the battery has held up fine, but the one intended for the alternator doesn't seem to endure underhood heat well, tripping after the car has been driven at 20-25mph in under 15 minutes. Alternator was nowhere near being stressed, while feeding six D585 coils and a FD fuel pump, even with the Taurus fan drawing a constant 20 amps, so I believe the breaker had heat-soaked, leading to it tripping so early.

Given the amount of damage a runaway stock alternator can do (see the Second Gen FAQ for details), and how much more an upgraded one can do, protecting the rest of the car's electronics should be mandatory. For this reason, I believe it would be invaluable to get some Temperature vs Current data for a selection of circuit breakers intended for underhood use.

Here is what I am running, its a Power Bastards universal alternator, single wire hook up. It delivers 110 Amps at idle and a full 220 Amps from 1200 RPM's on up. I have a full bridge 13B-REW/Cosmo set up that idles in the 1800 RPM range so I'm getting the full 220 Amps right away with zero issues running this alternator for over 2 years now. Its a universal fit which fits in the stock location, really easy. We used two zero gauge wires running to two optima yellow top batteries in the back behind the factory rear seats.

This is what its feeding:

3 in tank Bosch 044 pumps - 13.5 Amp draw at 80 psi (base pressure of 55 + 25 psi boost = 80 psi). 13.5 X 3 = 40.5 Amps

Maradyne Jetstream II dual radiator fan 24.8 Amps

Maradyne single fan jet stream oil cooler fans X 2 @ 12.4 Amps each. 12.4 X 2 = 24.8 Amps

This puts me at just 90 Amps not including the Motec and M&W ignition system or the stock FD stuff such as A/C, headlights, gauges (Aim sports Strada), etc.

With all of this stuff on my voltage stays constant between 14.2 and 14.4 when running with all accessories on, etc. My pumps are also getting a clean 14.2-14.4 volts.


Here is a pic of the alternator in the engine bay:

easy drop in? or what has to be done to fit it?

Keep it comming guys! Thread is filling up with more nice useful info. :)

And to think, why would anyone attempted to run a stock alternator under similar conditions? Thx for sharing!

Ordered an amp from Excessive Amps, It's been about 35 days and still not shipped. Barely replies to emails and if he does, it takes about a week. Going to dispute over paypal soon.

Can anyone recommend a high output alternator?

Have you tried calling them? They've always responded to me well that way. The amps are also custom made so they do take some time. I've had mine for several years and it works great.

IRP makes a 150 amp unit if it doesn't work out for you.

Just got the excessive amp from Nate, took a while to get here but at least it's here. Can't attest to performance but looks pretty well constructed.

This thread has me wondering how my car even runs. A few years back, I was having a break up issue on high boost. We replaced coils, ignition amp, fuel pumps, etc. and retuned with no success. Turns out the alternator wasn't making the amps at full load. We replaced the alternator and all was well. I don't recall what alternator we used.
But, I have high output radiator fans, 2 oil cooler fans, 3 fuel pumps, water/metg\h injection pump, and it is a 20b so I have 2 extra coils. I don't have an upgraded radio (don't want to compromise hearing the engine. haha) and no HID's.
It runs just fine. I'm wondering how?

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?)

"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 :icon_tup: 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 :lol:

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 :icon_tup:

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!