North American Turbocoupe Organization



4th Alternator
Alaskanzeus Offline
Senior Member
#1
I went through 3 oem alternators in 2 years, installed 2 winters ago a 3G 130amp now it sounds like this one is going to. Somethings draining these alts bad and its either the headlights, 500w rockford amp, or rear defrost. It seems more probable that it would be the amp but i notice the car stumble and whine at night when running the headlights. I dont use the amp that often i would say ive turned it on maybe 7-8 days in the last 6 months.
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Pete D Offline
Administrator
#2
Have you gone through and cleaned all the grounds and connections.

[This message has been edited by Pete D (edited 11-07-2004).]
Pete Dunham


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verge Offline
Member
#3
A 500W amp should draw 42 amps. If this is an RMS rating, then you are pulling WAY more than that at peak.

If you listen to music that peaks frequently while driving at night with the heater/ac fan blowing THEN you are asking for trouble. The current peaks combined with the continuous load will seriously strain the regulator circuit.

You have 3 choices:
1) Give your hearing a break and get a smaller amp [Image: smile.gif]
2) Install a huge "boomer cap"
3) Buy an even bigger alternator

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Now that its rolling, lets see what it will do!
Jackie Francisco
88 TC A4LD all options except leather, 2 1/2 inch Dynomax Super Turbo side exit exhaust, ported head, ported lower, gutted upper, "Home Depot" boost pressure regulator, NGK Vpower plugs, Walbro fuel pump.
If it aint broke, you aren't trying hard enough!
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Jeff K Offline
Administrator
#4
I am with Pete.... check major grounds, like batt ground cable, engine to frame ground, batt cable connections, etc. Dont just look at them, remove, clean, and reconnect.

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Jeff Korn

88 Turbo Coupe: Intake and exhaust mods, T3 turbo at 21 psi, forced air intercooler, water injection, bypass valve, Ranger roller cam, subframes, etc., etc.. // 86 Tbird 5.0 (original owner): intake, exhaust, valvetrain mods, 100 HP nitrous, ignition, gears, suspension, etc., etc.... // 91 Escort: Bone stock winter car // 02 Taurus Vulcan(wifes car)
Jeff Korn

88 Turbo Coupe: Intake and exhaust mods, T3 turbo at 24 psi, forced air IC, water injection, BPV, Ranger cam, subframes, etc., etc.
86 Tbird 5.0 (original owner): intake, exhaust, valvetrain mods, 100 HP N2O, ignition, gears, suspension, etc., etc.
05 Taurus SEL Duratec daily driver
04 Taurus Duratec (wifes car)
02 Pontiac Grand Prix GT
95 Taurus GL Vulcan winter beater
67 Honda 450 Super Sport - completely customized
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Joe F Offline
Posting Freak
#5
What Pete and Jeff said. Clean up grounds and all major electrical connections. Check battery ground and +12 volt cables themselves; if they are original, consider replacing them just for principles. To me it sounds like primarily connection problems.

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Be Cool,

Joe

JR's Place - My 87 TC
JR's Place - My '87 Turbocoupe
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Alaskanzeus Offline
Senior Member
#6
Ok will do this week, where are the headlight and rear defrost grounds located i know theres 2 grounds located on either side of the radiator mounting brackets.
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Mark_R Offline
Member
#7
Oil will kill an alternator so if you are flinging any oil in that direction expect more of the same.
88TC 5spd, bypassed BCS, 18 psi, ram air, Jacobs ignition
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Liquid_force Offline
Senior Member
#8
The fosgate amp isn't a problem.

RMS rating for a car audio amp is a power number measured during a test tone. It is the maximum power the amp can produce continuously. Incidentally, RF tends to under-rate thier amps so the actual continuous power capability of that amp is probably closer to 600w.

So: 600w/13.8v = 43
But -- you didn't consider the efficiency of the amp. At moderate volumes the efficiency of a typical class a/b amp operates at about 50%. So that 43A becomes about 65A.

Fortunately, with audio components playing music we have to consider the duty cycle, or crest factor of the music. Generally the current draw of a music passage is around 1/4 that of a test tone. And that's at full volume. Turn it down a bit and that duty cycle is even less.

So - with a 500w amp it's not likely the continuous current needs over a reasonable period of time will exceed 10-15A

My point is a 500w amp shouldn't be a problem for just about ANY charging system.

I ran about 1000w RMS off my old 75A alt with very few problems. Finally, at 226K it died (system or not, it was due to go). I replaced it with a used 110A SC alt and it works flawlessly - even at idle with all accessories on while playing a 50hz test tone at full volume.

FWIW - those power caps are useless in a system that's already struggling for current. It's just another component for the alternator to try to keep charged.

[This message has been edited by Liquid_force (edited 11-12-2004).]
88 TC -- Dark Blue 283k
RIP - 9/22/07
She was a great TC and went down swinging Smile
Now -- Me: A minivan, I'll spare you the details.
Her: '09 VW Tiguan AWD 2.0T 101k
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Qwertys Offline
Senior Member
#9
if you dont mind me asking while on the subject of alternators, i know higher amps is typically better, but what is the tradeoff? doesnt it require more HP and thus steal power from the engine? or is it a negligable amount.
the reason i'm asking is because i plan on running a lot of electronics from my car and wanted to know if i should get the 130 amp or 150 amp 3G alt.
'85 TC BPV and Ford FMIC
'88 TC Kirban AFPR, Autometer Boost, FP and A/R Gauge, 8.8 to 4.10 rear, Walboro 255lph Fuel pump, Garrett GT3071R T3/T4 Dual Ball bearing Turbo, Custom AWIC.
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Joe F Offline
Posting Freak
#10
The higher amperage alternators are capable of delivering that current, but only if something "asks" for it. Under normal load they won't take any exta HP from your engine and they might use a little less (than a stock unit), because being of a newer design they're slightly more efficient.

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Be Cool,

Joe

JR's Place - My 87 TC
JR's Place - My '87 Turbocoupe
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