reducing the alternator operating temperature?

I am running my 4th alternator in 2 years. Today I will rebuild one of my old alternators with the Iceberg rebuild kit which comes with custom rear cover with some additional cooling fins and also a oversize front bearing.

GM designed these alts to be used in Vette but made a mistake in estimating their longevity in such a hot environment. As the heat is the main cause of dying DC-130 alternators I was thinking that what if I replace one of the pulleys with a smaller one thus reducing the speed of the alternator I might get below the critical alt killing temperature. Is my logic sound?

Is there any negative effects in this? Lower alt output? I will install a new car stereo (have none now) plus 2 amplifiers, they will draw about 40 amps of power.

The MAD single pulley kit # 609-129 looks suitable. Any comments of it. Is there any place I could get it or similar kit a bit cheaper?

Thanks,
ToniH

 

The pulley on the crankshaft is the only one you can make smaller in diameter to reduce the alternator rpm. I wouldn't do it because it will decrease the output from the alternator at idle, and it will reduce the water pump flow, not a good thing for cooling as the factory pump already has inadequite flow at idle. My 87 I have owned for 13 years is on alternator 3, so I get about 4 years on an alternator. Drawing more current makes the alternator hotter and shortens its life. I don't know why you need a more powerful amplifier, my Bose can be turned up beyond the threshold of pain so what is the sense of even more audio power?????

 

> I don't know why you need a more powerful amplifier, my Bose can be turned up beyond the threshold of pain so what is the sense of even more audio power?

Well, I do so let me explain:

First of all i don't have ANY system installed now like I said. So they are not busting my alts.

Anyway to your question: more power does not only equal more sound volume but it makes the sound quality better - this is what I am after. Ie. you need more power to get the sound quality up (the power is better matched with your speakers). If you have nice 200W speakers but only give them 12W of power the quality sucks. 99% of car stereos sold today do not make more than 12.5W per channel of power - no matter what the front panel says (usually 4x35, 40 or 50W - all marketing bull). This is because the traditional car stereo powersupplies in those head units are of type which cannot make more with the 12V your car supplies to them - technology limit. External amps however use more advanced and expensive powersupply technology and they do indeed make more power.

This year Alpine and couple of other brought new top end head units to market which utilise this same power supply technology as the external amplifiers and therefore make more than 12W per channel. But they are very expensive.

So, my 2 year old $800 Pioneer head unit claims it makes 4 x35W but in reality it only makes about 12W like I said above. I have 200/50W (max/continuos power) rear speakers, 150/45W front mid level speakers and pair of tweeters + a 500W subwoofer. I therefore need a 4 channel amp + another amp for the sub (I could also use a 5 channel amp but I already have the separate ones). My 4 channel amp is a 4x75W/45 and the one for the sub is a 200/100W.

I will never play the system at max vol but I will enjoy the systems better than normal sound quality much more than without the amps.

I am sorry but I do not know the names of these power supplies in english but I hope I succesfully answered your question.

Any other opinions on the undersize pullies?

ToniH


[Modified by ToniH, 8:19 PM 6/23/2002]

 

Id stay away from spinning the alt slower to save it's life. Id find a new way to route some better ventilation to the alt to keep it cooler. You will need the alt to work and supply enough power to the system to properly charge the system. If you went with a smaller pulley, I think you will be buying more batteries on top of regularily replacing alternators.