DeTomaso Mailing List: April 1997, Message #9
     



From: Andy Poling <andy@realbig.com>

Subject: Re: WANTED STUFF INFO

Date: Tue, 1 Apr 1997 20:41:10 -0500 (EST)



On Tue, 1 Apr 1997 W4wj@aol.com wrote:

> 2) Is there a better alternator? (that's a stupid question!!!...)  What is a

> better alternator?



One with a solid-state regulator built in.  It will get rid of the ammeter

fluctuation and will provide more consistent voltage because the solid-state

regulator operates smoothly and continuously, unlike the stepped operation

of an old-fashioned relay-type voltage regulator.  Several of the

aftermarket Pantera places seem to carry modern replacement alternators.

They often also generate more power, which is nice (but remember that they

also place a commensurately higher load on the belt driving them).



>From the remainder of your questions, it sounds like you might be

encountering starting problems.  This is a common problem in cars like the

Panteras with front-mounted battery and Miatas (front engine w/ rear-mounted

battery).



The remote location is a disadvantage because the cable to the starter is

much longer.  On the other hand, it's advantageous because it means that the

battery is not subjected to the hostile engine compartment environment

(sustained heat is an enemy of chemical storage batteries).



Installing a high-torque starter won't necessarily help if the battery and

cable cannot supply it with the power it needs.



The cable from the battery to the starter and the connections at each end

are critical because the starter needs to pull *alot* of power from the

battery to turn that high-compression engine over.  The longer the cable,

the higher its overall resistance and the greater the resultant voltage drop.

Physics tells us (I *knew* those Physics courses would be useful one day)

that as voltage (Volts) drops, the current (Amperes) must increase in order

to have the same power (Watts).  Combine the voltage drop of the long cable

with the voltage drop in the battery (the battery's internal resistance

becomes significant at high current draw) and you're really demanding

serious Amps from the battery.



If you're looking at replacing your battery-to-starter cable, consider

replacing it with thicker (lower gauge) cable to reduce the internal

resistance of the cable.  I remember reading a rather good TIS on a

procedure to install a lower-gauge starter cable.  Unfortuntely my TIS's are

scattered all about my apartment at present, and I can't find it.  An old

shade-tree mechanic trick is to use arc-welding cable as battery cable.



You might see significant gains just from disconnecting the cable at the

starter solenoid, cleaning the connection (on both the solenoid and the

cable termination) well, and re-connecting it.  The same treatment at the

battery post connection also helps.



Lastly, don't discount the starter solenoid switch as the problem.  If it

has alot of starts on it, it will have had to complete a high-current

circuit many times and it might not be making as good a connection as it

once did.  If you're looking to save money, replacing the solenoid switch

might be a low-budget solution.  Of course, if the solenoid switch is tired,

the commutator brushes inside the starter might be tired too.  It's a

crap-shoot.



-Andy



72 Pantera: power             91 Miata: quickness              96 A4Q: traction

84 RZ350: all the above