Through the end of February, 2018 – use Coupon code mechman at checkout and get FREE SHIPPING on any order shipping to any of the 50 states that includes a Mechman GM Replacement Alternator!
Over the years, we’ve had a lot of requests for quality alternators for all kinds of different applications. We’re proud to finally offer them!
If you’ve read any of owner Tony Candela’s books, you’re well aware of the importance of a properly sized alternator for your vehicle. What makes one company’s 150 Amp alternator different from another company’s 150 Amp alternator? Why is one company’s 150 Amp alternator twice as expensive as another’s? The answers are simple: quality and performance.
Understanding Alternator Ratings
The Big Number – this is the one most companies put out there: 140 Amps, 150 Amps, 200 Amps, etc. When shopping for alternators, you simply cannot make an educated decision with only this number!
What You Really Need to Know
- Idle Output – This is defined as how many Amps the alternator can output at 800 engine RPM with the alternator spinning at 3x crankshaft speed.*
- Cruise Output – This is defined as how many Amps the alternator can output at 2,000 engine RPM with the alternator spinning at 3x crankshaft speed*.
*A properly pullied alternator should spin at three times the speed of the crankshaft; i.e., at 800 engine RPM, the alternator will be spinning at 2,400 RPM.
So, when you’re looking at that advertisement for a 150 Amp alternator, you’re looking only at its Cruise Output rating. Here in the real world, we enthusiasts spend an awful lot of time at stop signs, stop lights, and just idling. Idle Output is the REAL measure of an alternator’s performance and is a reflection of how well the alternator will perform under the toughest of conditions; it’s what separates the players from the posers! Alternators with excellent Idle Output are more expensive to manufacture and therefore more costly.
Here are some of the pitfalls of choosing an alternator that cannot keep up with demands at idle:
- Poor idle characteristics
- Dead battery
- Dim headlights
- Short alternator life
Choosing an alternator for your vehicle with an Idle Output rating that exceeds the total current requirements of all of your accessories (electric fans, fuel pumps, water pumps, ignition system, EFI, etc.) is the key to building a reliable charging system that won’t ever let you down! This process is described in great detail in Automotive Wiring and Electrical System Volume 2: Projects and EFI Conversions.
We’ve sold and installed hundreds of alternators from all of the best companies over the years. We’re proud to announce that we’ve chosen Mechman as our alternator partner!
Mechman “Hot Rod” Alternators
These are designed as direct replacements for 1963-1985 GM Vehicles originally fitted with a 10DN, 10SI, or 12SI alternator. They utilize 6-phase Hairpin stators which use less horsepower than traditional 3-phase designs. The following are the features of these outstanding units:
- Bolt-in Replacement for 10DN, 10SI, or 12SI GM Alternators
- Internally Regulated
- Internal Fans
- Available in 170A and 240A Sizes
- Available in Natural, Polished, or Chrome Finish
- 1-Wire Design with 400 RPM Self-Exciting Regulator**
- Heavy Duty 5/16″ Output Stud
- Fitted with V-belt Pulley
- 2 Year Manufacturer’s Warranty
**Devout readers of Tony Candela’s books will note that he is not a fan of traditional 1-wire designs. That being said, Mechman has recently migrated to a 400 RPM Self-Exciting regulator that will not un-excite during extended periods of idling – the main draw back to traditional 1-wire designs. 3-wire regulator units are available at the same price via special order.
The 170A and 240A units share the same housing. Download a complete Hot Rod Alternator Drawing including all dimensions.