Yellow Bullet Forums banner

1 - 20 of 22 Posts

·
Registered
Joined
·
638 Posts
Discussion Starter #1
Who has had sucess with running an alternator on a high (9k) rpm engine? Which alternator did you use? How was the reliability and longevity? Thanks in advance.
 

·
T/S 368E
Joined
·
30,467 Posts
.

It makes absolutely no difference what the engine rpm is.
If you do it right, the alt will spin the exact same on a 900" torque monster, and a 300" comp screamer.
That's why I have Jones set up all my pulley's and gears, they know what each needs to run properly.

.
 

·
T/S 368E
Joined
·
30,467 Posts
.

Forgot to mention I always use the HTD system.
I've used Gilmer & V-belts and the HTD stuff is much better.
Less stress & strain on the shaft, and I have never lost a belt like I did in the old days with a V-belt.

.
 

·
Registered
Joined
·
1,019 Posts
.

Forgot to mention I always use the HTD system.
I've used Gilmer & V-belts and the HTD stuff is much better.
Less stress & strain on the shaft, and I have never lost a belt like I did in the old days with a V-belt.

.
Where do you get your pulleys? I have been looking to change from a v-belt to a gilmer setup. I need a 2-1 ratio for the alternator and I have a 1 inch mandrel.

Thanks
 

·
T/S 368E
Joined
·
30,467 Posts
.

Not sure if they sell Gilmer, probably, but I get all my HTD, pulley's & mandrels from Jones Racing.
Warning, they are very proud of their parts, but they are top of the line.


http://www.jonesracingproducts.com/


.
 

·
Registered
Joined
·
2,970 Posts
.

It makes absolutely no difference what the engine rpm is.
If you do it right, the alt will spin the exact same on a 900" torque monster, and a 300" comp screamer.
That's why I have Jones set up all my pulley's and gears, they know what each needs to run properly.

.

Well put, the only way to go!!!
 

·
Registered
Joined
·
1,019 Posts
Take it for what its worth, but I disagree with this. This will depend on the alternator and the max engine rpm. In a dragcar, for an alternator to be effective, It needs to be able to adequately charge at idle. If it doesn't not, car can be inconsistent because the only time it is adequately charging is going down the track. For example with my car, I found the max load at idle with everything on was approximately 40 amps. I have a stock cs130 alternator that puts out approximately 50 amps at 2000 alternator rpm. So with my car ildleing around 1000 rpms, I needed at least a 2-1 ratio in my car. So I am winging the alternator shifting at 7300, to 14600 rpms. I read somewhere that most stock alternators can take a max of 18000 rpms. Mine has lived the last three years on my car with no problems. I found that when i didn't have the correct ratio, started at with a 1.6 ratio, I had inconsistency issues and the battery was never kept fully charged. Being it footbrake car, it even effected reaction time a bit. If you alternator is not maintaining 13.7 volts at idle, I would be willing to bet it causing some inconsistency issues. Like I said take it for what its worth.
 

·
Registered
Joined
·
1,611 Posts
I agree with Banjo. I believe the underdrive thing came about with OE alternator of years gone by. With the "race" alternators out there, I don't think it's as relevant.

And just for info's sake, I have run the car both with and without it operating, with close to a 2-1 ratio, (picture in above post). Belt on, or belt off, there was no realizable difference in ET. My application is very horsepower sensitive. It's a 1900 car making roughly 260hp. 3-5 HP one way or the other makes a significant difference.
 

·
Registered
Joined
·
1,019 Posts
Another thing I noticed with my car, I can watch what the car is charging at and determine the state of the battery. In the summer when i have to run the cooling fans and water pump alot more,It tends to draw down the battery. If I am going deep into the rounds, I will start to see the voltage drop to 13.8 which is usually where it starts to effect et and rt. So I will use a battery charger during the summer to try and keep the battery topped off. When the battery is fully charged I notice no differance with or without the alternator belt on.
 
1 - 20 of 22 Posts
Top