VERY IMPORTANT INFO! could explain alot of engine failures!!

[Willie]

I'm willing to publish my test results if we want to get several guys doing the same thing. We'll need a baseline first, with stock pullies. I have stock pullies. We'll need a very accurate voltmeter wired directly to the battery. I have a digital SPA voltmeter that I can program to read to the hundredth of a volt that is wired to the battery. Once we establish these figures, the same can be done with different pullies. Calculating the difference in alternator rpms is simple in order to compare to the baseline results.

Willie

 

[Willie]

Keep in mind a larger lower pulley with the original alternator pulley spins the alternator faster which could partially mask the problem.

Willie

 

[x NOODLES x]

Holy **** am I subscribing to this.

 

[04SilverSerpent]

With a stock pulley the Voltage dropped sooner??

 

[Special Blend]

Subscribing to this thread for sure!

 

[Willie]

....this is with a 4 lb. lower and the alternator pulley is a 3.20 metco.....here is some more info....tried this with the stock pulley too...the voltage loss started at 4,600 rpm....

A larger crank pulley by itself will spin the alternator faster. As I stated before, this may mask the problem because the alternator will put out more amperage.

I do not know the stock alternator pulley size. Is it smaller or larger than the 3.20" Metco?


With a stock pulley the Voltage dropped sooner??

Is this the stock alternator or crank pulley? It makes a difference.

Crank (Drive) Pulley >> The larger it is, the FASTER the driven accessories spin.
Alternator (Driven) Pulley >> The larger it is, the SLOWER it spins.

Just think of the sprockets on a 10 speed bike and which sprockets, front and back, result in faster rear wheel rotation. It's the same theory with the crank and alternator.

To avoid further confusion, everyone that posts about pulley sizes needs to clarify which one you're talking about!!!

Willie

 

[Jimmysidecarr]

I am also very interested in the solution to this problem... especially since I'm reving a tad higher now since the flash tune...

I think having a good strong and reliable charge going on under the weak spot will still be very important because that is where the revs usually are.....

The idea of finding CAPs that would stabilize the voltage at the higher revs. seems like an idea worth looking into :rockon:

That high rev/low voltage condition... if brief enough could theoretically be addressed by some adequately sized caps.... I think :shrug:

For sure ... I'll be following this :read:

Jimmy :thumbsup:

 

[SWEET03COBRA]

interesting, nice to see good people out there wanting to help the rest of us.

 

[IronTerp]

tried this with the stock pulley too...the voltage loss started at 4,600 rpm....

A larger crank pulley by itself will spin the alternator faster. As I stated before, this may mask the problem because the alternator will put out more amperage.

I do not know the stock alternator pulley size. Is it smaller or larger than the 3.20" Metco?


With a stock pulley the Voltage dropped sooner??

Is this the stock alternator or crank pulley? It makes a difference.

The stock alternator pulley is, I believe, 2.60". Isn't it kind of a paradox that when maintaining the stock alternator pulley on a 4 lb lower pulley application, that the voltage is dropping at an even sooner RPM figure???

As wjfawb0 stated, is the alternator spinning so fast with the stock alternator pulley, that it's losing effectiveness in supplying amperage to the electrical system?

Can understand possible ramifications of underspinning the alternator at high RPMs but am confused of findings when overspinning the alternator.

Maybe an alternator pulley in the 2.90/3.00 range with the 4 lb lower pulley, is a possible solution?

 

[Steeda30]

I'm running a 2.81" upper and 2lb lower, stock alt. pulley and I am not seeing a lean condition on my wideband A/F. :shrug: Is this supposed to be a problem for all cars or?

 

[pj_rage]

Adding capacitors may "solve" the problem, but are more so just masking it :shrug:

Hopefully we can get to the root of the problem and properly correct it :thumbsup:

Just to get this straight, is the deduction so far that the faster the alternator spins, the larger the voltage drop? I'm not sure the internal workings of an alternator, but generally, the faster you spin a generator, the more voltage you will read :??: Unless, as the thing is spinning faster, the expected voltage increase is diminishing by an increased load on the system (i.e. maybe increased fuel demand). I'm just thinking outloud here, but is it possible that this phenomenon is happening only on cars with a BAP? I orignally thought that even with 8ga wire or so going to the BAP, if it starts drawing some serious current, it would cause a decent voltage drop, but some quick calculations proved that even a 15ft run of 8ga wire shouldn't drop any more than 0.5V @ 40A. I doubt the BAP is pulling more than that, but I really have no clue what they are drawing. If it were wired with 12ga wire instead, running 40A, it could be dropping more than 1V, though. Anyone know what types of current the BAP/fuel system is seeing under load? Or the typical wiring scenarios? Please ignore me if I'm way off base, but improper wiring especially could cause voltage drops under extreme loading :shrug:

 

[pipeliner]

I have been trying to trouble shoot a problem like this. I have stock pulleys.

Car seemed to go extremely lean all of the sudden after 6200 RPMS. I had changed the spark plugs to see if that was the problem but got no where on it. I also added more fuel to see if it would stop it from happening.

Every time I would shoot up. I am not going to test this theory. I will post my results as I get them.

 

[Easy]

how could ford not see this problem? :eek5:

 

[Rootus]

how could ford not see this problem? :eek5:

If it does not happen with a stock setup, then it is not a problem as far as Ford is concerned (and I would not expect any different). It is just another risk of making modifications to make more horsepower. I'm glad someone caught this before I installed a bigger lower pulley ...

 

[Jack]

I'd really like to see Hermans results with the only change being an addition of a 1 Farad Capacitor. These can be had at any stereo shop, even Best Buy carries these.


Since our cars are rarely above 5K rpms for more than a few seconds at a time, I would think a capacitor would be the perfect solution.


Thoughts?

 

[Willie]

The stock alternator pulley is, I believe, 2.60".

Thanks. This helps.

Let me clarify a few points. Going back to Hermann's original post:

4-lb Crank Pulley
Metco 3.20" Alternator Pulley
5,273 rpm 12.68 v
5,478 rpm 12.50 v
5,587 rpm 12.25 v
5,670 rpm 12.18 v
5,992 rpm 12.06 v
6,078 rpm 11.87 v
6,296 rpm 11.81 v
6,460 rpm 11.50 v
6,440 rpm 11.37 v

I wish I had specs with the stock alternator pulley because with the larger Metco piece, voltages will be less! By installing only a larger crank pulley will spin the alternator faster. With a larger alternator pulley (as above), it will slow it back down. From a prior reply, a 4-pound crank pulley is 8.6" d. Now I need to know the diameter of the stock crank pulley to calculate which combo results in a slower spinning alternator. Does anyone know?

I really don't like the way the aftermarket designates their pullies, i.e. 4-pound, 8-pound, etc. It really should be by diameter like ATI uses. Reason? Simple >> A "4-pound" pulley will result in 4-pounds only if the engine components such as heads, cam(s) are the same as what the aftermarket company tested their pulley at. With a freer breathing intake system, you will get LESS boost. So by rating pullies in pounds, it's not always accurate. Remember folks, higher boost will not necessarily produce more power because boost is only a reflection of resistance. A freer flowing intake system will produce less boost given better heads and/or cam(s) with the same blower. Sorry for the tangent.


Isn't it kind of a paradox that when maintaining the stock alternator pulley on a 4 lb lower pulley application, that the voltage is dropping at an even sooner RPM figure???

I'm not quite sure this has been validated, as I state above.


is the alternator spinning so fast with the stock alternator pulley, that it's losing effectiveness in supplying amperage to the electrical system?

hmmm. I've never heard that an alternator can LOSE its ability to maintain a proper charge by overspinning it. Then again, I don't know everything!


Just to get this straight, is the deduction so far that the faster the alternator spins, the larger the voltage drop?

Again, I don't think we can deduce this yet because I only see one set of datapoints (above). Here's what we need:

1) Stock crank pulley w/stock alternator pulley -- rpm vs volts.
2) Larger crank pulley w/stock alternator pulley -- rpm vs volts. This will spin the alternator faster and voltages should not change from #1. If anything, they should go up but the voltage regulator should keep things in check.
3) Larger crank pulley w/larger alternator pulley -- rpm vs volts. This will reduce alternator rpms from #2 but will need to know diameters to calculate how close this ratio is to the stock setup, #1.


I'm running a 2.81" upper and 2lb lower, stock alt. pulley and I am not seeing a lean condition on my wideband A/F.

With a larger crank pulley and the stock alternator pulley, you're spinning the alternator faster than stock. This will mask the problem if there is one. This is based on the assumption that a faster spinning alternator will produce more volts. This "additional" voltage is capped by the regulator so you'll never see it.


Since our cars are rarely above 5K rpms for more than a few seconds at a time, I would think a capacitor would be the perfect solution. Thoughts?

Yes. This alleged problem is very strange. I've never heard of such a thing on any other car. I can rev my IROC-Z to 6,500 rpms with no voltage drop.

Jacobs Electronics used to have a device called the AccuVolt. It connected directly to the battery and allowed system voltage to remain rock solid within a specified range. With it, it would maintain whatever voltage you set it at regardless of battery voltage (as low as 9.5 volts). This would be a very good solution but I don't know if Jacobs makes the AccuVolt any more....

Willie

 

[IronTerp]

Willie, you're putting some good thought into this. My problem is that there seems to be a ton of ambiguities with the data from the original post that just can't seem to be explained up to this point.

In trying to guesstimate the total number of 4 lb and up lower pulley installs in the Terminator crowd, we'd have to think upwards of 300 to 400 have probably been sold by Metco, LFP, and other vendors. Most of the guys that do this mod are probably reasonably aggresive with their snakes on the street and/or on the track. And how many 03/04's have had lower pulleys on them that have had short block failure?

According to another site's stats of blown motors:

Totals as of 8/13/05: 48 (4 “stock”, 23 Mod’d Eatons, 14 KBs, 5 Whipples, 2 Unknown.)


So, is this an isolated issue for some lower equiped Terminators or are all of us lower guys flirting with danger, regardless of our alternator pulley size, every time we stomp on the "Go" pedal????

 

[FireRed04Vert]

Willie...

First...the use of the larger alternator pulley with the larger lower will maintain close to factory rpm specs for the speed of the alternator. At all engine rpm's from idle on up. The lower speeds it up and the larger alt pulley brings it back down to where the factory wants it. If you do the math, you will find it's very close.

As to why the the voltage is falling off at higher rpm's...which is just the opposite of what old school thinking is...is exactly what Hermann is trying to discerne. My guess is you are going to find it's in the alternator itself, but more testing needs to be done.

Hermann...have you checked for amp draw during these tests instead of just voltage? Voltage tests will only show you half the picture. Let's see if there are some huge draws going on due to the BAP or something else wierd. Have you tried a new alternator? If you duplicate it with a new alternator, I would be very concerned as to what's going on here.

I believe these alternators are rated at 130 amps...but I'm not positive on that.

Hermann....I would try and pull the alternator off the car and take it to an electrical shop who can spin it on a test bench and put it under a load. You may have to go to a very small pulley to get it to these speeds. If the problem duplicates, then it's either a faulty alternator or a design flaw. If not, I would look for reasons on the car.

The fact that you can slow the alternator down and improve the situation tells me it's a problem with the design of the alternator...not the car. This may be one huge reason there is such a high failure rate on these alternators. If I were experiencing this situation, I wouldn't consider a capicator...that's just a band aid for a bad wound. I would invest in a high quaility aftermarket alternator that will withstand the rigors we put it through...and I would definitely use the pulley that keeps it at factory speeds or even slower.

 

[Bonefish]

Curious as I have a 2.80 upper and 4lb lower..street tuned..and I don't recall having any issues....but, I have a voltmeter to install..so, guess I'll check it.

 

[Willie]

First...the use of the larger alternator pulley with the larger lower will maintain close to factory rpm specs for the speed of the alternator. At all engine rpm's from idle on up. The lower speeds it up and the larger alt pulley brings it back down to where the factory wants it. If you do the math, you will find it's very close.

Ya know, when I was in college studying engineering, I really didn't like those pulley problems. Physics class, isn't it? I'll be the first to admit that I had one thing backwards. To reiterate (correctly this time), a larger crank pulley will speed up all driven accessories such as the alternator. To slow the alternator back down, you will need a LARGER alternator pulley. I was correct in the sense that to speed things up, you can either go with a larger drive pulley and/or a smaller driven pulley. Both will speed things up doubly!

Being a relatively new owner and not having owned any Ford vehicle since the late 70s, I'm still not quite accustomed to some of the terminology here. I also didn't know that these cars have a high alternator failure rate. Are there any higher-amperate aftermarket units available?


The fact that you can slow the alternator down and improve the situation tells me it's a problem with the design of the alternator...not the car.

Agreed. Strange though.....


Willie, you're putting some good thought into this. My problem is that there seems to be a ton of ambiguities with the data from the original post that just can't seem to be explained up to this point.

Exactly. More data needed!

Willie