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

[03 svtvenom]

Can someone put a write up on how to test our Voltage?

Where can we get a Volt Meter?
Where to place the Volt Meter for monitoring?
What other hand-held Devices can also mointor(aka Predator/Dash Board)
---Any subtracting/adding that needs to be done
---The PIDS that we need to select

Thanks from those of us who arent that technical

Alot of radar detectors have a volt meter. Mine does but I dont know how accurate they are supposed to be?

 

[iczar1]

Well I used my HEC Instrument cluster diagnostics to measure the batt. Read around 170ish crusing and dipped into the high 160's at WOT. So I guess this will have to do till I can get some sort of Volt Meter.

Anyone know what the PID is to measure the Alternator Voltage withe the Diablo Predator?

 

[big_goomba]

I came across a car i was tuning today that was perfect up to 5,200 rpm's then drifted lean very quickly. I tried everything to get fuel in it, then looking at the logs i noticed the maf counts were dropping from a point about 880 counts, (sct-2400 maf, ported eaton car)down to 850-860 while the rpm's were still going up!! That is making no sense unless un-metered air is getting into the intake tract pre-blower but post maf....check everything, all perfect with no leaks.... this car was making me pull out my hair!! Then i started to think about it, I thought maybe the blower was having reversion at that rpm point, which it wasn't. The car also has a 4 lb lower drive on it, I started wondering if it was possibly a voltage issue of some sort, i called my buddy ryan @ sct and he backed up my thoughts, thinking as the voltage decreased so did the power to the fuel system even though this car has a wiring upgrade and a Bap. I had never logged the voltage pid, but after doing so i found some great info....even with a metco 3.20 alternator pulley on the alternator the car the voltage stated to fall off... at 5,273 rpm's it had 12.68 volts, at 5,478 it had 12.50, at 5,587 12.25, 5,670 12.18..., 5,992 it had 12.06..., 6,078 11.87...,6,296 it had 11.81..., 6,460 it had 11.50...,6,440 11.37....and as it got over 6,200 it started to drift leaner than I would like to see so we lifted. The point of all of this is simple....as the rpm's increase on a car with a lower drive on it the voltage starts to drop off quickly, so all of you data loggers with raptor or x-cal-2's better start to log the voltage pid, it just may save your engine's life!! I am going to do a ton of datalogging with larger alternator pulleys even if we have to get some custom sizes fabbed up. EVERYTHING I FIND WILL BE POSTED AS I FIND IT! I would say this is in fact the cause of alot of the engine failures we have seen, not due to the tunes but due to the drop of voltage......this is one of the big advantages I get due to the fact I tune on the street in real world conditions....one more thing....as soon as we lifted off and the rpm's fell, the voltage returned This is going to HELP US ALL and i'm glad i could share this super important find!! Thanks to ryan @ sct for his input in solving a HUGE PROBLEM!!! Hermann :beer:

Any properly designed electronic device such as an automobile computer must have an onboard voltage regulation for the appropriate logic levels, i.e. 5V, 3.3V, etc. in order to function properly. That said, this voltage regulation would make it immune to any fluctuations in the 12VDC power line. Otherwise we'd be experiencing all kinds of problems...

All of the circuit designs that I've ever seen for measuring analog voltages have always used a reference voltage input which is the same voltage that goes to the sensor being measured. The reference voltage is necessary so it can track the signal from the sensor accurately regardless of any changes in the reference/sensor voltage. Although this sounds good in theory, I'm unable to confirm any of this without the electrical system schematics for the 03/04 Mustang Cobra's.

Does anyone have these schematics ?


I can understand how these voltage changes could have an adverse effect on the output of the fuel pump which is basically an electric motor, but not any of the sensors like the MAF, etc... Another thing I would like to know more about is the reason why they are governing the alternator output at WOT...

Does anyone else think that it might be so they could sqeeze more power out of the "Terminator" engine to reach the 390HP as advertised ?

 

[03blwn281]

so should I get this looked at since I have a 2.80 upper 4lb lower and a alt pulley

 

[fak3r]

subscribed

 

[mpe331lx]

Subscribing

 

[04MC]

Ok would be really nice if we can get some updates on this ... more input from other people also would be welcome.

 

[YoungJim]

All I can say is, well done, Hermann. Thank you for sharing that. I'll have another read through this when I have more time to absorb it fully, but I'd consider this to be a big piece of the foundation for my engine build on one of the new aluminum 4.6 blocks FRP put out. Thanks again. Jim.

 

[Hissssnsvt]

Wasn't it found that the PA Alternators were crap?

If you do a search you will find several posts about PA Alternator failures. Not sure if they ever corrected the problem.

But I bet there were alot of alternators sold!

LOL, bingo! I believe Hermann became a PA dealer right around the time of this post.:dw:

 

[hpbyhermann]

I still use their alternators....some have failed but mine has been fine

Actually I have been a dealer for them since the 5.0 days....nothing new or even recent.....this is the plain and simple version....you need to use a 3.5" alternator pulley with 2# lowers, a 3.7" with 4 or 6# lowers...and a 4" with 6# high rpm cars or 8# lowers...These are the setups i've used that will keep the alternator in the car and off of the floor, This isn't magic.....use that chart!:rockon: But be advised like anything else that is man made things fail....but if you use the recomended pulley sizes your reducing the chance of failure by a large percentage!!:thumbsup: I never have and never would recommend any part or manufacturer that is poor quality. Hermann

 

[ORANGE CRUSH]

Thanks Herman.

Sorry for my stupidity but I'm assuming it doesn't matter what upper you run?

Is there an actual chart or is it just what you posted in the above thread?

Thanks again for this find and all your hard work on the issue.

OC

 

[01cobravortech]

Actually I have been a dealer for them since the 5.0 days....nothing new or even recent.....this is the plain and simple version....you need to use a 3.5" alternator pulley with 2# lowers, a 3.7" with 4 or 6# lowers...and a 4" with 6# high rpm cars or 8# lowers...These are the setups i've used that will keep the alternator in the car and off of the floor, This isn't magic.....use that chart!:rockon: But be advised like anything else that is man made things fail....but if you use the recomended pulley sizes your reducing the chance of failure by a large percentage!!:thumbsup: I never have and never would recommend any part or manufacturer that is poor quality. Hermann

subs

 

[01cobravortech]

Actually I have been a dealer for them since the 5.0 days....nothing new or even recent.....this is the plain and simple version....you need to use a 3.5" alternator pulley with 2# lowers, a 3.7" with 4 or 6# lowers...and a 4" with 6# high rpm cars or 8# lowers...These are the setups i've used that will keep the alternator in the car and off of the floor, This isn't magic.....use that chart!:rockon: But be advised like anything else that is man made things fail....but if you use the recomended pulley sizes your reducing the chance of failure by a large percentage!!:thumbsup: I never have and never would recommend any part or manufacturer that is poor quality. Hermann

Hermann, I'm not trying to put you in awkward spot but I was looking at what one of the vendors on here recommends in terms of alt. pulley size in comparison with lower crank pulley size:

LFP is pleased to introduce our new Alternator pulley for the 2003 2004 Mustang SVT Cobra. The LFP Alternator Pulley is used with aftermarket Crank Pulley Kits to reduce alternator revolutions. As you increase the diameter of your Crank Pulley, your alternator pulley will have more revolutions. Over time, the increased revolutions may cause your alternator to over-spin. Prevent it before it starts by adding an oversized LFP Aluminum Alternator Pulley.
Application Chart:
- 2# Ring None
- 4# Ring 3.2''
- 6# Ring 3.5''
- 8# Ring 3.7''

They're recommendations are slightly different from yours. Do you agree with their size recommendations?

 

[IronTerp]

Wow!!! Thread brought back from the dead! Can we title this "The Great Alternator Voltage Scare of 2005"??? Wasn't the final conclusion that in the original scenario, a bad alternator caused the low voltage readings?

There has certainly never been substantiation that possible lower voltage readings from various supercharger/alternator pulley combinations have caused premature engine failures.

That being said, I believe that Herman's alternator pulley recommendations above apply to PA alternators and not to Ford OEM alternators. This issue of what sized alternator pulley to use with aftermarket lower pulley applications with factory alternators is still debateable, but the below would be some rough guideline from "general" consensus:

2 lb lower pulley = Most go factory alternator pulley (2.6") a few go 3.2"
4 lb lower pulley = Probably go 3.2", but some stay 2.6"
6 lb lower pulley = 3.2" and a few go 3.5"
8 lb lower pulley = Most go 3.5"

 

[01cobravortech]

Wow!!! Thread brought back from the dead! Can we title this "The Great Alternator Voltage Scare of 2005"??? Wasn't the final conclusion that in the original scenario, a bad alternator caused the low voltage readings?

There has certainly never been substantiation that possible lower voltage readings from various supercharger/alternator pulley combinations have caused premature engine failures.

That being said, I believe that Herman's alternator pulley recommendations above apply to PA alternators and not to Ford OEM alternators. This issue of what sized alternator pulley to use with aftermarket lower pulley applications with factory alternators is still debateable, but the below would be some rough guideline from "general" consensus:

2 lb lower pulley = Most go factory alternator pulley (2.6") a few go 3.2"
4 lb lower pulley = Probably go 3.2", but some stay 2.6"
6 lb lower pulley = 3.2" and a few go 3.5"
8 lb lower pulley = Most go 3.5"

Excellent my friend. I appreciate you clarifying this issue for me. I'm still trying to figure out what sized lower pulley my Cobra has on the car right now. Its a lower.

 

[03blwn281]

I've got a 2.8 upper and a 4lb lower and I notice a drop on my INTERCEPTOR gauge luckily. I called Mark from LFP and bought a ALT pulley and that was that..Thank god I had my INTERCEPTOR gauge!!!!

 

[01cobravortech]

I've got a 2.8 upper and a 4lb lower and I notice a drop on my INTERCEPTOR gauge luckily. I called Mark from LFP and bought a ALT pulley and that was that..Thank god I had my INTERCEPTOR gauge!!!!

Do you remember at what rpm you started to see a drop on the interceptor gauge?

 

[BLOWN_DSG_03]

Subscribed!!!

 

[Obi1Cobi]

I have had to change my alternator 3 times already and now i need a forth. I have a 2.8 blower pulley and all the idlers. i know it is spinning the alternator faster than stock and a bigger alt. pulley may correct the problem i think. My typical alt. issue starts with after boosting hard my volts shoot down to 10.5. Maybe it will go back up randomly, also, after the car sits for a couple of hours then it will go back up also.
Also, my car has always had a loss of everything electrical on a hard boost between 1st and 2nd and 2nd and third. its for a split second but its been there except right after i get a new battery for about three weeks. Ive had 4 new batteries, red tops. Any ideas?

 

[Phase1GSR]

Good find.