lights getting dim at wot around 5k rpms ?

[trailblazer sss]

Well I finally got my car back an decided to go for a drive. When getting on it my lights go dim an a battery light kinda flashes an I just let off it was almost like it cut the power a lil..triangle speed dyno tuned the car an I also have a sct with three tunes from Jon lund I just I.stalled one of em an drove it a lil an believe it or not it pulls a lil harder..iam about to go do some more runs I gotta figure out what the deal is the alternator was just replaced,its got a optima battery idk how old it is tho...what do yall think ??

 

[Ironhand]

Its the alternator.

If it wasnt replaced with one with the correct amperage then its useless.

 

[joseph.devenney]

Buy an OEM alt and they are SO much fun to change!!!

 

[trailblazer sss]

I was looking at the reciept for the alt. It came from Ford back in march 2010 306 dollars I changed the tune now it is a lil better doesn't do it till 5500 rpms but I guess ill be buying a alt now

 

[MoKo_03SVT]

im on my 4th alt in 3 years. your lucky you are getting the early warning signs (battery light) before it quits working! my first 2 alts gave me no signs what so ever. the last 2 tho DID give me the battery light. at first it started with just a quick occassional flash (on and off) in the higher rpms. then it started to happen more and more. then the light just stayed on...and that is when it was on its last leg. i got it changed that day.

it is def your alt!

 

[Blueline]

Its your alternator and dont keep getting on it. You not getting full power to your fuel pumps and you can go lean and........ you know what comes next. GL!

 

[04oxfordvert]

absolutly the alternator.mine was doin the same so i changed it and cured the prob! gl!

 

[trailblazer sss]

Do I have to go with a oem alt? What's the part number on the correct alt?

 

[rich5150]

Do I have to go with a oem alt? What's the part number on the correct alt?

Are you OVERDRIVING the blower? Or are you using the STOCK CRANK/Lower pulley? If you ARE using a BIGGER LOWER pulley, you're overspinning your alternator(they are obviously on the same drivebelt)...thus why you could have shortened the life of it. Def sounds like your alternator though..(reason for electrical issues)


A good replacement is one from Pa-Performance

Replacement 130A Alternator for 03-04 Mustang Cobra

Smaller ALT pulley to reduce RPM's on alt.
Metco 03-04 Cobra Alternator Pulley 2-4lb Lower Pulley (3.20) [MAP3200] : Lethal Performance, Performance parts for Ford Mustangs

 

[trailblazer sss]

The car has a 2.95 upper an tune,k&n an e,gaudy that's all..so no on overspinning the alt I would say

 

[Jimmysidecarr]

Alternator, check your voltage output at several different RPM points to verify.

Then read this thread:
http://www.svtperformance.com/forums/engine-tuning-214/675089-found-cure-our-alternator-woes.html

Which is from this sticky:
http://www.svtperformance.com/forum...e-you-post-read-terminator-faqs-new-guys.html

 

[SVT_Troy]

Read the threads that Jimmy posted...... I'm running a smaller pulley with a higher amperage alt....

 

[trailblazer sss]

it was the alt...replaced it an the battery because when i did the alt it was fine but my dome lights were dim an my headlights would flicker when i hit the window switchs so that was fixed with a new battery. thanks guys for the help.

 

[Blueline]

Good, thanks for posting the final fix!

 

[joseph.devenney]

If you bought a cheapo alternator from say autozone or o'reilleys you may be doing this again in a couple weeks!!! I know from experience!

 

[Jimmysidecarr]

Are you OVERDRIVING the blower? Or are you using the STOCK CRANK/Lower pulley? If you ARE using a BIGGER LOWER pulley, you're overspinning your alternator(they are obviously on the same drivebelt)...thus why you could have shortened the life of it. Def sounds like your alternator though..(reason for electrical issues)
A good replacement is one from Pa-Performance

Replacement 130A Alternator for 03-04 Mustang Cobra

Smaller ALT pulley to reduce RPM's on alt.
Metco 03-04 Cobra Alternator Pulley 2-4lb Lower Pulley (3.20) [MAP3200] : Lethal Performance, Performance parts for Ford Mustangs

Read the threads that Jimmy posted...... I'm running a smaller pulley with a higher amperage alt....

NO!

A smaller alternator pulley speeds up the already over driven alternator.

I am using a LARGER 3.2" Metco alt pulley with a stock lower to slow my alternator down. Still running the 1st replacement Motorcraft alternator.

Smaller drive pulley(crank) and larger driven pulley(alt or blower) slows things down..
Larger drive pulley(crank) and smaller driven pulley(alt or blower) speeds things up.

 

[Nitrous SSC]

^^^ I did the same thing with our Alt change. 3.2" pulley. Car charges perfectly.

 

[garbonzo1991gt]

Even with the stock lower the alts are over spun. I put a Heavy Duty PA Alt on mine with the 3.2" pulley and no issues since. 13.9v all the way up to 7000rpms with no drop.