Jump to content
SAU Community

Alternator Upgrade

PSI086

By PSI086,
in Engines & Forced Induction

 Share

Recommended Posts

PSI086 Community Regular

PSI086

Posted
Posted

Having voltage issues with my alternator and was looking at maybe doing an upgrade if it was necessary. What sort of amps would be sufficient for my set up. Car is a VL turbo running 2 x 044 pumps (1 is staged to come on at 10psi) , 6 x LS2 coils, 750cc low impedence injectors, Haltech ps2000, no thermo fans, basic stereo with no amps and battery in the boot. Currently have a RB25 alternator in the car which is 80 amps but my be failing higher up in the rpm as you can see in the data log below. Ramped up fine on 17psi but had a smaller drop in voltage, 22psi it broke down under boost.

post-17518-0-23166600-1422347358_thumb.jpg

Link to comment
https://www.sau.com.au/forums/topic/453163-alternator-upgrade/
Share on other sites
Dose Pipe Sutututu Grand Master

Dose Pipe Sutututu

Posted
Posted

you're having the same issue as I am :)

I'm currently running a 85AMP VL Commodore alternator (Bosch replacement) after replacing my 80AMP R33 alternator.. has gotten a touch better, but I'm getting around 12.8volts up top.. and the idle voltage is horrible.

I'm contemplating in getting this one:

http://www.ebay.com.au/itm/Nissan-Skyline-HR33-GTS-RB25DE-120-Amp-3-0L-6-Cyl-Turbo-Non-Turbo-Alternator-/131390382961?pt=AU_Car_Parts_Accessories&hash=item1e977a2371

R_34 Community Regular

R_34

Posted
Posted

I would look at upgrading the wire going from the alternator to the battery.

I checked on my RB20, I have 14.1V at idle on the battery but got 15.3V on the alternator.

I investigated a little more and I found that the wire coming from the alternator going to the power connector next to the battry to power all the car is responsible for the total loss in voltage.

So try to check it on your car and upgrade it if you find that is voltage is much higher than the one you see on your battery. Much cheaper and more efficient than getting a more powerful alternator.

  • Like 1
Dose Pipe Sutututu Grand Master

Dose Pipe Sutututu

Posted
Posted

I've added a second 4ga feed and still have issues.

It's because the alterntor itself cannot produce the voltage to suit the car's demand.

I tested the voltage on the alterntor and it's only like 0.2 volts higher than what's being logged on the ECU.

I'm assuming that the Bosch alternator has issues working at high RPM And the factory unit well is just old.

discopotato03 Grand Master

discopotato03

Posted
Posted

I found cleaning all the earth points in the engine bay made a difference to my S2 33 . Also the voltage regs don't last forever . I got caught out a while back and had to have my OE alternator rebuilt . The reg is the same as those on early Falcon Mitsi alternators - EA EB from memory . I don't think the OE R33 alt is listed in Australian parts catalogs but long time auto sparkys can usually work it out .

My car shows around 14V at the battery and a little higher at the alternator so good enough for me ATM .

Dose Pipe Sutututu Grand Master

Dose Pipe Sutututu

Posted
Posted

I found cleaning all the earth points in the engine bay made a difference to my S2 33 . Also the voltage regs don't last forever . I got caught out a while back and had to have my OE alternator rebuilt . The reg is the same as those on early Falcon Mitsi alternators - EA EB from memory . I don't think the OE R33 alt is listed in Australian parts catalogs but long time auto sparkys can usually work it out .

My car shows around 14V at the battery and a little higher at the alternator so good enough for me ATM .

Adrian, what voltages are you getting with your headlights on & the rear demister?

PSI086 Community Regular

PSI086

Posted
  • Author
Posted

My alt to battery wiring is brand new as I've just put a new engine harness in the car. Used 16mm welding cable which should be heaps I'd imagine. Is the size of the sense wire critical? I might pull the engine to chassis earth strap off and clean the connections again just to eliminate that.

Also what sort of amps would be sufficient for my set up? Something around the 90 mark would be heaps I'd imagine or am I bettter off upgrading to a 105-110amp unit?

t_revz Grand Master

t_revz

Posted
Posted

you dont need to upgrade amperage for your requirements. 80 amps is easily sufficient unless the stereo was a killer. it held 14v flat up till about 5k then something happened. looks like either something turned on that pulled excessive power or had a short. the vibration at that rpm is causing something to move(loose connection). the ignition supply to the alternator plug is failing.

does it dip revving up quickly? accelerating quickly or only when speeding up slowly?

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share
Go to topic listing


  • Similar Content

  • Latest Posts

    • Nizzy_R34
      r34's love to squeal

      By Nizzy_R34 · Posted

      just an update to this, poor man pays twice  Tried sanding down the pulleys but it didnt do the trick. Chucked another second hand alternator in the na car which I got for free off my mate and its fixed the squelling. Must have been unlucky with the bearings.    As for my turbo car, I managed to pick up a cwc rb alternator conversion bracket + LS alternator for 250 off marketplace, looked to be in really good nick. Installed it , started the car and its not charging the battery.... ( Im not good with auto elec stuff so im not sure if this was all I needed to do but I verified such by using a multimeter on the battery when the engine was running and I was only getting 12.2v )   I had to modify the earth strap for the new LS alternator , factory earth strap was a 10mm bolt which did not fit the bolt on the LS alternator which was double the size so I cut it off , went to repco bought some ring terminals that fit, crimped it onto the old earth strap and bolted it up to the alternator , started the car and same issue. Ran like shit and was reading 12.2 at the battery.  For a "plug and play" advertised kit thats not very plug and play but alas.  My question is , am I missing something ? Ive been reading that some people recommend upgrading the stock 80 amp alternator fuse to a 140 amp but I dont see how that would stop the alternator charging especially at idle not under load.  Regardless ive pulled it out and am going to get it bench tested by an auto elec tomorrow but it would be handy to know if ive missed something silly or have done something wrong.   
    • Duncan
      Engine sputter

      By Duncan · Posted

      My wild guess is that you have popped off an intake pipe....check all of the hoses between the turbo and the throttle for splits or loose clamps.
    • Duncan
      S1 Autech 260RS Wiring Diagrams

      By Duncan · Posted

      Awesome, thanks for sharing!
    • Duncan
      Nissan fuga 450gt android screen

      By Duncan · Posted

      To provide more specific help, more information is needed. What Android screen? What is its wiring diagram? Does the car's wiring have power at any required BAT and ACC wires, and is the loom's earth good?
    • GTSBoy
      Nissan fuga 450gt android screen

      By GTSBoy · Posted

      So, now all you need to do is connect the 2 or 3x 12v feeds into the unit to permanent 12v, ACC 12V and IGN 12V that you can find in the spot behind the stereo, and the earth, and then it will switch on with the car.
×
×
  • Create New...