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 Post subject: Alternator upgrades
PostPosted: Tue May 04, 2004 6:46 am 
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I need a new alternator. I think the one now ain't makin enough power to cope with the car. I think its the standard 12A one but its running on a 13B turbo. What other alternators can i use to keep the power up? Without much modifications to fit.

Cheers,
buzbox

additional information below added to this post by moderator sim_rx3 in the interest of keeping all the relivant alternator info on the front page, if you do have a problem with your install. read through the rest of the thread as you more than likely have not done something right like others have and its not functioning properly and more likely the answer will be there instead of filling the thread with the same questions. thank you

Quote:
A general run down of alternators to start with

Resistive style alternators

R100 rx2 rx3 rx4 rx5 rx7 series 1,2,3,4.

Load sensitive alternators

Rx7 series 5,6 & EL falcon

It is important to know what style your alternator is to get the wiring correct. If you don’t get the wiring correct the alternator wont function properly and quite likely shit itself within 6 months.

An alternator should charge between 13.8 to 14.3 volts. Any more or less and there is a problem


808/rx3 conversion from external reg to internal reg resistive style alternator

this will also apply to 323/rx7 series 1 etc but the original wire colours running into the 6 pin plug of the regulator maybe different..

and the B+ wire (white/red) is the original

Image

808/rx3 conversion from external reg to internal reg alternator for later load sensitive style alternators

this will also apply to 323/rx7 series 1 etc but the original wire colours running into the 6 pin plug of the regulator maybe different..

and the B+ wire (white/red) is the original and is to be disconnected from the alternator. the new 8 gauge wire replaces this

unfortunatly cause of this mod the amp meter will no longer work properly. im working on a mod to fix that problem.

Image

Diagram Series 1,2,3 (generation 1) to series 4 alternator

Image

Diagram Series 1,2,3 (generation 1) to series 5,6 and falcon alternator (pulley shaft size changes from 15mm to 17mm so MACHINING of the pulley of the early rx7 pulley and spacer is needed)

Image

Diagram for series 4 upgrade to load sensitive alternators.

Image


Diagram for Series 5,6 rx7 and cosmo alternator upgrade

no wiring mods needed and can be plugged in and bolted on (some slight filling off the back of the water pump mount ie firewall side of mount. may be needed to fit the EL falcon alternator)


PLEASE NOTE:

For a load sensitive alternator -
never connect B+ wire straight to the field pin on the alt. ive never given a connection diagram like that.
cause they dont like it, so don’t do it.

both B+ and field connection are to be straight from the battery positive terminal or if battery in the boot both B+ cable and field cable have to be connected to the starter motor constant volts supply


THE PULLEY FROM A RESISTIVE LOAD ALTERNATOR AND ITS SPACER NEEDS MACHINING UP TO THE SHAFT SIZE OF THE LOAD SENSATIVE ALTERNATOR.
BECAUSE OF THE RPM THESE ITEMS SEE, DO NOT DRILL THE HOLE OUT. GET IT MACHINED BY A PROPER MACHINE SHOP.



for the diode (this item must go in a load sensitive diode alternator charge circuit) goto dick smith

buy 2 x Z3229 diodes (each is rated at 6 amps) twist the leads together so the white band on the diode is on one side only.
there $1.39 each

and the white band end of the diode is to be on the wire running to the alternator, dont forget to solder connections!!

AND MOST IMPORTANTLY - DONT CUT CORNERS AND DO IT CORRECTLY. FAILURE TO GET IT RIGHT CAN MEAN MORE DAMAGE TO YOUR CAR EVEN MAYBE A FIRE

i accept no responsibility of your workmanship



UPDATE - 12/02/2009

Quote:
hi guys...

i got onto an awesome site on the net that do custom alternators as well.
i asked them about my car (i used the same version rx7 alt description that i knew is the same as my Luce alt. cause sure as shit as soon as i said Luce i would have got a HUH?? lol)

they do all styles of alternators

they are here - http://www.qualitypowerauto.com/

question i asked -

what do you have as an upgrade for a gen 2 rx7 (89-91) alternator.

answer -

We can provide a direct replacement alternator that will use the same mounts, use the same belt and connect with your factory wiring harness, just need to upgrade B+. It is a 200 amp alternator that will provide about 110 amp at idle. The cost for this unit is $475.00 (this is US dollars). We would need 5 working days to build this for you. Let us know if you have any other questions. Thanks for the inquiry.



UPDATE - 23/12/2012

another source for the diode. only one of these are needed since its rated at 15 amps.. http://www.jaycar.com.au/productView.asp?ID=ZR1152


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 Post subject:
PostPosted: Tue May 04, 2004 8:45 am 
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what kind of car and engine type do you have ? also do a search there was a big post about this ages ago

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 Post subject:
PostPosted: Tue May 04, 2004 12:32 pm 
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well you need to get a proper 13b turbo one! :P

i just got mine reco'd and now its charging at 16v on the highway, the microtech is shitting itself LOL Only idle though it charges at about 13.8 volts... ive had no problems least i know im getting a good spark to the coils :)

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 Post subject:
PostPosted: Tue May 04, 2004 12:36 pm 
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Grab an alt off a later car. S4/5 or S6 or JC Cosmo. In order I think they're 70amp, 80 amp, 100amp, 110amp.

They should all fit with minor mods, mostly to do with spacers in the mounts. Also, a suitable front pulley will be needed. The wiring shouldn't be too hard either, especially if you search, because there is info here somewhere already.

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 Post subject:
PostPosted: Tue May 04, 2004 6:31 pm 
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im pretty sure you can use a series 4 one with no electrical mods, well in a first gen rx7 n e way, i know there is electrical mods needed for series 5 and above

correct me if im worng

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 Post subject:
PostPosted: Tue May 04, 2004 6:35 pm 
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he said he is running a standard 12a one on a 13b turbo ... so simply just get a 13b turbo one.. s4/5.

andy

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 Post subject:
PostPosted: Tue May 04, 2004 8:04 pm 
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a s6 will bolt straigh up to the std 1st gen with a couple of easy mods

swap the front pulley to fit a single v belt
cut down mounting spacer to suit
sut down bolt that holds the alt
change cut of original terminals, and fit 2 1/4" spade terminals for the sense and light wires and a larger eye terminal for the main power wire

Quite simple

Petar


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 Post subject:
PostPosted: Tue May 04, 2004 8:12 pm 
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i have been told that if u use thicker cable, something like 8ga to and from the alternator it will give u a noticeable increase in power. (not hp)

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 Post subject:
PostPosted: Tue May 04, 2004 8:16 pm 
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8gauge is that like amp wire? or like speaker wire? or can you use battery terminal wire? since i will be doing an engine conversion soon, i might look into it

makes sense, current/flow

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 Post subject:
PostPosted: Tue May 04, 2004 9:15 pm 
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Do not use speaker wire, 8 guage is regularly used for power cable to amps or sometimes wire for subs :D and is suitable, even better go to 4 gauge. Either is about $6/m from jaycar. If you have trouble finding lugs for end go to truck electrician, probably get em to press it on too unless you got the crimp tool.

While your at it upgrade your main power cables also.


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PostPosted: Tue May 04, 2004 9:26 pm 
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main power cables? you mean like batty cables and shiz?

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 Post subject:
PostPosted: Tue May 04, 2004 9:43 pm 
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OK...series 3 are 60A standard
series 1/2 are 55A
series 4 70A
series 5 80A
series 6 100A
Cosmo 20B 120A

I believe RX4 are 60A as well, but use an external reg.

Ol Skool...I would get that checked out man...16V is way too much. you will quickly fry your battery and/or alternator...in fact, I believe you have the problem below.

Series 4 alt's are 70A and will fit straight on on series 3 and earlier (provided you have converted from external to internal reg).

series 5 and on alts will NOT work without wiring mods.

The difference is that the series 4 and earlier alt's are L/R type alternators. These alt's use regs to are excited by the ignition circuit.

series 5 and later use a L/S type regulator. These regs are excited by battery positive voltage, ie always on.

If you simply splice early wiring onto later alt's you will experience two things...

(1) your regulated voltage will be much higher than it should. Voltage is meant to be within 14.1-14.7 at 2000rpm or above, provided there is enough amps to cope with demand, and depending on temperature (reg's use a temperature gradient to determine output). When it "sees" the ignition voltage, as the old alt expect to see, it is much lower than battery voltage because the ignition circuit will have a lot more resistance due to the ignition coils, ignitors, and ignition switch. The alt will overcompensate becuase it is meant to read battery voltage. This makes more sense as it is battery voltage that the alt needs to be wary of.

(2) when the ignition is switched off, the B wire is still live, but the alt expects to see battery voltage at the "s" terminal. It doesn't - it sees 0V. for some reason, I believe this will fry the alternator. In fact, in the manual it says not to have the B terminal connected and the other terminal not - having the ignition switched off and using the old wiring will have the same effect. A few people AGES ago on the forum had a problem with series 5 alternators blowing or causing flat batteries...I believe this is the cause.

SO...long story short. The charge (B) terminal stays the same, the dash lights terminal (L) stays the same. But the reg terminal must be wired direct to a constant battery positive source.

This is what I did using the series 5 wiring diagram as my model.

I used a series 5 alt this way which worked perfectly sitting between 14.5 when cold and 14.0V when warm.

I just got a series 6 alt, which uses the same wiring, and its between 14.1 and 14.5V pretty much as well, only a bit better when the thermo and accesories are on at idle (but I have no idle compensation, being a carby).

Hope that helps!

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 Post subject:
PostPosted: Tue May 04, 2004 9:47 pm 
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OK...series 3 are 60A standard
series 1/2 are 55A
series 4 70A
series 5 80A
series 6 100A
Cosmo 20B 120A

I believe RX4 are 60A as well, but use an external reg.

Ol Skool...I would get that checked out man...16V is way too much. you will quickly fry your battery and/or alternator...in fact, I believe you have the problem below.

Series 4 alt's are 70A and will fit straight on on series 3 and earlier (provided you have converted from external to internal reg).

series 5 and on alts will NOT work without wiring mods.

The difference is that the series 4 and earlier alt's are L/R type alternators. These alt's use regs to are excited by the ignition circuit.

series 5 and later use a L/S type regulator. These regs are excited by battery positive voltage, ie always on.

If you simply splice early wiring onto later alt's you will experience two things...

(1) your regulated voltage will be much higher than it should. Voltage is meant to be within 14.1-14.7 at 2000rpm or above, provided there is enough amps to cope with demand, and depending on temperature (reg's use a temperature gradient to determine output). When it "sees" the ignition voltage, as the old alt expect to see, it is much lower than battery voltage because the ignition circuit will have a lot more resistance due to the ignition coils, ignitors, and ignition switch. The alt will overcompensate becuase it is meant to read battery voltage. This makes more sense as it is battery voltage that the alt needs to be wary of.

(2) when the ignition is switched off, the B wire is still live, but the alt expects to see battery voltage at the "s" terminal. It doesn't - it sees 0V. for some reason, I believe this will fry the alternator. In fact, in the manual it says not to have the B terminal connected and the other terminal not - having the ignition switched off and using the old wiring will have the same effect. A few people AGES ago on the forum had a problem with series 5 alternators blowing or causing flat batteries...I believe this is the cause.

SO...long story short. The charge (B) terminal stays the same, the dash lights terminal (L) stays the same. But the reg terminal must be wired direct to a constant battery positive source.

This is what I did using the series 5 wiring diagram as my model.

I used a series 5 alt this way which worked perfectly sitting between 14.5 when cold and 14.0V when warm.

I just got a series 6 alt, which uses the same wiring, and its between 14.1 and 14.5V pretty much as well, only a bit better when the thermo and accesories are on at idle (but I have no idle compensation, being a carby).

Hope that helps!

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 Post subject:
PostPosted: Tue May 04, 2004 10:05 pm 
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Gregg is correct on this one

with s5 onward the easiest way is to wire the reg terminal (sense termial) straight to the b+ terminal on your alt

oh and gregg it will cause flat batterys just hooking it up as std 1gen were,

i experianced this just this arvo :cry:

this was cuased by the std choke/check realy that the 1st gens have , the wire to the lights from the alt goes tothe coil side of the realy, and will cause the realy to close its contacts always (should only happen when ign on) therefore sucking round 1 amp and will drain a good battery in round 8 hours

so youve been warned :evil:

Petar


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 Post subject:
PostPosted: Tue May 04, 2004 10:13 pm 
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There you go then....I might stick this in tech reference, because plenty of people doing late model engine conversions into older cars are probably unaware of this issue...even series 5 engines into series 4s will require the same mod.

Mr Rota wrote:
with s5 onward the easiest way is to wire the reg terminal (sense termial) straight to the b+ terminal on your alt


The problem is saw with this is that under full electrical load, you would be getting huge current going through a skinny wire? Or is that a non-issue - I get confused sometimes which way the current is actually travelling. :lol:

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