brake vacuum

Heath · Post by **Heath** » Tue Jan 24, 2006 6:13 pm

Hey all,

In the past I had asked questions about how to boost my hilux's braking performance and now I have a couple more.

The original engine was a 2.2 petrol and has been replaced with a 3.8 v6 Chev. My question is does the chev produce the same vacuum as the old donk? I had heard that the bigger engines produce less vaccum in the manifold so was wondering if I replaced my alternator with a diesel one with the pump on the back of it would help.

This was prompted mainly because of the new gauges fitted a few days ago as the volt meter shows quite a drop when running around with lights on , fan going and of course wipers on. Sits about 14v when all is off and just running, drops to 12.5v with everything going (not with spots on). I have a set of work lights fitted but not yet wired up on the roll bar and a radio to wire up also so this then prompts me to ask should I also look at upgrading to a bigger alternator and / or battery or is this normal?

Heath

wjw · Post by **wjw** » Wed Jan 25, 2006 8:46 am

Hmm any idea how many amps your alternator is?

Heath · Post by **Heath** » Wed Jan 25, 2006 11:43 am

Pass looks pretty small probably the original one. How would I find out the size etc?

would fitting an ampmeter show if the electrical system is coping?

Heath

wjw · Post by **wjw** » Wed Jan 25, 2006 1:12 pm

There will be a label on the side/back of it... otherwise, what are the engine details and I'll have a look.

Sounds like the alternator isn't big enough and so when you have everything on, you start using your battery instead.

SupraLux · Post by **SupraLux** » Wed Jan 25, 2006 3:06 pm

...or your volt meter is cheap/faulty and its really only dropping a small amount... might want to check that first with a good digital voltmeter.

Another thing to check is that the big cable from the alternator to the battery has good connections... maybe double it up with another cable piggybacked to see if that makes a difference.

Does it start well? If its not, it could be an indication that the earth from the battery to the car or the battery to the engine isn't quite as good as it could be...

Just some ideas

Steve

Heath · Post by **Heath** » Wed Jan 25, 2006 3:40 pm

Starts okay (winds over for a bit before the LPG hits the carb but otherwise its okay.

Volt meter isnt the flashes (just a regular run of the mill repco one) but seems okay, will try with my Fluke meter and see how that measures.

I am picking the alternator is a bit on the small side and so is the battery.

We'll see soon I guess.

Heath

mumad · Post by **mumad** » Wed Jan 25, 2006 8:33 pm

I had similar problems with mine, used to drop down to 12 volts when i turned lights, etc on, was really bad at idel, the vacume pump on the factory 55 amp alternator shat its self so i put a 80 amp bighorn alternator on and i have got plenty of power now!! heaps to run all my lights, winch, etc, also put in one of those new shock proof maintenace free batteries that repco sell, 600 cca i think, has made a big difference aswell, well worth the extra cost.