Ska Posted December 7, 2008 Report Share Posted December 7, 2008 Does anyone know (IT_S8) if I can swap my alternator for one of a D3 diesel; whats the highest rated one anyway? Why? Because my lights are dimming when the bass kicks in. Ta+++ Link to comment Share on other sites More sharing options...
sloss Posted December 8, 2008 Report Share Posted December 8, 2008 I think that's more likely to be an earthing problem elsewhere. The Watts your sound system uses is sound ones not lecky ones.... the actual power it consumes is negligible campared, say, to sticking the heater fans on high. Check what full fan power and/or the heated rear window does to your lights. Link to comment Share on other sites More sharing options...
IT_S8 Posted December 8, 2008 Report Share Posted December 8, 2008 Does anyone know (IT_S8) if I can swap my alternator for one of a D3 diesel; whats the highest rated one anyway?Why? Because my lights are dimming when the bass kicks in. Ta+++ I couldn't say with any certainty..... The highest rated D2 alternator was 190 Amps, and thay was watercooled - Never seen one in the flesh though so not really sure just how much electrical gear you need on board for that to be fitted at the factory! The batteries are pretty hefty in these cars, it would take a heck of a lot of bass to cause lighting issues, given all the other electrical gear that they sustain happily, like heated seats all round, heated door locks, heated washer jets, heated front and rear screens, wipers, etc. They all would surely drain more current, but I can forsee that a pulsey bass beat might make a more of a rhythmic pulsing dim on the headlights if it were straining, and that could look a little, well, poor really. Assuming that you have good earths, and your amp is connected directly to the battery, so its not taking current capacity from anything else, then its probably a fair bet to consider uprating the alternator. By the looks of things, the 2.8 has a 120amp alternator, where the 3.7+ has a 150amp. None of the alternators listed seem to be engine specific, suggesting (on the D2 chassis at least) a degree of interchangeability but experience would teach me to only suggest this, and not guarantee it If you want to try a D2 150amp for size get in touch direct, we'll check the best we can that it will fit, and we can sort you out with a 'if it doesn't fit send it back' deal Link to comment Share on other sites More sharing options...
DJStrange Posted December 8, 2008 Report Share Posted December 8, 2008 The Watts your sound system uses is sound ones not lecky ones.... the actual power it consumes is negligible campared, say, to sticking the heater fans on high. Seriously, the biggest fuse you'll find in a car is usually 30 to 50 amps. My biggest amplifier has 80 amp fuses on it. I don't think Ska is talking about his Bose stuff here Sloss Ska, please don't go down the route of adding big capacitors... If you look around TalkAudio forums, there has been a lot of discussion about this issue. I think the two main schools of thought are "Big Capacitors" and a more methodical and logical one which is "The Big 3/Extra Battery/Bigger Alternator". I used to make my vectra lights completely dim to almost off with my set up before I sold the veccy, and that was after doing "The Big 3" - TB3 from now on. Ok, TB3 - check your earths to the chassis from the battery, alternator and amp(s). Upgrade or uprate if possible, particularly around the alternator - the standard earth cables for the alternator and battery are usually not big enough to cope with 1kw+ power draws from amps, especially when you've got the gadgets we have in our 8s (amplifiers might say 600 watts RMS for instance, but they may peak at close to 1.5kw at 13.4v which is what's draining power away from the lights). Extra battery - you can pick up those lightweight racing batteries for an extra bit of capacity for your biggest amp, use a split charge relay to provide it with some alternator output. This is supposed to be the smart alternative to big power capacitors, but I'm not going to get into an arguement about those. Bigger alternator - I think you've already sussed that one out, but hopefully you'll realise it won't mean anything if your earths and power leads are not up to carrying the extra oomph. 0AWG oxygen free copper is about the biggest you'll get I think (cable as thick as your index finger) for main earth to amps and battery. You could probably double up whatever is on the battery and alternator already, just run an identical length of the same size earth cable alongside whats already installed - easily doubles the capacity of cable to earth. Sounds like you're running quite a set up there Ska Link to comment Share on other sites More sharing options...
Ska Posted December 8, 2008 Author Report Share Posted December 8, 2008 IT_S8 - 150amps may have to do- will send you an email. I’ve seen pics and they don’t seem any different. Sloss, DJ is right I'm running something a little more intensive than the Bose setup: Even though it's an old, old skool system it does draw some serious current from the charging system and sounds good to my ears anyway! The system is almost all Alpine: Alpine Monitor HU, CD changer, Digital EQ/sound processor with time alignment (can delay the time the sound from a particular speaker arrives to your ears; a good thing seeing as I sit closer to the rear door speaker), TV tuner, multimedia player- DVD/VCD/CD/mp3/mp4/USB etc. (in the slot where the A8 owners manual lives- to add a 100Gb hard drive for movies and mp3’s), SAT NAV, V12 4x50wrms amp, Class D 500wrms @2 ohms bass amp and two Type R 10" subs. The door speakers are standard at the mo. DJ - already a member on talk audio and the12volt.com just haven't posted much just lurking in the back ground, picking up useful tips. Initially I was intrigued by Caps due to relatively lower cost, but caught onto the fact that they would not have the time to recharge before the next supply of juice is required as I listen to a wide variety of music. As far as a battery is concerned, then I guess that has to be sealed and requires a spilt charging system which also = loads more weight. The dimming light symptoms do point to a lack of supply from the alternator and you’re spot on when saying I should upgrade the earths and power supply. But you have also to contemplate is that although Peak power is only momentary you may find the OE alternator not up to the job as speakers tend only to be around 60% efficient at peak load. So my system the system would produce 1400 watts of power to my speakers at about 60% efficiency. This means that the input power to the amplifiers is 1400/0.60= 2333w. From… P = V x I Assuming the battery's voltage is 13v (12.2 – 14.4 range) then the current required from the alternator is… I = P / V I = 2333/13 180amps Doh! Well so I have been told! Looking to add a roof monitor and change the speakers and perhaps try installing the amps and numerous black boxes under the boot floor (currently flat on the boot floor against the seat with subs firing through the rear shelf speaker holes), but I’m weighing that up against err extra weight and the “can I be arsed!” factor. How’s your set up going? Link to comment Share on other sites More sharing options...
sloss Posted December 9, 2008 Report Share Posted December 9, 2008 Pwheee! I stand corrected..... that's a lot of kit you have in there! Link to comment Share on other sites More sharing options...
DJStrange Posted December 9, 2008 Report Share Posted December 9, 2008 (edited) Ha! Another TA forum lurker - I must admit I find TA a bit daunting, there's so many knowledgeable people on there, it puts me off posting anything! But crikey, the advice and know-how I've gleaned from there... Sloss - this morning after reading through my reply to your post above, I might have come across as a bit patronising, it wasn't meant that way bud, sorry. It's surprising just how much power a decent sized audio system draws! Hmm, I don't know how much those batteries weigh, but I know a simple split-charge relay will only weigh peanuts (cheap ones for caravans are tiny and should be enough). The problem with high output alternators that are anything but OE is price - they cost a fortune, so I can empathise with you for looking at the D3 stuff, probably a good option to consider. My install has come to an abrupt halt for the time being since my gearbox expenditure, but I'm hoping to get a bit of time to have a proper look at it during the xmas hols, if only to install the amps and sub and get it up & running on the standard speakers if possible. Door builds and sound proofing will have to wait until well into the new year I reckon. The good news is that my beast just passed it's MOT, one less thing to worry about... Edited December 9, 2008 by DJStrange humble pie... Link to comment Share on other sites More sharing options...
Ska Posted December 9, 2008 Author Report Share Posted December 9, 2008 (edited) How are you planning the amps. I am considering moving it all here Got the idea from Mike Just got to figure out how to cool it all. You'll notice I'm supporting the boot floor with a screw driver while I took the pic, yes I realised afterwards by mistake that the handle is also the proping leaver:rolleyes: Edited December 9, 2008 by Ska Link to comment Share on other sites More sharing options...
DJStrange Posted December 9, 2008 Report Share Posted December 9, 2008 I'm going for some sort of box-out for the amps, I built one for the vectra and mounted a couple of 120mm pc cooling fans on a fan controller off a relay. I'd use my wheel well but I daren't travel the distances I do without a spare, especially when I'm eventually towing the caravan off to another job. Alternatively, I think I'll be having a look at the two compartments behind the wheel wells (an amp in each), but I need to have a look at how much space there is and mounting/cooling/wiring options. The good thing about having the single 12" sealed is that it doesn't take up an awful lot of room really, so there's that to think about too... Lots of thinking and not much action at the moment!! Link to comment Share on other sites More sharing options...
Figure11 Posted December 9, 2008 Report Share Posted December 9, 2008 DJ, Just think what you could do with this space.. I havent had a puncture in 7 years! Its all risk managment. Mike Link to comment Share on other sites More sharing options...
DJStrange Posted December 9, 2008 Report Share Posted December 9, 2008 Yes indeed, I see the space. Not sure I want to change too much from standard S8 though to be honest - my turn to go all purist You using metal in your plans or something else? Fuel tank was it? Link to comment Share on other sites More sharing options...
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