LPG and SUBS..

[DAKSTER]

Hi guys,

Tried all kinds of subs and enclosures in my LPG VS. Trying to keep my boot as a useful container, which means having a compact and well located sub/subs which are not exposed to damage by the contents of the boot. LPG makes this a little hard, because obviously the tank takes up all the space behind the seats.

I currently have a little single 8" sub in a portable enclosure, which actually almost meets my needs.. I like bang not boom (rock not rap) and the sub is mainly just to get some extra kick into the bass, and add just a little rumble. I do NOT want a multi 18" 50 million watt setup. It would just get in the way.

I've considered separating the area where the LPG tank sits and using that as an enclosure, with the tank inside, heavily wrapped in sound foil. Would this work? I am thinking there is probably enough space around the tank to provide enough air volume, just not sure what having the tank in the middle of the box will do to the sound. I'd just have to make sure I have some decent speaker grills on for protection and that would leave me the rest of the boot to use for carrying kids in (oops carrying kids stuff i mean )

I'd love to hear ideas and see pics of compact boot installations that include an LPG tank or don't use the space where it would sit. I'm thinking a couple of 8" (or maybe 10" but that might be a bit boomy for my taste dunno..)

Look forward to seeing some ideas thanks !

[Verynice]

gas or subs, one or the other, you chose

[DAKSTER]

no brainer that one.. LPG is higher octane you just gotta tune to take advantage of that.. and I get to laugh at those paying double the price for unleaded.. but I think I can get subs as well

[StoneX]

I'm pretty sure you're not meant to enclose the gas tank, so I'd double check before you build an enclosure around it.

You can easily fit a 12" into the rear corner of most boots with a fibreglass box that is moulded to the shape of the car. These can take up minimal usable boot space. Then just get a grille for the sub.

[edit] Not telling you to get a 12", just saying you can and still use minimal space.

[a1k3m1]

haha im with verynice on that one .. subs or gas dude!!! ..

But seriously dude, if you were caught with some kind of enclosure over the gas tank you would be in a bit of trouble.... as it would block off easy access to it if you were to crash or something, i know with the VY boots you can buy off ebay a fibreglass enclosure that fits nicely into the corner of the boot (Near the Tail lights) that will let ya put your Sub in without taking up too much room.. I dunno if they make them for the VS's .. i dont see why not?

should look into that dude!!

[Verynice]

if it was me, id get rid of the gas

[DAKSTER]

If big boom was my priority then getting rid of the gas or losing the rest of the boot would be the only option. Its not, and I enjoy being able to travel 1000km for 50 bucks or so, so the gas is staying lol

I've seen those fibreglass pods for the corner, and they have all had 12" holes cut into them. Obviously this could be filled and recut though, no biggie. I'd be interested in hearing more about those if anyone has one... do they fit well, are they strong, and of course do they cut the mustard soundwise. That corner is the only other place I can see to put them that's for sure.

Making the assumption that 2 subs are louder than one ( doesn't actually seem logical, the maximum volume would be the loudest source wouldn't it? but somehow I just find myself thinking 2 is louder than one... ) Point of that to me is that if 2 is louder than one, I can use less volume=less distortion to get the same decibels? Anyone know anything about this? Remembering that I don't need the local windows to rattle with soundwaves, just boost my rock music a bit.. is there any value in installing a pair instead of one?

I believe that 8" is all I need, it seems to have the clearer sharper cracking bass I want rather than the boomy vibrating stuff the bigger subs put out.

If I build my own box with a pair of 8", in the corner where the fibreglass ones sit.. do the speakers need to be compartmented or can they happily share the same enclosure?

Is the sound affected more by enclosure shape or enclosure volume? ie if I mount 2x 8" subs in that corner, is it worth making a narrow extension of that box past the wheel arch just to improve the enclosure volume, even though neither speaker would actually be in that part of the box?

Thanks again

[Kieran263]

Why not put 8's in the parcel shelf?

[azzfox]

Gas is for BBQ's

To take advantage of LPG you would need injection. Mixers are too much of a headache/restriction. You seriously get 1000km for $50? Its either tuned really lean or you granny it lol. From what Ive heard you fill up almost twice as much on LPG compared to petrol so it generally doesnt work out that much cheaper. I cant say Ive never owned a car on LPG, I plan to keep it that way

[bogan_vk]

keep the gas and just put one 12'' sub in the corner of the boot , if you mounted them in the parcel shelf and you ever had to go for a rwc they will rape you sideways for cutting metal out and weakening the child seat anchorage points.

[DAKSTER]

I get 9.1 l/100k with the cruise on the legal limit wherever that's wise and i sit on about 130 in the sticks. So ok, yep its not 50 bucks my bad.. at todays price of 64.9c/l , at 9.1l/100k its $59.05 for 1000k. Thats highway miles of course, you can take 200k off that range around town. Dyno is 147kw, no racecar but plenty enough for an old fart like me. I personally dont notice a lot of difference in performance.. it maybe is a bit flatter on takeoff when running gas thats about it.

Gas can be made to perform better than unleaded, because of its higher octane. Pretty sure this would require more than just a simple tune though, probably need some engine mods and injection yes. I have made no mods, its a factory gas installation (very rare for a VS) and my local gas guy has been playing with the computer a little to bias the tune more towards gas as of course, as a dual fueler, tuning is always going to be a compromise.

If I was going to be getting rid of anything it would be the petrol tank lol.. enabling me to tune purely to suit the gas would have major benefits on all counts.. but gas is still not available everywhere yet believe it or not and in some parts of central QLD its so expensive that petrol becomes affordable again... so for now at least it keeps both tanks.

Consumption is 7.9l/100km at a steady 110kmh on the highway for petrol, and 9.1l/100km for LPG. Todays prices at the local servo are 147.4 for unleaded and 64.9 for gas ... you do the math

[DAKSTER]

8" in the parcel shelf are not an option unfortunately. There is no room for them above the gas tank, and spacers to bring them up would have them pretty close to touching the window. The way the parcel shelf metal is designed isn't helpful in that regard either, as bogan says, to fit them in something would have to be cut.

[bogan_vk]

i have gas research straight gas and i would never go back to petrol myself especially seeing people put nearly $100 in their fuel tanks to fill up whilst im putting under $30 in and not losing any power.

[DAKSTER]

My daily drive is a Kia Cerato. This is a car I highly recommend by the way.. awesome little car, goes well, handles well, and has all the lux features. Its a 2L auto. BUT the Berlina, on gas, is much more economical than the Cerato... and of course leaves it for dead performance wise.

[azzfox]

I agree LPG can be made to perform better than ULP but not using a mixer, harder valve seats is probably all thats required as far as engine work goes. When you bung LPG onto a motor that was designed for petrol the valves usually shit themselves over time because LPG doesnt offer any lubrication. LPG also burns alot hotter. But it would definatly need to be injected. Gas research? I think its called as bogan said. I would actually be interested in this myself but its been a long time since I first heard about it and never looked into it.

Come to think of it, it you were going to run straight injected gas on the V6 (or any injected motor) you could replace the standard injectors with the gas ones instead of drilling into the intake manifold. But then I would need a dicky tank in the boot which sort of brings us back to the original subject lol.

By the way Im not sure if the L/100km works when on gas. It may be still estimating fuel usage while on gas. Then again it is all factory. *shrugs*

[DAKSTER]

All the totals, litres used, remaining, l/100km all seem to tally with what goes into the tank with either fuel. In the Berlina, the single fuel gauge displays whatever fuel you are using at the time, and the consumptions and remaining kms etc change when the tank gauge changes, so I assume the trip computer knows whats going on too. There is no separate little green lights gauge like the aftermarket ones, the petrol gauge is also the lpg gauge.

* With the factory dual fuel, you have to come to a complete stop to switch fuels, it will not let you do it whilst moving. This can be rather annoying because even just to check how much fuel you have left in the other tank, you have to stop to change over to make it display the other tank. A second gauge would have been better, though I do like that its a proper gauge and not just 4 green lights like the aftermarket ones.

* I also don't see the problem with changing over on the fly, my old EL Fairmont with aftermarket gas used to do it with no issue.. mind you the Fairmont trip computer just got confused with the aftermarket gas and was useless to me while on gas.

If you use straight gas, then you remove the problem of the tank in the boot.. replace the fuel tank with it underbody. Once you have the car set up and tuned properly for gas only, you cant help but reap the benefit of 110 octane. Maybe sometime in the future

[DAKSTER]

Back to the original question of speakers.. now wondering if it wouldn't be a good idea to compromise and try to mount some 7x10s on spacers on the parcel shelf, with some extra power to them, instead of a proper sub. I've heard these things can pump if set up right, anyone had any experience with them?
Again, my listening is rock.. a system that plays ACDC well will do me nicely. Don't need big subs for rock, just something that turns 'thump' into 'kick in the back' lol

[Verynice]

hahaha, i love the LPG ULP debate.

i'd definately get subs for ACDC, sounds killer on them

[StoneX]

Two subs are obviously louder than one, but one 10" will be as loud as two 8's and take up less room. The box volume will determine if a sub is "boomy" or "punchy", not the sub's physical diameter.

[Nic92]

Two subs are obviously louder than one, but one 10" will be as loud as two 8's and take up less room. The box volume will determine if a sub is "boomy" or "punchy", not the sub's physical diameter.

depends on box.. 2 8's have more cone area than just one 10"

[StoneX]

But generally, an 8" won't have the same Xmax as it's equivalent 10", therefore the 10" will be able to move more air.

[Nic92]

mr thinks he knows it all ^


na jk..

oh and also depends on power/setup/ mainly box thou, coz my friends 13w7 owns my 18"..

and depends on what level the woofer is in the series of the brand

[DAKSTER]

ok so a ten inch in a smallish enclosure will have more punch, a bigger enclosure more boom?

I'm thinking a simple rectangular enclosure to fit in the space in the corner of the boot now. I'll make a box and then add some shape to it with fibreglass so it fits the corner well. That would be a usable volume I think, but maybe on the smallish side so providing the punch (better word thank you) that I want?

What about porting? Is the length and diameter of the port critical? Is it even necessary to have one? If so, how would you calculate what was needed? I understand that to win any competitions some of this stuff is vital, but would it still sound good if you just bought a plastic port of any size and just whacked it in anywhere?

Are there any issues with fitting amps inside speaker boxes? I'm thinking 400w so not a huge heat source I hope, but does being inside a subwoofer box do it any harm? I wont need access once fitted, I just set gain at about 75% and leave it at that. I only use the head unit sub controller after that. Thats what I have been doing with the single 8" I currently use anyway, but that only has 100W and a fairly small portable enclosure. With that one, the amp is just screwed to the top of it.

[Verynice]

boom = ported box
bang = sealed box

[DAKSTER]

I should add that I dont actually use high volume that often. When I do, its probably low volume by your standards, I dont know.
I do know that the max volume of most head units sounds disgusting when turned up to full volume, and turning it down till the distortion stops makes it too quiet for me.
So what I am doing here.. I want to have more decibels than the current 4x50 head unit is providing, but only have to turn the volume knob to half to achieve that. Having more power than you need means not having to turn it up too far and distort it to reach the volume you want.
The sub helps lift the volume, and gets me the punch I am lacking with the 6" (Pioneer TS-D 260W splits all round) cabin speakers. I am also adding a 4x100 amp for the cabin speakers. With a 400W sub in the boot, I can't see me needing anything more. I just want to make sure I get the right sound from the sub to suit my tastes, and not have it take up all of what remains of my boot.

Does the speaker need to be exposed? Can I build the box so the speaker is concealed and protected, and let air pressure and sound out with a vent or something?