The STUPID thread

[1stKill]

hey does anyone know roughly how much 1kg less unspung weight would equal in srung weight?

Most of a cars weight is supported by its suspension. It suspends the body and associated parts so that they are insulated from road shocks and vibrations that would otherwise be transmitted to the passengers and the vehicle itself.

However, other parts of a car are not supported by the suspension, such as the wheels, tyres, brakes and steering and suspension parts not supported by springs. These parts are all called unsprung weight. Generally, unsprung weight should be kept to a minimun.

[Kenshin X]

hey does anyone know roughly how much 1kg less unspung weight would equal in srung weight?

Most of a cars weight is supported by its suspension. It suspends the body and associated parts so that they are insulated from road shocks and vibrations that would otherwise be transmitted to the passengers and the vehicle itself.

However, other parts of a car are not supported by the suspension, such as the wheels, tyres, brakes and steering and suspension parts not supported by springs. These parts are all called unsprung weight. Generally, unsprung weight should be kept to a minimun.

thanks lee. now can u tell me how much 1kg less unsprung weight would equal in sprung weight? LOL :P

[1stKill]

hey does anyone know roughly how much 1kg less unspung weight would equal in srung weight?

Most of a cars weight is supported by its suspension. It suspends the body and associated parts so that they are insulated from road shocks and vibrations that would otherwise be transmitted to the passengers and the vehicle itself.

However, other parts of a car are not supported by the suspension, such as the wheels, tyres, brakes and steering and suspension parts not supported by springs. These parts are all called unsprung weight. Generally, unsprung weight should be kept to a minimun.

thanks lee. now can u tell me how much 1kg less unsprung weight would equal in sprung weight? LOL :P

1kg less unsprung weight should not make any difference to sprung weight,arn't they seprerate weights ....i think i maybe in over my head here :P

sprung,unsprung,sprung,unsprung,sprung,unsprung....equals springed

[Hiro]

There's no real conversion between sprung and unsprung weight, unless you talk about lap times or ride - reducing unsprung weight improves the suspension's ability to react to changes in the surface or cornering, which improves handling.

[Kenshin X]

There's no real conversion between sprung and unsprung weight, unless you talk about lap times or ride - reducing unsprung weight improves the suspension's ability to react to changes in the surface or cornering, which improves handling.

oh nice. would fuel efficiency will be improved too or negligible?

@lee haha

[Hiro]

If it was weight saved in the wheels it might make more of a difference, elsewhere it would make as much as anywhere else in the car.

[mmm_sx6]

Getting a little confused with sound systems in a car so hopefully someone can help me out.

1. With impedances, am i correct in saying that the higher the impedance, the clearer the sound, but the lower the impedance it, the more power going to the sub therefore louder but less clear? if not correct me please.

2. I currently have a sub rated at 1000wmax and 500wrms. The amp powering it is rated at 400wrms(mono). Is this bad for the sub?

3. I am considering changing the amp to one that is 500wrms monoblock, during my search for such an amp, i continually keep seeing these kinds of figures...

Rated Power

continuous power 250W x 1 @ 4-Ohms RMS

400W x 1 @ 2-Ohms RMS

500W x 1 @ 1-Ohm RMS Total Power

500 Watts

Which figures should i be looking at when selecting an amp?

Taking into account that it is a DUAL 4-OHM VOICE COIL sub. How could i wire it up to lower the impedance from 4ohms to 2ohms? (if that makes any sense/is it possible?)

Cheers B)

[Buff Hamster]

Generally the higher the ohms the better the sound but it does demand more power.

No your sub on be damaged using a lower powered amp. I HIGHLY doubt you will ever listen to 400wrms. Unless you want to go deaf faster.

[DJKOR]

Taking into account that it is a DUAL 4-OHM VOICE COIL sub. How could i wire it up to lower the impedance from 4ohms to 2ohms? (if that makes any sense/is it possible?)

Wire the two coils in parallel. That means with each coil having a positive and a negative, you join the positive ends to each other, and the negative ends to each other. When two equal resistors (in this case the coils) are in paralleled with each other, they equal half the value of one of them.

[mmm_sx6]

If I was to hypothetically buy a high power amp with the following specs:

• 500W RMS x 1 @ 4 Ohms
• 900W RMS x 1 @ 2 Ohms
• 900W RMS x 1 @ 1 Ohm

Could i safely run my 500wrms sub at 4ohms instead of finding a cheaper amp and dropping the impedance down to 2 ohms?

Can you see anything wrong with this? is it overkill? will it damage any components (electrically)? apart from my boot? lol

[Buff Hamster]

If your sub is 2ohms but dual voice coil then you can hook it up in series so the total ohms is 4.

[mmm_sx6]

Awesome, thanks for the replies.

I can just hook the sub up directly to it because it is DVC 4ohms, and the amp is also 500wrms at 4ohms, so it should be ok!

[DJKOR]

Awesome, thanks for the replies.

I can just hook the sub up directly to it because it is DVC 4ohms, and the amp is also 500wrms at 4ohms, so it should be ok!

That depends. Is it a dual 4-ohm voice coil or a dual 2-ohm voice coil?

A dual 4-ohm voice coil, where each coil is 4-ohms, can only run as a 4-ohm sub if you connect each coil up to two separate channels on an amplifier. Otherwise, you can either connect the coils in parallel to make 2-ohm, or in series to make 8-ohms.

A dual 2-ohm voice coil, where each coil is 2-ohms, can be run as either 2-ohms by connecting each coil up to two separate channels on an amplifier, as 1-ohm by connecting the coils in parallel, or 4-ohms by connecting the coils in series.

Your initial post gave the impression you have a dual voice coil sub where each coil is 4-ohms and considering that is is more common to state the rating of each coil when you define "dual voice coil", I would be thinking the same.

[mmm_sx6]

Oh sorry about that, glad you brought it up though because now i'm a little confused. On my reciept it says Dual 4-ohm subwoofer so i assumed it meant 4 ohms on each coil and on the website it says

• 1000 Watts of Maximum Power

• 500 Watts RMS

• Dual 2-Ohm Heat Resistant Voice Coils

I take the site specs as more reliable.

Now i know for sure (i know i should have made sure before) that it is 2 ohms on each coil (few other sources say the same).

This now means that i am looking for an amp with a lower rating.

I think i should just leave it wired separately, not in series or parallel. This would mean that i want an amp that is rated at 500w rms @ 2ohms right? If this is the case, then thats good, ill save some money.

[DJKOR]

I think i should just leave it wired separately, not in series or parallel. This would mean that i want an amp that is rated at 500w rms @ 2ohms right? If this is the case, then thats good, ill save some money.

Personally, you would be much better off wiring the coils in series and finding an amplifier that can do 500W into 4-ohms. If you try to separate the voice coils onto different channels, you are just wasting away with inefficiency.

[mmm_sx6]

I think i should just leave it wired separately, not in series or parallel. This would mean that i want an amp that is rated at 500w rms @ 2ohms right? If this is the case, then thats good, ill save some money.

Personally, you would be much better off wiring the coils in series and finding an amplifier that can do 500W into 4-ohms. If you try to separate the voice coils onto different channels, you are just wasting away with inefficiency.

A good suggestion was what i was waiting for. Ill be doing that to get the most out of it. Thanks for help. Really appreciate it!

[Seby123]

how much would i be looking at spending to get a twin turbo supra up to say 450HP

[jeffy]

how much would i be looking at spending to get a twin turbo supra up to say 450HP

$10,000 ?

[Seby123]

fuuuu thats too much try again :P

[jeffy]

hrmmmm $8,000 ?

[Kenshin X]

being the idiot that I am, I overfilled my engine oil 6mm above the full mark. I drove for around 30kms with the engine over filled and hitting lift here and there. havr i caused any damage? no white smoke was blowing out of the exhaust and no foamy oil in the sump when i checked the dipstick. that's why I thought it was ok. temperature gauge was on level when warm.

edit: i couldn't sleep so i went out and loosened the plug and drained some of the oil now its approx 3mm below the full mark. the car felt "normal" but when i drained abit and took it for another spin, it felt "better" maybe a stupid placebo effect again?

[Hiro]

6mm extra in your sump will probably be fine, the level drops by easily double that when the engine is running so you shouldn't have problems with windage etc. If it was an extra 2L or so then I can see issues but chances are if the car didn't feel any different and there were no visible signs like smoke then all is well.

Does sound like placebo effect though after you drained it, would have felt better simply because you weren't worrying about it anymore :P

[HoldenBoi]

Ok, genuine question here - and no, i don't plan on doing this to my car...

If it is possible to use two turbo chargers in unison, is it also possible to have a twin super charger setup? Or would that, by itself, consume too much engine power to make it worthwhile?

For a Rolla Stivo?

HAHA - Dude, I'm not planning on doing this to ANY car! I wouldn't even know what I'm looking at...

I'm just asking in theory - is it possible, what would it involve, what sort of performance would you see etc etc... Are there even any cars that use such a setup?

ANYTHING'S POSSIBLE IF YOU HAVE ENOUGH TIME & MONEY!

I once saw a big block chev with twin blower setup; no idea how it performed though...

[Hiro]

Plenty of old-skool aircraft engines had sequential supercharger setups. This was where the term "intercooler" came from, as it was placed between the two stages ("inter" = in between). The proper term for an intercooler in a car is a "charge air cooler" or "aftercooler" (as it is after the supercharger phases).

We're talking about 20L V12s here though, and the superchargers were to combat the loss of power at altitude due to thinning air, but the concept is the same.

[Kenshin X]

damn that question was almost 4 years ago... -_-