supercharging a VR

Am I right in saying therefore that the SC produces a more progressive delivery than a turbo? from what I understand the SC builds rapidly from around 4K which would suit the vsr?

Also, arnt the SC's cheaper? Im sure I remeber Vince at Stealth quoting around 2.5k for the SC.

 

As far as I know my old racer was the quickest VR6 in the country. Unless anyone can prove otherwise?

 

im with TT here, no matter how good your SC is, it is sucking power from the crank.

you have a turbo driven by a belt, and a turbo will spin like 200,000 rpm, thats hell of a gearing at 8k rpm, and that ammount of gearing would suck 100% of the gain,

turbo all day long,

 

got to be a turbo, the chargers are limited and do suck power- friend works in the aeroplane business and did his Msc on turbos and chargers.

 

I once read (and don't quote me on this, I read it, it doesn't necessarily mean I agree with it or know if it's true) that the big superchargers on the silly power V8 dragsters actually take as much power to turn as the bog standard hemi V8 lump can produce!

 

no i'm with you on this, friend said that some standard chagers drain a system of 25% of the power they can produce. so a massive engine running silly power would probably be close to that power out put of a lesser V8.

 

you can get chargers well in excess of 1lire capacity, that's a lot of air to move and subsequently compress

tt

 

You've all lost me now.. my car is fast, that's all I need to know.


I biast to superchargers because, at the end of the day, I have one.


I personally can't see my charger needing that much power to spin. Really. Think we are going a bit over the top..


Lets just race next summer instead!

 

imagine running up teh street with a handkerchief in your hands catching the wind. now imagine the same ith the sail from a yacht. they're both moving air, one just a lot more. the more air you move, the the more work is required. all chargers do is move air (and turbo's), boost is a restriction to flow.

tt

 

terrible thing, envy.

and your point is? I'm not comparing mine to a posi disp SC.

I was pointing out to Jeff, that the mega power sapping type of SC that he was referring to, is a different type to mine, and that my SC was similar to a Turbo.

where the f*ck did I say this? I didnt - read the post ffs.

my SC uses a belt drive and exerts a drag on the engine - from the belt friction and the work needed to turn the rotor - but to no where near the same as a posi displacement type.

This is complete utter b*****ks. read what you have written ffs.

A turbo will boost earlier and thus making engine torque earlier - in effect making a flat torque curve.

This is how it might look.

RPMTurbo SC
3000 8psi 1psi
3500 8psi 2psi
4000 8psi 3psi
4500 8psi 4psi
5000 8psi 5psi
5500 8psi 6psi
6000 8psi 7psi
6500 8psi 8psi

So you see - two different systems.

They wil both produce max power at about the same rpm. But the turbo will have a much broader torque band.

This is pretty much what I said to Jeff above, as to why a Turbo would tramp on a SC of a similar max-power down the 1/4 mile.

From now - READ the post, then REPLY.

Simple.

Jules

 

This is where I was getting confused, the loss of power at the crank would be minimal on my charger, if any.. turning the power steering pump aloneisa far more difficult task for the crank surely?

 

hmmmmm JC emotions running high

what was the 1st line of my post - "don't take offence at this" but you launch into a torrent of abuse.

so what you're basically saying is that your charger is the dogs nadgers and bends the laws of physics. fair enough, you've told me, what do I know. i specify and run-up chargers and turbos on engines as part of my day job, every day. but i think it's time for me to quit, as everything i've ever learnt is obviously wrong. maybe you should patent your knowledge and sell it to every OEM so that they can put these wonderful chargers on their engines, because obviously if they knew about them already, they'd have put them on every engine they produce.

i DID say your charger was more efficient due to it's design, but it does require a hihger rotational speed to do this. The power taken from the crank to do this increases and therefore you have a greater load placed on the engine. Just because you don't feel the lag and it's not as pronounced as a turbo, doesn't mean it isn't there. You probably keep it spinning fairly fast so generally OK but there would be times when a NA engine would have a better pick-up. yes, it is faster to pick-up than a turbo but not as quick as NA.

and where did those boost figures come from - Noddy's 1st book of engine design? I'd love to see a turbo that boosted like that. the fact you're even comparing them such shows your ignorance and lack of understanding.

you still don't seem able to grasp the charger is taking power from the crank. my comment about the 9v battery and motor was merely to illustrate this. until you do, don't even bother post your imbecile comments on here cos i'll make you look like the idiot you obviously are

tt

 

Rob gets todays phat vr6 award for the best Meldrew impression

don't even try and argue with him on this mate, you in the deepwater now

 

and sinking!

trendy that has to be the funniest thing i have read all day-i'm off down the pub! where figures count-the female variety!

 

tt - I'm here to learn - like everyone else. If something I've said is wrong - then I concede - but:

please point out where I said or implied this?

I dont think this - you are wrong in saying that I said or implied this. I even said that the Turbo would be better - twice I think??

I can clearly see with SC is driven via the crank, so its taking it power from there. I also understand that it takes more power the fast it goes. So what is it that you are saying I'm wrong on?

but I clearly said it in my post?

Those boost figures were for illustration only, which I also said in the post at the time.

So at the end of this, I dont see what the problem is? We seem to agree on the principles of how all 3 of these charger systems work, yet you seem to think I dont... which I believe is because you are mis-reading my posts maybe?

Instead of just putting a blanket over the whole post and saying its all rubbish, tell me whats wrong then I (and others) can learn.

Right?

Jules
Edited by: jcorallo

 

[asking question with head ducked].....

This is facinating stuff but am I right in saying that the SC option is cheaper as its a bolt on affair? I ask because an extra 80bhp (SC) with the other mods I have or plan may be plenty for a FWD golf (ie. I dont want to brag about 350bhp turbo if I cant get this power / torque down if you see what I mean).

 

350bhp is great when you can get the power down, I have enough trouble with Traction as it is.

 

TT, you're wasting you're breath.....they've spent 1000's on their beloved chargers, and will defend them to the death regardless of the laws of physics, just leave it and be happy with the thought that you know better.

 

I gotta agree with this.

 

i really can't be ar5ed to argue anymore to be honest. i'd rather keep my views to myself in future as i can't be bothered with the hassle and haven't got the time for this
tt