thought id ask you all about you opinions about induction. i am torn between turbo, nitrous and supercharger. they all have their upsides and they all have their downsides, maybe kicking off a debate on the forum will help me make a decision in which road to take.

im running a 1776 (will eventually go bigger but i wanna see how much i can get out of this motor 1st), for arguments sake, lets assume i already have a suitable bottom end, heads and will have a cam custom ground to suit any of the 3 choices, what are/have been your experiences and which would you choose and why.

turbo. more efficent than a supercharger and not illegal like nitrous.

get this book and have a read first... http://www.amazon.com/Turbochargers-HP49-Books-Spark-Ignition-Applications/dp...

obviously, efi/intercooled is better but drawthrough can be good too.

turbo would be better and more readily availalbe for VW applications

they all have there pros and cons as u say
ive never played with NOS and probably never will but after building turbo and supercharged vw engines i found heat was a biggest problem with the turbo
the bloke that has my turbo kit now setup an intercooler and is having a bit more luck than me but had to pull the CR down so far that its a dog off boost

I think a supercharger is more suited to a VW motor as it doesn't put such a high heat load into the exhaust ports like a turbo does. Hot exhaust ports will kill VW heads.

Porsche used a different head design on their early engines, with the exhaust valve kicked out on an angle to allow air flow between the intake and exhaust ports in the head. Then when they went turbo they used ceramic liners in the exhaust ports. VW's have none of those features.

Modern design superchargers (belt driven turbo style) are very efficient and not that far off turbos, but they cost big $$$$.

I'm no expert mate, but this is what I came up with:
I was going to try a draw through supercharger. When set up properly I think it would be a solid option. The toyota type blowers (which I was going to buy) are a positive displacement arrangement which basically means they push large volumes of air without compressing it (thus heatnig it) significantly. This really helps keep intake temps down. Drawbacks I read about were that many superchargers (the vane type) do not like to have fuel run through them and wear more quickly. Also boost is more limited but at least you have it on tap from idle. Not a great deal of fabrication required to set it up...ask Joel he did it!
I am intrigued by nitrous...is it illegal on the street? Boooo!
Finally I went with turbo efi. Reasons being that everything can be managed and controlled by a computer (ecu) and therefore if programmed correctly you will have precise control of fuel delivery, spark timing and boost for any given engine speed or load (and temperature!). I'm still setting my installation up. Obviously it is only as good as the tuning job. You should definitely also run an intercooler on an aircooled turbocharged engine. Heat is the enemy!! There are heaps of options available for efi depending on what you're after. Lowered compression ratio is a must. I use shims under the cylinders and "semi hemi" stock type 3 heads. My setup is mainly for torque and will be purely a daily driver. 12psig boost and hopefully 160hp should be achievable and be reliable. It's also a 1776 :-)
Centrifugal superchargers (basically a belt driven turbo) are just as Wes said. Efficient but they cost big $$$$!
I'm probably talking crap though...will be keeping an eye on this thread :-) Hope to learn more too!!

mmmm NOS, go nitrous you can make your fuel jet a bit bigger in the fogger to run on a safer side. you can have a well streetable engine on the street as you dont use NOS on the street but bigger power at the track.. thats my 2 cents. cheers

intercooled supercharger and EFI

supercharged it gives torque from start and dosn't ban on and load up the rods and such.i have build a supercharged 1641 and a 1600 the torque is fantastic .these ran with a 8 lb bost without causing any problems you could potter around with no worries,i used water cooling using the blowers own pressure so you only had water when you needed it and i also ran a trucks gearbox oil cooler with a 12 inch fan,this was more for oil capasity (the more oil the cooler the motor)
so whitch to go as i have used both and supercharging a simple and cost efective fit
good luck

why not go all 3 three :P

space out the barrels/heads and get urself a comp ratio of 6.5:1 and go nuts lol

I have had a vortech blower on a commodore motor and after a friend built a turbo one there was no comparison. I would turbo everytime. My vortech was running twice the boost for the same result. This is double stress on components. Sure mine would get off the line harder but once his spooled there was no catching him.

The only way to do this is setup 3 exact motors and see which is best eg. reliable, useable power and outright hp.
Any volenteers?

T54

if you welded water jackets round your heads you might be better off with the heat issue. i've seen it done on a few cars now.

My friend had a Sprinter with a 4AGZE. Had a 12lb boost pulley on it (I think). It went pretty hard, really grunted away at almost any rpm.

He then took the supercharger off and put a turbo on. Sure it had more HP and was ultimately faster, but only when the revs were high. It had lost the low end grunt and strong feeling that the supercharger gave.

Look at what VW do. In the 1980s, they chose to fit a supercharger - the VW 'G-lader' - to the Polo, Golf/Jetta and Passat, rather than a turbocharger. They also used a G-lader on the 'Polo Sprint', the one-off test vehicle fitted with a rear-mounted Wasserboxer flat four. The G-charger used orbiting spirals rather than rotating components.

The Mk4 and Mk5 GTIs got a turbo, but it's a high-revving performance engine.

For normal Golfs, VW now fits BOTH a supercharger (for low-down boost) AND a turbocharger (for high-up boost). This is the VW 'twin-charger' - the best of both worlds. It gives 2.0-litre performance from a 1.4-litre engine. A bit hard to adapt to a Beetle engine, though.

http://www.drive.com.au/Editorial/ArticleDetail.aspx?ArticleID=40001 

I'm struggling to see any advantage to nitrous. You have to keep refilling the bottle, + your mixtures are screwed up, + its illegal.

You must have too much money to waste if you're rebuilding and hotting up a temporary engine. If you're piulling an engine apart to replace a cam you should at least put 94's on. Grab a counterweighted crank and be done with it.

I wouldn't advise even contemplating forced induction without an intercooler. You're throwing horsepower out the window and adding unnecessary heat in the process.

Yeah, I can't see the point of nitrous. Where's the fun of it if you can't give it a squirt at every set of lights without having to refill something.

if it's not going to be registered do what ever,if your going to drive it on the street nitrous would be my choice you can have less of every thing cam compression head work fuel octane etc i would sugest your 1776 with a set of arp bolts and and exhaust and a non stock carb set up.Then have at it with the gas!Say it makes 60 to 90 hp at the wheels a well set up system is safe and you could end up with up to 180 hp at the flick of a switch,and you have got a car that is like jeckyl and hyde!As for it being illegal like i always say who are you a cop

I've driven a N/A, turbo and supercharged Fiat/Lancia twin cam and I would take the positive displacement supercharger every time. The supercharger is so much more flexible - the torque is always there.
Centrifugal superchargers are the worst of both worlds - lag at low speeds and the high power draw to spin them.

Quote:

Originally posted by coletrickle As for it being illegal like i always say who are you a cop

Quote:

Originally posted by volumex Quote: Originally posted by coletrickle As for it being illegal like i always say who are you a cop Problem isn't the cops, it is the insurance companies. If you smash into someone/something and you have nitrous - then insurance is not going to pay out. Having to live in squalor for the rest of your life to pay back what could be millions of $$$$ would not be pleasant. Don't think it will never happen to you, as it does happen.

dude i live in squalor nowThe point i was trying to make was that the speed limit is 110 max how much low end torque etc do you need the more power you have the more tempted you are to use it so a nice stockish engine that you can turn into a hot rod at off street events disconnect the bottle and drive on the street has got to be pretty hard to beat.For example i drove my brothers 73 dodge dart 440 10.1 650' solid cam pump gas etc to willowbank yesterday on street tyres thru the mufflers it ran 11.49 @119mph its got 500hp atw it's a horrible car to drive at the speed limmit its completly legal but the cops still pull it over to give you a grilling.I think i'm gonna have to ressurect my favorite engine of all time and gas it.

Quote:

Originally posted by T-34 Quote: Originally posted by volumex Quote: Originally posted by coletrickle As for it being illegal like i always say who are you a cop Problem isn't the cops, it is the insurance companies. If you smash into someone/something and you have nitrous - then insurance is not going to pay out. Having to live in squalor for the rest of your life to pay back what could be millions of $$$$ would not be pleasant. Don't think it will never happen to you, as it does happen. If you have nothing - they cannot take it from you

last to weeks total hrs worked 21 hrs might top 15 hrs this week not a lot to garnish thereand if i had to i recon i could live of grid doing cashies. Its not like i havent dissapeared before

for ease and the abundance of information available i'd go turbo.
My stock 1641 with little TO2, SU and 6.5:1 compression ran 14's in my fat '70 beetle and was on it's way into the 12's in the current car before it torched a piston.
It was street driven didn't get too hot and the only issue was sooty plugs with the low compression.

with that said i'm now looking at supercharging but this will be for Warwick next year. Current engine with same turbo setup but some new goodies will be fitted this weekend.

If you ever saw Dave Butlers supercharged VW drag car you'll know how awesome a supercharged flat 4 can sound.

This probably doesn't apply to modifying VW engines, but it's interesting anyway.

Unlike car engines, aircraft piston engine output is not determined by the engine capacity (ie bore/stroke). It is determined only by the mass of fuel/air mixture that can be consumed efficiently, which is controlled by the supercharger. So aircraft piston engine designers improve engines in this order:
1. Improve the supercharger
2. Improve the fuel (to delay the onset of detonation)
3. Develop mechanical features in the engine to take advantage of 1 and 2.

Rolls Royce did extensive development work on the 27-litre Merlin V12 during the war, with output being raised from 700 hp in 1939 to nearly 2,300 hp by 1945. This was achieved with two-stage, two-speed superchargers. These gave the Merlin the same power output as the much larger capacity (36-litre) V12 Griffon engine, with similar reliability, and much better performance than the 28-litre Allison V12 (which only had a single stage supercharger, or a turbo supercharger, depending on the aircraft).

This is a lecture about the Merlin, and its supercharger development, given by Rolls Royce engineer A.C. Lovesey in 1945:

http://www.wwiiaircraftperformance.org/merlin-lovesey.pdf 

blowers have that certain cool factor on a vw
but like andrew said turbos are just so much cheaper and easier to get hold of
was always good value at shows the people that thought my bug had A/C , people seem to think that supercharging a vw is impossible for some reason

Agree with Wes, im a boostjunky of any descrription so a turbo spooling sounds nuts but the whine of blower is hard to beat