ShopTalk Forums | Aircooled VW Tech & Restoration Help

My question is which is better turbo (which takes time to spool up depending on intake pressure) or supercharger (also refered to as a blower, which is in direct proportion to r.p.m.'s)? I've seen twin blowers on both Ghia's and Beetle's, but both were completly drag cars, at Houston Raceway Park at a show I went to a couple of years ago. And the Ghia beat the Beetle, both went in excess of 120 mph and under 10 sec's...WOW! So which one is more "streetable"?

------------------
it's not a car...
it's a cult!!!

Turbos definitely seem more popular. Maybe they are easier to do?

Having built both types of forced induction engines......I can say that only mechanical numbskulls assemble supercharged engines.....turbo is the only way to fly for a high revvin 4 cylinder...leave the blowers to the guys with 50% volumetric efficiency, and their 8 cylinder iron sled slugs>>>>>

Both have their place. Most drag racing V8s feature superchargers because that's where they excel... high speed runs where every hundredth of a second counts. Even then, there are a number of turbo cars out there that are putting the blown cars to shame.

Turbos, however, build more power. Just imagine 1,500 bhp out of a Formula 1 90 cid motor.

Turbos also produce more "economical" power vs superchargers. There's a reason why factory turbo cars out number factory blown cars by a huge margin. On one hand you have the Grand National, Porsche 911 Turbo, and Omni GLHS. On the other you have the Thunderbird Super Coupe, Toyota MR-2 (supercharged), and the Buick Regal (supercharged). Sadly, all three of these supercharged cars are considered flops.

Turbo's are almost free power. They run off the exhaust pipe, you only worry about heat and resticted exhaust. Blowers need a belt to drive them, this takes HP away from the motor, so you need more power to get power. This is what I've been told by guys who've been there.

Definately turbo for a four cyl dude, you can control turbo lag by reducing the boost anyway, plus it's not like you'd run high PSI on the street and street gas for that matter!

Also, just to remind everyone, the newer generation MR-2's are now turbocharged, as opposed to supercharged.

Is there any online sites selling turbo kits for bugs? Coming from a turbo DSM, buying my beetle last friday, I'm feeling the need for boost again.

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by eyeVee:
Is there any online sites selling turbo kits for bugs? Coming from a turbo DSM, buying my beetle last friday, I'm feeling the need for boost again.<HR></BLOCKQUOTE>

Yes there are. CB Performance makes a few (both draw-thru and blow-thru), but they are all EFI kits-- with really dumb computers.

Turbo City sells both style kits as well.

KRE (Kawell Racing Engines) sells full-on race draw-thru systems.

Fischer Engineering II can also fix you up with a modified CB blow-thru EFI system.

Another advantage of turbo is that you will not lose power as quickly at altitude, the wastegate will get used less and less as you climb

------------------
'79 SB Convertible, Front disc brakes, all braided stainless steel brake lines, sport springs, Polyurethane bushings, KYB all four corners

The only problem I see with turbo's is routing the exhaust in a VW.On inline motor's this is easy as the exhaust is all on the same side.

Has anyone tried a centrifugal supercharger?I am thinking of going down this way as although you do lose power driving the pulley, you should recoup this power in the effiency of the impellor over a roots type supercharger.

The amount of boost available in the paperwork I have seen is the same amount as turbocharging.

It is basically a belt driven - turbo impeller. There are a number of makes on the market, Rotrex(Danish), Vortex(USA?) and Powerdyne(Australia).

Two other advantages is the size, smaller than turbo(about a third smaller) and the reduced total weight involved.

we are already building a test model; I'll keep you posted. BTW, centrifugal superchargers cost a LOT more than a turbo, like 3X as much.

John,
The quotes I have requested suggest that overall total cost is little less with the centifugal superchargers. The cost of the unit may be more but less required in the installation. eg exhaust work.

each have advantages and disadvantages, but turbo is cheaper.

Hi Don
You described the essential differences between turbo and superchargers with how your behaves between the two setups. You may have got a lot more bottom end with a more suitable cam than a K8 with your turbo setup.

I looked at your page but some of your photos didn't load.

Regards Steve C

Hi Don
Did you use an intercooler?. Pauter make some nice split duration turbo cams. Some good reading http://www.clubvw.org.au/illawara.htm http://www.clubvw.org.au/leigh_harris.htm http://www.autospeed.com/A_0084/article.html read the part about water-air intercooling, its more suited to VWs and what I will be using.
Regards Steve C