Dax Clearance Question

[BenBaron]

Hello all,
Just to carry on the conversation about turbocharging a Rv8 3.5. I have been talkng to the bloke at boost performance and I need a few measurements as I am only at the engine rebuild stage of my project (doh).
If some lovely person with a RV8 and a DAX could measure the clearance horizontally from the rocker covers to the chasis rails or bulkheads (or whatever comes inbetween). I need two measurements from the front of the heads and from the back.
Presuming of course that both sides of the engine are eually spaced from obstructions.
Also if possible the bloke would like a piccy of the engine bay at a birds eye view.

Sounds like a bit of fun to do it, although Im gonna need a holley/webber conversion first.(doh)

Thanx in advance


Ben

[Philip]

Hi Ben,
Ive just checked the measurments and thers 230mm from the rear side of the rocker cover to the nearest panel(which is were the clutch master cylinder sits) and there is about 260mm between the rockercover, at the front, and the brake master cylinder. Theres also about 230mm minimum clearance for the height of this area between bonet line and footwell panel. Ive got a foto somewhere ill dig it up and put it on this thread if no one else does before me. Im very interested to put a supercharger on mine over the coming winter, but im finding it difficult to find any information on the web. I dont want to start ringing round yet untill I know I have the cash. Why are you going for a turbo instead?
Phil

[interestedparty]

Starting a discussion about the pros and cons of supercharging versus turbocharging would be to open a can of very wriggly worms indeed. I prefer turbos personally as I like the way they sense driver demand, it's only when you want the extra power that you get it (eventually) whereas superchargers are on all the time.
John

[robert]

>whereas superchargers are on all the time.
>John

Unless you run a manifold vacuum boost regulator, which is how I can get 20 plus MPG on a motorway cruise, and I get no lag either.

Admittedly, the blower is constantly leaching power from the engine, however the addition 1 psi of boost more than compensates.

Can opened. :7 :7

Robert
Forum Admin

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[Philip]

Im no expert at all on this subject, but from what I gather a super blower will sap a little power from the engine but it will return it and more through out the entire rev range. Surly this has got to be better than having something that comes in at high revs like a turbo??
:7 :7

[interestedparty]

Actually, superchargers are less efficient than turbos in a mechanical sense because the energy to run them comes for the crankshaft, whereas turbos are driven by heat energy that would otherwise go down the exhaust pipe. Also the rpm at which turbos take effect can be varied by careful selection of the compressor size, small ones take effect lower down the rev range, have less lag but ultimately run out of boost earlier. Big ones do the opposite, more lag, less boost at low rpm, but lots of fun when you wind it up. Careful sizing will produce an effect somewhere between these two.
John

[Philip]

Like I said, Im no expert. Would a supercharger be more reliable than a turbo, due to it not being exposed to as much heat, and also to retro fit a supercharger looks easier than a turbo, purely because your not messing about with exhaust manifolds?

Another point is a SUPER CHARGER sounds better, when talking to your mates down the pub, than a Turbo. Turbos are something Deisels have}> }>

[interestedparty]

I think both types of device are very reliable if installed correctly. Turbos need some room to mount on their (ideally) custom made manifolds. Superchargers also need room, and need to have their nose pulley in line with the (probably extended)crankshaft pulley. Which type is easiest to install will depend on a variety of factors.
Superchargers are used by Jaguar and Mercedes etc and turbochargers are used by Porsche, Ferrari, Subaru etc so not much in it from the name association thing.
John

[robert]

John

There is also the heat issues to contend with in a turbo application.

Robert
Forum Admin

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[interestedparty]

Yes indeed there is heat to deal with in the turbo installation. However, as long as there is some space around the turbo then the technology is out there to provide adequate insulation to the surroundings. Also, the heat is less of a problem than one might think as it is only present in large quantities when the turbo is producing full boost, when the car will be moving quickly enough to provide good cooling airflow.
John