Engine for circuit racing

[Tim]

I am debating with myself whether I should build a type 1 or a type 4 engine for circuit racing. Most information I can find from the web are for drag racing. To my knowledge, a type 1 is lighter (helps better weight distribution), higher rpm, more parts available, cheaper to build, while a type 4 is more low-end torque, more reliable but is heavier which weakens the already poor handling of a Beetle. My target is a 2000cc+, either a type 1 94mmx86mm or a type 4 96or102mmx86mm. Which is better suit for circuit racing?
Also, what cam, valve size, and c.r. I should use? The octane rate of the fuel is 97.
Thanks
Tim

[Massive Type IV]

TI engines are strong for drag racing, but thats the only area they are really proven to be beter than a TIV.

I would choose a TIV for any type of racing where continuous RPM are present, TIV engines are great for road racing.

The weight is not an issue, when going upright the weight difference might be as little as 27 pounds, using "Nickies" that number will be cut down to within 5 pounds, they are so light..

for high RPM apps you need bigger bore and less stroke, 71x102 is a great one, right now I'm douing a 69 (destroked) x 96 combo thats gonna be a screamer.

[Hermann Ortlepp]

Jake is right.
Use a big type 4. In South Africa there is a number of type4 powered sercuit racing beetles.With the right cooling the type4 is a very relyable engine. The type1 is also expensive to build ( to last ) in long distanse racing.
The low rpm torque of the type4 is very nice when racing on a tight track.

Hermann Ortlepp
Beetland
South Africa

[Tim]

Thanks for your professional advises. I think I've got my answer - a T4.
Tim

[Oliver Knuf]

Do you have any limitations for your circuit racing? We built for the German Kafercup even 64mm x 100mm Type 4's, or 75,9mm x 92mm or 78,4mm x 90,5mm or 72,6mm x 94mm, just to test different strokes for the 2l limitations! Please give more details to the race aspects, then you get more help of what to build!

[Tim]

The event is called "collectable car racing" which doesn't have any limitation on modifications as long as the engine is under 3000cc NA. The circuit is the one as shown in the attached picture. An average 1800cc race modified Honda Civic EF9 can do 2 min/lap in this 4.3km circuit.

[Oliver Knuf]

A very nice circuit with a lot of high rpm/high km/h parts, nothing for a Type 1, when racing over longer distances than 50km. It will get too hot. Maybe a good Type 4 with e.g. 96mm bore and 82mm or 84mm lift on the crank would be the thing to go, but vice versa a 78mm x 100mm/102mm/103mm would be also a real killer. I would choose some of the Type 1 style heads, that are available for the Type 4, together with a free exhaust system, around 2-2 1/4" a cam around 300° US, valves between 44mm/40mm to 48mm/40mm and carbs, maybe 48 IDF's to start with. Even the IDA's are race track approved and reach a much better power band than IDF's. Porsche cooling and a big front oil cooler is a must. More?

[Tim]

This is an ultimate choice. More will be the PFI with TWM throttle bodies and Electromotive distributorless ignition.