# VW 1835cc vs 1915cc: Why is the 1835cc more popular?

Discussion in 'Volkswagen' started by Vigilant1, Nov 22, 2018.

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1. Nov 22, 2018

### Vigilant1

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When we talk about "small" VW aero engines (those with a 69mm stroke), I get the impression that most folks go for the 1835cc (92mm bore and 60HP) rather than the 1915cc (94mm bore and 65HP). Since the cost of the parts is the same, the weight is (virtually) the same, and boring the case for a 94mm cylinder is no more trouble than for a 92mm cylinder--why don't more folks take the "free" 5 extra HP? Scott Casler only charges $25 more for the 1915cc engine than the 1835--$5 per HP is a deal that is hard to beat!

I'm guessing that the relatively small amount of metal between the cylinders in the case and the heads with 94mm cylinders might be the reason folks prefer the 1835cc with its 92mm cylinders. Is it that, or is it something else/additional?

Thanks

Last edited: Nov 22, 2018
2. Nov 22, 2018

### Hot Wings

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The thin wall 92s don't make as much power as the 90.5s and the 94s don't make as much as the thick wall 92s. The thin walls just distort too much over time.

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3. Nov 22, 2018

### Pops

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Thanks for the answer. Like I always say, the 1835 cc VW engine is the "Most Bang for the Buck". Most HP, reliability, low cost, with the lightest weight for the money.

Weld and fill in the area at the flywheel end of the case behind #3 cylinder, bore for 94 mm pistons and jugs and then use the heavy wall 92 mm pistons and jugs.

https://www.appletreeauto.com/92-X-69-PISTON-KIT-THICK-WALL/

CB will weld, machine, etc for what you want at extra cost on a new case.
http://www.cbperformance.com/product-p/043-101-003.3.htm

Last edited: Nov 22, 2018
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4. Nov 22, 2018

### Vigilant1

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Thanks. So, I assume the same reasoning ("don't go above 92mm cylinders") would be the same for the engines of even longer stroke. That would mean avoiding the Revmaster R2300 (94mm bore x 84mm stroke) and the Hummel/Casler "2400cc" engines (94mm bore x 86mm stroke). 2180 cc would be as big as we go, then. Nobody seems to bother making kits or complete aero engines in 2234cc (92mm bore x 84mm stroke) or 2287cc (92mm bore x 86mm stroke). I guess there's not much point anyway. If we are limited by the ability to shed heat from the head to approx 75 HP, going larger than 2180ccs just let's you hit 75hp at slight lower rpm/higher torque.

5. Nov 22, 2018

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