I'm just starting the research phase for my next engine and was wondering if anyone had ever taken the slightly odd move of building a single rotor turbo?

Let me explain.... I currently run a pre-85 13B 4-port in a lotus 7 replica. Car weighs around 1200lbs so a little HP goes a long way. However there is considerable room for weight saving all the way around and I'm aiming to try and get closer to 1000 over time. One of the areas to slim down is the engine. Whilst considering going for ally side plates I thought it was worth doing the sums to see where I could go bang for buck with the single rotor concept, especially as no-one seems to have turbo'd one before.

In terms of spec I'd be satisfied with 220 FWHP very happy with 250 and delirious if I could get more.

Any thoughts?

Bill

 

stick with ur 2 rotor... there is a reason u dont see 1 rotor engines.. cause they run very rough... if the run at all.. u will have huge problems tryin to run a single rotor.... imho

 

One rotor engines work fine. Paul Yaw has a few pictures of a 1 rotor he built on his website. Without turbo it does 100 hp with a carb. You'll probably find that it is more expensive to build a 1 rotor since you need to have an eccentric shaft machined, and get all of the other neccesary little things made (shorter engine bolts, smaller oil pan, etc.).

 

The eccentric is about $1k. It'll be dry sumped so needs a custom pan anyway. (NB dry sump is just to get the weight lower in the car).

 

Hey,
http://www.atkinsrotary.com/onerotor.htm
$6000 NA W/carb

 

My dad raced his Lotus 7 back in the day .

How about a stock TII hybrid turbo for size on a 1 rotor? That could be a short turbo manifold Or if you have the $$ for alloy sideplates maybe a VATN turbo would be good to help recover the loss of torque from dropping a rotor by spooling so fast.

One of my dream cars would be a turbo P-port 1 rotor in a Fiat 500!

I have a 1300lb Honda N600GT, so I know you don't need ANY hp to get a light car off the line...not that the N600 is fast.

 

the weight balance in that car would be awesome with a 1 rotor

 

When I visited Pettit racing a few years back Cam showed me his personal single rotor turbo car. It was so cool.

Cam is definetly a dog lover.

 

That's good news, I'll drop pettit a line and see what they are willing to give out on the info front.

Regarding the turbo, I would seriously love to run an aerocharger, but I have yet to see one that doesn't get horribly inefficient above about 14 PSI which may be low on the boost for the power I am after.

 

Hey Bill,
If the primary reason you're looking at a 1-rotor is to reduce weight, consider that you'll be adding a fair bit for the turbo hardware. Does anyone have an idea about the comparitive weights of an NA 13B vs a 1-rotor and the necessary turbo hardware? I'm thinking it might be more practical to explore the power limits in NA trim.
Of course, there IS a very large appeal in the uniqueness of this proposed project, so if you want to do it anyway, I say go for it!

 

I was at Pettit last summer for a dyno day and there was a 1 rotor SA there....made 100hp or so. Not sure if it was Cam's or what but they should know all about it.

 

Good question on the weight. The information I have (which is sketchy) suggests that a single rotor engine is 75 pounds lighter than a twin.

Provided you are not using cast manifolds the sort of turbo I need shouldn't eat too much of that. But it needs careful budgeting.

But there is a lot of 'because I can' in this :-)

Bill