I have looked and have not found any dyno sheets for a 20B N/A peripheral port. I know they would be hard to come by so I thought I would ask if anyone here has seen one and if they would be willing to post it. I have a 20B peripheral port N/A engine being built for my Porsche 914 and I was hoping see what the power curve of the engine would look like. It would be nice to know where the powerband is for gear selection on the transmission. Can anyone help?

 

Your gear selection for you transmission should be based on your actual motor dyno. Every PP motor is different mainly due to porting and configuration. Probably if you give some details of your setup we'll be better able to give you a ballpark. Also what is this vechicle intended use? Street, road race, drag etc. All of that makes a difference for gear selection .

 

I'm building the car primarily for use on the road course in a local GT series. The transmission is a 5 speed Porsche 915 gearbox with the ring and pinion flipped and converted to side shifter. The wheels and tires are as follows: Kinesis 17x12's in the back (315/35) and 17x10's in the front (285/40).

I was hoping to see what the power curve on a 3 rotor PP looked like to get a general idea of where power is made. I have a Haltech E-11 and the Tweak-it independant 55mm throttle bodies. I'll probably use 550 cc primary and 1600 cc secondary injectors. Spark plugs to be determined. The rotors are series 5 NA.

My thoughts are that the engine will produce linear power and a flat torque curve. What is your experience with these engines?

 

You'll be fine with 6 X 720 or 850cc injectors. The 55mm do kill some power/torque below 8K rpm but with a 3-rotor it should be just fine. Depending on intake length the 55mm normaly peaks power in the 9.5 to 10.5k rpm on a 13B. For a 20B you should keep intake length longer to have a much broader rpm, power and torque band and to also limit redline rpm. With the right length power will peak around 8.5 to 9k rpm and will make for a very quick and fun car to drive. Only testing will determine proper intake length. That also goes for exhaust header length too.
You should contact Carlos Lopez from CLR as he have done many 3-rotor PP combinations. I believe he's GT1-20b here on the forum.

 

Here's a shot of the car the engine is going in. Currently it weighs 1400 lbs without an engine.

 

Thanks for the info. I was speaking to Carlos last year about 3 rotor engines but haven't talked with him for some time. What do you think the power potential of a 3 rotor peripheral port is (hp/torque over rpm)?

 

Picture of the throttle bodies:

 

Haha, those are the exact same ones I used last year! Very nice products, you'll like them alot.

 

Just wanted to let you know that your project is very, very nice and extremely inspiring me to do the whole 20b swap. And N/A to be exact...good luck, man! Looks awsome.