Rotax 912 UL exhaust

[Jetman]

I'm in the process of purchacing a Rotax 912 UL(80hp) engine. I need to customise the exhaust pipes to fit the specific trike. The exhaust must look like these in photo attatched. Question : a)Is it possible to make these changes without affecting the performance of the engine b) If so, who can do it for me.?

At this moment the exhaust pipes are longer, but I want to change it to the lengths of the pipes in photo attatched.

Thanks
Skin

[Morph]

Install the motor in the trike, take the wing off, take the trike to an exhaust place. I used Cowley

[Jetman]

Is it that simple?. Do the lengths of the pipes effect any performance??

Skin

[Morph]

A 4 stroke is different to a 2 stroke. 2 Stroke engines need a tuned exhaust.

Are you buying the exhaust from Comet? They will ship you a silencer, some circular doughnuts and some straight pieces. The exhaust guys cut and match to get it to fit. Any performance exhaust place will be able to do it for you. I literally installed by engine on it's engine mount and took the whole lot to Cowley. I told them what clearences I needed and viola a perfect installation. Remember the exhaust headers get to 800degC make sure they stay clear of any plastic, water or oil pipes and wiring.

[ystervark7]

Hi Skin

On a 2 stroke the length is critical as mentioned. On a 4 stroke it is less of an issue but it will change your performance. Normally the peak torque is shifted up or down in the rev range. The volumetric efficiency (VE) is also changed. The implication of the shifting of the VE is that the fuel at the different rev ranges should be changed. In the case of a 912 it is designed to run rich so you will probably be OK if the change is not radical. Keep a careful eye on your EGT's after the change because if it is to lean it will overheat ....
It might influence your fuel consumption so it will be interesting to let us know how much difference it makes. I would also be very interested to know the difference between the EGT's of the front and the back cylinders. If other 912 owners know the difference on their front and back EGT's please post it for comparison. (I am busy experimenting with a 912 fuel injection and the difference between the front and the back is about 100 C which is way out to much)

[Massimo]

Skin i agree with Morph install the engine and then take it to the pro's. I used Wild Cat in Meadowdale. They are up the road from Aviation Engines old spot. They are very helpful and have done a few aircraft exhausts already and a very professional job. I cant seem to find their details though.

[Jetman]

Thanks Massimo, Morph and others. Will do so!!!

Cheers Skin

[dono]

Mornng Hendrik

Here are the contact details for WildCat performance exhausts:

55 Activia Rd
Activia Park
Elandsfontein
Tel: 011 822 2400

Pass the road you would turn left, to go to, Comet Aviation and carry on up the hill. You would then turn right into Activia Rd and WildCat are on the left.

Donovan

[Rudix]

Interesting subject!

Does anyone know of someone who would come out to the flying field to do the measuring and build of the exhaust system? Taking the plane (Savannah) to them is not really an option and the exhaust pipes are not direct so it would be difficult to do a drawing.

I have been told the Van der Graaf will do that? (At a price) I am just not sure who to talk to.

Regards,
Rudi

[Massimo]

Rudi i battled for months with the eaxct same problem. I could not just put my 701 with wings onto a trailer. The only guys that were willing to help out were the guys from Wildcat. I had to beg and plead a bit but eventually they came out to the factory on a saturday and made up the exhaust system. Then they took it back and welded it all back together. I then fitted it after that. You will need a welding machine on site though and make sure they bring all the necessary bends, pipes and flanges. Otherwise get yourself a car trailer and take it to them.

[Rudix]

Rudi i battled for months with the eaxct same problem. I could not just put my 701 with wings onto a trailer. The only guys that were willing to help out were the guys from Wildcat. I had to beg and plead a bit but eventually they came out to the factory on a saturday and made up the exhaust system. Then they took it back and welded it all back together. I then fitted it after that. You will need a welding machine on site though and make sure they bring all the necessary bends, pipes and flanges. Otherwise get yourself a car trailer and take it to them.

Thanks Massimo!

I will see if I can convince them, I do not like the idea of taking the wings off and taking the body to them, way to much risk of damage.

We do have a full workshop with welding (TIG) facilities.

Regards,
Rudi

[Stephan van Tonder]

Hendrik - you could also try this guy - Viper exhausts in Kempton Park. Abel is his name. 011 394 1895

[Boet]

I have a set available. Stainless steel. 082 8041896