I set one of the FD sleeves I bought from Rotary Works in the exhaust port of one of my 20b housings and realized the bottom of the sleeve sits above the stock unported exhaust port. I thought maybe the sleeve was bad so I compared it to an FD housing and the sleeve seems correct. However, what is different is the exhaust port points down. Have you guys ran your sleeve like this or bent the sleeve? I'm worried bending it will create undesirable turbulence in the exhaust port. Any input would be appreciated.



thewird

 

The rotary works sleeve works best if porting up not down. The more you port down the more the sleeve will show... In order to fix and have a smooth transition, is to fill/welding / machine and grind smooth the TI exhaust sleeve. Like so in the pic..

 

Humm Interesting

 

I guess my concern is if having the sleeve exposed like that will cause the sleeve to melt over time? I wasn't planning to port down much. You can see the trace in the picture if you look closely. I was planning to port up quite a bit though so I guess it works out. Who needs torque right . Do you think it will be ok in circuit conditions?

thewird

 

It's not that there is anything different with the RW sleeve. I've noticed the same thing when using a stock FD sleeve in the 20B housings. Pushing the opening edge of the port down won't help the situation. The 20B casting is just different than the 13B stuff.

 

Any sharp edge will get hot in the way for sure. You will be fine as Titanium melts at 3000 degrees.

A smooth transition is better than any turbulence. Just run it, if it bothers you than the pics i posted
will guide you ...

 

I had noidea the melting point of titanium was that high. I'll run it as is. Thanks.

thewird

 

What you think? Port isn't finished but that's roughly what I'm planning to do shape wise. You can see the black spot that I didn't touch as it points down.



thewird

 

I wonder if you could heat the Ti sleeve and bend the lower leading edge down.

I say this because I had an experience with Ti that showed me that although it has a high melting point it gets malleable at a very low heat.

One auto-x I hit a cone with the tip of my Ti exhaust and it put a BIG flat spot on the tip.

I beat on it for about half an hour with a ballpeen and wasn't getting anywhere, it kept springing back (I have some experience shaping sheetmetal).

The idea struck me that when I hit the cone the exhaust was hot, heated the tip gently with a propane torch and shaped the tip back round very easily and quickly.

I am sure various Ti alloys will behave differently with heat as the pure Ti I have worked is quite malleable at room temperature and this exhaust very resilient until heated.

Check with the manufacturer.

 

what would happen if you remove the sleeve altogether? What are the benefits/drawbacks?

 

You have a drop in velocity and EGTs, more heat transfer to housing and the sonic component of the exhaust wave is reflected back into the port without refraction.

That isn't to say removing the sleeve is never useful.

If you are working with a much larger timing (up and down) than the sleeve allows you remove the sleeve instead of tapering the face to the sleeve diameter. This will be a high rpm NA with tuned long primary exhaust so the sonic reflection can actually tuned to your advantage.

In general- bad idea.

 

Is swapping the exhaust sleeve even necessary for power outputs of 400-500?

 

Would probably be fine. Just make sure your goal is actually 400-500. If there is any chance you might change your mind later, just change the damn sleeve. It flows better.

On a side note, I'll be pulling my motor apart this winter to see how it fared through the season and I suspect a have a coolant seal thats starting to go from running the motor so hot all season.

thewird

 

Totally understood, i wont want to go much higher than that since the motor is an early B series and i am using OEM bolts. I wanted to keep the ports stock. Thanks for the info!