Tuesday, May 24, 2016

Giving Scarlett more breathing room

Back in January of this year, I had installed the Raceway Two-into-One exhaust headers onto Scarlett, my 2014 URAL Patrol Sidecar rig.  I had elected at that time to keep the right-side stock muffler and use it.

I'd had no real issues with the stock muffler but recent rides convinced me perhaps I was "stifling" Scarlett in terms of her ability to push exhaust gases out of the engine.

Scarlett's recent trip to the vicinity of Provo, Utah and back had revealed a rather severe lack of top end power when negotiating hilly portions of highway.  Her MPG ratings had plummeted as well since I'd had get gearbox rebuilt by URAL but I'd blamed that on the use of the OR1.02 EFI mapping which was known to be "rich".

So, I ordered some exhaust pipe reducers and they all finished arriving today.  Took me a while to remove the remaining stock muffler from Scarlett but with just minimal cursing, it came off.

I had, originally, cut a portion of the header pipe that came from Raceway to accommodate the length of the stock muffler.  Using the new adapters, I added back the length and it worked out just perfect to line up the Harley-Davidson Sportster muffler that fellow Uralista Darrell had given me prior to all this.

 The installed adapters/reducers.  Took three of them to get the right
fit for the muffler and the header pipe extension.  I'll be adding one more 
clamp I think, forward of the one you see above.

If you look closely, you can see I was able to reuse the bracket that was
used by the stock muffler's circular holder.  Lucky.

Took Scarlett out for a test drive, she sounds a bit louder than normal of course with the HD muffler but not annoyingly or obnoxiously so.  I drove her to the local toll road and warmed her up.  The first run through was a bit dismal, no power going uphill and thereby no real acceleration.  This first run, I used the stock speedometer to gauge speed and it was not giving me the readings I wanted.

Decided to mount the Garmin Nuvi GPS that I'd received from SonjaM back in 2013.  

Did another run of the same test course and this time, she ran much stronger.  It's like the EFI computer adjusted for the newer freer-flowing conditions provided by the Sportster muffler and rendered better performance?  Not sure.

Using the GPS, I was certain this time (as opposed to the highly inaccurate speedo from Ural) that I was holding steady speeds of 60 MPH.  This second run, she did both uphill portions just fine, holding 55-50 MPH, in fourth gear, with no struggling though I was at WOT.  (Wide Open Throttle).

So, satisfied with the initial test run, I filled up her tank (25.5 MPG) and we'll see how the new muffler affects the next tankful's MPG results.

On a further positive note, no backfiring from exhaust leaks when decelerating using engine braking.

More to follow.  Perhaps I've become spoiled with Fiona's more powerful engine, but if Scarlett can once again hold 55 MPH while going up hills on the highway, I'll be happy.  After all, I've learned to not exceed 55 MPH on the slabs if I want any kind of decent MPG.

If future tankfuls of gas render same dismal MPG ratings, then I'll have to again explore going back to the OR1.01 EFI Mapping or failing that, putting Scarlett back to using the stock mufflers.

6 comments:

RichardM said...

I imagine that it would take a short time for the EFI to adapt to the new muffler. I'm not sure how restrictive the stock system is but I though that people had to redo the jetting when installing new mufflers. Is Daryl seeing the same mileage?

I've been considering the 2 into 1 manifold as well since I've ended up floating on the stock mufflers a couple of times.

Vincent Santamaria said...

The MPG on my 2015 cT suffered a bit with the new map but still is decent at 38 to 42 MPG although I do not ride her hard. I have the cats in place and am running Moptop mufflers. I can pull my test hill in the mountains in fourth gear with ability to accelerate a bit where my 2012 Yamal would require a downshift.
I would not consider going back to the previous map.
Enjoy your blog.

Charlie6 said...

RichardM, that's what I am thinking as well re the EFI adapting since the second test run over same route was much better. First run, she felt like the air filter was clogged. Darrell's mileage did suffer but his averages are in the low to mid 30s, not low to mid 20s like Scarlett before the new muffler.

The ground clearance you gain from losing the port muffler is outstanding.

Vincent Santamaria, thanks for the feedback on your rig. We'll see how it all works out.

SonjaM said...

The GPS is still alive and working? This thing must be ten years old or older, that's way beyond a normal lifespan of such a gadget ;-) you must have treated it very well.

Charlie6 said...

SonjaM, its been acting up a bit lately, I think it's finally on its inevitable downward spiral towards electronic death. Still, it's been a faithful guide since you and Roland gifted it to me, thanks again.

CCjon said...

On Darrell's recommendation, I did the same mod, switching to HD mufflers. Better ground clearance, easier rear tire removal and sounds better too. Did not have the EFI mapping issues, but did reject the carbs.

Sounds like the 2 in 1 is working great for you.