.551 Cams in an EFI 1200

[sprink]

Interesting. I had never seen the disc setup sold as an add on.

[Tomcatt]

Originally Posted by sprink

Interesting. I had never seen the disc setup sold as an add on.

That's the 2 1/2" inlet version, there's also a 2" inlet version #444-2003, plus 3" & 5" disc versions. Kinda handy. I trim them to get the fit right and weld them onto existing baffles. Sound reduction without hurting performance.

[Tomcatt]

Thought I'd link my suspension set-up to keep this consolidated:
Post: http://xlforum.net/forums/showpost.p...0&postcount=10
Thread: http://xlforum.net/forums/showthread...80#post5752180

[Tomcatt]

Parts all accumulated, just waiting for warm enough weather to do the Bassani mods and install along with the Target Tune install. I did get a couple warm days so the exhaust system is off. Looking into the exhaust ports everything looks perfect. Just a very even light dusting of carbon in the SE heads exhaust ports.

[Tomcatt]

I've had some warm weather to get out in the garage and fab the Bassani / SuperTrapp baffle mod . Pics attached.

I also mocked up the headpipes install to check wideband O2 clearances. They clear, just... Rear O2 appears to need to be installed in its' headpipe before installing the exhaust. Front goes in after the exhaust is in place. Headpipes and collector are a one piece assy.

I'll have more when I get new exhaust gaskets installed and the exhaust in place.

Pics are Bassani baffle and adapter with stainless nuts welded in place, baffle with adapter set in place before welding and then completed assy.

[sprink]

Looks good.

[sportsterpaul]

Tom, you running the open cap or closed cap?

[Tomcatt]

Originally Posted by sportsterpaul

Tom, you running the open cap or closed cap?

Right now it's assembled with 20 discs and a closed end cap. I don't like hanging more discs than that out on the end. After I get it together and running and get some VE's established in Target Tune I'll play with the open end cap and the number of discs. Best performance with an acceptable noise level.

[Tomcatt]

Progress.
Exhaust is installed. I went with 15 discs and a closed end cap to start with. No heat shields installed. Now I'm dealing with Target Tunes' BIG connectors and LONG wires getting it all routed. I want to get it up and running and clean up the wiring later.

[Tomcatt]

This is going well. Sometimes I make choices that work out well.

Sometimes I don't... 15 discs with a closed end cap didn't work very well. It wasn't a happy motor with this combo. VE's indicated two torque peaks with a dip in between like Hammers SuperTrapp exhaust dyno tests showed. Plus it wasn't happy at part throttle. So, I tried 18 discs and an open end cap. Why 18? It works out well using the 1 3/4" bolts I had for the disc pack.

The engine likes the Bassanni/SuperTrapp modded exhaust. I've more work to do tuning but I have good VE's from 3,000 to 7,000 rpm and it runs nice. Except at 2,500 rpm anyway. There's a definite hole at 2,500. The VE's sink... It would be a big deal with a carb (reversion) but EFI handles it pretty well leaving what mostly feels like a rough spot. Runs good above and below.

I wish I'd gone Target Tune with wideband O2's sooner. I wasted a bunch of time (1 1/2 yrs?) trying to (auto) tune with narrowbands. Even Target Tune can be fooled and require some manual help with VE's (fuel "stealing" between cylinders?) but it's head and shoulders above what I was seeing using basic auto tune. The lower rpm "buck and lurch" I could never tune out before is gone.

Last autotune session gave 54 mpg with a 28T front belt sprocket. Need to work on cruise AFR's and timing to try and improve that.