Reply With QuoteThe compression ratio will not change, that is static set when the engine is built. But the back pressure in the exhaust system will. less or very little back pressure will mean that the ecm will have to be adjusted.
Does anyone think that my compression ratio will change much by taking the stock muffler off and run a 2.5" straight exhaust. Also will it hurt the motor by just running the header only.
The compression ratio will not change, that is static set when the engine is built. But the back pressure in the exhaust system will. less or very little back pressure will mean that the ecm will have to be adjusted.
how would I be able to do that with the stock one...and is that just for the header or will I have to after adding the pipe.
You would want to do it if you did a custom exhaust.
ECM Spy is what you need to do a TPS reset, so basically reset the ECM for the new pipe. The software is free to download and there are DIY threads on the forum to follow.
You do also need this cable to hook up to the bike.
ECM Cable $50
http://www.ecmspy.com/
Ok now ? what would happen if I dont do this...and can harley do this for me by chance instead of havin to order a cable?
Your bike will run better.
ok it will run better but any internal damage until I can get a cable
what exactly do I need to download from that site cause there is a lot of stuff on there
just go on ebay and buy the ecmspy cable it will come with a disk with the program on it.
your bike will still run ok without it but u will get a lot of back firing on decel and loose alot of low end power
oh ok but no harm done for now right thats all im wondering cause I got a lot of crap to get for it so it will be a couple weeks before I can get one.
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