I would say to go with the 257 cam instead of the 253 and raise the compression, but knowing that most dealerships simply drop in the canned map, you aren't going to be tuned correctly when it comes out of the shop as they have no download for the 257 as far as I know. Not that it would be tuned right anyway with the lean fuel and half-assed timing in the HD download. With the injection the key to any build is to get someone that knows how to get it on the dyno and get it optimized. The 103 that comes out of the factory is a dog, but the combo has the potential to be a real nice runner. We use the Andrews 67 cam (a direct cousin of the 257), ported heads from a couple of different sources and around 10.2 compression and get around 116-120 on the TQ and about 110 - 114 on the HP depending on the pipes.brwk said:
GRock, do you have a short (or long, for that matter) primer for timing w/ the SERT?GRock said:
). He's doing a little on his own, and learning that way, but it's a slow process, and he's got my bike at the moment for a retune with the Samson Rolled Thunder mufflers anyway. I hate to see him alone in the wilderness on this if there is any sage wisdom you could share with him.Do you mean how to tune timing because he is not sure how to do it with the SERT, or what to do with timing in general?? Timing is really something that comes with experience and knowing the potential for certain combinations of parts. Engine dynamics has so much to do with timing, and understanding where flow is ahead of the slope or lagging behind with regard to cam timing is very important. In other words, where a late closing valve may have a detrimental effect on low end power, it really is an asset in high rpm as now flow is lagging behind a bit and the late closing intake allows more time for a higher pressure cylinder fill. To time for this event at both ends you have to understand flow dynamics. It is really not an easy thing to teach by writing about it. It takes hands on with a bike in front of you getting comparison readings for different parameters of the tune. And many guys get too involved in timing on street bikes. Many times we will simply adjust timing to allow a cooler, smoother running engine for the mid and lower range. And give a general advance to the upper end to take advantage of whatever valve timing there is. If you get that accomplished, don't drive yourselves too crazy trying to milk timing for a pound or two of TQ and a couple of ponies. Too many guys try to maximize power and end up with rough running and hot engines.MegaGlide said:GRock, do you have a short (or long, for that matter) primer for timing w/ the SERT?
My tuner was trained by Doc, and is one of the sharpest techs I've come across, despite his only being 21 yrs old. He is always willing to work with me on issues, and wants to learn. He gets the fuel dialed right in and his mechanical work is top drawer. Only problem is, there is no place for him to learn timing w/ this thing. Certainly not from the MoCo (whose lack of available info on the SERT I got to blast pretty good in a phone survey this afternoon...
You know I'd be at your place for my tune if it was at all possible, but it isn't.
And like I said, he's a good kid.
Thanks in Advance,
