Right off the top, I have no affiliation with Thunder Alley what so ever. I have been researching for a system for my bike that has a spark arrestor and would give me some more power. I talked with Bob today for about 25 minutes in regards to his pipe for the 450. He told me he does not do any dyno because he has no faith in them, they can put out whatever the individual conducting the dyno wants to have them say. His pipes are made from seat of the pants testing. He did say that from the individuals that have tested his pipes or purchased them that there is an increase in power all through the rpm range. He was perfectly honest as to say he couldn't tell me what kind of power increases there are as far (ie 8500 rpm = 47.6 hp). Basically it comes down to the fact that I agree with him, it all depends on who is doing the dyno. I have compared every system is listed in Feb Dirtrider and if you go strictly off of the dyno #'s the White Brothers "E" series is the best pipe for the 450. Every pipe in the test lost out to the stock sytem in aleast ten of the rpm ranges where the White Brothers only lost out to the stock in five of the rpm ranges and yet this system didn't even make it into there top picks
We also talked about the sound and he said that they had tested there pipe at 101db and here again it all depends on who is doing the test and how it is conducted. The Feb Dirtrider shows the stock system at 102db. I talked to promotobillet about their spark arrestor and quiet insert and they said that when they tested the stock system it came out at 96 or 97 db and with their quiet insert it came out at 94db. So here again is an example of who is doing the testing and how it was conducted.
When I told Bob that I wanted to keep the bike as quiet as possible because unfortunately sound is becoming and issue, he told me that in all actuality if you wanted the best performance and keep the exhaust note low to stay with the stock exhaust and purchase the spark arrestor and quiet core from promotobillet. Now as far as promotobillet goes I had seen a few post in here from them that they were going to do some testing to se what kind of power loss there would be with the quiet insert. They have not been able to conduct the test yet so couldn't tell me anything there though. They did tell me though that if I was not happy with it they would be more than willing to take it back.
Well in a round about way some of this post was in response to the TA comments which after talking with Bob is that if you purchase one of his pipes and don't like it he will gladly take it back. The other portion is the sound issue. I've seen alot of comments about who cares if the pipe is loud. Well like I said before noise is becoming an issue. For those that ride in southern Ca they banned fourstrokes from Barona Oaks track for about 2 months last year do to the noise. If you stop and look around at where most of the tracks are loocated around here you will notice housing developements going in all around them. So don't be surprised one day when you go to your local track and find them doing sound checks and you can't ride because your bike is to loud.