I did a 95 Inch Build with the following parts and was wondering if using a 4 degree advance key if that will allow the cam to come on sooner? If so, how much quicker will the cam come on? 500 RPM's? I know everyone says a 2-1 pipe will bring the torque on quicker but I will be staying with the Rinehart true duals. When doing the key I am assuming will need to do another Dyno? and will it raise my compression and if so, how much? Will it affect fuel mileage? Don't know much about advancing cams so, looking for alot of input. My goal is to take my torque from 80fpt at 2500 rpm to 90fpt at 2500 rpm.The bike is a 2006 Road King Custom. I have put 2400 miles on the build and just got back from a trip riding two-up if that helps with why I am asking the question. Do not get me wrong the bike runs awesome just looking for a way to get the torque to come on sooner without changing the pipes.I havehad no issues at all with pinging so not wanting to create any also.Thanks for any help you guys will give me. I have attached my dyno for you guys to look at. Thanks

Heads Ported and Polished, valves, guides, 5 angle job
Heads milled for 9.8:1 compression
Jugs Bored 95"
Wiesco Forged Flat Top Pistons
Andrews 37G gear drive cams
Adjustable Pushrods
Oil Pump
Lifters
SERT
Rinehart True Duals




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Most people use the 2 degree advance key with the 37 cam....that brings it down about 240rpms but it also brings your peak hp down too....it's all relitive to each other .The 4degree will hit 480 to 500rpm sooner. Since your engine will be breathing better at different throttle positions you will need another dyno session.

 

Is mine goal a attainable by using the advance key? By what you have said I need to use the 4 degree key to get close to my goal correct? Is there any down side to using a advance key? Will it affect the compression any or will it be prone to pinging by using the advance key? In your guys professional opinion's is it worth adding the key totry and get to my 90fpt at 2500 RPM's?

Doc: Thanks for your reply. How much will it affect the horsepower by using the 2 or 4 degree key?

This is my first build and hindsight is always 20/20 if you know what I mean so, If I add some more money into this build I want to make certain that it is the thing to do. Iknow you guys haveyears of experience building engines and that is why I am here.

 

With your compression ratio and set up, what I would not like about advancing that cam 4 degrees is now the intake valve would be closing at 52 degrees after BDC so you will be losing some cylinder pressure, and the exhaust valve will open 52 degrees before BDC so will be losing more on the power stroke, I think you will be happier with a 2 degree advance.

 

With what has been said running a 2 degree advance key will move my power down in the RPM band around 250 RPM's correct?
With that being said that would only yield me about 4 to 5 torque more at the 2500rpm range according to my dyno. Am I looking at this correctly? My question is I am not sure I will be able to feel the 4 or 5 lbs of torque difference at that level? Thanks for the information but I still wonder if it will provide me with enough difference to justify the work. Anything else you guys could tell me would be greatly appreciated.

 

I have been looking for the same answers! I want to do this build with the roller chain conversion possibly instead of gear-to-gear and there is only a 4 degree advance gear available from what I can tell. I only see other builds using the 2 degree key though. I think that is because the tradeoff of adding the full four degrees isn't worth what is lost on top.

Road King 22, why do you feel that you need more (90 lbs.@ 2500rpm) torque down low? You have 78 lbs. @ 2500 now, right? You must be unsatisfied with what this build does when riding two-up, correct? I have been told that I would have more than enough torque for this type of riding with the 37. No?

Have you changed your gearing to 3.37:1 instead of our stock 2006 gearing? That would make a big difference for getting off the line. A four hundred dollar fix if you do it yourself and no getting into the cam chest.

 

I'd agree with the 3.37 route . I"ve had both 3.37 and 3.15 and the 3.37 is noticeably better down low, although you give up some top end. If you have the 6 speed tranny then no worries.

 

Boomshaw,
Don't get me wrong with my build as I am very satisfied with the way it turned out. The only time I wish I had more power is when Iam riding two up loaded with luggage through the mountains. Any time else this thing has plenty of power. I have a freind that has the CVO Ultra Classic with the 110cu engine. He is amazed at the power that my build produces and when we run the bikes I am right there with him. After looking around and doing research I have found that my True Duals are what is robbing some of the low end torque. The reason I say that is I have seen the same bike with a build similar to mine run a true dual vs a fatcat 2-1 exhaust and they have gained about 12-15 torque and 2500 rpm. I am trying to make my mind up if that will be worth the cost to see if that outcome works for me. As far as the gearing I am not wanting to up my rpm at a certain speed to gain my torque. Fuel mileage is more important to me than the torque right now as I am getting 45-50 mpg if I can keep my wrist in check. Hope this helps let me know if I can answer anymore questions for you.

 

Stay with the 2* advance and change the final drive to 3.37...this final drive will get you out of the falt spot the Tru Duals make MUCH quicker. You will have better acceleration, better pulling power and you won't be sacfricing the HP on top that you would be with the 4* key.

Reese...the 4* advancekey will close the itnake sooner not later for better low end performance.