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Ironbutt
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Discussion Starter #1
Had the Heritage dyno tuned yesterday and here are the results:



Other than the nasty little torque dip i'm pretty happy. My exhaust is not tunable so i guess there is no way around it.

Mods include:
95in SE cylinders
SE Hi comp pistons
GMR CNC heads
S&S 510 gear cams
RB LSR 2-1 exhaust
CV carb by Dakota kid
SE adjustable ignition
 

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Welcome! that dip is pretty nasty, look at the scale of the graph.... Find a way to get rid of that baby... This is when it starts getting spendy :D
Remember, you know the power is in there now all you gotta do is get it delivered properly... Good luck!
now go out and ride really FAST!!!! (my very favorite thing to do!)
 

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Gotta agree with the guys. Nice numbers-hard part id now getting rid of that dip. Would have to think that you could feel that. Good pipe, so look at re-jetting on the carb.

karlrockdrain
 

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I had a Dakota Kid carb on my previous 95 with a very similar rich spot and there was no way to get rid of it with the needle options DK supplied. I bought a CV44 race tuner kit and experimented with the needles and ended up with the leanest 'K' needle as the best compromise. Can you modify the exhaust baffle in principle?
 

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I paid.........did you??
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miles to go said:
Other than the nasty little torque dip i'm pretty happy. My exhaust is not tunable so i guess there is no way around it.
It's not your exhaust causing that.............it's your carb and tuning.

That is almost a 20 point dip, that is huge!! And look how rich your AFR is when it happens. You either need a better tuner who can play with the carb, or get rid of that carb and go with a better one.

Steve
 

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Dip

I'd bet that pipe is doing it.
We have seen 'em come in on bikes, and have tuned with 'em. They are not sold in this building.

When you turn that dip into an arch you'll have it, but then you'll see the peak hp come down. That pipe needs some type of major obstruction in the end of it to get that all-important low end torque to happen correctly. When that occurs, the bike will pull so much harder, and the mpg will also increase.
 

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Ironbutt
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Discussion Starter #9
I checked the graph from my last dyno - before the heads, carb and exhaust were redone. There is a torque dip in the exact same spot - not as pronounced but it's there. The bike runs well and i don't really notice the dip. It does have what i would call a kick at around 3500 rpm. Unless someone has a cheap solution i'll probably just leave it alone. I could spend a lot of money trying to smooth out this dip and the bike still not run any better.

And reference Hillside comment, the previous exhaust was Vance&Hines straight shots and i had a dip in the same spot. As i said, the dip is more pronounced now.
 

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A couple of thoughts.

This is pretty typical of a carb, see it fairly often. It's also pretty typical of a low restriction 2-1 exhaust and I'm not a big fan of putting an intentional additional restriction in the exhaust but that's just me. Inherently you're trading something off the top to "fix" the dip. Not a trade I usually favor. Having said all that, I've seen dynos of a lot of LSR's and not all of them do this, so it depends on the combination that it is working with on whether it exhibits a dip after the initial hit. With efi, you have a much better chance of minimizing it, worked on it on my build to get it to 3-4 lbs. Now, if you think about it, this is a snapshot of wide open throttle. Part throttle will behave differently and this is not something that you notice in normal riding. During WOT, you may pass through it once, depending on where you start from and then after that, if you shift in the 5500 - 6200 range, the next gear falls back into the torque peak, not below it. Do I think this one can be improved? yeah, no doubt and I would work on the intake/carb side and try some different ignition advance in that region to see what could be done to minimize it. Someone that has a lot of carb experience with doing modifications and racing application could help it for sure and then finding a tuner that is willing to work up a custom ignition map would be helpful also. Just a reminder, fuel and ignition timing are interactive.

The LSR has always done a good job of making good numbers and if the motor is willing, it revs quick too.

Congrats! ;) that's a nice 95" build and I'll bet it pulls hard and sounds good.
 

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Ironbutt
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Discussion Starter #12
Totenkopf said:
A couple of thoughts.

This is pretty typical of a carb, see it fairly often. It's also pretty typical of a low restriction 2-1 exhaust and I'm not a big fan of putting an intentional additional restriction in the exhaust but that's just me. Inherently you're trading something off the top to "fix" the dip. Not a trade I usually favor. Having said all that, I've seen dynos of a lot of LSR's and not all of them do this, so it depends on the combination that it is working with on whether it exhibits a dip after the initial hit. With efi, you have a much better chance of minimizing it, worked on it on my build to get it to 3-4 lbs. Now, if you think about it, this is a snapshot of wide open throttle. Part throttle will behave differently and this is not something that you notice in normal riding. During WOT, you may pass through it once, depending on where you start from and then after that, if you shift in the 5500 - 6200 range, the next gear falls back into the torque peak, not below it. Do I think this one can be improved? yeah, no doubt and I would work on the intake/carb side and try some different ignition advance in that region to see what could be done to minimize it. Someone that has a lot of carb experience with doing modifications and racing application could help it for sure and then finding a tuner that is willing to work up a custom ignition map would be helpful also. Just a reminder, fuel and ignition timing are interactive.

The LSR has always done a good job of making good numbers and if the motor is willing, it revs quick too.

Congrats! ;) that's a nice 95" build and I'll bet it pulls hard and sounds good.
Thanks Tote. The bike does pull hard, and the pipe sounds awesome. I'm sure the tune could be better but i don't know any other tuners in this area and i'm tired of throwing money at it. Think i'll just ride and enjoy it like it is for a while.
 

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Not sure you want to go to the extent to get rid of the dip due to what tote said.
Some possible cures for the rich sag. lean the accelerator pump shot (yes it can be done on the cv), SLOW the slide, trim the lower edge of the slide, change emulsion tube hole sizes and locations. Add timing in the sag area.
These techniques are above and beyond what I would expect the average tuner to understand but the good ones will. Or just buy a CV44 and change the pilot to 48 and run the lean or second needle and it will all fall into place.
As far as the pipe there are cheap cone reducers that can be tack welded into these type of pipes to add a little pressure pulse restriction.
 

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Ironbutt
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Discussion Starter #14
nw_guy4_fun said:
Not sure you want to go to the extent to get rid of the dip due to what tote said.
Some possible cures for the rich sag. lean the accelerator pump shot (yes it can be done on the cv), SLOW the slide, trim the lower edge of the slide, change emulsion tube hole sizes and locations. Add timing in the sag area.
These techniques are above and beyond what I would expect the average tuner to understand but the good ones will. Or just buy a CV44 and change the pilot to 48 and run the lean or second needle and it will all fall into place.
As far as the pipe there are cheap cone reducers that can be tack welded into these type of pipes to add a little pressure pulse restriction.
So, are you saying that i could change to the CV44 and get rid of the dip? Wish i would have known that before i did the Dakota kid rework. I could have bought a new 44 for the same price. I was originally going with the 44 but went with the Dakota rework on the advice of Doc and some others.
 

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Pipe

miles to go said:
Thanks Tote. The bike does pull hard, and the pipe sounds awesome. I'm sure the tune could be better but i don't know any other tuners in this area and i'm tired of throwing money at it. Think i'll just ride and enjoy it like it is for a while.
We have dyno tuned hundreds, if not a couple thousand bikes over the years.
There is no free lunch.Always a trade. The pipe is too free flowing for the build. Torque,torque and more,torque, for a street bike. Hp is in fact mandatory for the dragstrip, when you live in that narrow dedicated WOT,air-shifter environment. No doubt about that whatsoever.
What we developed here many years ago were actual torque nozzles,our better yet, it is an exhaust venturi, that goes in the tail end on the pipe. In this application, it would be a custom sized unit that slips inside the pipe. We would start with an arbitrary number for the I.D., and then working with that on the dyno, we would continue to increase the I.D. in our machine shop, monitoring the bottom end torque. Once we would witness that just starting to drop, that's it. Done. Suprisingly in some cases, you can see peak hp come up, but usually not.
A torque deficit in the riding range(2500-4500) is not what we want to see here, neither do you.
Scott
 

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The Dakota Kid carb work is pretty involved and features modified slides, air bleeds and a bore size of 42 mm. I have seen 3 of them in mild builds and all of them without fail showed the rich dip. In my case a combination of baffle mods (Propipe) and needle experiments along with float level did it. Briefly considered messing with the emulsion tube, but wasn't required after all. Torque/rich dip gone. Cam was a 37G with Dewey's heads.
 

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I agree with Scott & Tote, but thought i would also ad i can not understand why you would want to ride @ 2,000rev in top gear? you might think you are being easy on your motor, but you are doing more damage to the bottom end, it is easier on it if you are over 3,000 rev so if you ride the way the motor likes it you will not have a TQ dip just shift down a gear.
when you could rebuild harley bottom ends the ones with most damage were always the riders that road at low rev's in top gear, it hammers those roller bearings, you could still pull the new style cranks apart but as there is no replacement or oversize rollers to buy why would you bother. so look after it while it lasts.
hope you understand what i'm saying.
also if i got on your bike and was on ther lights with another HD that never had that TQ dip below 3,200, it would not matter as i would not have revs below that rev.
and like Scott & Tote say, to fix that dip you need to restrict the flow in the pipe as it is like increasing vellocity, but! you can have too much Velocity when that happens you freeze up.
also i have noticed when you are riding fast on a well tunned harley with low restiction pipes and your doing about 4,500 to 5,000 rev you can feel the motor runs more smoothly, also with low restiction pipes i have noticed they tend to excellerate smoothly and respond to throtle more smoothly through the rev range, were a restricted pipe will have strong TQ at low revs but once your up high going faster they feel rough and vibrate more also don't ecellerate as smooth and hard above 5,000.
might be just me but i could never get a supertrapp to work for me, it had good low end TQ and i got it to move TQ & HP around and i could adjust sound leavel, but i could never get this funny feeling it gave the bike at a curtain rev out. and as soon as i went back to stock head pipe with cycle shack slip ons baffle removed, the bike lost some low end TQ but 3,500 and up it just went away and felt great all the time till rev limit hit. what i'm talking about is street riding, now i just race, but could ride this bike anywhere if i wanted, but i have more fun racing and seems safer to me.
cheers
also Miles to go, leave it as it is and enjoy your ride!
 

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Hey, that's no torque dip...

.... this one is bigger!!!! I think my problem is 2" intake valve with the .615" lift is killing my velocity and low end torque suffers as the motor tries to catch up. I am also running the RB LSR 2-1. I have since cut the acc. pump back to a #50 (Mik 45) to try and help it. I can really feel it when I go to WOT at about 3000 rpm. This next spring going to try and find someone that can really tune a motor and help me.
 

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Ironbutt
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Discussion Starter #19
Anyone know a good tuner in the St Louis area?
 
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