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421 serval


jimbo1986

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The runs are so different because one was loaded and one wasn't. There is a huge difference between the two. If you could just gear the bike and run it the same way on the dyno, then they wouldn't make dyno's with a Load cell. The guy who dynoed the bike is one of top dogs for banshee's and raptors on the west coast, his stuff is quick as well. He was really suprised when he saw the PC's beat out those CPI's.

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If the PC's do so well maybe someone should test some FMF Fattys. There just about the same pipe and from most dynos Ive seen over the years they performed better then the PC's. JMO.

 

 

I'd be curious to see that too. What about the fmf knarlys? Are the any different then fatties or just thicker?

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You can absolutely load a bike correctly with out a load cell in fact its not even needed on a sweep pull. Load cells are to designed to do non sweep tuning like efi steady loads and mid throttle tuning. Not that it can't properly be utilized on a sweep pull but they can a also can be over used. The whole reason I question the load process is because of the big dif in between the loads which means the pipe was not able to build proper heat.

 

As far as the pro circuit pipes go I would like to see the dome design that made them work better. Like I said there are other factors that make a pipe work.

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As far as the difference in loaded vs unloaded, all of the pipes we tested had the same results loaded vs unloaded. You would have to talk to Jeff at fast on the dome design.

 

I had the pc's on the bike before I bought the serval setup. Before we went to the dyno I expected to be going home and ordering the cpi's. After the dyno time the pc's stayed. It doesn't matter anymore as I no longer own the bike.

 

Andy, I'm curious why your dyno sheet showed the serval peaking around 8,500 rpm. Even with the pc's mine peaked over 9k and close to 9,600 with the cpi's. Nate McCoy's also peaked around 9,600 with cpi's and stock carbs.

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The bike was jetted conservatively. An a/f meter was not used. We had no reason to lean the bike out to make the pc's look better. I had nothing to gain by making the pro circuits look better than the other pipes. I did the testing to find out what worked best for my bike. I could care less what people run on their bikes. It seems like you have an answer or reason for why our testing was inconclusive so I'm done here. I guess everyone will have to wait until a reputable builder has time to put all the different setups on the same dyno with the same bike in the same day to find out what the best setup is.

Edited by 05stroker
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The bike was jetted conservatively. An a/f meter was not used. We had no reason to lean the bike out to make the pc's look better. I had nothing to gain by making the pro circuits look better than the other pipes. I did the testing to find out what worked best for my bike. I could care less what people run on their bikes. It seems like you have an answer or reason for why our testing was inconclusive so I'm done here. I guess everyone will have to wait until a reputable builder has time to put all the different setups on the same dyno with the same bike in the same day to find out what the best setup is.

 

 

Ok, this debate is back to it's old roaring ways.

I'm going to chime in here with some input as someone who has run a dyno and doesn't have a dog in this fight.

 

It's easy to get all confused about loaded and unloaded runs. DON'T! Every dyno number you have heard in this sport is UNLOADED. Yes a load cell is an additional tool that can be helpful in the dyno tune of a bike. They are very helpful in holding a motor at a set RPM to study the Air Fuel Curve and power levels at that RPM as you adjust fuel injection settings. But how do you determine if the motor is loaded properly? What if the bike normally carries a 250 pound rider up a steep hill in deep sand?

Will that pipe get hotter in real life than another guys?

What if that 250 pound guy climbs that hill slowly and doesn't get a lot of air over the pipe?

What if the dyno operator has a massive fan blowing harder on the pipes than the bike would see in motion?

But I do have some serious questions regarding the info that was gathered on these back to back pipe runs......

 

It was stated, that NO Air Fuel Readings were taken. Yet this dyno is "Better" than most because it has a load cell and can test "Real world" conditions.

Well, how do you know you were jetted conservatively if you don't have the A/F data?

All these pipes were tested with 28mm carbs. Guess what? Your NOT going to see a Better flowing, higher HP pipe do well if the motor can't breath hard enough to take advantage of the pipe!

If a customer comes and runs his bike on the dyno and his filters are filthy....guess what? It needs smaller jets than when they are clean. Less air = less needed fuel.

I had a motor that with some BB CPI's dyno'd at 81 HP jetted to an A/F ratio of 13:1. I put SB Shearers on it and it jumped to 95 HP. But it needed a different jet to get back to the 13:1.

Lesson = you have to re-jet to a common A/F if you really want to compare anything. (I'm not saying anyone "Leaned down a motor to make PC's look better" I'm saying how do you know WHAT YOU DID, if you don't have the A/F data?)

Also, the gear ratio that was listed 14/46 is the opposite of what you do for an unloaded run. You want to gear the bike to be more like a 15/41 to lengthen the run, get more heat in the pipe and get a longer sample time.

For me.....the issue here is that I'm not a firm believer that the 28mm carbs aren't part of the problem.

Again...keep in mind that the motor we are talking about was built for EXTRA low end. Even more than the standard Serval. So the goal was massive bottom end power.

 

Now I want to be clear here so people's feelings don't get hurt. Snop... built a motor that runs awesome. He likes it. The customers/friends he rides with like them. It fit's THIER needs well with the carbs and pipes he chose.

I'm sure 28's work on his motor with those pipes. (We have Built stock cylinder bikes making 70 HP with stock carbs and FMF Fatty's) So it's not a stretch to think that a set of 28's can support 80HP with PC's.

But I feel that slightly larger carbs might aid overall airflow into the motor, thus letting the bigger pipe do it's job better. I would have liked to see the pipes tested with 33-34's.

 

I've run two into one carbs on a few bikes over the years and Snop always said that I should toss the single carb and get twin 28's.

He tells people with 350's and a few bolt ons to get 28's.

421 Servals need 28's

I've got 28's on a 370 long rod bike right now. I'm not a hater of 28's.

But for kicks.....search Snop's post history. Apparently there is only one carb that has ever been the RIGHT carb for a Banshee.....and one pipe. :huh: Mikuni 28's and PC pipes for the win!

Lastly, the silencer he says makes the most power is CRAZY long! It sticks out WAY past a factory rear grab bar.

Now I don't claim to be a top builder, but I read what they post on more than one site. I'm not seeing a big following of PC support in the builder community.

I would think that with all the R&D and desire to sell this new design...that if the PC was the BEST pipe...Calvin would be sure to have some people look into that for him.

I'll be the first to admit that this cylinder needs time to try all these ideas. But in reality...we only have Snop's and Andy's dyno posts to base a lot of future theory on.......

I still say that Snop's motor works well for his needs. nothing wrong with having a motor you like.

Andy is selling the Serval like hot cakes too.

But I still see some holes in to data that only time and testing will fill in. till then.....this debate will continue to play out. But lets not get all heated and hating. the goal here would be to share info so that the products available to all of us will continue to improve. :)

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