Hello guys. Looking at doing a few little mods. Pipe will be jaws, air box vents, fix kit of some kind, ( not sure if I'm going cast or forged pistons. ) and I'm thinking about porting. Just not sure how much hp gain from porting. I called a few shops and been told 8-14 hp, depending on the shop I called. I'm guessing closer to 6-8 hp. Any suggestions on fix kit, or porting would be great.
Porting. ?
- Thread starter 08dmax
- Start date
Brock
Well-Known Member
The shops that I know of and trust for porting are iantomasi and Terra Alps. They will give you the true honest numbers of gains.
As for others. I can't comment as I haven't had a chance to dyno their stuff to make sure it works.
The true way is to dyno it stock and get a stock evaluation, they add to see gains. Only true way in my opinion.
As for others. I can't comment as I haven't had a chance to dyno their stuff to make sure it works.
The true way is to dyno it stock and get a stock evaluation, they add to see gains. Only true way in my opinion.
The two places I got a close to honest number was Ted=Terra alps. And brent linderman = articedge. Both about 12- 14 hours from me. Biggest difference I got was pistons used in the (fix kit). One cast one is forged. But I'm going to half to find some info about the difference between the two.
Brock
Well-Known Member
Cast vs forged debate. Ouch, that never gets old,lol
Cast:
Their alloys have have silicon, a material that gives the pistons natural lubricity and limits heat expansion. All modern pistons have silicon in them. However, cast pistons have historically had the most. Some of them have as much as 25 percent silicon by volume.
Probably the greatest benefit of the cast piston is the efficiency of its mass. The multiple-piece molds allow intricate contours inside and out, resulting in light weight, good expansion control, and predictable heat flow through the part. That is, the piston designer can plan in the specific thickness in each place in the part that is desired, to result in expansion at those places that is warranted. So predictable is the cast piston's heat in fact that race tuners view the undersides of the piston to gauge the combustion efficiency of the engine. In much the same way others read spark plug, they read the dark splotches under the crown.
The cast piston is however expensive to manufacture. Die casting is costly, because it requires huge machines that do very specific jobs, and can't be easily adapted to do more than one kind of job. The result is that the casting process for pistons is relegated to the large piston supplier. The downside is that the cast piston is often found only in OEM specified sizes and types. There aren't a lot of different cast pistons to chose from if you are modifying an engine. The upside of this situation is that since only large piston manufacturers can afford to make cast pistons, they are usually competently made. In fact, the cast piston generally typifies the best technology that the piston industry has to offer. However, this doesn't mean it's the best piston for every application.
Forged:
The earliest forged pistons were also made with poor alloys. In many cases however they were even worse than the alloys the cast pistons used, because when the cast piston finally got silicon, the forged piston did not. The same brittleness that makes the cast piston crack when bumped hard would have resulted in even larger defects had it been used in a forging. Consequently, during the time that the cast piston defined a piston's normal expansion rate, the forged piston was far behind the technology. The forged piston had to be fitted loose, which made it noisy and wasted power. Recently however, silicon has been introduced to the forged piston. A mixture of alloys has been found that together with silicon do not result in defective forgings. For example, nickel has been found to offset the silicon's tendency toward brittleness
The forged piston has historically had a crude interior shape. The forging ram is straight, which results in a rectangular rather than an inticate interior. There is too much mass there. Consequently, the forged piston has poor dimensional stability. Its expansion is not very controllable. Many engine builders overcome these two problems (too much weight, unpredictable expansion) at least partly by removing by hand the extra material inside the forged piston. This allows them to fit them tighter and rev them higher. However, many forged pistons also have overly thick skirts as well as unsophisticated interiors. This is because the forging produces a piston blank, remember, and not a finished piston. The piston wholesaler takes this blank, and from it, carves out several different sizes and shapes of pistons. If the piston being made happens to be the largest the blank supports, it ends up with the thickest skirt. While hand reworking (or CNC milling, as many do now) the forged piston can lighten it and make it behave more like an intricately made cast piston, there is still excess weight due to the thick skirt.
Unlike the cast piston, the forged piston is easy to manufacture. Smaller piston manufacturers therefore specialize in this piston type, even if some of them may not be as competent at making pistons as are the larger cast piston makers. Forged pistons have quickly become the choice of custom engine builders because they can be had very quickly, and in virtually any configuration desired.
Summary:
To sum up, the cast piston is light and very dimensionally stable. It is found in high-rpm mass-produced engines that are not subject to modification or prone to detonation. The piston is however fairly brittle, and the cost of its manufacture has limited its availablity outside the OEM sources and applications. On the other hand, the forged piston is inherently heavy and less dimensionally stable. It is a good choice for engines in which detonation is probable, and its wide availability has made it the choice of engine modifiers. The special demands of these end users has given the forged piston its own niche in the powersports market. The next time someone tells you how superior one piston type is over another, tell them the truth.
Cast:
Their alloys have have silicon, a material that gives the pistons natural lubricity and limits heat expansion. All modern pistons have silicon in them. However, cast pistons have historically had the most. Some of them have as much as 25 percent silicon by volume.
Probably the greatest benefit of the cast piston is the efficiency of its mass. The multiple-piece molds allow intricate contours inside and out, resulting in light weight, good expansion control, and predictable heat flow through the part. That is, the piston designer can plan in the specific thickness in each place in the part that is desired, to result in expansion at those places that is warranted. So predictable is the cast piston's heat in fact that race tuners view the undersides of the piston to gauge the combustion efficiency of the engine. In much the same way others read spark plug, they read the dark splotches under the crown.
The cast piston is however expensive to manufacture. Die casting is costly, because it requires huge machines that do very specific jobs, and can't be easily adapted to do more than one kind of job. The result is that the casting process for pistons is relegated to the large piston supplier. The downside is that the cast piston is often found only in OEM specified sizes and types. There aren't a lot of different cast pistons to chose from if you are modifying an engine. The upside of this situation is that since only large piston manufacturers can afford to make cast pistons, they are usually competently made. In fact, the cast piston generally typifies the best technology that the piston industry has to offer. However, this doesn't mean it's the best piston for every application.
Forged:
The earliest forged pistons were also made with poor alloys. In many cases however they were even worse than the alloys the cast pistons used, because when the cast piston finally got silicon, the forged piston did not. The same brittleness that makes the cast piston crack when bumped hard would have resulted in even larger defects had it been used in a forging. Consequently, during the time that the cast piston defined a piston's normal expansion rate, the forged piston was far behind the technology. The forged piston had to be fitted loose, which made it noisy and wasted power. Recently however, silicon has been introduced to the forged piston. A mixture of alloys has been found that together with silicon do not result in defective forgings. For example, nickel has been found to offset the silicon's tendency toward brittleness
The forged piston has historically had a crude interior shape. The forging ram is straight, which results in a rectangular rather than an inticate interior. There is too much mass there. Consequently, the forged piston has poor dimensional stability. Its expansion is not very controllable. Many engine builders overcome these two problems (too much weight, unpredictable expansion) at least partly by removing by hand the extra material inside the forged piston. This allows them to fit them tighter and rev them higher. However, many forged pistons also have overly thick skirts as well as unsophisticated interiors. This is because the forging produces a piston blank, remember, and not a finished piston. The piston wholesaler takes this blank, and from it, carves out several different sizes and shapes of pistons. If the piston being made happens to be the largest the blank supports, it ends up with the thickest skirt. While hand reworking (or CNC milling, as many do now) the forged piston can lighten it and make it behave more like an intricately made cast piston, there is still excess weight due to the thick skirt.
Unlike the cast piston, the forged piston is easy to manufacture. Smaller piston manufacturers therefore specialize in this piston type, even if some of them may not be as competent at making pistons as are the larger cast piston makers. Forged pistons have quickly become the choice of custom engine builders because they can be had very quickly, and in virtually any configuration desired.
Summary:
To sum up, the cast piston is light and very dimensionally stable. It is found in high-rpm mass-produced engines that are not subject to modification or prone to detonation. The piston is however fairly brittle, and the cost of its manufacture has limited its availablity outside the OEM sources and applications. On the other hand, the forged piston is inherently heavy and less dimensionally stable. It is a good choice for engines in which detonation is probable, and its wide availability has made it the choice of engine modifiers. The special demands of these end users has given the forged piston its own niche in the powersports market. The next time someone tells you how superior one piston type is over another, tell them the truth.
Dr.Notadoo
Well-Known Member
Great wright up Brock: IMO the only piston to use is the Suzuki piston found in the Cat. And cast all the way. In your conversation with Ted did he mention he is doing pipes? He is working on molds. Ck out his FB page shows pipe gains...
OutCast
Active Member
Porting will wake your sled up quite a bit. Ted built an Engine for my INDY. I have very little tune time into it, no dyno tune and under revving and it runs with some of the stronger motors built by other guys.
I can't wait to get it tuned next Winter.
I can't wait to get it tuned next Winter.
Brock
Well-Known Member
Kinda borrowed some knowledge from a friend on that write up.
Back to porting. It is an art and knowledge. Proof is putting it on dyno.
Dr.Notadoo
Well-Known Member
His pipe on stock Axys is about 10, with PCV he is at 15. All on his FB page not my #s.
Brock
Well-Known Member
Terra Alps made a pipe mod for me . (No internal stinger)
He stated 4 hp but increases hp up slightly from 7000 and carries it to 8400 rpm. Which will give more top end.
I dyno'd it and it was just that.
4 hp might not seem like a lot to guys. But it holds 4 hp in long wot pulls were some pipes loose power. That's the key.
He said it was this and it was.
I wouldn't trust just anybody to port. No way, seen mire lose hp then gain on the dyno.
He stated 4 hp but increases hp up slightly from 7000 and carries it to 8400 rpm. Which will give more top end.
I dyno'd it and it was just that.
4 hp might not seem like a lot to guys. But it holds 4 hp in long wot pulls were some pipes loose power. That's the key.
He said it was this and it was.
I wouldn't trust just anybody to port. No way, seen mire lose hp then gain on the dyno.
Neal@BMP
Member
- Messages
- 53
- Location
- Wisconsin
- Country
- USA
- Years Snowmobiling
- 28
- Snowmobile
- 2011 Rush 660
Or whatever is currently @ the shop
No internal stinger is the key to that pipe holding power on the longer runs. It's why we don't recommend doing a pipe mod to the stock AXYS 800 pipe. Not enough volume to get the heat out on longer pulls.
Brock
Well-Known Member
Yes I think so too.
Porting a cylinder with a head,shim,pistons and a pipe set makes sense ,but not alone.
The port height isn't as aggressive as the dragon 800's and is more aggressive then the cfi 800. Kinda in the middle, but wider too.
And your correct with porting a stock cylinder, it's not worth the money and little gains unless your boring and stroking the motor.
Brock
Well-Known Member
We seen that on the dyno .
Question??
What is the weight of your 800 piston with rings,clips,wrist pin and needle bearing??
Brock
Well-Known Member
That's a stock axys piston with everything.
I've been saying this for years. The pistons could stand to lose 30-50 grams. = less stress
Titanium wrist pins with dlc coating save 30-50 grams and could be added to your kits. I've been using them since 2000/2001.
Just saying
