SRX 1108 Race Sled Buildup

I know :) It's going to be fun. I'm really hoping for the 150 mph mark. I was only running a 51/37 helix in there, and 23/37 gearing. I know it will like alot more angle than that, and probably quite a bit more gear. I had basically 68.8 grams of weight in the primary with a 310 finish spring. I'm going to cut the weight down a bit and run a 282 finish. I won't get out to do more testing until after xmas, but i will post my results.
 
valin said:
I know :) It's going to be fun. I'm really hoping for the 150 mph mark. I was only running a 51/37 helix in there, and 23/37 gearing. I know it will like alot more angle than that, and probably quite a bit more gear. I had basically 68.8 grams of weight in the primary with a 310 finish spring. I'm going to cut the weight down a bit and run a 282 finish. I won't get out to do more testing until after xmas, but i will post my results.
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If your already under reving a steeper helix will only drag your RPMs down more unless your not loading the motor hard enough through the primary already.
 
Yes jtssrx, I realize that. I always setup my secondary first, with the steepest angles I can pull without losing rpm at the shifting points, then setup the primary.

I am not yet sure what finish angle I will be at with a helix, but it can certainly pull a much larger helix. I figure I will be around the 56 degree mark for a starting angle. I am going to start clutching next week and figure it out.
 
Good work Ryan, look forward to seeing that sled dialed in...
Let me know when your going out.. Shaun and I are out of town Thur. and Fri. picking up a couple of sleds but if your running on the weekend we would probably come out..
 
valin said:
Yes jtssrx, I realize that. I always setup my secondary first, with the steepest angles I can pull without losing rpm at the shifting points, then setup the primary.

I am not yet sure what finish angle I will be at with a helix, but it can certainly pull a much larger helix. I figure I will be around the 56 degree mark for a starting angle. I am going to start clutching next week and figure it out.
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There are a million ways to skin a cat. Most of the tuners I know including myself clutch from Front to back. The key is the squeeze the belt. The fast guys in the world run a strait angle helix. A multi Angle helix is generally a Band aid for poor clutching. I use multi angles because you don't always have a million Parts to work with. My suggestion for you is to get your full shift RPM set with your Primary. Then find a helix that goes well with that setup.

Just my 2 cents
 
For speed running I like to run a shallow helix and lot's of tip weight and just enought gear or you can run a steeper helix light weight and lot's of gear.I definatley think you need more gear.
 
Actually it is being sold in a few days.
It placed in the world series 4 consecutive years.It hasn't been ran the last 4 years.
It's a prostock 700 193hp@9600rpms.If you want more info pm me.
 
Here's a few pictures of the finished product. I am going to coat the pipes, but it won't be until the summer.
 

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Argh. It was a slow day. We were battling a headwind, and the ice is not nearly as good anymore.

The motor is now revving 9250, which is great. It's pulling very hard. I have not changed the helix yet, but it needs a higher starting angle. I have not done anything with gearing yet.

I did a few 1000' passes, then a 1500' pass at 137.8 mph.

I then decided to run a 2000' pass, and hurt the motor at about the 1800 ft mark. I am having a temperature issue on the PTO side. Tons of wash on the pistons.....too much fuel actually, which is right where I want it for testing. Zero detonation on the top of the pistons, but I am getting some detonation elsewhere because I noticed that the wrist pin is spinning at some point, which tells me that it is building heat extremely rapidly at some point. The question is why.

At the 1800-2000' mark something is going on. I can run the motor all day at 1500' with no issues, and it builds about 30 degrees total water temperature in that distance, which is far from excessive. I found a cooling issue in the cylinders that is most certainly hindering the flow, and it is going to help out the flow of coolant much better.

Here's a picture of the possible cooling issue. The base gasket on this cylinder matches the base of the motor, so you can see how small the cooling ports are. Just inside the cylinder, the ports become easily as wide as the base port, so the issue is only where it meets the base, and is about 1/4" deep.

In relation, the second picture is a factory SRX 700 (780 actually) cylinder. You can see the difference is size for the cooling ports.

Just to avoid questions or comments, the rough material you see on the Price cylinder is glass. I just finished glassbeading the outside of the cylinders, and haven't washed them yet.
 

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Please post pics of piston. What do the other cyl look like? You could also be foaming the fuel in the float bowl. That would also be why fuel flow fell off on your dyno run at peak rpm.
 
pics of the piston you hurt and pic of the inside of the dome underside of the piston will tell alot.
 
Here's a quick shot of the piston's top. I'll get pics tomorrow of the underneath.

If, by chance, the fuel is foaming in the bowls, how is this prevented?
 

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If everything is true (crank, flywheel, clutch), it can be as easy as adding weight to the bell or bowl of each carb. Or add softer longer intake boots and ISO-MOUNT to carbs to the chassie as best you can so it isolating vibration from the engine at rpm.
But the only good way to know if you have it (and fixed it) is fuel flow numbers on the dyno.

Way back when we use have to run updated needles & 390mj in mod 570 Exciters to get any life out of them. Then we epoxy lead fishing sinkers or wheel weights to the bottom of carbs on 1988 Exciters with twin pipe mod engines. They would live with 300~310mj after that easy mod.
 
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Well, I have figured out the issue. Fuel. There is so much timing with the SX ignition that, even with 13.5:1 compression ratio, I can't run Torco 112. I'm going to have to bump up to Torco 116. If that still doesn't want to go the distance, I'll have to drop the timing a bit. The motor is going to go back together tomorrow, so I'll get back out to the lake late in the week. I'll keep you all posted.
 
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