Howard At CNC EngineDyamics, Thanks!
10-27-2011, 02:22 PM
#26
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Re: Howard At CNC EngineDyamics, Thanks!
all these other top guys setting the records are just motivation....everything in the sport is developing...hey go big or go home...i ll be using grp aluminum conrods for next season...
10-27-2011, 02:22 PM
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10-27-2011, 05:55 PM
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Re: Howard At CNC EngineDyamics, Thanks!
Good to see it coming back together. Take this with a grain of salt as it's your cash and time, but think you might want to take a step back on your tuning and go over it again. Two motors in a short time period is no kidding. I wouldn't put the blame straight on the rods without saying that something else wasn't on the ragged edge. I realize it's a race car and that's what we do....push the limits. But either way...good luck.
10-27-2011, 06:50 PM
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10-27-2011, 07:38 PM
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Re: Howard At CNC EngineDyamics, Thanks!
I don't believe it has to do with tuning. Tony gets my data logs and they have enough info for him to make adjustments as needed.
First failure race motor had about 80 hits on it, the wrist pin came down off the piston. second motor, I engine breaked that bitch too long and well lost 2 rods, I won't do that again!
First failure race motor had about 80 hits on it, the wrist pin came down off the piston. second motor, I engine breaked that bitch too long and well lost 2 rods, I won't do that again!
10-27-2011, 08:59 PM
#40
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Re: Howard At CNC EngineDyamics, Thanks!
He's right, first thing I would assume with two engine failures close to each other, but once you realize how they failed you can see it wouldn't be tuning related.
10-28-2011, 06:24 AM
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10-28-2011, 08:27 AM
#43
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Re: Howard At CNC EngineDyamics, Thanks!
Right. The way I understand it is that it's the about inverse of making power. It pulls on the rod rather than push and that's why you see bearing/bolt/piston pin failure. If I have it wrong, somebody please tell me. lol
10-28-2011, 08:31 AM
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Re: Howard At CNC EngineDyamics, Thanks!
To clarify what really happens...
The rod and bolt combination has incredible strength in compression. But, during the exhaust stroke the piston has nothing but back pressure holding it back from stretching the rod & fastener and flying out of the top of the engine, now the rod & fastener is in tension. The better the grade fastener and rod material the higher the engines rpm can go mechanically. Remember the rod bolts' strength is based on its tensile strength. Typically the rod bolt is torque'd to a "high" percentage of its tensile strength, below its yield strength, for maximum clamping force. So when you free rev, mis-shift, slip the clutch, break the trans, break an axle, or just exceed the mechanical limits of the engine you will exceed the fasteners' tensile strength due to the heavy rotational mass trying to pull **** apart and for having no load on the engine.
Now lets take this information and use the engine as a reverse air pump and engine break it from 11-12rpm. 4th baaaaaaaa 3rd baaaaaaaaaaaaaa 2nd baaaaaaaaaaaaaaaa not only are you stretching your rod fasteners you are putting that "crap oil" Tony sells you to the test...lol (I'm just kidding about the oil) Regardless of what oil you use you will shear it and accelerate the bearings demise. 9 times out of 10 the rod bolt you spent big money on stretches then breaks. The crank then swings around and shears the rod about midway point sending that piece either out the front the block or down through your oil pan. The piston then travels at light speed into the head, hopefully the valves are open to slow it down from compressing the chamber closer to the cams thus reducing the port volume and changing valve angles. (You know who you are
) The bearing is a victim of circumstance. At the end of the day the Engine builder and Tuner gets blamed. When in all actuality you have exceeded the mechanical limits of the setup by running the engine improperly.
Aluminum Rods are KING! Well, not really. They assist in prolonging the damage from happening if you still want to sound like some clown cruising into town from the interstate. There is an AVG of 100grams of weight savings by going to the Aluminum rod. When I first had GRP do rods for the LS and GSR back for myself and a 7 second FWD Honda they came with ARP 8740 fasteners and worked well. Now they come with ARP 2000 material. Somebody must have told GRP their rod kept breaking so they overbuilt the rod now.
At the the end of the day it only takes applying one of the mistakes listed above once to reduce the strength of your fastener.
10-28-2011, 08:53 AM
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Re: Howard At CNC EngineDyamics, Thanks!
To clarify what really happens...
The rod and bolt combination has incredible strength in compression. But, during the exhaust stroke the piston has nothing but back pressure holding it back from stretching the rod & fastener and flying out of the top of the engine, now the rod & fastener is in tension. The better the grade fastener and rod material the higher the engines rpm can go mechanically. Remember the rod bolts' strength is based on its tensile strength. Typically the rod bolt is torque'd to a "high" percentage of its tensile strength, below its yield strength, for maximum clamping force. So when you free rev, mis-shift, slip the clutch, break the trans, break an axle, or just exceed the mechanical limits of the engine you will exceed the fasteners' tensile strength due to the heavy rotational mass trying to pull **** apart and for having no load on the engine.
Now lets take this information and use the engine as a reverse air pump and engine break it from 11-12rpm. 4th baaaaaaaa 3rd baaaaaaaaaaaaaa 2nd baaaaaaaaaaaaaaaa not only are you stretching your rod fasteners you are putting that "crap oil" Tony sells you to the test...lol (I'm just kidding about the oil) Regardless of what oil you use you will shear it and accelerate the bearings demise. 9 times out of 10 the rod bolt you spent big money on stretches then breaks. The crank then swings around and shears the rod about midway point sending that piece either out the front the block or down through your oil pan. The piston then travels at light speed into the head, hopefully the valves are open to slow it down from compressing the chamber closer to the cams thus reducing the port volume and changing valve angles. (You know who you are ) The bearing is a victim of circumstance.
At the end of the day the Engine builder and Tuner gets blamed. When in all actuality you have exceeded the mechanical limits of the setup by running the engine improperly.
Aluminum Rods are KING! Well, not really. They assist in prolonging the damage from happening if you still want to sound like some clown cruising into town from the interstate. There is an AVG of 100grams of weight savings by going to the Aluminum rod. When I first had GRP do rods for the LS and GSR back for myself and a 7 second FWD Honda they came with ARP 8740 fasteners and worked well. Now they come with ARP 2000 material. Somebody must have told GRP their rod kept breaking so they overbuilt the rod now.
At the the end of the day it only takes applying one of the mistakes listed above once to reduce the strength of your fastener.
The rod and bolt combination has incredible strength in compression. But, during the exhaust stroke the piston has nothing but back pressure holding it back from stretching the rod & fastener and flying out of the top of the engine, now the rod & fastener is in tension. The better the grade fastener and rod material the higher the engines rpm can go mechanically. Remember the rod bolts' strength is based on its tensile strength. Typically the rod bolt is torque'd to a "high" percentage of its tensile strength, below its yield strength, for maximum clamping force. So when you free rev, mis-shift, slip the clutch, break the trans, break an axle, or just exceed the mechanical limits of the engine you will exceed the fasteners' tensile strength due to the heavy rotational mass trying to pull **** apart and for having no load on the engine.
Now lets take this information and use the engine as a reverse air pump and engine break it from 11-12rpm. 4th baaaaaaaa 3rd baaaaaaaaaaaaaa 2nd baaaaaaaaaaaaaaaa not only are you stretching your rod fasteners you are putting that "crap oil" Tony sells you to the test...lol (I'm just kidding about the oil) Regardless of what oil you use you will shear it and accelerate the bearings demise. 9 times out of 10 the rod bolt you spent big money on stretches then breaks. The crank then swings around and shears the rod about midway point sending that piece either out the front the block or down through your oil pan. The piston then travels at light speed into the head, hopefully the valves are open to slow it down from compressing the chamber closer to the cams thus reducing the port volume and changing valve angles. (You know who you are
) The bearing is a victim of circumstance. At the end of the day the Engine builder and Tuner gets blamed. When in all actuality you have exceeded the mechanical limits of the setup by running the engine improperly.
Aluminum Rods are KING! Well, not really. They assist in prolonging the damage from happening if you still want to sound like some clown cruising into town from the interstate. There is an AVG of 100grams of weight savings by going to the Aluminum rod. When I first had GRP do rods for the LS and GSR back for myself and a 7 second FWD Honda they came with ARP 8740 fasteners and worked well. Now they come with ARP 2000 material. Somebody must have told GRP their rod kept breaking so they overbuilt the rod now.
At the the end of the day it only takes applying one of the mistakes listed above once to reduce the strength of your fastener.
.
10-28-2011, 10:59 AM
#49
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Re: Howard At CNC EngineDyamics, Thanks!
im not at near the level you guys are at, im just hoping to get my car into the 9's and 150+ trap speeds. However ive been around drag racing and been drag racing for a long time and know quite a bit. One of those things is yeah, engine braking is extremely difficult on the rod fasteners and probably like he said a lot of the damage caused by people who do that.
I never engine brake when slowing down. My car as it was prior to these upcoming upgrades was trapping high 130's and so far i havent been to a track yet that didnt have plenty enough room to cross the trap, put the clutch in, coast for a bit and then gradually apply the brakes and easily make the last turnoff. Both tracks that I go to have a 1/2 mile of braking distance. If you cant stop your car in 1/2 mile actually trying to brake right after crossing with a heavy pedal effort then something is wrong. Should be no need to engine brake and so on.
I know its still quite a difference from 170 trap speeds to almost 140 trap speeds but not that much. I usually just cross, push the clutch in, coast for a bit probably till i come down to about 100-110mph and then gradually brake. Never once have i ever had issues being stopped or slowed down well before the last turnoff. Most of the time i can make the 1st turnoff which is 3/8 of a mile after the finish. I dont know what the other tracks you run at have as far as braking distance. But personally i think every track should have at least a 1/2 mile distance.
I never engine brake when slowing down. My car as it was prior to these upcoming upgrades was trapping high 130's and so far i havent been to a track yet that didnt have plenty enough room to cross the trap, put the clutch in, coast for a bit and then gradually apply the brakes and easily make the last turnoff. Both tracks that I go to have a 1/2 mile of braking distance. If you cant stop your car in 1/2 mile actually trying to brake right after crossing with a heavy pedal effort then something is wrong. Should be no need to engine brake and so on.
I know its still quite a difference from 170 trap speeds to almost 140 trap speeds but not that much. I usually just cross, push the clutch in, coast for a bit probably till i come down to about 100-110mph and then gradually brake. Never once have i ever had issues being stopped or slowed down well before the last turnoff. Most of the time i can make the 1st turnoff which is 3/8 of a mile after the finish. I dont know what the other tracks you run at have as far as braking distance. But personally i think every track should have at least a 1/2 mile distance.
10-28-2011, 11:05 AM
#50
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Re: Howard At CNC EngineDyamics, Thanks!
I can say that at 170+ you don't want to take your time getting on the brakes after you cross the line. It IS a lot different than from 140. I've never been anywhere I couldn't stop with just the brakes, but it doesn't mean it's easy to stop with just the brakes sometimes. Depends on the track more than anything, but you don't waste valuable braking space after you cross the line on a fast car like this. That 1/2 mile goes away quick at 170mph.