Boosted stroker motors, yes or no?
11-16-2012, 09:39 AM
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Boosted stroker motors, yes or no? I keep hearing that boosting a stroker motor is bad voodoo. Why do people recommend not stroking? Is it because the piston wears faster with the stroked shortblock? How does it make a difference whether it is N/A or boosted?
I see sponsors and regualr people do forced induction with strokers a lot.
I see sponsors and regualr people do forced induction with strokers a lot.
11-16-2012, 09:46 AM
#2
Long strokes are frowned upon in iron blocks because of the sleeve length. When you increase stroke it obviously pulls the piston down further in the bore at BDC for a longer cylinder fill. In an iron block what happens is the skirt of the piston ends up being pulled far enough below the sleeve that it allows the piston to rock in the bore. This scuffs the skirts of the piston and after a while can allow oil consumption issues.
With some of the coating technologies of today that piston manufacturers are using on their piston skirts the chance of scuffing them is reduced, but the problem of the sleeve being too short persists.
A LS2 block has longer sleeves and doesn't have this problem or at least to the extent of an iron block. When a company like ERL or RED re-sleeves an engine the sleeves they use are usually longer than the stock sleeves to remedy this problem.
I think it all comes down to how much faith you have in your engine builder and your individual set-up. Me personally I wouldn't be afraid of stroking a turbo motor with up to a 4" crank.
With some of the coating technologies of today that piston manufacturers are using on their piston skirts the chance of scuffing them is reduced, but the problem of the sleeve being too short persists.
A LS2 block has longer sleeves and doesn't have this problem or at least to the extent of an iron block. When a company like ERL or RED re-sleeves an engine the sleeves they use are usually longer than the stock sleeves to remedy this problem.
I think it all comes down to how much faith you have in your engine builder and your individual set-up. Me personally I wouldn't be afraid of stroking a turbo motor with up to a 4" crank.
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11-16-2012, 04:08 PM
#8
Wasn't trying to take anything away from you, just adding a little bit more info.
Anytime you add stroke to an engine of any type, you are correct, it will try and basically shove the piston out of the side of the block. Increased rod length, and adjusting pin height with your piston combination will significantly help.
Also as Martin said piston coatings are REALLY helping wear in engines now.
We experimented with micro-blue coatings about 6 years ago, the amount of reduced friction and reduced wear on parts is unreal.
Anytime you add stroke to an engine of any type, you are correct, it will try and basically shove the piston out of the side of the block. Increased rod length, and adjusting pin height with your piston combination will significantly help.
Also as Martin said piston coatings are REALLY helping wear in engines now.
We experimented with micro-blue coatings about 6 years ago, the amount of reduced friction and reduced wear on parts is unreal.
11-16-2012, 04:12 PM
#9
Wasn't trying to take anything away from you, just adding a little bit more info.
Anytime you add stroke to an engine of any type, you are correct, it will try and basically shove the piston out of the side of the block. Increased rod length, and adjusting pin height with your piston combination will significantly help.
Also as Martin said piston coatings are REALLY helping wear in engines now.
We experimented with micro-blue coatings about 6 years ago, the amount of reduced friction and reduced wear on parts is unreal.
Anytime you add stroke to an engine of any type, you are correct, it will try and basically shove the piston out of the side of the block. Increased rod length, and adjusting pin height with your piston combination will significantly help.
Also as Martin said piston coatings are REALLY helping wear in engines now.
We experimented with micro-blue coatings about 6 years ago, the amount of reduced friction and reduced wear on parts is unreal.
I know that compression height, pin height, rod length and ring land thickness play their own parts in this equation also, I'm just not near as well versed in engine building as I am other areas. I'm building my stroker motor myself though with the help from my boss Jonathan, but until then I'm pretty green in assembly.
11-16-2012, 07:47 PM
#10
What the difference in a 370 vs a 408 on longevity? I mean are you going to get 100,000 miles out of a boosted 370 or 408 spinning 7,000 rpms with a big turbo on it? Answer is no. Is the wear difference noticeable? Probably not. I say stroker motors do well on a big single better than a smaller non stroked motor because torque numbers are usually higher in the lower rpms and this offsets the later spool time of a larger turbo. When it comes to high rpm power the non stroked motor shines. On a street car I say the stroker motor shines. Just my 2 cents. . .
11-16-2012, 08:09 PM
#11
I had a ProCharged 383 LT1 in my '95 TA. No problems.
My solution (which others may disagree with) is simple. Over build. Spec out parts that can take 1000HP. Then build an engine making 800HP.
The TA was a daily driver, with periodic blasts, not a full time race car. But it had about 160K on it when it grenaded.
My solution (which others may disagree with) is simple. Over build. Spec out parts that can take 1000HP. Then build an engine making 800HP.
The TA was a daily driver, with periodic blasts, not a full time race car. But it had about 160K on it when it grenaded.
Last edited by Dirty Dog; 11-17-2012 at 06:35 PM.
11-17-2012, 02:08 PM
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I had a ProCharged 383 LT1 in my '95 TA. No problems.
My solution (which others ay diagree with) is simple. Over build. Spec out parts that can take 1000HP. Then build an engine making 800HP.
The TA was a daily driver, with periodic blasts, not a full time race car. But it had about 160K on it when it grenaded.
My solution (which others ay diagree with) is simple. Over build. Spec out parts that can take 1000HP. Then build an engine making 800HP.
The TA was a daily driver, with periodic blasts, not a full time race car. But it had about 160K on it when it grenaded.
11-17-2012, 06:11 PM
#14
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Without a taller deck though, you're never going to find the room for a longer rod, or being able to move the pin any further up towards the crown on a boosted engine.
Even the off the shelf pistons have the pin cut right through the oil control ring.
Even the off the shelf pistons have the pin cut right through the oil control ring.
01-21-2013, 12:49 PM
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i can bet your not going have big problems with a boosted 408 as these builds are done quit a bit, now a lot depends who builds the engine, how good the machine work is done.. and how much prep work is done and attention to detail before assembly.. check, recheck and recheck!!! as with any increase stroke engine, the difference is made up in the piston pin height depending on rod lenght and what stroke crank you want to run, offset grinds, or what have you...... I say if a 408 is what you want BUILD IT...
01-21-2013, 03:53 PM
#19
Iron 390...best of both. Cubes and its a short stroker.......
FWIW....my 4.125" stroked 427ci built in 2002....with the shortest sleeves ever made back in 2001-2002 took me to 173,000 miles without any issues at all. Needs to be built right, thats all.
Also......perhaps the best turbo engine builder on the planet...NRE...does most of his engines with stroker cranks and they are all just fine. His 454ci LSX iron block makes 2,500 HP........
I like the disassemble video of one of his LSX TT 1,000+ HP engines doing over 100 dyno pulls....tears down the engine and all the parts literally look brand new out of the box.
Just gotta build'em right......
.
FWIW....my 4.125" stroked 427ci built in 2002....with the shortest sleeves ever made back in 2001-2002 took me to 173,000 miles without any issues at all. Needs to be built right, thats all.
Also......perhaps the best turbo engine builder on the planet...NRE...does most of his engines with stroker cranks and they are all just fine. His 454ci LSX iron block makes 2,500 HP........
I like the disassemble video of one of his LSX TT 1,000+ HP engines doing over 100 dyno pulls....tears down the engine and all the parts literally look brand new out of the box.
Just gotta build'em right......
.
Last edited by LS6427; 01-23-2013 at 02:15 PM.
