Any DeStrokers or Short Strokers out there with 4.125 bore
09-17-2007, 05:51 PM
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Any DeStrokers or Short Strokers out there with 4.125 bore I am just wondering if anyone is running a 4.125 bore block with the standard LSX crank. I would think it would rev a hell of a lot quicker than the 4.00 stroke on the 427.
Or in the end, are you just defeating the purpose of the big bore by giving up the cubes you get with the 4.00 stroke?
Or in the end, are you just defeating the purpose of the big bore by giving up the cubes you get with the 4.00 stroke?
09-17-2007, 10:20 PM
#2
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Originally Posted by Derek 357i
I am just wondering if anyone is running a 4.125 bore block with the standard LSX crank. I would think it would rev a hell of a lot quicker than the 4.00 stroke on the 427.
Or in the end, are you just defeating the purpose of the big bore by giving up the cubes you get with the 4.00 stroke?
Or in the end, are you just defeating the purpose of the big bore by giving up the cubes you get with the 4.00 stroke?
If you don't have rules go big!
09-18-2007, 07:41 AM
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I just saw the new Carol Shelby supercar uses a 4.125 bore and 3.62 crank in the twin turbo application. I didn't see anywhere if it was a GM or Ford based engine, but that stroke makes me think the former. Did he see the light?
09-18-2007, 01:57 PM
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Originally Posted by Derek 357i
I just saw the new Carol Shelby supercar uses a 4.125 bore and 3.62 crank in the twin turbo application. I didn't see anywhere if it was a GM or Ford based engine, but that stroke makes me think the former. Did he see the light?
09-18-2007, 09:39 PM
#7
Originally Posted by Old SStroker
If you don't have rules go big!
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09-20-2007, 07:33 PM
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Destroking an engine is a good idea if you want high end hp and limit low end tq.
I have been thinking of doing this for road-racing, because you can turn more rpm, it will spool up faster, and you can use any of the great flowing big bore heads.
Also when you come off of corners you won't have to feather the throttle as much because there won't be as much low end torque.
I hear so many people say they wan't a ton of low end tq for road racing, but you can only put so much power down to the ground.
With a destroked motor you would have similar top end power and you would spool up sooner and probably have better control of the car on corner exit as well as when stroker boy is shifting you will keep on spinning right by him!!
Just my opinion
I have been thinking of doing this for road-racing, because you can turn more rpm, it will spool up faster, and you can use any of the great flowing big bore heads.
Also when you come off of corners you won't have to feather the throttle as much because there won't be as much low end torque.
I hear so many people say they wan't a ton of low end tq for road racing, but you can only put so much power down to the ground.
With a destroked motor you would have similar top end power and you would spool up sooner and probably have better control of the car on corner exit as well as when stroker boy is shifting you will keep on spinning right by him!!
Just my opinion
09-20-2007, 08:06 PM
#9
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Originally Posted by LT-4Play
Destroking an engine is a good idea if you want high end hp and limit low end tq.
I have been thinking of doing this for road-racing, because you can turn more rpm, it will spool up faster, and you can use any of the great flowing big bore heads.
Also when you come off of corners you won't have to feather the throttle as much because there won't be as much low end torque.
I hear so many people say they wan't a ton of low end tq for road racing, but you can only put so much power down to the ground.
With a destroked motor you would have similar top end power and you would spool up sooner and probably have better control of the car on corner exit as well as when stroker boy is shifting you will keep on spinning right by him!!
Just my opinion
I have been thinking of doing this for road-racing, because you can turn more rpm, it will spool up faster, and you can use any of the great flowing big bore heads.
Also when you come off of corners you won't have to feather the throttle as much because there won't be as much low end torque.
I hear so many people say they wan't a ton of low end tq for road racing, but you can only put so much power down to the ground.
With a destroked motor you would have similar top end power and you would spool up sooner and probably have better control of the car on corner exit as well as when stroker boy is shifting you will keep on spinning right by him!!
Just my opinion
Sometimes you find that you are faster in a higher gear where the (stroker's) torque response to the tires is "damped" not by lack of torque but by the lack of gear. When you have the traction to put more down it's there. In the hands of a competent driver more torque makes it faster. No offense intended.
09-20-2007, 08:53 PM
#10
Originally Posted by Old SStroker
That's one approach. Another is to build a strong flat torque curve (stroker) that will pull you along with fewer gear changes and put the HTC (human traction control) in the driver's right foot.
Sometimes you find that you are faster in a higher gear where the (stroker's) torque response to the tires is "damped" not by lack of torque but by the lack of gear. When you have the traction to put more down it's there. In the hands of a competent driver more torque makes it faster. No offense intended.
Sometimes you find that you are faster in a higher gear where the (stroker's) torque response to the tires is "damped" not by lack of torque but by the lack of gear. When you have the traction to put more down it's there. In the hands of a competent driver more torque makes it faster. No offense intended.
09-20-2007, 11:03 PM
#11
Originally Posted by LT-4Play
Destroking an engine is a good idea if you want high end hp and limit low end tq.
I have been thinking of doing this for road-racing, because you can turn more rpm, it will spool up faster, and you can use any of the great flowing big bore heads.
Also when you come off of corners you won't have to feather the throttle as much because there won't be as much low end torque.
I hear so many people say they wan't a ton of low end tq for road racing, but you can only put so much power down to the ground.
With a destroked motor you would have similar top end power and you would spool up sooner and probably have better control of the car on corner exit as well as when stroker boy is shifting you will keep on spinning right by him!!
Just my opinion
I have been thinking of doing this for road-racing, because you can turn more rpm, it will spool up faster, and you can use any of the great flowing big bore heads.
Also when you come off of corners you won't have to feather the throttle as much because there won't be as much low end torque.
I hear so many people say they wan't a ton of low end tq for road racing, but you can only put so much power down to the ground.
With a destroked motor you would have similar top end power and you would spool up sooner and probably have better control of the car on corner exit as well as when stroker boy is shifting you will keep on spinning right by him!!
Just my opinion
I'm not sure I follow the logic.
09-20-2007, 11:40 PM
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Originally Posted by Derek 357i
I just saw the new Carol Shelby supercar uses a 4.125 bore and 3.62 crank in the twin turbo application. I didn't see anywhere if it was a GM or Ford based engine, but that stroke makes me think the former. Did he see the light?
09-21-2007, 09:22 AM
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The idea of the whole thing came about from the same guys that brought you the C5-R and C6.R. Pratt and Miller ran a destroked 7.0 block with the CTS-VR and did pretty good in the Speed GT class. And yes I do understand the Vette is faster than the Caddy!
Technically the C5-R and C6.R are destroked they run a 4.000 stroke and a 4.125 bore. Most strokers are at least square some are over square, 4.100 stroke and 4.000 bore etc.
When road racing there is no one way, I've watched vintage racing where you have NASCAR quality small blocks spinning at almost 9000 rpm hanging (sometimes passing) with 427 and 454 bb that are turning less than 6000. At Road America which is basically a big dragstrip. Different strokes for different folks.
My theory is that the destroked motor will be easier to drive, rev faster and higher than it's stroked brother. More than likely it will be easier on it's components and the driveline for that matter.
Eather way the car will go like hell!!
Technically the C5-R and C6.R are destroked they run a 4.000 stroke and a 4.125 bore. Most strokers are at least square some are over square, 4.100 stroke and 4.000 bore etc.
When road racing there is no one way, I've watched vintage racing where you have NASCAR quality small blocks spinning at almost 9000 rpm hanging (sometimes passing) with 427 and 454 bb that are turning less than 6000. At Road America which is basically a big dragstrip. Different strokes for different folks.
My theory is that the destroked motor will be easier to drive, rev faster and higher than it's stroked brother. More than likely it will be easier on it's components and the driveline for that matter.
Eather way the car will go like hell!!
09-21-2007, 09:29 AM
#14
Originally Posted by LT-4Play
The idea of the whole thing came about from the same guys that brought you the C5-R and C6.R. Pratt and Miller ran a destroked 7.0 block with the CTS-VR and did pretty good in the Speed GT class. And yes I do understand the Vette is faster than the Caddy!
Technically the C5-R and C6.R are destroked they run a 4.000 stroke and a 4.125 bore. Most strokers are at least square some are over square, 4.100 stroke and 4.000 bore etc.
When road racing there is no one way, I've watched vintage racing where you have NASCAR quality small blocks spinning at almost 9000 rpm hanging (sometimes passing) with 427 and 454 bb that are turning less than 6000. At Road America which is basically a big dragstrip. Different strokes for different folks.
My theory is that the destroked motor will be easier to drive, rev faster and higher than it's stroked brother. More than likely it will be easier on it's components and the driveline for that matter.
Eather way the car will go like hell!!
Technically the C5-R and C6.R are destroked they run a 4.000 stroke and a 4.125 bore. Most strokers are at least square some are over square, 4.100 stroke and 4.000 bore etc.
When road racing there is no one way, I've watched vintage racing where you have NASCAR quality small blocks spinning at almost 9000 rpm hanging (sometimes passing) with 427 and 454 bb that are turning less than 6000. At Road America which is basically a big dragstrip. Different strokes for different folks.
My theory is that the destroked motor will be easier to drive, rev faster and higher than it's stroked brother. More than likely it will be easier on it's components and the driveline for that matter.
Eather way the car will go like hell!!
The point that OLDSStroker was trying to make is that there is no point to run a smaller engine when the rules allow for it. When displacement limited, then yes, a larger bore and consequentially a shorter stroke will allow for more power "potential" due to being able to run a better (read larger) head. It will allow larger valves, which in turn will allow more air(hopefully!!)
Yes the smaller, higher revving engines will produce great upper HP, but the rpms do take their toll. Engine life is decreased by the increased rpms and average cost is greater I would guess.
09-21-2007, 10:54 AM
#15
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SStrokerAce seriously autocrosses (SCCA Solo II) his stock-engined '00 Camaro SS. He's well up in the regional points now. When he went from running 1st gear in the upper rpm range to 2nd gear in the low/mid range of the torque curve, he got faster. There was aproximately the same torque available at the tires (very sticky gumballs),with perhaps more in 1st, but it was more controllable in 2nd. That's the analogy I used for the Big vs. Small displacement engine.
He's very good, but he got better (quicker) when his EVO instructor suggested using the higher gear. I will say riding with him on an airport Solo II course is an "E-Ticket" ride!
The C6R cars are easy to drive from what I hear, especially the LeMans restricted ones. Table-top flat torque in copious amounts even with tiny restrictors.
FWIW: I guess most folks consider 'destroking" as decreasing the stock stroke (or whatever you are running), not comparing it to the bore as in "bore/stroke ratio". B/S >1 (Bore larger than stroke) is considered "oversquare", B/S = 1 (same Bore and stroke) is considered "square" and B/S < 1 (Bore smaller than stroke) is considered "undersquare".
Current wisdom for endurance engines and some "gernades" like Pro Stock (with displacement limits) is as much oversquare as you can get. F1 engines have B/S > 2, Cup B/S > 1.28, and PS B/S >1.3 or thereabouts. Original LS7-based 5.7L CTSV-R B/S>1.25. I think they pushed them back to LS6 architecture a couple of years ago so they may now be B/S ~1.07. The Daytona Prototypes with 5L LS6-base engines are B/S~1.2 because they are limited in bore size by the rules.
He's very good, but he got better (quicker) when his EVO instructor suggested using the higher gear. I will say riding with him on an airport Solo II course is an "E-Ticket" ride!
The C6R cars are easy to drive from what I hear, especially the LeMans restricted ones. Table-top flat torque in copious amounts even with tiny restrictors.
FWIW: I guess most folks consider 'destroking" as decreasing the stock stroke (or whatever you are running), not comparing it to the bore as in "bore/stroke ratio". B/S >1 (Bore larger than stroke) is considered "oversquare", B/S = 1 (same Bore and stroke) is considered "square" and B/S < 1 (Bore smaller than stroke) is considered "undersquare".
Current wisdom for endurance engines and some "gernades" like Pro Stock (with displacement limits) is as much oversquare as you can get. F1 engines have B/S > 2, Cup B/S > 1.28, and PS B/S >1.3 or thereabouts. Original LS7-based 5.7L CTSV-R B/S>1.25. I think they pushed them back to LS6 architecture a couple of years ago so they may now be B/S ~1.07. The Daytona Prototypes with 5L LS6-base engines are B/S~1.2 because they are limited in bore size by the rules.
09-21-2007, 06:22 PM
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Originally Posted by Old SStroker
SStrokerAce seriously autocrosses (SCCA Solo II) his stock-engined '00 Camaro SS. He's well up in the regional points now. When he went from running 1st gear in the upper rpm range to 2nd gear in the low/mid range of the torque curve, he got faster. There was aproximately the same torque available at the tires (very sticky gumballs),with perhaps more in 1st, but it was more controllable in 2nd. That's the analogy I used for the Big vs. Small displacement engine.
He's very good, but he got better (quicker) when his EVO instructor suggested using the higher gear. I will say riding with him on an airport Solo II course is an "E-Ticket" ride!
The C6R cars are easy to drive from what I hear, especially the LeMans restricted ones. Table-top flat torque in copious amounts even with tiny restrictors.
He's very good, but he got better (quicker) when his EVO instructor suggested using the higher gear. I will say riding with him on an airport Solo II course is an "E-Ticket" ride!
The C6R cars are easy to drive from what I hear, especially the LeMans restricted ones. Table-top flat torque in copious amounts even with tiny restrictors.
My big interest in the smaller stroke is Road America, plain and simple. At RA most of the corners are 3rd gear corners, if you run a square or oversquare motor you will have your hands full all day on corner exit, the car will simply be able to light up the tires as soon as you try to put power down. This would require you to feather the throttle, and be on your game all day long. A destroked engine will give you the same peak power and give you a couple of extra rpm so you can stay in a 3rd in areas that you would have to short shift into 4th for a 1/2 second. In a C5 with 3.42 gears and a M12 box at Road America and having a motor that car spin past 7k rpm would be great especially if you can give the car more throttle on corner exit and still hit the same top speed.
Yes a stroker with a skilled driver will pull on you on corner exit but if he has to short shift, say 5 times a lap and you can avoid those same shifts and let er' spin my guess is you will have a faster lap time, and be able to concentrate on your braking and cornering instead of extra upshifts and downshifts.
Also if the C6.R runs a 4.187 bore with a 3.xxx stroke that would prove my point even better seeing that the car is easy to drive and has a small stroke.
09-21-2007, 11:30 PM
#17
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Originally Posted by LT-4Play
I started out autocrossing before I started doing HPDE's and I agree 100% that when you run autocross courses in 2nd you have more control and run much faster times. Because you are able to control the car much better on corner exit and just work on carrieing your momentum. That is also with a car that puts down maybe 350 rwtq peak and less than 3000 ft lbs at 3000 rpm, once you start looking at say a 413 LS2 you are closer to 400+ ft lbs at 3000 rpm, then the car isn't as controlable. I'd like to try it but haven't been able to yet.
My big interest in the smaller stroke is Road America, plain and simple. At RA most of the corners are 3rd gear corners, if you run a square or oversquare motor you will have your hands full all day on corner exit, the car will simply be able to light up the tires as soon as you try to put power down. This would require you to feather the throttle, and be on your game all day long. A destroked engine will give you the same peak power and give you a couple of extra rpm so you can stay in a 3rd in areas that you would have to short shift into 4th for a 1/2 second. In a C5 with 3.42 gears and a M12 box at Road America and having a motor that car spin past 7k rpm would be great especially if you can give the car more throttle on corner exit and still hit the same top speed.
Yes a stroker with a skilled driver will pull on you on corner exit but if he has to short shift, say 5 times a lap and you can avoid those same shifts and let er' spin my guess is you will have a faster lap time, and be able to concentrate on your braking and cornering instead of extra upshifts and downshifts.
Also if the C6.R runs a 4.187 bore with a 3.xxx stroke that would prove my point even better seeing that the car is easy to drive and has a small stroke.
My big interest in the smaller stroke is Road America, plain and simple. At RA most of the corners are 3rd gear corners, if you run a square or oversquare motor you will have your hands full all day on corner exit, the car will simply be able to light up the tires as soon as you try to put power down. This would require you to feather the throttle, and be on your game all day long. A destroked engine will give you the same peak power and give you a couple of extra rpm so you can stay in a 3rd in areas that you would have to short shift into 4th for a 1/2 second. In a C5 with 3.42 gears and a M12 box at Road America and having a motor that car spin past 7k rpm would be great especially if you can give the car more throttle on corner exit and still hit the same top speed.
Yes a stroker with a skilled driver will pull on you on corner exit but if he has to short shift, say 5 times a lap and you can avoid those same shifts and let er' spin my guess is you will have a faster lap time, and be able to concentrate on your braking and cornering instead of extra upshifts and downshifts.
Also if the C6.R runs a 4.187 bore with a 3.xxx stroke that would prove my point even better seeing that the car is easy to drive and has a small stroke.
I don't understand how your tires don't get the power down. Still using the GY EMTs?
With a broad flat torque curve the big, slow engine doesn't "short shift" to a higher gear. Rather you can pull from a lower rpm in any gear and actually shift less that a smaller peakier engine.
Not trying to change your mind. Just point out some things.
09-22-2007, 12:30 AM
#18
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A short stroke may make good peak power but not have low end torque. I think what LT is trying to say is this may work in a road race car when you apex the corner at 3500rpm, do you want max toque then, no I don't have my foot to the floor until I'm around the corner and hit 4200. So a short stroker may work, it will hit the power band when you need it. It worked in the TransAM series. 4.06 bore x 3.0 stroke.
Short strokers work if you are looking for big peak power and don't need the low end torque. This is a good combination in a light car.
Short strokers work if you are looking for big peak power and don't need the low end torque. This is a good combination in a light car.
09-22-2007, 02:24 AM
#20
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Originally Posted by Derek 357i
I am just wondering if anyone is running a 4.125 bore block with the standard LSX crank. I would think it would rev a hell of a lot quicker than the 4.00 stroke on the 427.
Or in the end, are you just defeating the purpose of the big bore by giving up the cubes you get with the 4.00 stroke?
Or in the end, are you just defeating the purpose of the big bore by giving up the cubes you get with the 4.00 stroke?
Bigger bores allow more ultimate power and the bigger the stroke the more you will see of that power at lower rpms.
Destroking as a rule is never done to go faster in racing but since we have cubic inch rules and the bore determines ulimate power potential you will usually see the biggest bore you can run unless rpm is very limited.
So another words the stroke is only decreased since the bore is increased and the cubes have to stay the same.
A TRUE DESTROKER would be like if F1 or NASCAR or PS ran the largest bore possible within their rules and then ran even LESS stroke than needed to max out the displacement. You will not see this on any normal race engine ever.