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Discussion Starter · #1 ·
Let's say I built up another motor with a larger turbo, but I would like to retain the stock computer and use a piggy-back controller. Now, let's say the new setup is designed to pull hard all the way to about 7.5K rpm. Does the piggy-back allow the higher RPMs or will the factory computers stop it in the 6K range? If so, how can I get around it without cutting out the stock ECM and piggy-back in favor of a standalone controller. Any inputs would be helpful.
 

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With the stock computer controlling fuel/timing, you cannot raise the rev limit. If someone figures out how to go into the factory computer and modify the rev limit, then that would be the only way.
 

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the mighty dynoworks srt is shifting at 7500rpm but they are using a tech3 standalone...
 

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yeah, there at 7500 revolutions per minute.
 

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With the stock computer controlling fuel/timing, you cannot raise the rev limit. If someone figures out how to go into the factory computer and modify the rev limit, then that would be the only way.
Actually, being able to modify the stock ECU would make a lot of things obsolete :) like piggy backs, and mopar staged upgrades :)
 

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Discussion Starter · #12 ·
Compared to any other motor with a nearly 4.00" stroke. Even most big block motors have at least a 4-inch or longer and they rev pass that
 

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there is not doubt with some head work done and some cams reving to 7k or 7500 will make some power especially on these big turbo cars that don't spool till 4000 or so and are still not at there peak power when redline comes. but no ecu short of a stand alone will allow it to rev that high.
 

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edge007 said:
with a 101mm stroke @ 6200 rpms the mean piston speed is 4108 ft/min or 68.5 ft/s.
Upping the redline to 7500 rpm increses the mean piston speed to 4970 ft/min or 83 ft/s.
And isn't that considered really high? The Spec V has a 100mm stroke and they are worried about revving higher then stock.
 

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Born2Drive said:
And isn't that considered really high? The Spec V has a 100mm stroke and they are worried about revving higher then stock.
Actually, it depends on the size of the stroke vs. the size of the bore.When an engine is undersquare (like ours) it has a tough time revving, but has good low end torque (comparitively). ON the other hand an engine with a bigger bore than stroke is oversquare and will be able to rev higher due to less piston travel and time at tdc and bdc. The best setup for free revving is a square engine in which the bore and the stroke are equal.
 

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GTTechnics said:
Actually, it depends on the size of the stroke vs. the size of the bore.When an engine is undersquare (like ours) it has a tough time revving, but has good low end torque (comparitively). ON the other hand an engine with a bigger bore than stroke is oversquare and will be able to rev higher due to less piston travel and time at tdc and bdc. The best setup for free revving is a square engine in which the bore and the stroke are equal.
Thanks man, i think i understand it now.
 

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Discussion Starter · #19 · (Edited)
As far as ring flutter, just need a better design. I have heard a belt-driven vacuum pump helps the cure that. OK, if not the stock, what is recommended for a Stand-alone system? How can I use it and have the factory PCM run the dashboard, ABS, and other non-powertrain items without throwing codes?
 
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