Author Topic: Reving past red line  (Read 4550 times)

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Offline tortoise

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Re: Reving past red line
« Reply #15 on: September 12, 2016, 12:53:52 AM »
My experience on the big white dyno is that once you reach the highest point of the torque curve in high gear you are all in.  The engine  wont pull past that peak.
Maybe try a little bigger back sprocket.
« Last Edit: September 12, 2016, 12:55:36 AM by tortoise »

Offline SPARKY

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Re: Reving past red line
« Reply #16 on: September 12, 2016, 01:12:09 AM »
I under geared and set on record at 298  at 7850----I changed the combo to go through the traps with a smaller tire and right around peak hp at 6850  this was with my old eng which peak hp was at 6875---

that actually gave me 15 more ft lbs of TE as the tire was smaller and I hat much more torque available at that place in the power curve


HR  you got a record I got the first NA Blue hat for a Lakester-- the record was for a day the hat is forever a JD likes to say  :-)
« Last Edit: September 12, 2016, 11:36:19 AM by SPARKY »
Miss LIBERTY,  changing T.K.I.  to noise, dust, rust, BLUE HATS & hopefully not scrap!!

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Offline fordboy628

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Re: Reving past red line
« Reply #17 on: September 12, 2016, 06:03:56 AM »
My experience on the big white dyno is that once you reach the highest point of the torque curve in high gear you are all in.  The engine  wont pull past that peak.

My guess is that: that rpm is where your drag hp = bhp available.

When power available = power required, that defines top speed, as no further acceleration is possible.   Sometimes you can "wiggle things around a bit" with tiny splits of gear ratio (say 2% or so) but this might only result in an engine rpm change, at the same or similar speed.   Kinda depends on the aspect ratio (flatness) of your power curve.

BUT, depending on the situation, a tiny gain MIGHT just get you a record.   If it is your last option, you SHOULD try it.    After all, nothing gained by not trying . . . . .

 :cheers:
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Offline Interested Observer

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Re: Reving past red line
« Reply #18 on: September 12, 2016, 08:39:16 AM »
Quote
My experience on the big white dyno is that once you reach the highest point of the torque curve in high gear you are all in.  The engine  wont pull past that peak.

Quote
My guess is that: that rpm is where your drag hp = bhp available.

While, in this instance, the car would not pull beyond the torque peak doesn’t mean that the torque peak somehow defines the limit of what is possible.  It is almost certain that the hp peak was further up the rpm scale and that a gearing change would bring the hp peak into play and allow improved speed.

Indeed, the drag may have equalled the horsepower available at that speed, but more power was probably available if the gearing had allowed reaching the higher rpm.  The trick is to match the maximum power to the drag and hopefully avoid dips in the curve that prevent approaching the max (a la Grenade).