L-98 REV LIMITER
Drifting
Joined: Nov 2000
Posts: 1,722
Likes: 0
From: Big D Tx
Cruise-In II Veteran
yes the 165ecm and the 730ecm for TPI both have a rev limiter in the prom. From the factory it is set to like 9500rpm so youll never see it. I burned my own prom and have it set to 5300 currently, not like it will pass 4900 like vash said.
Team Owner
Joined: Mar 2000
Posts: 83,384
Likes: 88
From: Boston, MA
Originally Posted by nicks87vette:
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Does a l-98 have a rev limiter?
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Craig Marcho has burned me a chip, and we set the fuel cutoff at 6600 (i think), and back on at 6550 which should hopefully bounce it around 6600 RPM if I ever screwed up that badly and hit it.
As far as I know, a fuel cutoff is the only "limiter" our L98s can have. No ignition kill. So don't be running any nitrous oxide and hit the cutoff at the same time. [img]http]//www.corvetteforum.cc/ubb/eek.gif[/img]
Pro
Joined: Jun 2000
Posts: 686
Likes: 0
From: Crystal Lake, IL USA
The mask 32 code used in 86-88 vettes will cutoff fuel based on either MPH or RPM. Four locations in the PROM control this. If you care to bit-bang, they are:
$C3A5 1 byte MPH fuel cutoff (default=255 dec)
$C3A6 2 bytes RPM cutoff (default=98 dec)
$C3A8 1 byte MPH fuel enable (default=254 dec)
$C3A9 2 bytes RPM enable (default=103 dec)
The MPH values are used directly, ie 255 MPH, but the actual RPM is calculated from the PROM value using this equation:
RPM=(65535*120)/(8*value)
For example, the default RPM cutoff is 10031, obtained by plugging 98 into the formula and the enable is 9544 RPM.
Considering the PROM values, GM certainly did decide to let the 305 intake do the rev limiting...
$C3A5 1 byte MPH fuel cutoff (default=255 dec)
$C3A6 2 bytes RPM cutoff (default=98 dec)
$C3A8 1 byte MPH fuel enable (default=254 dec)
$C3A9 2 bytes RPM enable (default=103 dec)
The MPH values are used directly, ie 255 MPH, but the actual RPM is calculated from the PROM value using this equation:
RPM=(65535*120)/(8*value)
For example, the default RPM cutoff is 10031, obtained by plugging 98 into the formula and the enable is 9544 RPM.
Considering the PROM values, GM certainly did decide to let the 305 intake do the rev limiting...
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Team Owner
Joined: Mar 2000
Posts: 83,384
Likes: 88
From: Boston, MA
Originally Posted by Hendej:
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The MPH values are used directly, ie 255 MPH,[/B][/color]
I guess I'll have to up that somehow. Should be tricky in an 8 bit system. [img]http]//www.corvetteforum.cc/ubb/smile.gif[/img]
Pro
Joined: Jun 2000
Posts: 686
Likes: 0
From: Crystal Lake, IL USA
So THAT is what is holding me back.....!!
I sure do wonder if that is what held the '88 Callaway Sledgehammer back when it topped out at (only) 254.76 MPH. Somebody forget to null out that section of code?
[This message has been edited by Hendej (edited 08-01-2001).]
I sure do wonder if that is what held the '88 Callaway Sledgehammer back when it topped out at (only) 254.76 MPH. Somebody forget to null out that section of code?
[This message has been edited by Hendej (edited 08-01-2001).]
Team Owner
Joined: Mar 2000
Posts: 83,384
Likes: 88
From: Boston, MA
Originally Posted by Hendej
I sure do wonder if that is what held the '88 Callaway Sledgehammer back when it topped out at (only) 254.76 MPH. Somebody forget to null out that section of code?
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