Early C4 Tach Reading Question
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Early C4 Tach Reading Question
I was curious where the factory rev limiter was on my 1988 Corvette with the L98 so I held it in gear and spun it up until the tach said 7000 rpm and then I got scared and backed off. I know, not very wise with valve float and the possibility of a piston punching a valve but it ended up being okay. However, the reading on the digital tach was super sporadic past about 6000rpm where the tach reading would change several hundred rpm constantly without my speed, load, throttle input, or sound changing. Do these cars just suck at reading the engine speed past 6000 rpm? And if so, how can I change that for the better? I'm building an L98 that will rev past what the the factory motor can but would like to keep the factory digital cluster.
Team Owner
Joined: Sep 2001
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From: Athens AL
C7 of the Year - Unmodified Finalist 2021
C4 of Year Finalist (performance mods) 2019
There is no rev limiter, its a fuel cutoff and in the L98s OE programming, its like 10000rpm....because the intake will never let you get there.
Thread Starter
Instructor
Joined: Jan 2022
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Team Owner
Joined: Sep 2001
Posts: 62,145
Likes: 1,730
From: Athens AL
C7 of the Year - Unmodified Finalist 2021
C4 of Year Finalist (performance mods) 2019
If you've modified the intake at all to get higher, then yes you'd probably hit valve float.
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Instructor
Joined: Jan 2022
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The question is for real but I obviously doubted the accuracy of the tach past a certain point, which is why I’m asking the question. In my original post, I said I spun it up “until the tach read 7000rm,” not stating that the motor was actually doing that. I guess the better way to phrase the question would be why does the tach become inaccurate past a certain point and can that be remedied?
