Drastang

my mph/rpm gauges are off have been for years I have a tuner it's not the tire size. worse the faster I go seems to be about 5% faster than actual rpm/mph...would a aftermarket gauge help? any ideas I'd love them.

anyways, with just tuner, flowmasters, custom cia. around what rpm range should I stay under when making a run. atm estimating by my messed up gauges and how the car is running I'm liking 6.8k.

Z28KLR

So what happened that cause them to read incorrectly, were the needles removed for installation of an overlay?

The rev limiter will cut off fuel at around 6250 rpm, even if you could rev it to 6800 I'd be willing to bet that with a stock valvetrain it would only do it once.

It sounds to me like the needles have been removed. If you use your tuner to view pcm data you can remove the needles and put them back where they should be pointing; this happened to me when I installed an overlay where as soon as I started the car the rpm shot to like 2000 and the speedo needle lifted off the peg and showed like 10 mph while I was parked. Pull the needles off, start the car and then while seeing the pcm's reported engine speed place the needle back into the correct position. For the sppedo, pull the needle off and also remove the peg it rests on at 0 mph. Place the needle back on, pointing to about 5 or 10 mph (use your imagination since obviously there's no graduated marks there) below where the peg sits, lift the needle up and then replace the peg so it rests on it securely.

Drastang

it's been like this almost as long as I remember. I'm it's 2nd owner other guy put 6k miles and some interior trim on it but the gauges look stock, in my race tune I have no rev limit and in my street it's 6.5

guess I never noticed but yeah my mph gauge jumps a lil when I start up, also my cold start rpm jump to 2k just like you said, i'll try the fix when I get some time next week thank you.

Z28KLR

You really oughta change your rev limit settings. Unless you have aftermarket cams and heavier valve springs, there's honestly no point in revving it past 6,000 rpm. The power curve starts taking a dive at around 5600, when racing I have found a good shift point to be at around 5800; beyond that the engine is making more noise than it is power. Much higher than 6000 can damage the engine anyway, which is why the factory shuts it down at 6250. And regardless of cams, a stock cast iron crank shouldn't be spun faster than 6500.

Your car though dude, just throwin that out there.

Drastang

i had about 3 paragraph of crap,(estimating) short story i normally shift just over 6k or i can't plant the power with the stock 17's hell i can break lose in 4th(*sigh* just a few more months drag radials) I've done that for 13 years, i do understand where you are coming from, i guess my car is just use to it. i was crazy as a late teenager in this thing a lot of getting out of "sticky icky ; )" situations. i always wanted to dyno this thing because of how bad i beat all these lil turbo awd bitches.

Drastang

just went on a few end of 2nd gear runs and yes top rpm was 6034 around 64mph and at my dash I saw over 80 and around 6.3k so guess I will mess with gauges this weekend thankyou