021less

iTrader: (28)

I am just wondering if the motor makes any kind of wierd noises like sounding like it is hitting off the rev limiter. Just wondering if this might be happening with my car. Sometimes it seems like it is hitting the limiter at 6400-6500 but the limiter is actually set at 6750. Could i be getting valve float of could my stock tach just be off that much?

speed_demon24

iTrader: (6)

It depends if you are getting valve float or if the valves are bouncing on the seats when the valve slams shut. The stock tack is probably lagging behind too though, what is your cam/valvetrain setup?

021less

iTrader: (28)

cam is an ms4 with prc dual springs on stock ls6 heads with a double roller timing chain with 7.4 tsp pushrods

blk00ss

iTrader: (66)

I would put money on it that its jsut your rev limiter. Yes they can be that bad off.

021less

iTrader: (28)

thats what i was thinking hopefully anyway, the car never loses any power up till then.

vettenuts

iTrader: (4)

You could throw it on a dyno and verify, just in case.

LS1Z28_98

My tach, depending where you are on the tach, is from 300 to 700 R.P.M. off. In my case the stock tach is showing more R.P.M.'s than are actually being turned

skifast87

The stock tach's have always been bad. Especially up high a lot of guys solve this by getting a shift light. My vote is your tach is lagging bad

021less

iTrader: (28)

ok, thanks fellas, that is what i was thinking, and i believe you are right. I just didn't know if it was common for them to be off up to 300 rpms. I figured it wasn't exactly accurate, but didn't know they could be that bad off.

blk00ss

iTrader: (66)

In first gear I have to shift my car around 5500rpm's or else I'll be bouncin off the limiter. Limiter is still set at 6200.

Z28FirefighterI1

iTrader: (16)

Ya the stock tach is on the money if you rev it slow, on a free rev I'm hitting my 6500 rpm shift light when my stock tach is at like 4000 rpm's. Opps.... Just a little mistake by GM. Get a gauge shift light, it goes right in a gauge pillor and has a digital tach built in. Auto meter and SW make them, there great.

BQTransAm

iTrader: (1)

If you are smoking the limiter and the tach is saying you still have some rpm to go, you aren't getting valve float, your tach is just slow. Just get a shiftlight.

I had valve float happen last summer on my car, torquer cam and prc duals. Springs had between 15 and 20k miles of abuse on them. I went to race a buddy, and the car wouldn't pull past 5500, it just flattened out. Tried everything little first, cleaning sensors, changing air filter, as it was filthy, thought maybe I got bad gas or something. I bought a new set of valve springs and took the car out and it pulled its *** off.

021less

iTrader: (28)

ok, took it down to vengeance had all my codes checked out, everything is good and it is just a slow *** tach. Thanks for the help fellas.

GuitsBoy

iTrader: (4)

If I hit it hard in first, Ill bury the motor into my 7000 rpm limiter before the tach reads 6K. A shift light is a MUST with a cammed car.

021less

iTrader: (28)

for real, depending on what i run tomorrow night will determine on what i ask for for christmas..... It will either be guages or a roll cage...hhhhmmmmmm.... I'm hoping roll cage cause i can buy the damn guages no problem (if my wife will let me).