My car has the lt4 hotcam kit in it with about 1,000 miles on it. When I rev it it seems to stop reving at 6,000 rpm's. I had the stock rev limiter set to 7,000 rpm so im thinking im getting valve float with the lt4 springs. Does this sound right? Also Will the hotcam make power above 6,000 rpm's? Id like to rev it a little higher if I could make a little more power up top. What would be a good spring to get the most out of my hotcam? And Whats a good shift point with 342 gears and stalled a4?

 

hmm sounds like a problem. my friend has an Lt4 SS that was upgraded to the hottcam back in '98 dynotuned by Ed Wright she pulls to 6400 with no problems....... what else was changed?
many have this cam and spring combo without this problem.just trying to get more understanding.

 

Nothing else was changed, just the hotcam kit. The car revs strong all the way to 6 ggrand where it just stops reving like its hitting a wall. I pretty sure your friens lt4 car has lighter valves and allows the use of lt4 springs without valve float. The lt1 valves are heavier than the hollow lt4 valves

 

oh for sure, i know about the lighter valves but other people have this set up with Lt1s and regular valves and do not have this sort of problem. that's the only reason i asked if anything else was done.. do you know what your valvespring installed height is?

 

While the LT4 springs are just good enough for the LT4 hot cam, it shouldn't stop reving at 6k. I would suspect your valve lash adjustment of your rockers to be the problem.

 

IMHO the LT4 springs suck unless used with LT1 or LT4 (non hot) cams. Get some nice beehives.

 

Ill have to check my valve lash, I only set then 1/4 turn past zero lash. Maybe I should run them at zero lash? Not sure on installed height? I just installed them the way they came. No shims

 

1/4 turn should be ok, I always use 1/2, but that wouldn't cause you to stop reving. Did you adjust them with the car off or running? I would readjust them with the car running.

 

I adjusted them with the car running

 

what does it do at 6k? stop revving like it hit a limiter? start bucking like a missfire?

 

Yup feels like it hits a limiter

 

Anyone have this problem with the lt4 springs?

 

if it seems like a limiter then I'd have someone check the tune and make sure it's set at 7k not 6k

when did it start doing this? after the cam swap? after the tune?

another thing is maybe your trans won't shift under WOT due to either a failing transmission, vacuum leak, bad map, etc

one time I had a severe vacuum leak and my car wouldn't shift under WOT and would hit a wall until I let off and got back on it

 

I never tried to rev it past 6 grand with the stock cam. Its shifts fine right at 6 grand. Im reving it in park. When it just wont go past 6200

 

why do you need to rev it that high in park anyways?

 

I bet its the rev limiter your hittin. I doubt pcm for less would set the limiter at 7k on that setup. Hell bryan has mine set at 6800rpm. I would think 6k is all you need to rev it to anyways.

 

factory tach could be off (common) at high rpm, you could be higher than you think. how does the car run otherwise?

 

Usually gm tachs read low by 200rpm.

 

It runs good otherwise. I told Bryan to remove the limiter all together. I also told hime to get rid of the lockup @ 95mph wich he didnt do, so who knows?