Mark A. Rogalski

iTrader: (1)

Seems like it should do more HP and for longer with these adds.

98 WS6 (31k miles). Crane 1.8 rockers, pushrods, etc. this week
Z06 cluth assembly and hydraulics this week
LT Jet Hots and a true dual exhaust system.

I was told "The car had a spark knock, even though you could not here it much, so we tuned it to get the knock out."

Any idea on what's going on here? The car seems to have steady power now..but less of it.

WS6FirebirdTA00

iTrader: (33)

u dont have to hear knock to have it. if the clutch was put in this week it may not be broken in and could be slipping on you at high rpms

BlueSix

Looks fine to me, makes peak power at 5500 rpm and then begins to fall off.

ATTI2D

iTrader: (1)

Has the intake been off.. I had a problem with KR and traced it to the wireharness for the knock sensors. It would kick back timing 4* and go to low octane tables. Worth a shot to check.

Mark A. Rogalski

iTrader: (1)

No, never had the intake off.

MeentSS02

iTrader: (11)

I wonder if you need to change the valve springs...

WS6FirebirdTA00

iTrader: (33)

he has another thread going and he said he went to dual springs

MeentSS02

iTrader: (11)

Nevermind that then...

BrentB@TEA

looks like valve float.
I don't think the heavy aftermarket rockers are a good idea on LS1 cars. When you change the ratio to something even more agressive I think it is even worse.

verbs

valvefloat. change your valvesprings.

Nickn20

have that graph printed out on a landscape(wide) view and repost it, I think it just looks skewed possibly, the unsmooth lines may be KR.

jaberwaki

does not look like valve float at all to me...
usually valve float produces a choppy tq curve in the upper rpms sometimes so bad it looks like a decending iratic heartbeat...
the 2 places i would look are.

1. his valve train is Way too heavy for what he has, as stated before swap back the 1.7's, also if this is a stock cam, then the spring pressure is too much for what you got, a heavy valve train will definatly restrict high rpm performance..

2. He has a 98, with an untouched intake, meaning he has a ls1 not ls6 intake, could he be hitting the wall there?

mikey

iTrader: (6)

It is valvetrane harmonics caused by wrong spring / rocker combination. Change back to the stock rockers and it will go away. Are you using PRC spring or equiv?

Mikey

Mark A. Rogalski

iTrader: (1)

You guys have been awsome. When you say "to heavy" you mean that it is to stiff? It is all new Crane 1.8s, Crane dual springs, Crane pushrods, Crane titanium retainers all for the LS1 engine. I thought this lightens the valvetrain.

jaberwaki

yes too stiff, the springs anyways,
also the 1.8 rockers as mikey said are wronge for your set up, keep the push rods and the retainers...

mrr23

iTrader: (3)

the rockers aren't wrong for his setup. i have the same vinci/crane dual springs, titanium retainers, pushrods, and 1.8 accelerated lift rockers with the stock cam as well.

here's my before and after dyno. it's not valve float, too much spring pressure, or rockers too heavy. it's just plain stock cam petering out.

and the wife's car made more power before the rockers that his did after he put the rockers, LTs and dual exhaust. at the time the wife's dynos was run, all it had was lid, filter, MAF ends, bassani 1 3/4 optimum length headers, hi flow cats and borla 3" catback and on stock tune. and to boot, her's is an auto with stock converter. so, it should be lower than his. seeing that his is a manual. her car also has about double his miles 60K at that time.

so. i'd say he needs to look elsewhere.

jaberwaki

your post doesn't make any sence...
you say its his stock cam puttering out (at 54-5500) then post a graph of yours pulling to over 6000...
you say his set up is not wronge, but say your wifes car was making more power then his, before she put in the rockers...
with your mph on a stock cam i must assume you are spraying right?
well then the duel springs might be ok for you, but they are too much for his N/A stock cam ...

Mark A. Rogalski

iTrader: (1)

I agree Jaberwaki, it is something with the way these Crane components were installed. Stock cams are fine with these additions. According to Joe Vinci, the components I added from Crane enhance the performance and don't impeed it espeacially with the OEM cam.

mrr23

iTrader: (3)

my post makes complete sense once you look at it properly. with the mph on a stock cam yes i am spraying. but the dyno is NA. so again, it's not the springs themselves being too stiff as you say. if that dyno was with spray it wouldn't be 333hp that for sure. because i use 175 n2o on top of that 333rwhp number. if you look closer a the graph, her car peaks at the same 5400 rpms. then tapers off. granted not as much as his does.

what you are saying about the springs being too stiff for a stock cam is what's wrong. because apparantly they aren't too stiff for my stock cam. now, what mark is saying about the components installed wrong, it might be in the way they set the preload for the lifters.

70 TA

I know of someone else that had the same problem recently with these rockers where the valve springs couldn't keep things under control.

I'd say its better to use a cam that has the lift you want ground into it for use with stock ratio.