Hey guys, new on the board......

I have a 408ci with 11.3 c.r.
stage 3 lq9 heads (2.08/1.60)
comp cam (246/248 .603/.615 @114lsa) wth ferrea eudurance dual springs
gm lifters, chromoly pushrods, yella terra rockers

diamond pistons, callies crank and rods, iron block

etc.

The other day, i had her dynod and i was dissappointed at the results. I feel that the dyno wasnt "running" right, gus who normally dyno 440hp were dynoing 410hp!!

Anyways, i hada a huge dip from 5200 to 5800. It only showed up on the last three runs and in the same place. It could be tune related and the afr did lean ot bad at that point but i thought it to be mechanical.

Anyways, that night, i got home and heard and horrible rattling noise from the valvetrain. very, very frequent and nothing like a rod knock...

however, it went away and has been gone soon afer that.... the car does idle a bit rough, but still smooth though...

i wanted to know wat you guys think, im dropping the covers and checking the valvetrain.....

Also, i wanted to add a set of crane gold'z 1.8 accelerated rockers. Do ya'll think i will see any positive results and if in my application it is even necesary or even applicable?

thanks,
Angel

Sorry fot the long read!

 

Wow, we very seldom see any LS1 stuff in here! I have heard bad things about the YT rockers. People seem to try and stay away from them.

What kinda numbers did you put down?

 

well, im trying to see if i can swap them from the 1.8'z and not have any issues..

im seeing some "false knock" in low rpm range and at idle.....my current timing is around 24-27 at those levels so that might cause some knock....but i feel that it may be also something mechanical.

s for the numbers, teh engine dyno'd close to 600hp (591hp/553trq.) wth a ls6 manifold/ported tb. Im currently running a ls1 manifold, STOCK tb, lid and bellows!!!! major restriction for such a big motor...i know!!!

im hoping for 470/480 when all is said and done....maybe 500rwhp!!

so, those anyone have any experience or knows something about these 1.8 rockers and how they would react in my application?

im a bit confused on why this was moved from the advances section. I thought that since its a stroker motor and something of a technical question, which would require some knowledge and and opinion on your favorite choice of lid or exhaust, i thought that it belonged there......mods, please enlighten me if you wish.....

 

If it made 468RWHP thats about right for 591FWHP less intake,and drive train loss. Ya didn't say what the weather was and many things can cause a dip in the curve,fuel pump, headers,exhaust,tune,knock retard,air intake,etc. Ya have to check it and find out what it is.
More ratio rocker's will help some but maybe only 5-10HP at the most. Ya need to find out what is wrong with it before changing a bunch of stuff and get lost in the chase for HP.
It would seem to me it would have something to do with installing it in the car and possibly the intake.Without enough air it won't make HP.

 

the weather was pretty nasty, hot and humid.....not sure exactly but not nice at all. Also, the fan "cooling" was a large, but not bi enough commercial fan......lke the ones you see behind the lines in a football game...without the mist..and much older!!!

im dropping the covers soon and checking for a lose rockers or something. I got a noise the other day but is now gone!! completely.

I have here o hp tuners and she is gettin 2-3* of knock at idle and up top about 6k. I know thewe 98'z had knock sensor issues so im gonna try a few things.

brotha, i know!!!!! im not to worried about wat my peak numbers at but i feel the engine is not giving its all.....like a dud..but definitely nothing an aftermarket intake wont cure.

if the motor went 591 wth a ls6, than a 90mm setup should net about 15hp more. thats 606hp. 484.8rwhp...my goal is 500rwhp n/a.......but i know i have a few determining factors that can make me come short of my goal, one being the auto trans. maybe with a th400 i could hit 500rwhp or more!!!!

im gonna put up a pic but i have to figure that out.....
thanks!!

 

hey ya'll....its been a while

Update on the beast.

I stayed with the yelle terras at 1.7 and figured out why i had the dip in the graph and low numbers.

Well, i was lookin at my logs of the run and noticed that thin take i have now (AGAIN, the stock 98 ls1 intake, though except for lid..finally!!) was the cause because the air flow through the manifold would just fall flat at the top of the run. That where you would notice the hp reading just hit a wal and stay flat.

Secondly, as i popped open the valv covers, it was obvious that i had a spring broken. After getting all of them off, i had a total of 5 broken valve springs!!!!! yeah, WTF!!!! I contact the spring manufacturer and had them take a look at it. Soon fter, i was called and told that i was gonna receive a new set because they feared that i got a bad batch.

I installed the good ones and i havent been to the dyno yet. I'll say that this was it because the car now and has been feeling great!!!!

If i had a M6 i think the torque would be more apparent since my stall is not crazy loose but it flashes and you dont get that"acceleration-in-gear" feeling....as ifyour building up the power. MY ride is more like...ok, just driving to BAM!!!!!!!!!!!!! WTF what just happened!!!!

So, that was a while back an i apologize for not replying sooner. I'm in the works with VRE, (by the way, probably the best guys out there when you ned something.) and i got a sweet deal on a 90mm fast setup and some suspension parts in the near future.

Let see what happens and if all goes well, Nick (VRE engine builder) and I have been discussing some ideas on how to get this vert noticed!!!!

 

I'd still ditch the yella terra's in favor of the stock rockers. There's no since in having the extra weight over the valve when you don't have to. You want your valvetrain to be as light as possible, not heavier.