Mark A. Rogalski

iTrader: (1)

315/330 are the numbers today?

It's a 98 WS6 (31k miles) and its a very reputable vette shop that just installed this week:
Crane 1.8's rockers with their dual springs and tit retainers
All new Z06 clutch assembly and new slave and master hydraulics.
Car also has a true dual exhaust with X-pipe and long tube Jet Hots.

They said "Although we could not hear it, it showed engine knock and we tuned it to eliminate that".

I asked why it seemed so low with those adds. They did explain that "The 98's were around 285rwp stock so there is some improvement. We also do tuning for the most reliability and not so much the most HP".

What up here? I did notice spark knock for the first time about 2 months ago. It always happends taking off from first gear. About 4 months ago I took the car in for a PCV recall and they replaced that at the dealer.

blkZ28spt

I don't know what you'd get out of the rockers (or why you'd get them instead of a new cam) but a stock A4 98 would probably dyno 285-295 rwhp, maybe a little more. Mine only made 319 rwhp with Jet-Hots, duals and a lid.

Mark A. Rogalski

iTrader: (1)

I did not need a new cam, I did however need new rockers........

This is the actual drain plug when I changed the oil.

blkZ28spt

Well then. So long as you realize that those 1.8 rockers will effect what cams you can run if/when you get to that point. Nobody ever really needs a new cam.

Did you research the 1.8 rockers before getting them? What kind of gains are they supposed to give? On an M6 with full exhaust and a tune 315 rwhp seems a little low, and that's not accounting for the rockers. It's not necessarily off by enough to think that something is wrong, you might just have a slightly below average engine.

Don't worry too much about dyno numbers anyway. Get it to the track and see what she does.

Mark A. Rogalski

iTrader: (1)

In my conversation with them it sounded like they had to de-tune it to get out that spark knock. I am running a 2 stage air filter that I probably over oiled.

I wonder if the spark knock is from a dirty MAF.

4mula

i gained 9 rwhp with 1.85 rocker arms.
needless to say ill be cammed by months end and the rockers will be off the car

mrr23

iTrader: (3)

here's the gains i got when swapping from stock rockers to the vinci/crane 1.8 accelerated lift rockers and dual springs.

dyno 9 before
dyno 11 500 miles later
dyno 14 10 months later

4mula

needle bearings

Cody Brooks

iTrader: (2)

I dyno'd only 307 rwhp with mods in sig and stock tuning last night. On the dyno trailer that was setup downtown in Altus last night. $50 for 2 runs, numbers were lower than a dyno that would be in a shop.

Anyone know how much lower this style of dyno runs as oppossed to a dyno in shops? I'd guess 30-40 horse difference in this style dyno from the ones in shops.

mrr23

iTrader: (3)

now case in point of using 1.8 rockers with after market cams. this is a dyno of the PROJECT AFR 03 corvette vinci is doing. it compares a comp cam 224/224 .581/.581 LSA 115 with 1.7 accelerated lift rockers VS vinci 055 216/224 .551/.551 (1.7) LSA 113 with 1.8 accelerated lift rockers. this brings the total lift to .583/.583. less cam, more rocker ratio (brings total lift to the same on both cams) did better overall.

blkZ28spt

Why would that "style" dyno be lower than one in a shop? What kind of dyno was it? Considering that you have a 222/224 cam, stock manifolds and Y-pipe, stock LS1 intake AND stock tune on an A4 (with stock converter) that 307 rwhp may be pretty accurate.

Cody Brooks

iTrader: (2)

a 2002 TA 6-speed with headers, catback lid and a few others dyno'd 300 rwhp right afterwards. I've seen stock TAs get 280 at the wheels in 6 speeds no way longtubes, lid, and catback picked up only 20 at the wheels many times headers pick up 20rwhp by themselves.

Cody Brooks

iTrader: (2)

what do you think I'll pick when I get the car tuned ?

the dyno was using winpep dynojet performance evaluation program.

Mike94ZLT1

iTrader: (3)

That vette dyno chart, was that the same car?

mrr23

iTrader: (3)

yes. here's the link to the PROJECT AFR car. 03 corvette convertible. started off with AFR 205 heads on a completely stock motor. then went from there.

http://www.vincihighperformance.com/...CT%20PAGE.HTML

BrandonDrecksage

iTrader: (1)

what was your a/f ?

Mark A. Rogalski

iTrader: (1)

OK, here are the results. WHY IS THE PERFORMANCE STILL SO LOW?

Ran through a full tank of Lucas fuel & injector cleaner.
I added a K&N and cleaned the MAF with electronics cleaner
Extreme Motorsports installed the SLP LS6 intake with EGR.
EM readjusted all the Crane rocker arms (Crane 1.8's, Crane pushrods, Crane dual springs, Crane titanium retainers)

The high run (RED) is with open headers.
The lower run (BLUE) is with the true dual exhaust connected

Runs are when it was about 92 degrees outside.

Patrick G

iTrader: (14)

You had needle bearings in your oil pan. That ususally means you had valve to piston issues in the past (maybe from over-revving or a missed shift). You may have some valves that aren't sealing 100%. You'll lose power like a **** if that's the case. New rockers won't help you there. I'd to a leak down test to be sure.

Mark A. Rogalski

iTrader: (1)

You know there is a historical problem and a GM service bulletin on those early LS1 rocker arms loosing thier bearings right? I agree there might be a problem but not sure it was caused by the rocker arm falling apart or high revs as the car still ran like a raped ape untile these Crane additions. Bottom Line - It ran much stronger before it went into the shop 2 weeks ago for all the Crane stuff.