WHY only 315/330 Dyno after Crane 1.8 rockers and with Headers & True duals?
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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.
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.
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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.
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Originally Posted by 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.
This is the actual drain plug when I changed the oil.
![](http://onfinite.com/libraries/313616/a03.jpg)
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Originally Posted by Mark A. Rogalski
I did not need a new cam, I did however need new rockers........
This is the actual drain plug when I changed the oil.
![](http://onfinite.com/libraries/313616/a03.jpg)
This is the actual drain plug when I changed the oil.
![](http://onfinite.com/libraries/313616/a03.jpg)
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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.
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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.
I wonder if the spark knock is from a dirty MAF.
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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
dyno 9 before
dyno 11 500 miles later
dyno 14 10 months later
![](http://www.stealthram.com/familypics/formula/dynos/dyno91114rockersandsprings.jpg)
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Originally Posted by Mark A. Rogalski
I did not need a new cam, I did however need new rockers........
This is the actual drain plug when I changed the oil.
![](http://onfinite.com/libraries/313616/a03.jpg)
This is the actual drain plug when I changed the oil.
![](http://onfinite.com/libraries/313616/a03.jpg)
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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.
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.
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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.
![](http://www.vincihighperformance.com/vinci/graphs/afrtest4vstest5sae3rdgearlock.jpg)
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Originally Posted by Cody Brooks
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.
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.
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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
http://www.vincihighperformance.com/...CT%20PAGE.HTML
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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.
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.
![](http://onfinite.com/libraries/460832/92b.jpg)
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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.
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2013 Corvette Grand Sport A6 LME forged 416, Greg Good ported TFS 255 LS3 heads, 222/242 .629"/.604" 121LSA Pat G blower cam, ARH 1 7/8" headers, ESC Novi 1500 Supercharger w/8 rib direct drive conversion, 747rwhp/709rwtq on 93 octane, 801rwhp/735rwtq on race fuel, 10.1 @ 147.25mph 1/4 mile, 174.7mph Half Mile.
2016 Corvette Z51 M7 Magnuson Heartbeat 2300 supercharger, TSP LT headers, Pat G tuned, 667rwhp, 662rwtq, 191mph TX Mile.
2009.5 Pontiac G8 GT 6.0L, A6, AFR 230v2 heads. 506rwhp/442rwtq. 11.413 @ 121.29mph 1/4 mile, 168.7mph TX Mile
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2013 Corvette Grand Sport A6 LME forged 416, Greg Good ported TFS 255 LS3 heads, 222/242 .629"/.604" 121LSA Pat G blower cam, ARH 1 7/8" headers, ESC Novi 1500 Supercharger w/8 rib direct drive conversion, 747rwhp/709rwtq on 93 octane, 801rwhp/735rwtq on race fuel, 10.1 @ 147.25mph 1/4 mile, 174.7mph Half Mile.
2016 Corvette Z51 M7 Magnuson Heartbeat 2300 supercharger, TSP LT headers, Pat G tuned, 667rwhp, 662rwtq, 191mph TX Mile.
2009.5 Pontiac G8 GT 6.0L, A6, AFR 230v2 heads. 506rwhp/442rwtq. 11.413 @ 121.29mph 1/4 mile, 168.7mph TX Mile
2000 Pewter Ram Air Trans Am M6 heads/cam 508 rwhp/445 rwtq SAE, 183.092 TX Mile
2022 Cadillac Escalade 6.2L A10 S&B CAI, Corsa catback.
2023 Corvette 3LT Z51 soon to be modified.
Custom LSX tuning in person or via email press here.
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Originally Posted by Patrick G
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.