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Ok, I have a question for the group. Engine specs below. I was expecting this engine to peak a bit higher in the rev range than it does. I am not really disappointed as this is more than enough for a 2300 lb car, more just curious if anyone has a thought on what they think is the main reason for the "low" peak RPM. I expected to make closet to 525whp but the shop does dyno verification for NASA or SCCA (cant remember) and supposedly it runs about 5-10% below dynojet numbers so Im not worried about that. My thought was the intake but maybe a combination of the 1-3/4 primaries and the intake.
A separate question, I was getting knock on reasonably low timing around peak torque, which I know timing at peak torque generally needs to be lower but this was surprising the tuner how low it was still knocking at and the engine should only be about 11:1. You can see the dip around 4500-5500. Anything to look out for on that? It was an issue on E85 and on 91 so octane not the issue, the crankcase is pretty well vented through -10AN vents.
L92 6.2, Aviaid dry sump, stock bottom end w/flycut valve reliefs
Heads milled 0.010
0.040 cometic head gasket
cammotion 234 intake, 245 exhaust, 0.629 intake lift, 0.612 exhaust lift, 112.5 LSA +3.5, titanium retainers, dual springs
Johnson 2110 lifters
BTR 11/32 0.080 wall pushrods
Comp BSR shaft rocker setup, 1.7:1
Fast LSXR 102 intake and 102 TB
1-3/4" primary headers to 3" glasspacks each side
TR-6060 transmission, aluminum flywheel and spec super twin
From: Coast of San Mateo County Between Pacifica & HMB
The Mid-Length Runners for the FAST Intake would push peak +300-500 RPM, worth ~ 12-15 from 6-7000 RPM,
likely losing ~20-30 lb' from 3000-5000 RPM. Easiest and least expensive mod to test.
Changing LSA to 114*+3* would extend peak but also soften mid-range torque.
1 7/8 LTs would lift curve throughout range with perhaps the smallest extension of peak rpm.
Near peak power looks good to me being from like 6-6600...
I have a 6.0 Bored .060 Over with about 11.8 CR, Cam Motion 233-244, 646-637, 114+3, and don't like the loss of midrange compared to prior Lunati 231-237, 114+2. Will probably swap out...
1 7/8 headers would definitely help. Hope they're long tubes.
No Detonation... And no idea why you would, sorry.
That double hump torque curve is a phenomenon I used to see a lot on the LS1 when the cam wanted to push the peak torque higher due to valve timing, but the intake runner length wanted to force it to stay at 4800. it's not a cause for concern at all. Your cam is healthy sized for a LS3 and fast 102 intake, so I'm sure that's all you're seeing. That runner length is also trying to keep your power peak around 6300 also. Either way, it's not a bad looking curve at all.
The timing knock - i bet this is false knock or possibly noise from another source. At E85 and 11:1, it's not actually knocking for fuel-related reasons. You don't mention a dampener. i've seen on LS2 and LS3 corvettes the stock dampener would knock at 19 degrees near peak torque and the ATI would take 24 without KR.
This is a cobra kit car so the headers are a bit different than standard car headers, they would probably be considered mid length, they run about 12-18" to a double collector and back to long 2" tubes before back into another short merge to a 3.5" exhaust (each side). The double collector has aerospike on each side.
Spark plugs are NGK TR6IX
The damper is an ATI with HTD drive cog to an Aviaid 3 stage dry sump. Pulling a couple degrees of timing made the knock disappear, it was never much. It was reading knock on e85 but that was with added timing for the e85 it wasnt reading knock at the same amount of timing as it was on 91. Ill take a look at the timing at peak torque and see where its at, I dont think its even close to 19, more like 15 from what I remember seeing.
I did have a cooling issue where too much water was bypassing from the return side of the radiator to the surge tank, which caused runaway heat at low RPM cruising but never was an issue that was noticeable above 2k rpm, not sure if that could possibly have been starving a little water from the heads but its a mechanical pump and the line was only 5/16" so I kind of doubt it was bypassing enough to matter at 5k RPM.
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Question about HP peak RPM 
