well here is the basic info on the car its a 01 z28
forged 383 ls1
Eagle LS1 4.00-Inch Stroke Crankshaft, 24X Tooth Reluctor Eagle LS1 6.125 H-Beam Connecting Rod Set with Upgraded
ARP 2000 Rod Bolts, 2.100 Crank Journal, .927 Wrist Pin
Diamond Racing Forged Flat-Top Piston Set: 3.905" Bore,
4.000" Stroke, 6.125" Rod Length, -2cc Valve Reliefs; .927" x
2.500" Wrist Pins Included
AP Texas Speed & Performance Exclusive Total Seal Ring Set:
3.905" + .005", 1.5mm AP Stainless Top, 1.5mm Napier 2nd,
3mm Oil
Clevite LS1 H Rod Bearing
Clevite H Main Bearing Set
Melling High Pressure Oil Pump
Comp Cams OE-Replacement Hydraulic Roller Lifters, SBC &
LS1
main & rods & heads studded arp stuff
maybe 1000 miles on shortblock
epp blower cam 232/240 115

stock unported 317 heads with a valvejob
patriot dual gold extreme springs .660 lift have maybe 14k miles on them and we're used on a car that had the tr raptr cam in it 238/244 112+2
ported ls6 intake and bbk 85mm tb

compression on the motor is roughly 10.2:1

fuel system is
siemens 80lb injectors
lonnies twin intanks with one on a hobbs switch
fast fuel rails
alky control meth setup

exhaust
pacesetter 1 3/4 headers and tsp old style y pipe
magnaflow catback

procharger d1sc @ 10psi
7.65 crank
4.25 blower
4" fmic with 3" aluminum piping
big red race bypass valve
poor mans belt wrap method

clutch is a monster 11" ceramic
6 speed trans with the basic upgrades
moser 12 bolt with 3.73 gears and auburn posi
spohn extreme duty 3" d/s

here is my issue the car made great power made 656/591 but the car fell off at 6300 peaked power at 6300 and then dropped off hard to roughly 618 and stayed flat to 6800....im baffled as to why the power falls off so hard at 6300 data logged it and the boost doesnt drop so there is no belt slip and talked to my tuner said that the clutch isnt slipping either anyone got any ideas????

i will get a dyno graph up tonight

 

Looking at the graph looks like its the heads.

 

Damn 500 ftlbs by 4500 rpm should be a monster. Not sure that I would thing the issue is in the heads. It could be that is where the cam wants to peak. Doesn't really look like valve float since the graph doesn't get all wavy.

 

The cam peaks somewhere in that area but better flowing heads will produce much higher horsepower results. A pair of AFR 225's would provide huge gains in power, as would raising the boost. 14 psi of boost would give you some good gains in power. Bob

 

i think its valve float just the way is starts to get wavy at the top end there.

you got some high rpms, and a good amount of boost on the back of the valve. Those Patriot Duals probally aren't up to the task, esp. if they have some miles on them.

 

to the top any more suggestions

 

I agree. Your springs are probably not up to the task of handling this cam and boost. Best to replace them with some fresh .660-.675" lift dual springs and shim them to within .050-.060" of coil bind. Should rev much better after that.

 

Anymore ideas and if it is springs what springs does anyone suggest?