10.5 Dave

iTrader: (5)

We finally got a chance to dyno my ARE 427 on Wed night and needless to say the numbers are weak.I know it's an ARE engine but I was hoping to see at least 520-530 rwhp.Mods are..........

ARE LS2 427
ARE/Patriot stage 3 heads
Crane 1.8 rockers
248/254 .621 intake .617 exhaust 114 +4 LSA (supposedly)
Fast 90 with LS2 TB
Halltech
Delphi 42 lb injectors
LGM 1 3/4 headers without cats
Stock Z06 exhaust
Spec 3 with alum flywheel
ECSC 4.10 gear
Fresh D&D MN12 tranny

The dyno graph shows the engine peaking at 6100 rpm and it nosedives.It only makes 320 rwhp at 6600.

I think the problem is the Patriot heads not being able to feed the engine up top.

What do you guys think?Oh BTW the car was tuned by Bill Wright aka Billium SS on here.

BlueSix

Can you post up a graph?

JS

iTrader: (4)

I dont think thats too bad,okay it peaks low but u can shift it at 6300
It will run forever at that rpm and 490RW is nothing to sneeze at Roofer...

I'd try a set of Carteks mid lengths in a 1 7/8 first before pulling the heads
U might see 15RW.....

evil02z

You might be losing some of it the the factory exhaust. I know the Z06 exhaust flows well but you're trying to push an extra 80ci of engine through it.

Tony Mamo @ AFR

iTrader: (13)

You are experiencing severe valve float past 6000 RPM's with a .600+ cam and 1.8 rockers.....too much valvetrain "intensity" with that much lift and the higher rocker ratio. You need to re-think your valvesprings, rocker arm choice, or both to establish better high RPM valvetrain stability. That might or might not help the bottom of the curve but it will most certainly help the top...also, AFR 225's anyone?.....LOL

Good luck resolving your issues.

Tony M.

JS

iTrader: (4)

Tony has a point,switch back to 1.7's and see what happens

Maybe it'll actually pick up

Silvr98z28

Good call.....happened to me last year at Thunder with jesel 1.8's and a big cam. Floated bad up top.

NOSjohn

iTrader: (9)

Yep, a ~620 cam WITH 1.8's...or is that factoring in the 1.8's?

Wicked_Hugger99

iTrader: (1)

What do those PP heads flow??? Did ya happen to get any TNT #'s or no???? Does the vette IRS eat up more power than a solid axle? just curious

Nickn20

ARE has patriot do thier heads now?

52172

iTrader: (2)

they are probibly patriot heads reworked by are

jrp

iTrader: (16)

thats the first thing i noticed.

Ben R

You probably have severe valvefloat and those cylinder heads probably leave a lot to be desired.

Mike K.

Did you guys notice this as well

Delphi 42 lb injectors
LGM 1 3/4 headers without cats
Stock Z06 exhaust


None of those are good except maybe the injectors for a 427, He definatly needs to let the exhaust breath alot better.

Tony Mamo @ AFR

iTrader: (13)

IMO, the exhaust system isn't holding him back much.....Lou (LG) just put up big #'s with the same system on a stock C6 Z06 with just the addition of his 1.75 LGM headers. The biggest problem is the TQ output which should have been alot higher, especially with arguably the best header for torque production in a C5 (the LGM's with thier long primary/merge collector design). Also, the valve float issue (potential issue) probably wouldn't have much of an impact at the point the engine generates peak TQ, so even with the top of the curve cleaned up a little, the question still remains whether this combo will ultimately be a good set-up or not.

Any headway on changing some of the valve gear or springs?

DONAIMIAN

iTrader: (18)

Hopefully you still have the stock rockers sitting around somewhere.

10.5 Dave

iTrader: (5)

.621 lift is with the 1.8's factored in.Stock Z06 mufflers flow quite well and are very light.I would have bought Kooks 1 7/8 headers but I already have the big dollar LGM headers and I don't want to buy new ones.

I'm going to buy a good set of heads and a cam directly from Comp this winter so I know that I'm getting.

92SilverSHO

iTrader: (3)

my buddy made 501rwhp with his 402 ls2. Thats with AFR 225s

JS

iTrader: (4)

I wouldnt pull the heads
Just switch to a mid length 1 7/8 header and it'll pick up power...

JakeFusion

iTrader: (7)

Doubtful. LG made 565rwhp with a 427 with their headers. I've seen MTI guys do the LSX90 and Kooks 1-7/8" and pick up 30rwhp on those 427s. But that was from TPIS or FLP headers, and most of that was probably the LSX90.

It's probably worth 5HP maybe 10HP, but the area under the curve would be hurt. 32" primaries with a high flow merge collector are better suited than 24" primaries on a 1-7/8" with standard collectors. How?

For a 427 that peaks at 6400 or so, 34" primaries at 2" would be ideal. But, no one makes anything like this. Using the formulas from A. Graham Bell’s Performance Tuning in Theory and Practice, we can calculate that if you have a 32" primary, you would now need a 2.1" diameter, so 2.10"-1.75" = .35" difference. If the header has 24" primaries, it comes out to requiring a 2.72" diameter, and thus 2.720"-1.875" = .845".

Personally, I'd use the one that is closer to 0, which is the LG header. If LG would come out with a 1-7/8" that is 32", it would be the best hands down.