cynic783

09 G8 GXP, 6Manual
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Chad Barton Spec - Comp Cam 233/246/.618/.615 113 LSA +0, LSL/LXL
Texas Speed PRC aftermarket LS3 250CC heads, 62cc chambers, hollow-stem intake valves
Approx 11.5:1 Compression
Tony Mamo Ported FAST 102
NW 102 TB
Dave Steck E85 Flex Fuel Conversion, Dave Steck Tune
LS9 Injectors
Deatschwerks DW300 (340LPH) Ethanol Capable Pump
Squash Performance C5 Returnless PTFE/Teflon Fuel System
ARH 1 7/8" Long Tube Headers, Catless Midpipe, Solo Axle Back
Mesiere Electric Water Pump
ATI Balancer, not underdriven
Stock 2-Piece Driveshaft, Rubber Giubos
GForce1320 750hp Axles
Camaro SS 1LE 3.91's w/Eaton TrueTrac Diff
Chad Barton Built

On E85, 70% actual alcohol content:



Not the magic 500rwhp I was shooting for, but very healthy and I'm satisfied. Overall very happy with my result. Hopefully this data is useful for someone else for comparison purposes.

BODUKE

That's a good number.

1989GTA

I agree, those are good numbers. Interesting that the peak hp point does not change to much with the long runner intake manifold. The camshaft moves it around a little but not to much.

Tony Mamo @ AFR

iTrader: (13)

Dan,

Nice results....good torque # but I would have expected to carry a little better.....that's why the magic 500 number slipped your grasp. You made enough peak torque to easily get there if the engine didn't roll over so quickly (something is preventing it from effectively filling the cylinders at higher RPM).

On paper looking over the cast of characters, IMO it should have peaked 2-300 RPM's later (HP) and if it did you would have nailed the 500 mark for sure.

Numerous things could effect this.....for now enjoy what you have and if down the road your up for excavating and finding some of that power that eluded you now look me up in the future.

480+/450+ is a fun driver and the power comes in early so Im sure the car feels great.

Cheers,
Tony

cynic783

Thanks Tony for your help with this project and thanks for the analysis.

The throttle response is explosive in this car, even at low engine speeds. It's almost frightening how hard it pulls and keeps pulling, but this is my first car this powerful.

I agree, something happens at 5500 and it kind of loses steam.

Chad Barton and Dave Steck have a plan of attack to get me to my goal. We are thinking there is an airflow restriction and/or that we can add additional timing. The tune is on the conservative side at this time.

MuhThugga

I wonder if your valvetrain is starting to get unstable beyond 5500?

What valve springs are you using and have you considered stepping up to 11/32 or 3/8 pushrods?

cynic783

Thanks for the idea. I'm running dual springs (BTR?) and regular 5/16 hardened pushrods. Chad sez he'd expect unstable valvetrain to show really jumpy on the dyno.

cynic783

1989GTA

I would say those numbers pretty well match your dyno numbers.

82cetuner

iTrader: (9)

did you do any back to back tests from 93 octane and E85? thinking of switching on my 12 to 1 compression ls3. how much timing is actually in it cause with e85 you should be able to jump it up a lot. im at 28 right now

redtan

iTrader: (5)

Hmm would've expected some better numbers out of that setup, and I agree it doesn't seem to be carrying past peak too well.

Those numbers are achievable by a stock headed stock intake LS3 (well maybe not the torque). With a ported FAST and aftermarket Trickflows I thought it would carry the power better.

ringram

What air intake are you running?

Did you log MAP vs Barro?

Maybe you have an intake/filter restriction

MuhThugga

I would look at some 3/8" Trend pushrods. They clear the heads without having to modify the holes and they don't break the bank.

Those 5/16" are probably flexing enough to cause that plateau up top.

BT08

You've got quite the list of goodies in your OP that should be freeing up some more power. I'm not too familiar with E85 tunes/setups for the G, but I do know that full top end builds on the L76 with a matching cam will net around 430 on pump gas. An LS3 build with all the aftermarket goodies up top really should be getting you closer to the number you're after.

The numbers are still VERY solid, so don't let it disappoint! I just feel that you should be in the low 5xx's with that setup.

handyandy496

iTrader: (9)

Maf or speed density...just read something on mafs catching reversion. Even 100mm Mafs.

pannetron

Stock or custom tune in the ECM?

cynic783

Here's my record pass. Fastest manual shift NA G8, no N20.

cynic783

Custom tuned by Dave Steck (DSX Tuning). He uses HP Tuners and tunes on the street. E38 ECM from 2009.

cynic783

I have a Texas Speed 100mm/4 inch MAF, honeycomb and LS7 MAF card.

I have quizzed my tuner about speed density. Maybe it's time to revisit that topic. What is "reversion"?

cynic783

No, I will have to check into that. It's a VCM over-the-radiator type.

Leading hypothesis from my builder is intake restriction.