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Discussion Starter #1
I'll be starting the L92/L76 install tomorrow on my Z51 A6 C6. I'll try to keep everyone posted as to how well it goes and if anyone has questions, please ask and I'll respond to the best of my knowledge. This "swap"of sorts seems to be a very affordable,stock appearing mod promising good HP and TQ across the board. CAM in Durham,NC will be doing the work and tuning and I'll fill you in on gains and drivability issues. Right now I'm at 422 RWHP and 397 RWTQ as it stands with a mild cam, LG headers(with cats),FAST intake and tune. Of course the FAST will be gone witht the install, but i'm hoping for at least 450RWHP and 420RWTQ when the C02 clears.
 

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I'm curious as well. If it makes good hp/tq, what a sleeper. Selling the FAST
?
 

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Discussion Starter #4
Yeas, I sold the FAST to the shop for labor costs. The car is in there right now and hoping to get it back either this Thurs/Fri or next tues. He had two other customers there ( a vette and a LS2 GTO ) both intersted in the swap. I'm hoping for at least 450RWHP and 420 RWTQ, reasonable I belive. The car will be getting a different cam, one the has more exhaust capabilities than the one I have now due to the flow characteristics of the heads, and the heads will be milled .20 to make up for the gasket to retain compression ratio.
 

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Yeas, I sold the FAST to the shop for labor costs. The car is in there right now and hoping to get it back either this Thurs/Fri or next tues. He had two other customers there ( a vette and a LS2 GTO ) both intersted in the swap. I'm hoping for at least 450RWHP and 420 RWTQ, reasonable I belive. The car will be getting a different cam, one the has more exhaust capabilities than the one I have now due to the flow characteristics of the heads, and the heads will be milled .20 to make up for the gasket to retain compression ratio.
Most shops are milling to .030 to maintain stock 10.9:1 compression using the standard L92 gasket. I wonder why yours is going less? Your compression will be lower unless they are using a non-standard (thinner gasket).
 

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Discussion Starter #6
The .20 may be a typo, my bad. The car should be ready tomorrow and I'll post results here if anyone is interested. I'll get as much info on the build as possible . :thumbsup:
 

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Discussion Starter #7
Just spoke with Jeff, car is 99% ready and will have a street test/tune tonight with dyno runs in the morn. My old shop (now defunct) never took my old ride for a street tune, just a dyno trip. It's really nice to have a good shop and tuner.
 

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Discussion Starter #8
RESULTS!!!!

Before HP 421.2 After 447.1
Before TQ 392.3 After 404.4

Not too bad for $1500 in parts and $800 in labor, IMO. The set up mirrors my previous (plus 2-4HP) from 2000RPM to 3250RPM, then it takes off, 20-30 rwhp and 20-25 rwtq higher all the way to red line...smooth as silk, drives and idles like a stocker. STEALTHY!!!!!!!!!!
 

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almost 30rwhp and 8 lb/ft of torque from heads!

Thats very impressive. Nice bolt on mods...

the 2300 in cost out the door is very reasonable too.

Thanks for the information and details.

Those L92 heads with the l76 intake are great.

Congratulations on hitting your target

That A6 like any automatic usually soaks up close to 20 percent compared to the manuals 15 percent.

Must be a blast to drive.
 

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Not bad at all:thumbsup:

Now go see what times you pull with the extra power:devil: :devil:
 

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How was the automatic with the cam.

Years back I remember with the C5 and the A4 a lot of tuners said you had to do a convertor to get the benfits of the h/c...

Does your car have an aftermarket convertor in it?

(I'm not sure the A6 needs it but thought I'd ask.)

Were the l92 heads worked? or just upgraded with valve springs and if so which?
 

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Discussion Starter #14
I used the comp duel springs and hardened pushrods and tit. retainers from my former heads( upgraded to them when I did the cam this past Jan). I don't have a converter, it doesn't pull me alot at idle/stops like an aggressive cam would. A converter would help at the track, but since it's my Dd, I don't think it's in my future, unless, of course, someone makes stock size 19inch DRs, then it's a possibility. Heads were not "worked", milled to help the compression ratio. The milling of .30 made the CR 10.25:1 instead of the 10.9:1 thats stock.A cam swap would even that up, and if I go that route( the only way would be if I don't see 11's at the strip, as this thing is as near to what I want otherwise as I could ask for), I'll add a pully as well and bump that HP and TQ number up a bit more. The A6 tranny is handling it without any problem. Paddle mode is NUTS and "S" is fun to drive.:thumbsup:
 

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those are nice numbers, but how come you didn't throw a cam in there?? With a hotter cam, you could be pulling 460-500 rwhp with those heads / cam
 

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Discussion Starter #16
You have to use a fairly mild cam with this setup. It's got low flow on the intake and low on the exhaust, so we went the opposite with the cam selection to "even" things out. It's actually a blower cam and with the compression ratio the heads provide, it would make for a great FI combo, but I like it NA:thumbsup: BTW, most people agree that much more than 450 to the wheels is pretty unusable on the street without a ton of suspension mods to the C6.
 

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I used the comp duel springs and hardened pushrods and tit. retainers from my former heads( upgraded to them when I did the cam this past Jan). I don't have a converter, it doesn't pull me alot at idle/stops like an aggressive cam would. A converter would help at the track, but since it's my Dd, I don't think it's in my future, unless, of course, someone makes stock size 19inch DRs, then it's a possibility. Heads were not "worked", milled to help the compression ratio. The milling of .30 made the CR 10.25:1 instead of the 10.9:1 thats stock.A cam swap would even that up, and if I go that route( the only way would be if I don't see 11's at the strip, as this thing is as near to what I want otherwise as I could ask for), I'll add a pully as well and bump that HP and TQ number up a bit more. The A6 tranny is handling it without any problem. Paddle mode is NUTS and "S" is fun to drive.:thumbsup:
The pulley will be worth 6-7RWHP, but 10 under the curve in some spots on the upper part of the RPM range.... I didn't gain any torque.... Good choice with the smaller cam... That probably helped your low end....

 

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Discussion Starter #19
X: nice graph, good lines there. Unless something is completely nutty with this combo and it won't go into the 11's, I'm not going to bother with the expense of another cam swap , so the pully is out for now,especially if it don't boost torque. I was thinking maybe an aftermarket exhaust would give me a little more TQ, but the $$$ to gain ratio is horrific, so I'll stay stock for now.:thumbsup:
 

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Evil,

If I understand this correctly the GM L92/L76 are GM parts. By installing them do you still void the warranty?, and do you purchase them directly from GM?

Thanks
 
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