VINCE

iTrader: (1)

I have heard many C5 owners saying that the C5 drivetrain robs more power the the F-bodies. Is this true?

slt200mph

iTrader: (42)

Yes it is true...the rear axle in the f Body cars uses less horse power the IRS...

VINCE

iTrader: (1)

Then that explains it.. Someone said like 18 percent for the M6?

Gordy M

iTrader: (2)

When the 2002 Z06 come out our corvette club had a GM engineer from the LS1 platform talk about the changes, improvements, etc. He mentioned that the drive train loss was about 12-13%, as I recall. This would equate to 350-360 RWHP.

66ImpalaLT1

There is no proof.

Grims

Look at the dyno numbers. C5's always dyno lower than the mullets because of the IRS.

Assassin

iTrader: (3)

I'm not so sure, they seem to rob power but then they seem to put the power to the ground better......... hmmmmm

slt200mph

iTrader: (42)

They do not put it down any better.... especially if they have the Badyear run flat tires on them....they weigh less than the f body...end of story... if you check the dyno numbers the f body does better time after time..the IRS is the difference...

Patman

I was getting better 60fts at the track this weekend compared to the automatic f-bodies there. My best of the day was 1.98 on the runcraps.

And the Colonel has cut 1.8 60fts on his runcrap tires in his C5. The C5 definitely puts it's power to the ground better.

demonspeed

iTrader: (7)

Would you say it's putting power to the ground better meaning it's making hp numbers to the ground better or it's getting better traction? I'll choose the latter...

66ImpalaLT1

How is that proof? I've never seen the same motor dynoed in both chassis. A few people have had the opportunity but didnt post before/after numbers. Thats what it would really take to compare them.

Even assuming the C5 has more drivetrain loss, I'll bet they are equal once you put a rear end in an f-body that can handle any amount of power.

Louis

iTrader: (7)

I have proof from the race cars back to back, same motor from chassis dyno to engine dyno and the loss is less than 15%. Obviously, you all would love to know what it makes, but I cant say

Patman

I mean it's hooking up better. The suspension on the C5 is definitely better.

VINCE

iTrader: (1)

My test results were with swapping a 408ci from a F-body to a Y-body and the #'s were lower, but several things were different, i.e., headers, bigger cam, no shortbelt this time, less aggressive tune. We were hoping for around the same numbers as before and I think I got them, but my supporting hardware was not there. I will need some custom Kooks with longer primaries for one and a more aggressive tune.

H-5-L

It's something like 8% for 6 speeds and 13% for autos.It's not just the IRS,but the torque tube,and tranny also.The torque tube is way bigger than a drive shaft.And 2001 c5s have more hp than 97-99s.So dynos are all over the place with different years.But you all know how it goes,dynos don't win races.And run-craps suck like mentioned above.I weighed my rear Y2Ks with run flats before i tossed them,62 lbs for one rear tire/rim and wheel sensor.
Also C5 autos have 2:73 or 3:15 gears compaired to the f-body autos with 3:23s

66ImpalaLT1

The spinning shaft inside the torque tube is a lot smaller and lighter than an f-body's driveshaft.

demonspeed

iTrader: (7)

That's what I figured. I just wanted to clear it up for someone that didn't understand.

H-5-L

True,but it's my opinion (oh..no) that with the bearings etc,it creates more friction/drag than a regular spinning drive shaft.Of coarse,it would be hard to compair.But it sure looks like a decent power robber,and then compounded with the transaxle.

LSK

And the extra U-joints from an IRS car are more efficient than straight axles? NOT!

Dean-o

I would say that it is between 12% to 15% for a standard. The f-body is 12% (6-speed), so if there is a difference, it is minimal. Let's say for arguement the difference is 3%, that would equate to 10.5 rwhp for a stock 350 hp LS1 motor. The Corvette weighs around 400 - 500 lbs less than an f-body! That more than makes up for 10 or 11 rwhp.