My numbers could be all wrong here... correct me if im wrong please... this is some hearsay and somethings that i remember reading... just dont have the sources in front of me

being awd vehicles lose more hp in the transfer sometimes it doesnt add up when i see our stock rigs pushin out 355 (member) to 373 (edmunds inside line) at the wheels... that just doesnt add up if awd drivetrains lose 20%... these readings would tell me we only lose about 15% thru the transfer which to me seems a little low

i know its tough to be exact b/c the rigs front axle uses about 10% of the power and this may all lead to my math errors

anyway... how much reallly do we lose in the transfer?

If it was 20% we would be recording 340 rwhp on the dyno no?

Reason why i looked into this is my buddy who;s entire family is affiliated with chrysler for years tells me my jeep (our rigs) are definitely undervalued at the factory.... he told me they push closer to 450 than 425...

that being said 450 hp would be 360 rwhp if we follow the 20%... which sounds more accurate

REASON i say this is the rig below built by hennessey has following specs:

Power:
# 530 hp @ 6,000 rpm
# 530 lb-ft @ 4,200 rpm

Performance:
# 0-60 mph: 3.9 sec.
# 1/4 Mile: 12.8 @ 109 mph
# Top Speed: 172 mph

I see guys pulling that time with simple mods.... HENCE this again leads me to believe that our 425 number isnt accurate

Just my 2 cents...

hmmm... maybe i should get a new license plate

425myazz

ha

honestly tho...why does crank HP even matter? and besides, couldn't dyno variance account for power "gain" as much as it could "loss"? if this is the case then a crank of 42-425 could be displayed as 353 etc on a dyno based on pure variaiton.

Not sure, but you are right. Something just doesn't seem right.

I've matched your 1/4 mile time (non-corrected) and all I have is a bwoody 4" CAI and a tune from andy.

How much did that hennessey package cost you?

Not sure, but you are right. Something just doesn't seem right.

I've matched your 1/4 mile time (non-corrected) and all I have is a bwoody 4" CAI and a tune from andy.

How much did that hennessey package cost you?

i was hypothetically sayin... dont have that package.. saw a srt8 hennessey package on ebay... currently the 08 srt530 hennessey is up to 40k....

just was lookin and saw the specs

honestly tho...why does crank HP even matter? and besides, couldn't dyno variance account for power "gain" as much as it could "loss"? if this is the case then a crank of 42-425 could be displayed as 353 etc on a dyno based on pure variaiton.

i totally hear ya... b/c getting a reading from the crank is so much easier and being that its much easier to market i assume thats why crank hp is even calculated...

but thats not my pt... what im saying is i think our rigs are producing more than 425 from the crank... i would think the gcsrt8 lose more than just 15% thru the drivetrain

my car is rated 310hp... it makes that at the tires.

I guess being a GM guy I've never put stock in the HP ratings because they were crap to start with. The 425hp rating on the 6.1L is definately 'conservative' but it's nothing new for a crank HP rating to be wrong. Just be glad it's not wrong in the other direction!!!

i was hypothetically sayin... dont have that package.. saw a srt8 hennessey package on ebay... currently the 08 srt530 hennessey is up to 40k....

just was lookin and saw the specs

Sorry, I'm at work and read the post too fast :o

I agree it's underestimated, I'd put it closer to 450, but what matters to me most is the feel, and holy sh1t it is fast. Pegging it in 1st around 3k rpms will snap your head right back in the seat. I mean it weighs 4700 pounds and sure as hell feels faster than my '03 Cobra, which sits at 425 hp and weighs 3700 lbs.

These are crank #'s btw.

i hear ya chim... ive had my rig for a year and she still impresses me... im sure the gearing helps big time with the neck snapping.... b/c being such a heavy vehicle just doesnt seem right that it literally jumps off the line.. 1st gear and pedal to the floor when she hits 3k rpm is hysterical... i just can imagine how she feels if shes worked like so many guys have done to theirs.... my buddies c5 is over 1500 lbs lighter and 350 at the crank and it doesnt even come close to what the jeep gives ya from a roll at 10 miles an hr or outta the whole... its not even close....

i hear ya chim... ive had my rig for a year and she still impresses me... im sure the gearing helps big time with the neck snapping.... b/c being such a heavy vehicle just doesnt seem right that it literally jumps off the line.. 1st gear and pedal to the floor when she hits 3k rpm is hysterical... i just can imagine how she feels if shes worked like so many guys have done to theirs.... my buddies c5 is over 1500 lbs lighter and 350 at the crank and it doesnt even come close to what the jeep gives ya from a roll at 10 miles an hr or outta the whole... its not even close....

I also believe they're underrated as most muscle cars were in the 60s and 70s. There appears to be a nice sweet spot with these vehicles... my 1965 Olds 442 did the same with 3.90 gears.

When I took my girlfriend's 83 year old mom for a spin in my 2009, I stabbed the throttle... the front lifted with a slight pull of torque steer, and it put her back in her seat. She's never been in anything that ran under 18 sec in the 1/4 mile before... the women felt a little exasperated, so I let off.

That was fun, but in retrospect, I should have gave her a ride in my Race Hemi car before i sold it. She probably would have enjoyed the ride more due to the vibration...

Now I need to take my 79 year old mom for a spin... and wake her up too. :)

The 6.1 is most certainly underrated. My 07 300C SRT8 dynoed 370 at the wheels stock. 20% loss would make that 462hp at the flywheel. To make 425, the drivetrain losses would have to be ~13% which is like unheard of for a rear driver with an automatic.

450-465 is definetly more realistic then 420-425.

grandma and that 18 second 1/4s... thats sick

i wonder... when im 80 does that mean my grandson is going to have a 7 second car that he/she takes to school?

just seems like cars are getting faster and faster....

The 6.1 is most certainly underrated. My 07 300C SRT8 dynoed 370 at the wheels stock. 20% loss would make that 462hp at the flywheel. To make 425, the drivetrain losses would have to be ~13% which is like unheard of for a rear driver with an automatic.

450-465 is definetly more realistic then 420-425.

So are you saying a GCSRT8 is similar to owning a modern day LS6 Chevelle?

Top 50 Fastest Muscle cars...

#.. YEAR/MODEL.............. ET/MPH.......... ENGINE... HP... TRANS / GEAR
5... 1970 Chevelle SS454.. 13.12@107.01.. 454 LS6.. 450.. 4-Speed / 3.55

i think the crank hp rating has sumgthing to do with gov. rgulations? most of the muscle cars are under rated from the factory nowadays. look at the 03-04 cobras, ls1 fbody's. they would dyno 315-320hp all day stock and were rated at 325-330 crank hp.

Well actually for the 03-04 Terminators, which were advertised as 390/390 crank hp/tq, guys were buying them off the lots and taking them to the dyno and getting 420-440crank hp. Part of this underrating was due to the fact that back in 2001, the Cobra's were advertised at 320/320, but were coming in at 310 or so. SVT, completely embarassed by this, decided to up the ante not only against GM, but also so that they never faced that sort of criticism again.

And yes, the LS1's were also underrated. My brother's former '01 SS was supposed to be around 330 but there's no way it was anything under 350-360.

So are you saying a GCSRT8 is similar to owning a modern day LS6 Chevelle?

Top 50 Fastest Muscle cars...

#.. YEAR/MODEL.............. ET/MPH.......... ENGINE... HP... TRANS / GEAR
5... 1970 Chevelle SS454.. 13.12@107.01.. 454 LS6.. 450.. 4-Speed / 3.55

Kinda, except the Chevelles 450hp was gross and ours is net. If hp was still measured in gross figures, we'd be well over 500.

Kinda, except the Chevelles 450hp was gross and ours is net. If hp was still measured in gross figures, we'd be well over 500.

Now I'm even more impressed with Chrysler. I've always wanted one of those bad azz Chevelles... I remember a couple of those LS6's around town that had M-22's with the gears singing. Everyone always stayed away from them...

And a few around here complain about a slight R&P whine or clunk here and there... these are plush compared to the old days.

I'm really enjoying this modern day SRT muscle car... digital tuning, pseudo cross ram manifold, fuel injected, factory headers. I don't know if everyone realizes and appreciates what these vehicles actually mean to the history of the muscle car...

Now if the transmission was a little more snappy straight from the factory I would be ecstatic.

i think the crank hp rating has sumgthing to do with gov. rgulations? most of the muscle cars are under rated from the factory nowadays. look at the 03-04 cobras, ls1 fbody's. they would dyno 315-320hp all day stock and were rated at 325-330 crank hp.

thats a good point

i think the crank hp rating has sumgthing to do with gov. rgulations? most of the muscle cars are under rated from the factory nowadays. look at the 03-04 cobras, ls1 fbody's. they would dyno 315-320hp all day stock and were rated at 325-330 crank hp.

Well now they should all be SAE and don't allow much wiggle room to fib about the numbers. I suspect they still have a way to do that but in the old days GM did it just to sell cars... it was the Corvette and not goverment regulations that gave the F-Body a 305/310hp ratiing instead of the 345/350hp rating of the C5.