GForce Engineering fully-fabricated 9” IRS With modified cradle

[Jon-MooredPerformanceLLC]

@Marc W didn’t you do testing with the 9in and lose 50 hp?

 

[Ta2ude]

@Marc W didn’t you do testing with the 9in and lose 50 hp?

I have read there is a 10-20 whp loss on a 800 hp car with the 9”.

 

[Marc W]

@Marc W didn’t you do testing with the 9in and lose 50 hp?

We did not come up with an exact number but you can read up on why the 9” exacts a hp price in drivetrain power loss. Has to do with pinion placement in relation to the ring gear. I basically went to the TH400 at the same time as the 9” rear. At that time a 3.40 ratio was the best you could do and that is too low to work with the 8spd if you were making 1000+ hp. I believe you can get 3.25 and 3.00 ratios with the 9.5” gears. Not sure. I haven’t shopped that for a while now. Back when I was doing that, it was really about trying not to break. The stuff available today wasn’t even dreamed of back then.

 

[Ta2ude]

So the farther I go down this rabbit hole the more complex it gets, leaving me with more questions than answers.
1) There seems to be a lot of discrepancy in regards to red eye driveshaft, axel and differential failures depending on where you look, some say problems and some say no issue. It’s hard to know what to believe, but wheel hop induced by pilot error may be the biggest culprit?
2) reducing wheel hop may be achieved through various BMR or AAD products
3) A modified cradle 9” rear end and 1 piece aluminum drive shaft with stronger 35 spline axels should address some potential failures but may slow down a stock red eye if traction gains aren’t substantial
3) Do you add more power via a PCM and tune before addressing suspension or after
4) When someone says they aren’t interested in doing power modifications you know it’s just a matter of time before the disease infects them

On a side note I am in Canada and the 9”IRS kit with driveshaft would cost me about $20,000 + Canadian with taxes duties and fees and I can get it with an extra set of axels for $5,000.
For me to buy the AAD performance Drag Pack I am at $3,530 plus whatever duties and brokerage fees they charge me.
The BMR cradle lockout kit would be about $430
A one piece aluminum driveshaft about $2000
Performance developments diff brace $1000

So do you go with the 9” IRS and modified cradle and plan on doing a stage 1 or stage 2 upgrade next year, believing that will be the extent of your performance modifications, or skip the “deal” and put the $5,000 elsewhere?

 

[Linda's Hell Cat]

So the farther I go down this rabbit hole the more complex it gets, leaving me with more questions than answers.
1) There seems to be a lot of discrepancy in regards to red eye driveshaft, axel and differential failures depending on where you look, some say problems and some say no issue. It’s hard to know what to believe, but wheel hop induced by pilot error may be the biggest culprit?
2) reducing wheel hop may be achieved through various BMR or AAD products
3) A modified cradle 9” rear end and 1 piece aluminum drive shaft with stronger 35 spline axels should address some potential failures but may slow down a stock red eye if traction gains aren’t substantial
3) Do you add more power via a PCM and tune before addressing suspension or after
4) When someone says they aren’t interested in doing power modifications you know it’s just a matter of time before the disease infects them

On a side note I am in Canada and the 9”IRS kit with driveshaft would cost me about $20,000 + Canadian with taxes duties and fees and I can get it with an extra set of axels for $5,000.
For me to buy the AAD performance Drag Pack I am at $3,530 plus whatever duties and brokerage fees they charge me.
The BMR cradle lockout kit would be about $430
A one piece aluminum driveshaft about $2000
Performance developments diff brace $1000

So do you go with the 9” IRS and modified cradle and plan on doing a stage 1 or stage 2 upgrade next year, believing that will be the extent of your performance modifications, or skip the “deal” and put the $5,000 elsewhere?

The real question is: do you want a street-friendly monster in the 750–850 HP range with mid-10s ET, or are you aiming for a track-focused beast pushing 1,000+ HP and dipping into the 9s?

 

[Ta2ude]

The real question is: do you want a street-friendly monster in the 750–850 HP range with mid-10s ET, or are you aiming for a track-focused beast pushing 1,000+ HP and dipping into the 9s?

At the moment I am interested in keeping it street friendly, as my wife and I enjoy driving it whenever possible in our Canadian climate but most of our drives are less than 60 miles on paved back roads. Going into the 9’s changes your requirements at the track up here so 10.001 would be the goal post for me currently.