[Firsthellcat]

Hello All, Sorry if this is an old thread, but reading posts and viewing videos of diff’s detonating got me to ask?
I just my HC 2 weeks ago and its just got over 100mi on it now. I have a set of replica HS wheels to mount on my Nitto 555RII, 275/40x20. ( The Nitto’s were on my ‘15 R/T ) I did have to but new whl’s. They’re 20x10.5 w/25mm offset. I was told these will work with no rubbing or any interference. ( If not, please chime in )

The question I have is: With very occasional trips to the strip, Union Grove, WI. , Do I really need the D4P? I know it’ll protect the diff, but I’ve read that any trips to the dealer and they see that, or more so I should say, a rep. And they could void the warranty ( concerning any diff/axle problems, bcuz you were drag racing? Why build a 700+ HP car they punish people for drag racing it? ) It’s not like I can just rip it off if I need to take it in. But, I don’t want to detonate anything either! I guess I could just run the street tires, bcuz would even the Nitto’s hook up too much?

I know to avoid the burn box with the OE tires, but do I avoid it even with the Nitto’s ? I would think not but now I’m not sure…

 

[shademaker]

The 25mm offset is for the Challengers. You should not have any rubbing. I have 305 Pzeros with a lowered spring, OE 10.5 25mm offset, no rubbing at all. Thats under load and turn as well.

I had the same experience using the Nittos as well.

 

[HC5120]

If I were concerned about breaking something, I'd just run a little more air in the tires so you have just a slight amount of spin, no dead hooking, and run the Nittos. Usually you start with the lowest tire pressure recommended and work your way up, but in this case just start with the highest recommended and work your way down. If you don't dead hook or hook hard, you are less likely to break something. Of course in racing there are no guarantees.

I haven't run those tires, but maybe start at 22 psi or around there. I ran a set of nittos about 15 years ago, lol.

Here is a video about that tire: drag racing video

I am sure there are people on here who have run these tires at the track, so hopefully one of them will chime in with their experience with the 555r2 and the hellcat.

 

[ScLeCo]

275/40x20

Don't worry you'll NEVER get enough traction to break anything with those.

 

[2ndgen]

They can't void your warranty for putting on a diff brace. That's not how warranties work. MMWA protects you there.
It's really dealer roulette, but at least for me, three dealers have worked on my car and none cared one bit about having a diff brace. They've even retorqued the bolts on it for me.

 

[Firsthellcat]

God to know. Thanks Guys!

 

[Bhdau1]

Buy the diff brace. Best to spend some money now and make the rear end more bulletproof. While your factory power level and the tires you are running will not grip enough to really do much damage from a dead hook (should you ever get one) the wheel hop is really what can cause a lot of damage. The P4D brace will make the driveline much stronger and really should have been a factory part on the car to start with. It will also give the rear end a more planted feeling. It may technically void the warranty on the differential only but then again I dont think they have ever had reports of one breaking with the brace installed so no worries. And to top it off, if it does break for some reason you can take it off the car in like 30 mins tops and there should be no evidence it was ever on there. Just save the factory bolts that are replaced and keep them handy in your garage just in case...

 

[Bhdau1]

Really the 1st 4 mods a new Hellcat owner should make in my opinion are a catch can, better tires, Powerstop Z23 or Z26 brake pads, and a diff brace. The brake pads are to eliminate the ridiculously excessive brake dust generated by the factory brembo pads. You will be washing your wheels damn near every day that you drive the car 5 to 10 miles or more. Everything else is starting down the rabbit hole of mods so to speak.

 

[Firsthellcat]

Awesome! Thank you!

 

[Firsthellcat]

Really the 1st 4 mods a new Hellcat owner should make in my opinion are a catch can, better tires, Powerstop Z23 or Z26 brake pads, and a diff brace. The brake pads are to eliminate the ridiculously excessive brake dust generated by the factory brembo pads. You will be washing your wheels damn near every day that you drive the car 5 to 10 miles or more. Everything else is starting down the rabbit hole of mods so to speak.

Interesting… have just over 100 mi on it now and the wheels look like I’ve been driving in a dust storm!

 

[Bhdau1]

Interesting… have just over 100 mi on it now and the wheels look like I’ve been driving in a dust storm!

LOL yep get used to it if you stick with the Brembo pads. while they may be the very best pads you can use, they are really designed for racing. Unless you are tracking the car buy a set of Powerstop Z26 pads. They are carbon ceramic and make damn near zero dust. They may have ever so slightly less stopping power if they get super hot but you will not be able to notice any difference around town or at the drag strip for that matter. They are not expensive but have been extensively tested by guys on here and friends I have that drive everything from SL550's to Redeyes and they all have nothing but positive things to say about them. The difference in dust generated between the two is so extreme you wont believe it. The Powerstop Z23's are also very dust free but are a little lower performance level. The other big bonus, no brake squeak or noise to speak of. The proper part numbers for the front and rear pads in the Z26's are for the front: Z26-1405, and the rears: Z26-1053. They are super easy to change. Once you have done one front and one rear you can do them damn near with your eyes closed. Just make sure you have a decent caliper spreader tool so you are not using a c-clamp and chunks of wood or other jerry-rigged crap.
PS> Also make sure you follow the break-un/bedding procedure once you install them. It takes very little time and needs to be done properly for max pad life and best performance. There are detailed instructions that come with them that explain how to do it.

 

[Xylander]

If you buy a diff brace, also install a driveshaft safety loop. The diff brace protects your diff, but the loop keeps your broken driveshaft from bouncing around under the car and damaging things, ripping off your body panels or impaling the bottom side of the car. I saw a Hellcat at Gainesville last year snap a DS and it went through the floorboard and out his rear glass. Cheap DS loops prevent such things. I'd never race a DR or slick without one.

 

[Firsthellcat]

Thanks for the tips!

 

[Firsthellcat]

PS Any suggestions for a DS loop?

 

[2ndgen]

PS Any suggestions for a DS loop?

Auto or manual?

For A8:

• Competition Engineering C3161
• S&M Performance
• BMR has a few
• probably some others

For M6:

• S&M Performance - doesn't fit with Barton shifter, fits 4" shafts
• G-Force - doesn't fit with Barton shifter
• Petty's - full crossmember with safety loop

several of the above are stocked by multiple vendors so you can shop around for pricing.

 

[Firsthellcat]

Auto or manual?

For A8:

• Competition Engineering C3161
• S&M Performance
• BMR has a few
• probably some others

For M6:

• S&M Performance - doesn't fit with Barton shifter, fits 4" shafts
• G-Force - doesn't fit with Barton shifter
• Petty's - full crossmember with safety loop

several of the above are stocked by multiple vendors so you can shop around for pricing.

Thank you!

 

[Sarna March]

and it went through the floorboard and out his rear glass

Never in my life have I heard of that result.
I have heard of cars pole-vaulting off their driveshafts, but OMG that sounds horrible.
Agreed. Driveshaft loops are an excellent safety item.

 

[Xylander]

Never in my life have I heard of that result.
I have heard of cars pole-vaulting off their driveshafts, but OMG that sounds horrible.
Agreed. Driveshaft loops are an excellent safety item.

I had one impale the bottom of the car and it got lodged in the rear seat bottom back in 1995. Car was a '70 Torino. I've also slung a clutch disc through the bell housing in my 2015 Mustang and it VERY luckily exited through the passenger window. If it would have went the other way, I'd not be here today. That instance is what got me to only build those Magnum XL transmissions with the optional armored kevlar bell housing, and I've since swapped my '55 gasser's trans to a similar kevlar bell housing. Said Mustang was running 18psi at somewhere around 1,350 bhp on a built Magnum XL trans.

As far as drive shafts go, most people break theirs on launch when speeds are low. You're not going to get a pogo stick DS like that. The biggest concern most people have is that a loose driveshaft can absolutely wreck your car. They usually flop around underneath and do things like hitting brake and fuel lines, damage the suspension and so on. Mine broke at the big end of the track. I heard it break and slap the bottom of the car and pulled the chute and started braking. The DS hit the ground and either dug into the pavement or hit a divot, which lodged into the surface and jacked it into the undercarriage before snapping in half.

Those two issues resulted in me always using armored bell housings and DS safety loops. For most dedicated track cars I take to the track, the DS loop is required anyway. These days I only take a vintage car to the track. It's usually not as fast as a Demon, but per the rules, it has to have all the safety gear, cage, windshield, etc. It's capable of running low to mid 9s, but I have it detuned to run low 10s. Vintage 392 Hemi max wedge engine and what-not, no sense in risking it anymore

 

[SickToo]

Hemi max wedge engine?

How could a combustion chamber be BOTH hemispherical and wedge shaped?

It can’t

Ever

Ya don’t have to lie to kick it : )

 

[DangCat]

Honestly just depends on the dealer and how picky they wanna be, some dealers will put on aftermarket parts on while other will tell you the warranty is void if you use tires other than P Zeros.

Find the dealership that is helpful and then modify away.

Good Luck!