Dodge Challenger Forum banner

1 - 20 of 119 Posts

·
Registered
Joined
·
2,192 Posts
Discussion Starter #1 (Edited)
Okay, instead of adding to previous threads, I wanted to start a new thread to combine my build items.

As some of you know, my car busted the ring land on #3 piston after my NSR cam install and I have sent the car to DTP to have it built correctly.

The mods list:

Kooks Long Tubes w/ cats
Edelbrock Victor II Manifold
Hellcat 92mm throttle body
Edelbrock Performer Heads (complete w/ springs)
ARP Head studs
API drop in Fuel pump
ATI Damper
MMX drop in Pistons and Rods (Pistons 0.035" oversized)
Premium rod and crank bearings
BWoody CAI
Solo Race Exhaust
MMX Custom Grind w/ limiter
Hardened push rods
Hellcat lifters
Deatschwerks 48lb 440cc Injectors

I considered a 426 short block, but I likely wouldn't have had a usable block core, so that would have added $1,600 to the cost. Any power gains would have been very negligible.

Considering I should be 500+ rwhp, I believe I have covered every potential weakness. The engine should rev easily to 6,800 rpms.

I went ahead and did a fuel pump and injectors, because I was already at about 83% duty cycle before the cam. I really didn't want to get to 90% on the stock injectors. The Deatschwerks will keep me around 80% and should be more consistent from cylinder to cylinder.

This has turned into a expensive NA build; however it will be done right.

DTP will tear into it after Christmas and we'll have some good dyno numbers in the future.
 

·
Registered
2016 Jazz Blue A8 Scat
Joined
·
691 Posts
Very interesting.

Following.

Why is your block not usable for a 426?

What pushrods, lifters, springs?
 

·
Registered
2013 Challenger SRT8
Joined
·
1,142 Posts
Definitely following this

Did you decide to do the forged internals because you have plans for boost in the future?
 

·
Registered
Joined
·
2,192 Posts
Discussion Starter #5 (Edited)
Very interesting.

Following.

Why is your block not usable for a 426?

What pushrods, lifters, springs?
Modern Muscle told me the core would need to be damage free. I suspect that isn't the case with my block.

The car already has hardened push rods from the first cam install and it also has hellcat lifters installed.

The Edelbrock heads use a upgraded spring that is rated for 0.630 lift. Modern Muscle told me I may need different length push rods depending on the measurements after everything gets put back together.
 

·
Registered
Joined
·
2,192 Posts
Discussion Starter #6 (Edited)
Definitely following this

Did you decide to do the forged internals because you have plans for boost in the future?
No plans for boost in the future. The block, being bored 0.035" over, would likely be the weak point under boost. I could have went 0.010" over and been safe with boost, but not 0.35" over.

All the drop in kits are forged, so it will be overkill to some degree.
 

·
Super Moderator
2016 SXT Plus Blacktop
Joined
·
16,912 Posts
Very enjoyable watching others spend their money on performance upgrades :) Looking forward to the show. A Guy
 

·
Registered
2015 Dodge Challenger R/T Scat Pack
Joined
·
1,189 Posts
Was wondering where you went. What caused the issue with your piston? Was it tune related or something hardware related like valve hitting the piston, etc?

Hope your new build goes well, good luck!
 

·
Registered
2015 Scat Pack
Joined
·
2,230 Posts
Following.

What wasn't "done right" on your Cam install?
 

·
Registered
Joined
·
329 Posts
Was wondering where you went. What caused the issue with your piston? Was it tune related or something hardware related like valve hitting the piston, etc?

Hope your new build goes well, good luck!
Sub'd and would like to know what happened as well?
 

·
Registered
Joined
·
2,192 Posts
Discussion Starter #13

·
Registered
Joined
·
2,192 Posts
Discussion Starter #14
I don't think there were any mechanical issues with the actual cam install. For the first 80 miles, the car ran flawlessly....and got better gas mileage while cruising.

Personally, I think there were (2) root causes:

1. I was very aggressive with reducing the knock sensor values in my tune. Since the factory knock sensor values are too sensitive, the common solution is to half their values. I went a little beyond that in some places. However, I also kept my timing pretty much stock and even slightly below in a few areas. I genuinely believe that I had little to no true knock with my tune.

2. After the cam install, the tuner tweaked my tune for the cam and ran the car on the dyno. After looking at his tune, he bumped the timing up significantly in several places. He was also quite aggressive in areas where I know my 6.4L is prone to experience ST KNK (5,200 rpms). The overly aggressive timing, paired with the reduced sensitivity of the knock sensors likely produced enough detonation on the dyno to fracture the ring land. It was then only a matter of time before the ring land broke off.

What I have learned:

1. Don't reduce knock sensor values below 1/2 of their original values.

2. If you still have knock at that point, reduce the timing until it is gone. This may mean using less timing than the stock curve, which is perfectly fine. The 6.4L doesn't want or need aggressive timing.

Once again... it all boils down to proper tuning. This is why I sent the car to Brent and DTP. Many places can do a proper install; however getting the tune right on these cars is a challenger... especially once you go with a cam or F/I.

Once you start adding power, the 6.4L pistons just don't afford you any wiggle room. This is true whether you go F/I or stay N/A.
 

·
Registered
2015 Dodge Challenger R/T Scat Pack
Joined
·
1,189 Posts
I don't think there were any mechanical issues with the actual cam install. For the first 80 miles, the car ran flawlessly....and got better gas mileage while cruising.

Personally, I think there were (2) root causes:

1. I was very aggressive with reducing the knock sensor values in my tune. Since the factory knock sensor values are too sensitive, the common solution is to half their values. I went a little beyond that in some places. However, I also kept my timing pretty much stock and even slightly below in a few areas. I genuinely believe that I had little to no true knock with my tune.

2. After the cam install, the tuner tweaked my tune for the cam and ran the car on the dyno. After looking at his tune, he bumped the timing up significantly in several places. He was also quite aggressive in areas where I know my 6.4L is prone to experience ST KNK (5,200 rpms). The overly aggressive timing, paired with the reduced sensitivity of the knock sensors likely produced enough detonation on the dyno to fracture the ring land. It was then only a matter of time before the ring land broke off.

What I have learned:

1. Don't reduce knock sensor values below 1/2 of their original values.

2. If you still have knock at that point, reduce the timing until it is gone. This may mean using less timing than the stock curve, which is perfectly fine. The 6.4L doesn't want or need aggressive timing.

Once again... it all boils down to proper tuning. This is why I sent the car to Brent and DTP. Many places can do a proper install; however getting the tune right on these cars is a challenger... especially once you go with a cam or F/I.

Once you start adding power, the 6.4L pistons just don't afford you any wiggle room. This is true whether you go F/I or stay N/A.
That sucks, sorry to hear that, but at least you're getting it fixed up good now. I know when I go to the track I always run a bit of race fuel to ensure there is no knock retard. It tends to show up more so in 5th gear at the end of the track when the engine is under the highest load. Even bumping the timing up 1 degree requires about 3 octane points to get it back to normal again I've found.

Are you installing a wideband on your car now with the cam?
 

·
Registered
Joined
·
1,152 Posts
+1 on the wideband. I installed mine when I started tuning with hp tuners.
I kept the same knock sensor values even after the cam swap - I'd rather sacrifice a few hp then have predetonation issues.
 

·
Registered
Joined
·
2,192 Posts
Discussion Starter #17
I've been running a Innovative LC-2 in on the drivers banks for a long time. I have everything setup in my tune and the wideband for 7% ethanol fuel. I was logging when the ring land let go and the AFR was good. Ironically, there wasn't any registered knock during the event either.

This makes me think the damage was done during the dyno tune and the WOT blip just finished it off.
 

·
Registered
2015 Dodge Challenger R/T Scat Pack
Joined
·
1,189 Posts
I've always heard that detonation is cumulative, meaning the piston can only take so much of it over time and then at some point it will just give out when it's reached that threshold. The dyno tune may have been what did it in and then it was just a matter of time before it just gave out.

Hopefully the new build will go smooth and you won't run into any issues this time around.
 

·
Registered
Joined
·
2,192 Posts
Discussion Starter #19
The build is moving along. They are waiting on Comp to send out the custom grind and that should be the last part of the build that is needed. Hopefully, it will up and running again soon.

Prediction: 525 rwhp on the DTP dyno.
 

·
Registered
Joined
·
2,192 Posts
Discussion Starter #20
A few pics...

Look closely at the # 5 piston, part of the ring land is missing on it as well.

They should have finished everything today and tuning will hopefully start very soon.

Brent at DTP has been awesome. Fantastic communication.

I've only run into one parts issue so far. The Deatschwerks injectors are shorter than the factory injectors and won't work with the Edelbrock fuel rails. You will need stock length injectors with the Edelbrock rails.

Fortunately, Brent had some GT500 injectors that will work and he let me have them at a good price.

The injectors were purely supplemental anyway and the stock injectors would have worked, although they likely would have been close to 90% duty cycle which I didn't want.
 

Attachments

1 - 20 of 119 Posts
Top