Anti reversion chambers on my 19 Charger 392

[milenkogt]

After reading topics by calvin elston and researching anti reversion chambers, I decided to purchase the 3" stainless variant from dynatech and install them on my 2019 Charger 392.

I purchased a set of stainless works catless midpipes and had the AR chambers tig welded into the midpipes.

I've been wanting to test these for a while and now have a platform I can utilize as a test bed.

The 392 is stock internals etc. The factory SRT manifolds are a clamshell/jacketed type with 1-5/8 primaries and 2.75" collector (as stated by ARH). The factory exhaust has 2.75" piping with factory X pipe as well.

Here is the factory 392/hellcat SRT exhaust manifold for reference.


Factory 392 manifold collector outlet. No merge, just dumps all 4 into the outlet.



Here are the modified catless midpipes with dynatech anti reversion chambers. I put them as close to the collector as possible without deleting the rear 02 bungs. It's around 14" from the collector which is close to what Hendren Racing stated in their blog/post about these.




And for reference this is the factory 392 (charger and challenger) exhaust aside from the Vibrant 1142 resonators shown near the IRS. Everything else is stock exhaust.



Stock 392 (6.4 cam profile states 46deg overlap)



I havent installed the modified midpipes yet because I'm wanting to establish a baseline dyno and then install the midpipes. There wont be any tuning involved either.

But I'll get as good of a before/after comparison of them as I can with as little time between dyno days as well due to work and school etc. Atleast it's cold out here in FL though currently.

Also I have the Dragy app that I'll throw in some data to help solidify any differences good or bad.

[BradH]

Pics of what the chamber looks like on the inside? Does it maintain a 3" ID, or does it neck down?

[milenkogt]

Dynatech anti reversion chambers/torque booster

Inlet side (exhaust flow from header or manifold)


Outlet side (you can see the expansion chamber that will reflect the negative wave)



I'm excited to see how these anti reversion chambers respond on the 392.

Also cat delete on the 392 cars show minimal gains from what I've seen. I'm not able to test stock vs catless, then catless vs AR chambers unfortunately.

So its catted/stock vs catless with AR chambers.

[milenkogt]

The dynatech 3" inlet and outlet neck down inside to what looked like 2.5 maybe 2.75.

The 3.5" inlet and outlet versions neck down to 3" .

[BOOT]

Thanks for the pics, plan to fab my own in the future and nice to have some manufactured examples.

[milenkogt]

Thought I'd share this as well. It's the Gen 3 hemi 392 factory cam profile with VVT.

The 392 is 11:1 comp, and cam specs from what I've found are

Lift .574" / .541"
Duration @ .050 215/221

Intake Opens (BTDC) 36.0°
Closes (ATDC) 250.0°
Duration 286.0°

Exhaust Opens (BTDC) 278°
Closes (ATDC) 10°
Duration 288.0°

VVT cam phasing range 37*

[milenkogt]

Thanks for the pics, plan to fab my own in the future and nice to have some manufactured examples.

No problem at all, hopefully it will help in your build. Would definitely like to see what you come up with.

I'd def like to see other setups with the anti reversion chambers that are either at the collector or post collector.

[Knight rider]

Interesting thanks for posting


Wish speed talk had a like button, don't always want to comment but nice to show you like or are nterested in a topic posted cheers

[milenkogt]

Interesting thanks for posting


Wish speed talk had a like button, don't always want to comment but nice to show you like or are nterested in a topic posted cheers

Thanks!

I wish there were more pictures and empirical data regarding the anti reversion devices located post primary tubes on various vehicles.

I agree regarding the "like or thumbs up" button. I guess this forum is quite clever because it promotes discussion vs hitting a like button and moving along lol.

[DracerX]

I'm very interested in seeing the results of this test!

[NewbVetteGuy]

actory 392 manifold collector outlet. No merge, just dumps all 4 into the outlet.

Is that picture supposed to be that way or is your manifold/collector a factory reject?!?

That is awful to look at.

They couldn't even do the cross pattern / clover leaf-looking thing?
http://www.headersbyed.com/wp_CrossedTubes.jpg

How many inches from the beginning of the merge to the end of the merge? (hard to tell from the picture but looks like an abrupt diameter change.)


Adam

[NewbVetteGuy]

Thought I'd share this as well. It's the Gen 3 hemi 392 factory cam profile with VVT.

The 392 is 11:1 comp, and cam specs from what I've found are

Lift .574" / .541"
Duration @ .050 215/221

Intake Opens (BTDC) 36.0°
Closes (ATDC) 250.0°
Duration 286.0°

Exhaust Opens (BTDC) 278°
Closes (ATDC) 10°
Duration 288.0°

VVT cam phasing range 37*

I'm going to be lazy and just ask how many degrees of duration the cam has or what the LSA is...
Can't be too much given the durations, right?

---Anyone making any predictions on peak torque gains or where they'll show up? (Because that sounds like a fun game!)

Adam

[milenkogt]

actory 392 manifold collector outlet. No merge, just dumps all 4 into the outlet.

Is that picture supposed to be that way or is your manifold/collector a factory reject?!?

That is awful to look at.

They couldn't even do the cross pattern / clover leaf-looking thing?
http://www.headersbyed.com/wp_CrossedTubes.jpg

How many inches from the beginning of the merge to the end of the merge? (hard to tell from the picture but looks like an abrupt diameter change.)

That is how SRT engineers designed and packaged that jacketed/clam shell exhaust manifold. Apparently works pretty well since its utilized on the 392 (485hp since 2011) and hellcat (707hp) engines. A lot of mid-high 9 sec Hellcats still use these manifolds because the off the shelf headers are $1200-1400 and just a pain to install.

The collector opens to 3". And its a tubular manifold that has a clam shell covering the primaries.

For a factory exhaust manifold its not terrible, but I wondered why they grouped the primaries that way as well. It's all about production cost and packaging.

[milenkogt]

Thought I'd share this as well. It's the Gen 3 hemi 392 factory cam profile with VVT.

The 392 is 11:1 comp, and cam specs from what I've found are

Lift .574" / .541"
Duration @ .050 215/221

Intake Opens (BTDC) 36.0°
Closes (ATDC) 250.0°
Duration 286.0°

Exhaust Opens (BTDC) 278°
Closes (ATDC) 10°
Duration 288.0°

LSA is 121

VVT cam phasing range 37*

I'm going to be lazy and just ask how many degrees of duration the cam has or what the LSA is...
Can't be too much given the durations, right?

---Anyone making any predictions on peak torque gains or where they'll show up? (Because that sounds like a fun game!)

Adam

The "degrees of duration" and "LSA" are in bold above, both advertised duration and @.050.

[milenkogt]

So here are the Stainless Works catless midpipes modified with Dynatech Anti-reversion chambers installed on my 392. This is one of the first production type vehicles publically shown that i've seen with these installed. So I made sure to post on multiple forums so people can see.

The Dynatech anti reversion chambers used are stainless steel 3" in/out. However, they taper down to around 2.75 internally which is fine since my factory exhaust is 2.75.

I'm probably going to modify the factory midpipes and remove the catalyst, but install the 3.5" x 3" Dyntach or Hendren Anti reversion chambers since they internall taper down to 3". Or i'll just use them in the supplied midpipes when I decide to install long tube headers down the road.

Factory 392 hemi midpipes vs Stainless Works/MMX catless mids with AR chambers from Dynatech.







I'm going back to have these dyno tested to see any kind of results. There won't be any tuning involved until later. Wanted to see if these worked on basically a stock untuned vehicle.