[bigjohn12rt]

RT 5.7 owners out there any years...what mods have ya all done to get more horses?

me so far cold air intake and ive noticed a difference..

im hearing headers,tune and exhaust?

 

[Newoldchallenger]

Depends what you want out of the car.
Head/cam/ headers packages and spray tend to be my go to on my 5.7s.


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[Nuke]

Replace the 5.7L cam with one from a 6.4L, do the same with exhaust manifolds, and adjust tune to take advantage for each upgrade. That’s separate from getting a custom tune for the car BTW.

The custom tune helps, but any significant performance mods added subsequent to the custom tune being done will require the custom tune to be adjusted to compensate. Or wait until all mods are on and then get the custom tune...

 

[Nuke]

Also, swapping out the 3.07 open diff with an LSD 3.90 diff from a 6 speed-equipped car is a good mod as well.

It doesn’t technically net any more horses, but the difference in torque multiplication at WOT between the 3.07 and a 3.90 rear end will certainly make it feel like you’ve upped the HP/TQ output.

This definitely requires a tune modification as well, assuming the car is pre-2015.

 

[5.7 owner]

Also, swapping out the 3.07 open diff with an LSD 3.90 diff from a 6 speed-equipped car is a good mod as well.

It doesn’t technically net any more horses, but the difference in torque multiplication at WOT between the 3.07 and a 3.90 rear end will certainly make it feel like you’ve upped the HP/TQ output.
What all do you have to change to go from a 306 to a 390 ,i have a 5;7 Auto
This definitely requires a tune modification as well, assuming the car is pre-2015.

What all has to be change to replace my 2012 306 to a 392 ,i have a Auto

 

[Nuke]

What all has to be change to replace my 2012 306 to a 392 ,i have a Auto

you would be going from an open style diff to an LSD one, so its not a simple pumpkin swap (for pre-2015s). The necessary extras besides actual diff are documented here in several threads. I'm blanking on them at the moment. I know the axles and hubs from donor car need to be included. Plus tone rings?

i can search around later when i get home, but honestly for this particular mod, the LXForums site is a better resource...well, easier to find the relevant threads for this mod, amyway

 

[sr71cbx]

K&N CAI w/Airaid dry filter, SRT exhaust headers, SRT mids w/cats, Flowmaster American Thunder SRT cat back exhaust, NGK iridium tip sparkplugs, Pedal Commander. Running on factory tune right now, sure picked up a lot of mid and top end power with no loss of low end torque that I could tell.......factory should have installed the full SRT exhaust on all the V8 Challengers as at least an option!
118,000+ miles on the car now, averaged 26 mpg last road trip in June.

 

[Nuke]

K&N CAI w/Airaid dry filter, SRT exhaust headers, SRT mids w/cats, Flowmaster American Thunder SRT cat back exhaust, NGK iridium tip sparkplugs, Pedal Commander. Running on factory tune right now, sure picked up a lot of mid and top end power with no loss of low end torque that I could tell.......factory should have installed the full SRT exhaust on all the V8 Challengers as at least an option!
118,000+ miles on the car now, averaged 26 mpg last road trip in June.

The aftermarket air intake system will flow differently at WOT, maybe more or maybe less, but either way there's likely some performance to be gained by having stock tune adjusted to eliminate any KR that's occurring at WOT.

I'm not saying there's enough to knock your 0-60 times into the 4s or increase your MPGs by any significant amount. But there is very likely some performance left on the table that can be reclaimed if you ever decide you want to squeeze every last drop of power out of the mods you've got.

Same goes for the SRT exhaust, except for a different reason (not missing perf due to KR but likely have some available that's not being taken advantage of).

Not sure what year model yours is, but if it's a 2015+, you'd have to spring for the updatable PCM, and in that case i don't think it would be worth the extra expense for the relatively low amount of performance you'd be gaining by going custom tune.

Just my opinions though, please treat accordingly.

 

[trippytro]

Long tubes, tuning, and a cam if price and emissions isnt an issue

 

[Nuke]

Long tubes, tuning, and a cam if price and emissions isnt an issue

Which one of those causes the car to run afoul of the emissions standards? and what’s the prob, a permanent CIL light?

 

[A Guy]

Physical inspection would cause a fail if the "technician" saw long tubes. Tuning and cam if the OBD test wasn't within allowable limits. A stock car will have numbers that don't even approach allowable limits. It would likely take something radical to not pass OBD, but if the tech does the physical inspection they are supposed to, the long tubes will cause it to fail, even if the OBD would pass.

Honestly, depends on the tech. No one will willingly ignore it, equipment is expensive, and losing their ability to do smog tests isn't worth it

A Guy

 

[trippytro]

Which one of those causes the car to run afoul of the emissions standards? and what’s the prob, a permanent CIL light?

All 3 really. Changing the cam is going to affect how much intake and exhaust is let go, long tubes are going to increase and improve velocity and shoot out tasty smoke from the back.

 

[Nuke]

I guess we have it relatively good here then, the emissions monitors’ active/passing status is verified by technicians doing inspections, and if those are all good to go, the vehicle passes as long as the CEL is not illuminated.

The physical exhaust gas measuring where they probe the tailpipe of a running vehicle is longer done, and as far as inspection of the car for non-OE parts, well that’s no longer done either that I have seen.

Isn’t that what the whole CARB certified thing is about when it comes to state inspections? I figured as long as non-OE equipment was found on a car being inspected in California, it was okay if the equipment had been previously tested and CARB certified for use on California based vehicles...

Though to be fair, the CARB certified label itself seems to be easy to get, if the certification of Schosche’s subwoofer boxes is any indication: https://www.scosche.com/car-audio/subs-enclosures#/page/1

Is California really that strict that even items having nothing to do with how the engine burns it’s fuel need to be certified regardless?

 

[A Guy]

Good point, I misspoke. Non CARB EO long tube headers would cause a fail.

BUT, the cats have to be in the original location, so there are no CARB exempt long tube headers (I know JBA makes some shortie headers that are exempt)

Is California really that strict that even items having nothing to do with how the engine burns it’s fuel need to be certified regardless?

Any modification of emission controls is illegal, so moving the cats, the O2 sensors, etc. is illegal (Federal law says this too though?)

My Airaid CAI has a CARB EO number https://ww3.arb.ca.gov/msprog/aftermkt/devices/eo/d-609-18.pdf

A Guy

 

[Nuke]

i don't know how likely it is for the average state inspection in California to involve an actual, physical inspection of the various components on the car that contribute to emissions efficacy, but if i were a betting man I'd wager its pretty unlikely.

I'm assuming the inspections are done by automotive shops that normally do hardware replacement and/or oil changes, just like they are here. And those places don't make any money inspecting a car for an inspection sticker. They make their money off regular customers bringing in their cars or normal break/fix stuff or oil and filter services if that's their mill-yew.

As such, it seems to me that there is little incentive to do a complete, physical inspection of all the components. They'd much rather just pass the car (if no CELs and all monitors are active and passed) and free up the bay for the next car, one which has some potential to make the shop some money.

 

[trippytro]

i don't know how likely it is for the average state inspection in California to involve an actual, physical inspection of the various components on the car that contribute to emissions efficacy, but if i were a betting man I'd wager its pretty unlikely.

I'm assuming the inspections are done by automotive shops that normally do hardware replacement and/or oil changes, just like they are here. And those places don't make any money inspecting a car for an inspection sticker. They make their money off regular customers bringing in their cars or normal break/fix stuff or oil and filter services if that's their mill-yew.

As such, it seems to me that there is little incentive to do a complete, physical inspection of all the components. They'd much rather just pass the car (if no CELs and all monitors are active and passed) and free up the bay for the next car, one which has some potential to make the shop some money.

Nope, goes to a smog or “star” certified shop only and they definitely pop the hood and get under it, as well as a sniffer

 

[Nuke]

Nope, goes to a smog or “star” certified shop only and they definitely pop the hood and get under it, as well as a sniffer

That makes me sad that y'all have to be subjected to such treatment. I'm sure they have their reasons for such invasive tactics, i only hope the reasons they used to justify using those tactics makes it all worth it.

 

[stevewhite]

grab a beer and let me tell you whats been done.....lol

 

[Gila Hemi]

My Shaker is now on the final leg of it's journey to becoming my dream car. I just ordered yesterday, a blue printed and balanced short block, stroked to 392, polished and ported heads, a cam and everything else needed to turn my ride into a 392 Stroker, with the boost on my Magnuson going up to 14 lbs.

Luke, I installed the Auto-Blip, and I can feel and hear the rev matching when I shift, but the Auto-Blip light never comes on, Do you know what needs to happen to make that light turn on?

 

[A Guy]

California doesn't have inspections, only biennial smog checks, so they are all smog check certified people. They are supposed to do a visual check, and check functional inspection of the vehicle's check engine light, ignition timing, exhaust gas recirculation system, fuel evaporative system, and gas cap (they put the gas cap on a jig and apply vacuum).

They no longer do a tailpipe sniffer car on rollers test on OBD equipped cars. Just do the visual, and run the OBD test. New cars purchased in California don't have to be tested for 6 years, but you pay a Smog Abatement Fee on your registration.

A Guy