Modding an ACR

[robiferretti]

Bought 09 ACR 2 weeks ago and am enjoying it. I can never leave well enough alone though.

I am not looking to go crazy, just a few things i'd like to address.

Throttle response seems to be a little sluggish (could be in my head)

Not that the car doesn't have enough power, its just that factory cars always room to make them a little better.

I dont want to touch the motor just want to squeeze what I can with basic bolt ons.

What intake is best for the car? I've read there is no benefit to the bling K&N kit, is it even worth swapping the filter in the stock box?

What exhaust components make the most power? Worth swapping headers but not mufflers and cats? I'd like to get some power out of it, but not make it too loud that I can't road trip it.

At what point do I need to re-tune it? Will a better flowing intake exhaust require a tune?

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[QUICKSRT10/SRT8]

I plan on doing the mopar race headers and exhaust and the engine controller

 

[robiferretti]

any details behind the decision?

 

[QUICKSRT10/SRT8]

any details behind the decision?

From what I hear if I do the headers exhaust and controller it's pretty much an ACX-X then

 

[Camfab]

I don't own one of these newer cars, however I have heard that the lazy throttle response you have is due to the drive by wire throttle. As in no throttle cable, electronic actuation. I have also heard that the Mopar Performance controller helps to minimize that issue. I'm sure someone else will chime in shortly.

 

[Camfab]

From what I hear if I do the headers exhaust and controller it's pretty much an ACX-X then

Actually the ACR-X engine is significantly different from a production engine, including different pistons.

 

[tattooed]

I'm planning to do full Belanger exhaust and Mopar ECU. I'll probably do the K&N Typhoon intake kit too.

 

[ACRucrazy]

Actually the ACR-X engine is significantly different from a production engine, including different pistons.

And the ACR-X engine controllers are completely different and can be re-flashed.

 

[robiferretti]

How are you guys deciding on the mods? I dont see much in the way of comparisons or data on them.

 

[ACRucrazy]

There is not much to do. The computers ****. Period.

Intake, headers, exhaust, mopar computer. Beyond that you are looking at pulling heads, porting an intake manifold, gears, suspension etc.

 

[Camfab]

The issue, if you want to call it that, is that the aftermarket has not been able to crack so to speak the computers on the -08 and up Vipers. So within reason you are limited to minor mods and the Mopar performance ECU. It sounds like you weren't intending on supercharging your car, so you should be fine with the mentioned products. One thing to note here, unlike other performance cars like the Vette for example which has a huge variety of aftermarket parts, the Viper does not. On a positive note, most of the stuff available is actually really good. The ACR-X headers are a great way to go for your car with the mopar ecu. Note that depending on your local you may have issues with smogging your car as these options are not street legal.

 

[ACRucrazy]

Throttle response seems to be a little sluggish (could be in my head)

Also this is not in your head, its in your car. Its the biggest issue with the 08+.
I find it annoying as hell. The DBW in this car is the worst I have ever had.

 

[hou99gts]

FYI, doing all the intake, exhaust, and ECU mods listed above is worth only about 30-35 rwhp from what I have seen. My 09 ACR is stock at 556 rwhp, others in my area who have converted their ACR's to ACR-X clones with all those mods are at 585-591 rwhp if my memory is not failing me. Significant investment per hp gained.

 

[robiferretti]

FYI, doing all the intake, exhaust, and ECU mods listed above is worth only about 30-35 rwhp from what I have seen. My 09 ACR is stock at 556 rwhp, others in my area who have converted their ACR's to ACR-X clones with all those mods are at 585-591 rwhp if my memory is not failing me. Significant investment per hp gained.

I guess that is what I was getting at. Haven't put the car on a dyno but I was curious what component is restricting HP?I just want the car to be free flowing and reliable. Builders design car, government tells them what they have to change to make it street legal, I want to change it back to how it was intended. If most of the HP gain comes from a set of High flow cats and a different air filter I wont bother wasting my money on the other stuff.

 

[ViperGeorge]

Have the heads and intake ported - no need for Mopar PCM with these mods and it will pass emissions. Want more? Add headers, high flow cats, and new exhaust - will need Mopar PCM. Mopar PCM will improve DBW response but eliminate the decel popping so many of us like. It will fail emissions in several states though as it does not set IM Monitors required for an OBD II plug in test.

 

[MtnBiker]

Also this is not in your head, its in your car. Its the biggest issue with the 08+.
I find it annoying as hell. The DBW in this car is the worst I have ever had.

I noticed this right away coming out of '09 Z06 which has a very responsive throttle.

What can be done about this?

 

[Camfab]

I noticed this right away coming out of '09 Z06 which has a very responsive throttle.

What can be done about this?

Read reply #5 and #15.

 

[Boxer12]

Welcome, the car is super and you will enjoy it a lot. Many owners lose control at low speeds so the throttle response is tuned to make the car more forgiving. The MOPAR ECU improves it, and so does a light weight fly wheel while rear gears give it seat of the pants acceleration. Suggest you join VCA and read threads in Grail Trail. Also, search the earlier threads, there has been a ton written about the various bolt on options.

 

[bushido]

When I first bought my ACR. The throttle response was a little bit sluggish,but after putting 1500 miles on the car. It seems to be fine now. My car is a 2010 so I'm not sure about the 08s,or 09s..

 

[redtanrt10]

Rob, as others said, mopar ecu will improve throttle response. the ECU wants 93 or better octane but it will run fine on 91, justs pulls back some timing. Headers work real well on Gen IV's, 30 RWHP with stock exhaust, 40 with a corsa or belllanger exhaust, the K&N filter will give a few hp but not on the dyno.

From there ported intake and ported heads. Each gives 15-20 RWHP, intake costs about 1/3 of what the heads will cost (with better studs, new gaskets and labor).

On DC's dyno a stock Gen IV has between 515-535 RWHP. With headers,exhaust and ECU most see 570-580 RWHP.

I did all that plus ported the intake and heads and I've got 605 RWHP. That's the stopping point today due to the lack of Chrysler releasing the codes. There are variances between stock motor hp, there are slight variances between headers and exhaust systems, the porting by vendor and the different dyno's used around the country.

Get the mopar ECU and headers and see what you think, you willl feel the difference immediately. From there I'd get the intake done, heads help but the HP gain is pricey. Good luck, Mike

 

[bushido]

Also if your suspension is in stock setting. The labels/tags not broken on the shocks. I reccommend putting more rebound on the shocks. IMO with the stock setting the car feels like it's riding on no shocks. Like jumping on a pogo stick. Going around corners with a dip or a bump. Even a small one the car just shoots/springs back up real quick which can make you lose control. When I first got the car I thought it handled like $hit,but after cranking more rebound. It completely transformed the car. I got my rebound at 8 rears and 9 fronts..

 

[lmcgrew79]

My stock 08 coupe produced 520 HP and 487 Tq. Its since been acr cloned with the exception of mcs suspension vs kw. With the lighter sidewinders, rotors, mopar pcm, corsa exhaust, and hf cats, it put down 548 hp and 538 tq.

 

[hou99gts]

Also if your suspension is in stock setting. The labels/tags not broken on the shocks. I reccommend putting more rebound on the shocks. IMO with the stock setting the car feels like it's riding on no shocks. Like jumping on a pogo stick. Going around corners with a dip or a bump. Even a small one the car just shoots/springs back up real quick which can make you lose control. When I first got the car I thought it handled like $hit,but after cranking more rebound. It completely transformed the car. I got my rebound at 8 rears and 9 fronts..

Interested in your street shock settings, comp. and rebound, front and rear. Mine is still set to stock for the street. Thanks-

 

[SYNFULL]

Wondering what everyones thoughts are concerning hi-flo cats verses no cats. I have a 08 and am planning on doing acr-x headers with corsa exhaust and mopar pcm (possibly ported intake also).
My 99 acr had Belanger headers with random tech exhaust and no cats. The sound was great but it really smelled sometimes. I am not concerned with emissions as I drive under the exemption limit.
Thanks

 

[SNKBYT]

My mods on my 09ACR are Headers, hiflow cats, mopar computer from Woodhouse. Have added Smooth tubes, k&n filter, ported intake. Left the stock catback exhaust. Maybe gave up a few HP, but like the quieter sound at idle, and the bark at high RPM's. Dynoed 611 RWHP.

 

[robiferretti]

Did you get a stock baseline dyno? Were all the mods were done in one shot?

My mods on my 09ACR are Headers, hiflow cats, mopar computer from Woodhouse. Have added Smooth tubes, k&n filter, ported intake. Left the stock catback exhaust. Maybe gave up a few HP, but like the quieter sound at idle, and the bark at high RPM's. Dynoed 611 RWHP.

 

[lmcgrew79]

Wondering what everyones thoughts are concerning hi-flo cats verses no cats. I have a 08 and am planning on doing acr-x headers with corsa exhaust and mopar pcm (possibly ported intake also).
My 99 acr had Belanger headers with random tech exhaust and no cats. The sound was great but it really smelled sometimes. I am not concerned with emissions as I drive under the exemption limit.
Thanks

Hi-flo cats are probably pointless with the mopar pcm, but i got them before my pcm and was worried about throwing codes.

 

[lmcgrew79]

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Here was my baseline and after mods.
Dynos are pointless for setting hp records and are better just to see what you actually gained using the same dyno, IMO.

 

[Steve M]

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Here was my baseline and after mods.
Dynos are pointless for setting hp records and are better just to see what you actually gained using the same dyno, IMO.

Something was very wrong on your before dyno...I'm guessing your stock PCM wasn't happy about something that day.

Wondering what everyones thoughts are concerning hi-flo cats verses no cats. I have a 08 and am planning on doing acr-x headers with corsa exhaust and mopar pcm (possibly ported intake also).
My 99 acr had Belanger headers with random tech exhaust and no cats. The sound was great but it really smelled sometimes. I am not concerned with emissions as I drive under the exemption limit.
Thanks

I didn't run cats on my previous car, and hated the stench that it caused. Getting out of that car smelling like gas was not cool or pleasant, so personally, I'll never run without them even though I don't have to pass emissions of any sort.

 

[klamathpro]

Many owners lose control at low speeds so the throttle response is tuned to make the car more forgiving.

I don't buy that. You will still loose control, just 0.8 seconds later.