Notes on Gen 4 mods

[Dan Cragin]

I have a little explanation sheet I use for my customers choosing exhaust mods for the Gen 4's . Take a look, it might answer some questions. My attachments come over with varying font size.

2008-2010 VIPER ENGINE PERFORMANCE PARTS DESCRIPTION​

Generation 4



EXHAUST MODIFICATIONS

The new Generation 4 engine responds very well to exhaust modifications. The increased rpm limit and variable cam timing works well with a tuned aftermarket exhaust system.

There are numerous exhaust options for the Generation 4 engine. Below is an explanation of the characteristics of each.

Note: Use of headers on a 2008-2010 models will not pass emissions in California.


SIDE EXHAUST SYSTEMS (Retains production catalyst)

(10-12hp)
Changing the side exhaust gives your Viper more tone, character and marginal power gains. Other benefits are reduced exhaust related heat and attractive polished or chromed exhaust tips.


Belanger/ DC

This system is made by Belanger for DC Performance and features stainless Magnaflow mufflers and chrome tips. This system is for those who like a system with a louder sound and more tone. Available in 2 ½ inlets (for hookup to stock exhaust) or 3-inch inlet for hook-up to Headers or high flow cats.

Corsa

The Corsa “track” system is a very high quality stainless system with resonance canceling mufflers and polished tips. The system has good tone and very little resonance. This system is for those who like a quieter system with more tone. Available in 2 ½ inlets (for hookup to stock exhaust) or 3-inch inlet for hook-up to Headers or high flow cats.






HEADERS


ACRX Merge Headers (35hp)

These headers are the same as used on the ACRX racecar. They are an all-stainless design with merge collectors. The come with high flow cats and turnouts or without cats. The benefit of this header is best peak power and a tuned sound. This system can be used with the stock mufflers or with the DC Belanger or Corsa side exhaust.

BELANGER Headers (30hp)

These headers are a mild steel tri-y design. They are ceramic coated inside and out. They can be supplied with high flow cat or no cats for hookup to the stock mufflers or Corsa exhaust. The system can also be supplied as a complete system with headers, cats and side pipes. A benefit of this system is good low-end torque and less radiated heat under the hood.


Ported Intake Manifold (17-24hp)

Our custom ported intake manifold increases upper rpm airflow into the engine. This modification will pass emissions and work well with the stock computer or the Mopar Performance Controller.


Performance Engine Controller (5-15hp)
This controller removes the lag associated with the production controller, has revised fuel spark and cam position tables, Rev limit increased to 6500 rpm with softer fuel cut. 1-4th skip shift removed. Use 93 octane fuel for best results.


* Off road use only.

Air-Oil Seperator
Oil vapors pumped into the intake manifold produces engine knock and reduces power. This emissions compliant oil separator keeps the oil from entering the intake manifold. A must for modified or track engines.

 

[BlknBlu]

This is a great thread starter, I think we can post what works and does not work for people interested in upgrades.

1. 3.55 to 3.73 gears will increase total MPH and quicker 1/4 mile times.

2. After market air filters are not advantagous however aftermarket systems have not been proven to increase HP.

Bruce

 

[KenricGTS]

Thanks for info! Very helpful

 

[Art 138]

Air-Oil Seperator
Oil vapors pumped into the intake manifold produces engine knock and reduces power. This emissions compliant oil separator keeps the oil from entering the intake manifold. A must for modified or track engines.



Do you have a pic of the oil separator??? I would be interested in one....

 

[Twister]

very good write up...So the acrx headers are good...Will they work on a gen3?

 

[KenricGTS]

Dan, do you recomend 355s or 373 gears??

 

[TrackAire]

very good write up...So the acrx headers are good...Will they work on a gen3?

Twister,

I went down to DC Performance to watch Bad Boyzz Garage Gen III beast get dyno tuned. Toddy designed his own intake, cam, head, valvetrain and exhaust package. DC Performance did the dyno tuning. The car is naturally aspirated.

Toddy obviously has a good combo:

-626 rear wheel horsepower at 6000 rpm
-600 foot pounds of torque at 4800 rpm
-All on 91 octane (that was the impressive part)

He is putting out more hp than my Gen 4

I'd say the ACRX headers worked pretty damn good!! I'm jealous of the numbers he posted...very impressive engine work by Bad Boyzz Garage and good tuning by Chris at DC Performance.

I'm sure Toddy will be chiming in with videos of his dyno pulls.

Cheers,
George

 

[Dan Cragin]

The 3.33 ratio or 3.55 ratio works best on the Gen 4's. Too much wheel spin with the 3.73's.

We are doing the oil seperator in shop currently but will have a mail order package ready soon.

In regards to the Merge American Racing headers, we carry these for Gen 2-4 models.

We are about to test our new Gen 4 cylinder head package and think the results will be very good.

 

[KenricGTS]

The 3.33 ratio or 3.55 ratio works best on the Gen 4's. Too much wheel spin with the 3.73's.

We are doing the oil seperator in shop currently but will have a mail order package ready soon.

In regards to the Merge American Racing headers, we carry these for Gen 2-4 models.

We are about to test our new Gen 4 cylinder head package and think the results will be very good.

So, for 1/4 mile and accelaration should I stay with stock gears with my 10 ACR or go with 3.33 or 3.55s? And in your expert opion the 3.33 or 3.55? My ACR will have ACRX headers stock mufflers, Mopar ECU, ported lower intake, K&Ns. Thanks for your time!

 

[VIPER GTSR 91]

Great post and info Dan. Thanks.

 

[alpha85]

Note: The track record for the ACRX was set using Belanger Headers.

 

[Dan Cragin]

For the drags you want good peak power and traction, once you get that you need to make sure you do not break parts. The bolt on packages for the Gen 4's are really great, with our new head package I think 700hp is possible with good reliability. Merge headers make best peak power but both ACR and Belanger work well.

Once you have the power you need good traction, the new Giken differential, a 3.33 gear and some DOT drag tires will get you off the line.

A more positive shifter and higher durometer transmission mount will improve full throttle shifts.

An adjustable shock, better spring rates and alignment can help too, a that point you are getting serious.

If you really want to launch then a ceramic dual disc clutch and modified CV shafts will take the abuse of hard launches without failing.

When it comes to drag racing there are so many things you can do to your car, but at some point you are crossing the line between a good handling sports car and drag car which the Viper really is not (without major changes).

 

[99FRC]

For the drags you want good peak power and traction, once you get that you need to make sure you do not break parts. The bolt on packages for the Gen 4's are really great, with our new head package I think 700hp is possible with good reliability. Merge headers make best peak power but both ACR and Belanger work well.

Once you have the power you need good traction, the new Giken differential, a 3.33 gear and some DOT drag tires will get you off the line.

A more positive shifter and higher durometer transmission mount will improve full throttle shifts.

An adjustable shock, better spring rates and alignment can help too, a that point you are getting serious.

If you really want to launch then a ceramic dual disc clutch and modified CV shafts will take the abuse of hard launches without failing.

When it comes to drag racing there are so many things you can do to your car, but at some point you are crossing the line between a good handling sports car and drag car which the Viper really is not (without major changes).

How long before you have more info on the heads? When you say 700hp, are you thinking 620-640rwhp is possible?

 

[Viper X]

99 FRC,

Depending on what you believe "driveline" loss is, either 15 or 20%, most modded Gen IV's, i.e. headers, intake, race controller, 93 to 95 octane gas, catch can, K & N's are very close or already at 700 peak crank hp on a chassis dyno like a Dynojet using SAE correction factor.

Don't see 620 to 640 peak rwhp on a chassis dyno SAE in the near future without making internal changes or cracking the computer code, maybe both.

Dan

 

[Marc]

Nice try Dan, you always distort numbers in order to make sales, my Gen IV
street car makes 595RWHP with Belanger headers and the stock controller only.
Shall I do the math for you?

Just look at the Stack Performance dyno video: YouTube - Viper Dyno Day and exhaust sound tests at Stack Performance (part 2 of 2)


Just let me know when I should take my Belanger's off my CompCoupe . . .

 

[Viper X]

Hey Marc,

FYI, Stack's dyno was very generous that day. We all made better numbers on it that day than we have ever made on DC's Dyno.

Dan

 

[redtanrt10]

Marc, as Dan said Stack's dyno was very generous that day. At Stack I pulled 586/550, 90 days later at DC, I was 553/531. Later I did a back to back at Stack with the mopar ECU and increased 9 hp. A few months ago DC did back to back pulls on my viper with their intake and I increased 17 hp to 580 hp, maybe this would equal 613 hp at Stack?

Also, if that was your green/black vert that did 595, I was told by Aaron it had the ecu and a corsa? I think the corsa is worth around 5 hp over the belanger mufflers. Mike

 

[Supr_Vlln]

Hey Marc…don’t get your ******* in a knot in your first post. And forget “math” try English Reading 101 first…Re-reading each of Dan’s post above I do not see any distortion of numbers or pushing of sales.

In fact, if that is your green Gen 4 vert in the video and you want to talk about “distortion” take a look at yourself…just Belanger headers and a stock controller and you made 595RWHP, huh? How about 3 mins and 20 secs into the video where Ryan the owner of Stack says you have:

-Belanger Headers
-Corsa Exhaust
-170 thermostat
-And Mopar ECU

And hate to burst your bubble, but your 595RWHP isn’t really 595…only on Stack’s dyno. On that dyno day, my car with exhaust mods and tune dyno’d 489 and one week later with no other changes it dyno’d 472 at DC. A bunch of stock Gen 3’s that day were turning in 450-460-ish numbers which we all know is horse manure because stock Gen 3’s should be turning in 440-ish. So yes Stack’s dyno is on the happy side by about 10-20RWHP which is great for all the dyno queens and bench racers…so welcome to about 575RWHP.

DC’s dyno may seem on the conservative side, but actually I find it to be quite accurate. My drag car has run 10.7 at 127MPH at Fontana’s 1/4 mile and 6.68’s at 103MPH at Irwindale’s 1/8 mile. I then dyno’d the car at DC and the RWHP figures matched up with my drag racing data. That is real world confirmation right there.

Oh and just for the record…I was the guy that shot, edited, and posted the video…not to mention data logged most all the cars that day and did a write up on it. Were you even there?

Here is the original post: http://forums.viperclub.org/srt10-s...video-viper-dyno-day-exhaust-sound-tests.html

So yea your “math” needs some work…next time crib off of the Asian kid sitting next to you.

 

[Dan Cragin]

Hi Mark,
We have always provided accurate numbers from each of our dynos and test in a repeatable manner. The dyno is a testing tool and the numbers vary from shop to shop but the percentage of change in power from modifications is pretty consistent.

The guys at Stack are great and do very good work.

I install several types of headers including Belanger and have outlined the benefits of each here on the boards.

I hope this helps clarify.

 

[99FRC]

99 FRC,

Depending on what you believe "driveline" loss is, either 15 or 20%, most modded Gen IV's, i.e. headers, intake, race controller, 93 to 95 octane gas, catch can, K & N's are very close or already at 700 peak crank hp on a chassis dyno like a Dynojet using SAE correction factor.

Don't see 620 to 640 peak rwhp on a chassis dyno SAE in the near future without making internal changes or cracking the computer code, maybe both.

Dan

DC is talking about porting the stock heads on the Gen IV. That in combination with headers,exhaust,filter,intake manifold mod,and Mopar PCM should be good for 600+rwhp.

 

[caseyse]

DC is talking about porting the stock heads on the Gen IV. That in combination with headers,exhaust,filter,intake manifold mod,and Mopar PCM should be good for 600+rwhp.

600+ rwhp would be nice to see.

 

[SR 27]

Dan C., sent you a private message.

 

[SilveRT8]

Love this Gen 4 thread, especially with all the valuable info provided by both Dan. I see a ported lower intake in my near future,
My question : Wich Air filter is best for the Gen 4 ? How much HP to expect from this ?

 

[TCurtner]

I have a little explanation sheet I use for my customers choosing exhaust mods for the Gen 4's . Take a look, it might answer some questions. My attachments come over with varying font size.

2008-2010 VIPER ENGINE PERFORMANCE PARTS DESCRIPTION​

Generation 4



EXHAUST MODIFICATIONS

The new Generation 4 engine responds very well to exhaust modifications. The increased rpm limit and variable cam timing works well with a tuned aftermarket exhaust system.

There are numerous exhaust options for the Generation 4 engine. Below is an explanation of the characteristics of each.

Note: Use of headers on a 2008-2010 models will not pass emissions in California.


SIDE EXHAUST SYSTEMS (Retains production catalyst)

(10-12hp)
Changing the side exhaust gives your Viper more tone, character and marginal power gains. Other benefits are reduced exhaust related heat and attractive polished or chromed exhaust tips.


Belanger/ DC

This system is made by Belanger for DC Performance and features stainless Magnaflow mufflers and chrome tips. This system is for those who like a system with a louder sound and more tone. Available in 2 ½ inlets (for hookup to stock exhaust) or 3-inch inlet for hook-up to Headers or high flow cats.

Corsa

The Corsa “track” system is a very high quality stainless system with resonance canceling mufflers and polished tips. The system has good tone and very little resonance. This system is for those who like a quieter system with more tone. Available in 2 ½ inlets (for hookup to stock exhaust) or 3-inch inlet for hook-up to Headers or high flow cats.






HEADERS


ACRX Merge Headers (35hp)

These headers are the same as used on the ACRX racecar. They are an all-stainless design with merge collectors. The come with high flow cats and turnouts or without cats. The benefit of this header is best peak power and a tuned sound. This system can be used with the stock mufflers or with the DC Belanger or Corsa side exhaust.

BELANGER Headers (30hp)

These headers are a mild steel tri-y design. They are ceramic coated inside and out. They can be supplied with high flow cat or no cats for hookup to the stock mufflers or Corsa exhaust. The system can also be supplied as a complete system with headers, cats and side pipes. A benefit of this system is good low-end torque and less radiated heat under the hood.


Ported Intake Manifold (17-24hp)

Our custom ported intake manifold increases upper rpm airflow into the engine. This modification will pass emissions and work well with the stock computer or the Mopar Performance Controller.


Performance Engine Controller (5-15hp)
This controller removes the lag associated with the production controller, has revised fuel spark and cam position tables, Rev limit increased to 6500 rpm with softer fuel cut. 1-4th skip shift removed. Use 93 octane fuel for best results.


* Off road use only.

Air-Oil Seperator
Oil vapors pumped into the intake manifold produces engine knock and reduces power. This emissions compliant oil separator keeps the oil from entering the intake manifold. A must for modified or track engines.

How do I obtain the ACRX Merge Headers (35hp)??
You may PM me if you wish.

 

[Viper X]

DC is talking about porting the stock heads on the Gen IV. That in combination with headers,exhaust,filter,intake manifold mod,and Mopar PCM should be good for 600+rwhp.

No doubt 600 rwhp and a bit over is possible with internal changes as stated above, like head porting / polishing or intake porting / polishing.

Increasing compression will also make a few more ponies.

I think the biggest jump in hp / tq on modded cars will be cracking the computer code to improve the tuning by adding fuel and timing along with running higher octane fuel.

I have a couple of friends with ACRX race cars. One of them made over 600 rwhp on the chassis dyno as delivered, so we know it can be done. The ACRX engines come with forged pistons, as most of you likely know.

We all need to be careful as we head down this path as the OE cast pistons and rods were likely not designed around these higher output levels.

It would be nice to hear from SRT on this subject.

Dan