08 viper air fuel problem

[viperpat]

I have dyno'd my 08 viper on two different dyno jet dyno's the car is low on power at 508 HP the air fuel mix is 10.3 should be 13.1 we think it may be a slow reading 02 censor.
Has anyone with a 08 had this type of problem or computer problem. Any ideas dodge is not sure of the problem they are working on it, i am sure i am not the only 08 viper owner with this problem. I would have never new i had a broblem if i had not dyno'd the car 500 HP is still a lot of power. I think the car is down 45 HP i did add a KN filter and magnaflow exhaust, and that brought it up to 546 about what it should be stock.
any ideas?

 

[ulllose]

Wow yes it seems to be way down on power........I have saw one post stating that there 08 made 560 to the wheels stock. Good luck with that one

 

[VIPER R]

Check Viper Alley, they show an 08 dyno'd at 560 HP.

 

[Nader]

Have you run against other cars to get a baseline on aceleration? Might be the dyno especially if you didnt realize it until dynoing it.

 

[Viper X]

My .02 cents is as follows:

I ran around Buttonwillow chasing a 2008 coupe in my modded GTS about a month ago. I gained on him in every straight. We're about equal drivers (I never caught him and he ran about 2 seconds better than I did, when comparing best times of the weekend over a three mile track). They have done a very good job with the 2008 suspension compared with 2006 and the tires are much better too.

My GTS weighs in at 3420 with a full tank and I weight 250. Total weight of the two cars was about the same that day. My GTS makes about 510 rwhp and 535 rwtq on the local dyno when warm.

My guess is that most of these 2008 cars make about that level of power when warm and being driven.

Many tuners do a cold pull to demonstrate max power on the dyno. Some tuners don't use SAE corrections. I guess that I'm saying is that these cars are very strong stock, but 540 or 550 rwhp from a stock engine will likely be on a cold "max hp" pull. It will not likely be achieved under warm or most normal operating conditions.

Dan

 

[MikeR]

My .02 cents is as follows:


My guess is that most of these 2008 cars make about that level of power when warm and being driven.

Many tuners do a cold pull to demonstrate max power on the dyno. Some tuners don't use SAE corrections. I guess that I'm saying is that these cars are very strong stock, but 540 or 550 rwhp from a stock engine will likely be on a cold "max hp" pull. It will not likely be achieved under warm or most normal operating conditions.

Dan

My car and every other Viper I saw dyno, when N/A made more power the warmer it got up to a point where it then stopped. So a cold pull isnt always the best pull. Usually 3rd or 4th run. At any rate his numbers are low or the dyno reads low.
And stock the Viper always seemd to run a little rich.

 

[JonB]

..........any ideas?..........

How many miles were on the '08 when you dynoed it?

Did you perform a gentle break-in?

Had the battrey or PCM been disconnected for any reason prior to dyno?

 

[Les Quam]

I haven't experienced a problem with mine? Hey Jon why are you asking about the gentle break in are you a believer? Bill Pemberton told me the factory engineers made a big point in regard to breaking the 08s in properly?

 

[STORMCAT]

Pat,
I didn't know you had installed the K&N's .. This has happened on some vehicles .The oil from the K&N left a coating of oil on the MAF sensor making it read incorrectly. You need to be real careful when cleaning the MAF wire. You could clean it with some CRC no residue electrical contact cleaner..?? It might be worth a shot.. I look forward to seeing the car !! Brian

 

[Viper X]

Hey Mike,

I probably should have defined "cold pull" better. A cold pull is done on a warm engine that has been allowed to sit and cool. The coolant temp is about 130 to 140F and the intake tract is close to room temp. Some tuners even put ice on the intake manifold before making this pull.

This is the ideal temp for making hp / tq and drag racing the car competitively.

All Vipers experience heat soak. Hp / tq fall off with increasing engine temps. No Viper engines that I know of make more hp or tq when hot. Chevrolet small block V-8's on the othe hand do well when warm and even a bit hot.

Viperpat's car sounds like it has O2 sensor issues or other tuning issues but it may also have been tested when hot.

Dan

 

[RTTTTed]

I notice that he wrote that the engine was running fat (10.2 instead of 13.1).

Looks to me that would explain his power loss.

Ted

 

[dragon rider]

The car does seem to make low baseline #s from other people hp post. 540-550 is about the average. Your 40 hp gain from an intake an exhaust are exceptionally high. If all 08’s made those types of hp gain from those basic mods, 600 hp would become the norm. I guess what I’m trying to say is that Gen III’s would gain about 10-15 rwhp from the same mods. The Gen IV air box is supposed to be getter and the exhaust less restrictive. Maybe the first couple of times dynoing, the shop did not create optimal conditions for you as Viper X stated earlier. For example, I would drive my car 50 mile or so and put in on the dyno immediately for real would hp #’s 451 hp 480 tq. Then as Viper X stated earlier, I would let the car cool down and in 25 min or so make 20 more hp and 20 more tq. That’s just my 2 ½ cents.

 

[Flash1034]

So....What is the best way to break-in a new 08 Viper? Run her hard from the get-go or smooth and easy for the first 500 miles or so?

Flash

 

[B767DRIVER]

So....What is the best way to break-in a new 08 Viper? Run her hard from the get-go or smooth and easy for the first 500 miles or so?

Flash

Here you go:

The following is a recommended break-in procedure for a Gen III car (2003-2006) recently published in Viper Magazine by Herb Helbig, the recently retired "Grail Keeper" at Chysler. While it is clearly more conservative than the break-in listed in the 2008 manual. Here goes:

BREAK-IN PROCEDURE (0-1,000 MILES)

WARM UP ENGINE FIRST

MAX SPEED 70 MPH (113 KPH)

AVOID EXTENDED ENGINE IDLING

NO FULL THROTTLE STARTS/ACCELERATIONS

VARY ENGINE RPM

CHECK ENGINE OIL EVERY FUEL FILL

0-200 MILES

LIGHT THROTTLE RUN-UPS THROUGH GEARS: MAX SHIFT POINT 2,500 RPM

CHANGE ENGINE OIL AT 200 MILES

201-400 MILES

LIGHT THROTTLE RUN-UPS THROUGH GEARS: MAX SHIFT POINT 3,500 RPM

401-600 MILES

LIGHT THROTTLE RUN-UPS THROUGH GEARS: MAX SHIFT POINT 4,000 RPM

601-800 MILES

LIGHT THROTTLE RUN-UPS THROUGH GEARS: MAX SHIFT POINT 4,500 RPM

801-1,000 MILES

LIGHT THROTTLE RUN-UPS THROUGH GEARS: MAX SHIFT POINT 5,000 RPM

1,001-1,500 MILES

Sterling

 

[Flash1034]

Thanks for the info.

Flash