American Racing Headers + 373 gears + MCS suspension = Awesome Viper

[FLATOUT]

What headers are you running, and with or without cats?

[IndyRon]

BBG 1 7/8" new style shorties, no cats.

[FLATOUT]

BBG new shorties, no cats.

Ok thanks I couldn't remember what you put on. The ECU's are screwy in these cars period.

[Jack B]

Interesting - a few observations:

1. My pull was on the road, therefore and whole bunch of variables are added. In addition, the sensor on my car is in the collector, whereas, you are using a tailpipe sniffer. Even with those differences, the a/f is close over 5500 on my G5 and your G4.

2. There is a definite correlation in a/f between our cars, however, your car shows extremely lean at max torque, I would think knock-retard is pulling timing on your car. Max torque likes a little richer than max hp. If you drop the smoothing you will probably see the hp dip near max torque.

3. Without digital intervention, the headers should lean the a/f once you go open loop.

4. It looks like your operator did not use the dynojet brand of a/f logging, that is good since they suck. You cannot turn off smoothing with the embedded system.

5. It does not matter now, however, you lose a lot of detail with a 5 smoothing. You will probably gain some hp (on paper) if you drop the smoothing, plus, it tells us more about the engine's power output.

Jack,
Thanks for posting that up. I don't have timing advance on mine but do have A/F ratio with subsequent runs.

First graph is stock (blue) vs. Gen5 int/Mopar PCM (red) vs. Int/PCM/Headers (green). You can see the A/F ratio with the PCM slightly richer at the bottom but leaner at the top. Then with headers, leaner everywhere. The headers run was pull 8 so the computer had a chance to adjust.


Now, this graph is boltons including headers during subsequent back to back runs no shutdown or cool-off. Runs are in numerical order 5, 6, 7, etc corresponding to subsequent runs. The car is pulling fuel with each run but it is targeting a different baseline it seems vs. when it was on stock manifolds which is confusing to me. Whether the car has headers or not, I would think the PCM wants to see 12.xx A/F at xxxx RPM regardless of modifications, although it is obviously pulling fuel with subsequent runs even though I'm over 1/2 point leaner than with the same PCM and stock mani's.

[Voice of Reason]

KB Viper I just noticed who you are by seeing the cross post on the other forum. Glad you joined over here!

[IndyRon]

Jack, I have the WinPep software and all the .bin files so I can manually scale and adjust everything including smoothing. Good points on the max torque issue. I'll check that out. As far as the wideband, it was a ~36" pipe stuck up the DS exhaust so I would say the sampling site was approximately 6-12" behind the collector.

Ultimately I think it will be a little trial and error with the HPtuners software to find the optimal A/F for max HP and max TQ for these motors. Who knows, maybe they want closer to 12.5 or maybe there are up there at 13.3. I won't know until I experiment I guess. I'll need knock logging software for the tuning. I don't remember if the HPtuners software does that.

[Jack B]

I have HP Tuners GM version and that version does record KR. It also allows you to log the full a/f map versus load and rpm.

Different topic, I have the Corsa's on my G5 and before I put in the wideband I dyno'ed and could not get the sniffer into the muffler. I have the first full production Corsa sold for the G5, it may be different than the current models.

Jack, I have the WinPep software and all the .bin files so I can manually scale and adjust everything including smoothing. Good points on the max torque issue. I'll check that out. As far as the wideband, it was a ~36" pipe stuck up the DS exhaust so I would say the sampling site was approximately 6-12" behind the collector.

Ultimately I think it will be a little trial and error with the HPtuners software to find the optimal A/F for max HP and max TQ for these motors. Who knows, maybe they want closer to 12.5 or maybe there are up there at 13.3. I won't know until I experiment I guess. I'll need knock logging software for the tuning. I don't remember if the HPtuners software does that.

[IndyRon]

I have HP Tuners GM version and that version does record KR. It also allows you to log the full a/f map versus load and rpm.

Different topic, I have the Corsa's on my G5 and before I put in the wideband I dyno'ed and could not get the sniffer into the muffler. I have the first full production Corsa sold for the G4, it may be different than the current models.

I wish I took a pic as I was surprised what the inside looks like. It was just a straight pipe. It had 2 areas of circumferential slots (holes) corresponding to the 2 mufflers and that was it. There was nothing to obstruct the exhaust path. Maybe they changed them?

KB Viper,
Thanks for posting up the comparo. Not much difference really in extra RPM at cruise but I'm sure a seat of the pants improvement!

[345s-bspinnin]

headers with no drone what so ever, man this car sounds amazing. the 373 gears make a completely different rig. here are before and after shots of the rpms at 80, 75, 70, & 65.

Looks like you have been having a lot of fun with your car as shown by your lower MPGs on the pics with 373 gears

[KB Viper]

Looks like you have been having a lot of fun with your car as shown by your lower MPGs on the pics with 373 gears

That might be deceptive as most likely I was slowing down to get to speed and snap those pics which made the mpgs look better.

[Nine Ball]

okay, now I want 3.73 gears in mine. Anything to help launch better, this car needs.

[KB Viper]

okay, now I want 3.73 gears in mine. Anything to help launch better, this car needs.

I'm telling you, you won't regret it.

[1Koolasp 16ACR]

Does The Speedo Need To Be Corrected ?? Or Is That Automatically Done At The Wheels ,Not The Tranny

[KB Viper]

Automatically done.

[Jack B]

Wheel sensor

Does The Speedo Need To Be Corrected ?? Or Is That Automatically Done At The Wheels ,Not The Tranny

[Jack B]

G4 trans - that is my ground hog day statement

okay, now I want 3.73 gears in mine. Anything to help launch better, this car needs.

[Jack B]

5% diff

I wish I took a pic as I was surprised what the inside looks like. It was just a straight pipe. It had 2 areas of circumferential slots (holes) corresponding to the 2 mufflers and that was it. There was nothing to obstruct the exhaust path. Maybe they changed them?

KB Viper,
Thanks for posting up the comparo. Not much difference really in extra RPM at cruise but I'm sure a seat of the pants improvement!

[Nine Ball]

G4 trans - that is my ground hog day statement

$4000 trans vs $500 gear swap.

I have a good trans

[mjorgensen]

Does The Speedo Need To Be Corrected ?? Or Is That Automatically Done At The Wheels ,Not The Tranny

The speedo will read right, but anything deeper then the 3.73 gears will affect the use of the cruise control so don't get carried away. We have done quite a few 3.73 swaps and they are great fun!

[Jack B]

1st Gear
2010 trans = 18% improvement
3.73 = 5%

2nd Gear
2010 Trans = 15% improvement
3.73 = 5%

$4000 trans vs $500 gear swap.

I have a good trans

[Ryanr206]

Does anyone make a 4.10 for the cars?

[Nine Ball]

1st Gear
2010 trans = 18% improvement
3.73 = 5%

2nd Gear
2010 Trans = 15% improvement
3.73 = 5%

Damn you and your good logic. Haha

I think I'll just keep the white car for roll racing and roadcourse stuff. The blue one is more fun to drag race, anyways

[IndyRon]

Does anyone make a 4.10 for the cars?

I haven't done the math, but I don't think you could finish the quarter in 4th with 4.10's and stock redline...at least on stock size tires.

[Jack B]

THE 3.73 gear is the max for 1/4 mile.

I haven't done the math, but I don't think you could finish the quarter in 4th with 4.10's and stock redline...at least on stock size tires.

[IndyRon]

Even though it is expensive the answer is the 2010 trans. Great 1st/2nd gear ratios especially with the factory 3.55's out back and great for cruising.