[Aussie 300C]

I installed the Borla 125 (5" tips) system yesterday after I had 2 runs on the dyno standard. Both came back at a VERY impressive 201kw or 270hp. Not bad for a 250kw engine. I then put the Borla on took it for a 30 min drive and did 6 more runs on the dyno. Mixtures changed for the worst and it only pulled 198kw. Seems to be more responsive but I'd like to know that overall power had gone up to at least 215kw/288hp at the rear wheels. After driving it for another day I have noticed the fuel economy has gotten worse too.
Anyone know what might be the problem?
Apart from that I do have a bit of drone in 1st and 2nd and some in 3rd but it's not as bad as I thought it might be.

 

[crhemi]

I saw mpg improve after Magnaflow instalation, although I think its goes down over time cause we step on it more to here that Hemi roar!

 

[JustForFun]

Did you pull Fuse 11 when you did the cat-back install?? You should do this when adding ANY performance mod. This allows the PCM to reboot itself and relearn your cars config taking into account your new toy.

Give it a try.

JFF

 

[Northern Rider]

I installed the Borla 125 (5" tips) system yesterday after I had 2 runs on the dyno standard. Both came back at a VERY impressive 201kw or 270hp. Not bad for a 250kw engine. I then put the Borla on took it for a 30 min drive and did 6 more runs on the dyno. Mixtures changed for the worst and it only pulled 198kw. Seems to be more responsive but I'd like to know that overall power had gone up to at least 215kw/288hp at the rear wheels. After driving it for another day I have noticed the fuel economy has gotten worse too.
Anyone know what might be the problem?
Apart from that I do have a bit of drone in 1st and 2nd and some in 3rd but it's not as bad as I thought it might be.

The freeflow exhaust has altered the air/fuel ratio and the ECM computer is unable to adjust. You will need a tuner that can reprogram the ECM such as the new SuperChips one being released on Feb 15th.

There are a couple of group buys going on this programmer on the forum.

 

[II kings 9:20]

The freeflow exhaust has altered the air/fuel ratio and the ECM computer is unable to adjust. You will need a tuner that can reprogram the ECM such as the new SuperChips one being released on Feb 15th.

There are a couple of group buys going on this programmer on the forum.

What he said.

 

[jconnolly1119]

NR and KIng's are absolutely correct about the ECU.....but consider this as well

heat soak

you say you took a 30 minute drive after installing the Borla before doing 6 dyno pulls.....

did you take the same 30 min drive stock??

it could have some negative effect.....

in addition to the ECU not properly adjusting

 

[stevesrt8]

soaked

dynos, dynos. Bench racing at its finest.

A bag of ice (for us) was worth a half second in the quarter mile! I'm betting he got hot for sure.

Take it to the strip. And bring a cooler!

 

[Meister]

...heat soak

you say you took a 30 minute drive after installing the Borla before doing 6 dyno pulls.....

did you take the same 30 min drive stock??

it could have some negative effect...

It certainly does, Aussie 300C.

Short version: Heat soak most definitely has a significant negative effect on power output for any engine. Our LX Hemis, as setup by the factory, are particularly susceptible by it.

Expanded version: My 300C begins to show the effects of heat soak at 190 degrees F. At the track, day or night, if I ever allow coolant temp to exceed 190 I'll be down a tenth for all remaining runs from that factor alone. If coolant temp is ever allowed to reach 200 degrees, times will be down by 2/10ths thereafter, environmentals and other factors considered.

Cooler thermostats, expecially when accompanied by a fan mod, help greatly. At GIFO3, replacing, on the dyno, the stock 203 tstat with the Prestone 383-170 resulted in a gain of 7 rwhp for CoolVanilla's '05 Magnum on the next and all subequent runs.

 

[ubeenbit]

This post interest me. I really hope a custom tune is not required to take advantage of an exhaust improvement. I hope and would think DC has adaptive learning built into the ECM. I can understand taking a while to learn the new engine characteristic and a reset of the ECM required to force it into learning the new flow characteristic. My bet is like others have said the engine adds fuel and pulls timing for different temperatures, resulting in lower power. Now the question I have is does it pull it on ECT or ACT or both. I bet it is both and a resistor in place of the ACT sensor would probably bring some timing back and get you some power back with very little invested.

Jason

 

[Meister]

This post interest me. I really hope a custom tune is not required to take advantage of an exhaust improvement. I hope and would think DC has adaptive learning built into the ECM. I can understand taking a while to learn the new engine characteristic and a reset of the ECM required to force it into learning the new flow characteristic. My bet is like others have said the engine adds fuel and pulls timing for different temperatures, resulting in lower power. Now the question I have is does it pull it on ECT or ACT or both. I bet it is both and a resistor in place of the ACT sensor would probably bring some timing back and get you some power back with very little invested.

Jason

AIT is a biggie, Jason. The resistors I've experimented with have been most effective when the ambient temperature is quite elevated. On a 110 degree day last summer, for example, alternate 0-60 runs with & without my resistor were consistently .15 seconds faster when using the resistor (G-Timer II).

By broadest torque band, measured on the dyno at GIFO3, was attained with the resistor fooling the PCM.

Some pictures here: http://photobucket.com/albums/a243/computermeister/

 

[Meister]

Dyno numbers: resistor in & out

ubeenbit - Here are the numbers from GIFO3 (SVG Dyno, Sacramento, CA). The first three runs were with my resistor plugged into the AIT Sensor lead, thus spoofing the PCM, the next 3 runs were with the AIT Sensor lead re-attached to the AIT Sensor (stock setup), and the final 3 were with the 6" Dub-Air Funnel Ram performance cone air filter element attached to my K&N Typhoon intake system in lieu of the original 6.5" K&N filter element:

Avg1: Resistor: 282.9 hp @ 5266, 297.0 ft-lb’s @ 4553, Held 290 ft-lb’s or > from 4432 - 4652, Held 280 ft-lb’s or > from 4427 - 5295
Avg2: AIT sensor: 282.6 hp @ 5241, 290.3 ft-lb’s @ 4679, Held 290 ft.lbs. or > at 4679, Held 280 ft-lb’s or > from 4385 - 5270
Avg3: Funnel Ram filter 278.5 hp @ 5175, 287.8 ft-lb’s @ 4640, Never attained 290 ft-lb's, Held 280 or > from 4496 - 5204

 

[ubeenbit]

ubeenbit - Here are the numbers from GIFO3 (SVG Dyno, Sacramento, CA). The first three runs were with my resistor plugged into the AIT Sensor lead, thus spoofing the PCM, the next 3 runs were with the AIT Sensor lead re-attached to the AIT Sensor (stock setup), and the final 3 were with the 6" Dub-Air Funnel Ram performance cone air filter element attached to my K&N Typhoon intake system in lieu of the original 6.5" K&N filter element:

Avg1: Resistor: 282.9 @ 5266 297.0 @ 4553 Held 290 or > from 4432 - 4652 Held 280 or > from 4427 - 5295
Avg2: AIT sensor: 282.6 @ 5241 290.3 @ 4679 Held 290 or > at 4679 Held 280 or > from 4385 - 5270
Avg3: Funnel Ram filter 278.5 @ 5175 287.8 @ 4640 Never attained 290 ft. lbs. Held 280 or > from 4496 - 5204

I am confused on what the numbers you are giving. I understand the difference between the runs, I am unclear on this 282.9 @ 5266 297.0 @ 4553 is that HP and then torque.

Jason

 

[Meister]

I am confused on what the numbers you are giving. I understand the difference between the runs, I am unclear on this 282.9 @ 5266 297.0 @ 4553 is that HP and then torque.

Jason

That's correct Jason. The original post has been edited accordingly. Here they are for convenience:

Avg1: Resistor: 282.9 hp @ 5266, 297.0 ft-lb’s @ 4553, Held 290 ft-lb’s or > from 4432 - 4652, Held 280 ft-lb’s or > from 4427 - 5295
Avg2: AIT sensor: 282.6 hp @ 5241, 290.3 ft-lb’s @ 4679, Held 290 ft.lbs. or > at 4679, Held 280 ft-lb’s or > from 4385 - 5270
Avg3: Funnel Ram filter 278.5 hp @ 5175, 287.8 ft-lb’s @ 4640, Never attained 290 ft-lb's, Held 280 or > from 4496 - 5204

 

[ubeenbit]

Did you dyno stock? What did you have done at the time of the above dyno? Should I start another thread, I am not sure of the ettiquete here.

 

[Meister]

Did you dyno stock? What did you have done at the time of the above dyno? Should I start another thread, I am not sure of the ettiquete here.

Let's shift this topic to here: http://www.300cforums.com/forums/pe...ng-lx-hemi.html?highlight=modding+the+lx+hemi

Thanks.