Back pressure and the camaro...

[Darth_Emma]

Originally Posted by mikeSS

quick question, is that dyno with the torque converter ?

Both runs are with the torque converter. As I said, the only difference was the cats.

[GretchenGotGrowl]

Originally Posted by Darth_Emma

Maybe you don't find the empirical data on the dyno sheet I provided useful, but I think the OP and others may find it useful information.

Very useful. Most chassis dyno pulls start between 2-2.5K. I have only seen a few start below that and maybe the lowest being 1.5. If you looking for power from a car, you aren't getting much going WOT from 0 to 2000 RPM and then shifting, so why do a chassis dyno pull way down there?

[Darth_Emma]

Also, when I'm accelerating, I'm rarely below 2k. When I want power, I'm up higher in the rpms. The only time I'm down low is cruising or idling. I don't care what my power is when I'm cruising or idling.

[mikeSS]

Originally Posted by Darth_Emma

Also, when I'm accelerating, I'm rarely below 2k. When I want power, I'm up higher in the rpms. The only time I'm down low is cruising or idling. I don't care what my power is when I'm cruising or idling.

+1

[GretchenGotGrowl]

Originally Posted by Darth_Emma

Also, when I'm accelerating, I'm rarely below 2k. When I want power, I'm up higher in the rpms. The only time I'm down low is cruising or idling. I don't care what my power is when I'm cruising or idling.

At the track it is great to have the low end power, but you can launch well above 2000 even without the torque converter.

[nicave13@gmail.com]

I first want to state I agree with everything on here about scavenging, back pressure and performance. The only thing not mentioned, and maybe not that important to a lot is true low speed torque in the drive-ability range. What I'm really talking about is normal day to day driving. Take my car as an extreme example. I run DOD or 4cyl mode on my L99 auto. Had it turned off b4 $3 gas, now I use it. Yes, there is a MPG gain, slight. My car gets 27mpg regularly on highway and 21 in town, yes I drive slowly. To accomplish this my engine is always in 6th gear and running 1000-1500 rpm. This is 40-60mph where I do 90% of my driving. In this manor I'm running as a 4cyl at 1000 rpm at 40mph. Currently all stock the engine pulls it no problem.

Here is my question. What is the best mod to keep this low speed torque and gain some sound. I "feel" any significant loss of back pressure will be detrimental to this usable torque. Short/ long tube's or cat delete would drop back pressure and increase sound, but what about the low speed torque? Full catback would surely improve sound, but again, what about off idle torque where I do all my driving?

Thoughts?

[litle88]

My thought is your agreeing to some topic from 18 months ago lol.

[SPCBA]

Originally Posted by nicave13@gmail.com

I first want to state I agree with everything on here about scavenging, back pressure and performance. The only thing not mentioned, and maybe not that important to a lot is true low speed torque in the drive-ability range. What I'm really talking about is normal day to day driving. Take my car as an extreme example. I run DOD or 4cyl mode on my L99 auto. Had it turned off b4 $3 gas, now I use it. Yes, there is a MPG gain, slight. My car gets 27mpg regularly on highway and 21 in town, yes I drive slowly. To accomplish this my engine is always in 6th gear and running 1000-1500 rpm. This is 40-60mph where I do 90% of my driving. In this manor I'm running as a 4cyl at 1000 rpm at 40mph. Currently all stock the engine pulls it no problem.

Here is my question. What is the best mod to keep this low speed torque and gain some sound. I "feel" any significant loss of back pressure will be detrimental to this usable torque. Short/ long tube's or cat delete would drop back pressure and increase sound, but what about the low speed torque? Full catback would surely improve sound, but again, what about off idle torque where I do all my driving?

Thoughts?

Basically...back pressure is the enemy. Back pressure does not equate to a scavenging effect. The LS3/L99 is different than a 60s 350. Back pressure is not what we want in our engines. I would say get a stepped header and whatever cat back you want WITH an x-pipe.

If money is considered and you arent looking to gain any power or upgrading later I would say get the axel back of your choice.

If you go to a 2inch primary header to a 3inch exhaust you may move the power up the band but wont "lose" power. That sounds like what you do not want so my suggestion above would be what it sounds like you are searching for.

Originally Posted by litle88

My thought is your agreeing to some topic from 18 months ago lol.

Stop being an ass. You are not cute or funny. With all the badass internet thugs on this forum its amazing anyone asks any questions. You would have been typing "use the search button raaaa please think I am important and tough on the internet," if he did not.

[litle88]

I'm an ass for making an observation?

I think you need to stop being the Camaro5 guardian or submit an application for a moderator title!

YES use the search button is what I always say! So what?!?!

Second because you were so worried about calling me an Ass you missed his question.

He wants a mod to make more "sound" and keep his so called TQ to use while he is in "4 cyl mode" YOU AZZ!

Nicave13 you can just get an axle back of your choice or leave it stock since your worried about loosing mpg, up to you.

[BigRed585Lbs]

Not using "Search" is like not using Google. The information is available and you'll eventually find it, but life's too short. Use what the forum gives you.

JMO, NT.

[WheelmanSS]

We're still talking about back pressure? Can't we move on to snake oil?

[14pilot]

Brothers, why can't we all just ditch the BS hype term "backpressure" and just get along with what really matters, "exhaust flow velocity"... LOL !!!

I can only dream of the day when we all discuss velocity, blow down, pressure drop, scavenging, shock wave harmonics, reflected wave tuning lengths, and etc...

Until we throw out all the "wife's tales" about how an exhaust systems works, I just wanna cry... No IC engine ever wants any backpressure !!!

[SPCBA]

Originally Posted by litle88

I'm an ass for making an observation?

I think you need to stop being the Camaro5 guardian or submit an application for a moderator title!

YES use the search button is what I always say! So what?!?!

Second because you were so worried about calling me an Ass you missed his question.

He wants a mod to make more "sound" and keep his so called TQ to use while he is in "4 cyl mode" YOU AZZ!

Nicave13 you can just get an axle back of your choice or leave it stock since your worried about loosing mpg, up to you.

Perhaps you missed it while you were preparing to defend your internet thug prowess. So here it is again.

Originally Posted by SPCBA

If money is considered and you arent looking to gain any power or upgrading later I would say get the axel back of your choice.

complete with miss spelling and all.

[WheelmanSS]

Originally Posted by 14pilot

Brothers, why can't we all just ditch the BS hype term "backpressure" and just get along with what really matters, "exhaust flow velocity"... LOL !!!

I can only dream of the day when we all discuss velocity, blow down, pressure drop, scavenging, shock wave harmonics, reflected wave tuning lengths, and etc...

Until we throw out all the "wife's tales" about how an exhaust systems works, I just wanna cry... No IC engine ever wants any backpressure !!!