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View Full Version : Just intalled 4" turboback..wonder if i should have went 3.5" DP?


Lococoin
Sat, February 20th, 2010, 12:08 AM
I just finished installing a 4 inch magnaflow turboback exhaust with straight through muffler on my 2000 superduty 7.3 6 speed. I use it mostly for towing or hauling and am worried about loss of lower end torque.

How much torque on average do you lose with a 4" DP?

I have read that i should have lower EGT's vs a 3.5 inch. Is the loss in torque worth the gain of having lower egt's?

Right now i am regretting going full 4", as I did not realize there would be a change in low end torque.

Any insight would be appreciated.

Thanks!

Robert6401
Sat, February 20th, 2010, 06:37 AM
The loss in low end torque does not outweight the gains of lower EGTs and faster turbo spooling. You did the right thing, don't worry. If you don't already have a chip, having put on the 4" system is going to be much better for you when you do. Enjoy it, and try to get out of this buyers remorse.

cleatus12r
Sat, February 20th, 2010, 10:23 AM
Loss of torque?
HA!

There will be a slight reduction in flow velocity in the immediate junction between the turbine housing and the downpipe but in a 7000# lb. truck you'll never notice a couple HP at low RPM.

If backpressure is good, then I should be able to pop wheelies once I get around to doing the "potato stuffed in tailpipe" mod.

Lococoin
Sat, February 20th, 2010, 10:54 AM
That's good to hear! Thanks guys.

Buddy Starr
Sat, February 20th, 2010, 11:20 AM
:agree: 4 inch Turbo back on a Super duty is the right way to go!!!

majek5
Sat, February 20th, 2010, 01:16 PM
Loss of torque?
HA!

If backpressure is good, then I should be able to pop wheelies once I get around to doing the "potato stuffed in tailpipe" mod.

Does that really work?:hehe::hehe:

Longshot270
Sat, February 20th, 2010, 01:46 PM
Does that really work?:hehe::hehe:

I'm not exactly sure about the gains from it because I know someone who did that potato mod on a guy's jeep but it still drove home the same as before...but his exhaust was ported from rust which I assume removed all of the performance gains from the potato. :hehe:

907DAVE
Sat, February 20th, 2010, 01:57 PM
I'm not exactly sure about the gains from it because I know someone who did that potato mod on a guy's jeep but it still drove home the same as before...but his exhaust was ported from rust which I assume removed all of the performance gains from the potato. :hehe:

He probably did it wrong!

You are suppose to hammer it in with the end of a broom handle, you have to get it in there as far as it will go for max HP.:smiley_roll1:

Longshot270
Sat, February 20th, 2010, 01:59 PM
He probably did it wrong!

You are suppose to hammer it in with the end of a broom handle, you have to get it in there as far as it will go for max HP.:smiley_roll1:

Or maybe it was just a magical jeep, that thing blew more black smoke than half of the diesels...and it ran on 87 regular! :hehe: