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LB7 Turbo Downpipe

The simple fact is that the factory down pipe and factory up pipes were design to give a certain amount of clearance and be manufactures quick and easy. Opening the downpipe on a Duramax works plain and simple. Now as for how much it worth to anyone you would need to price all the parts that your getting. If you replace the downpipe ONLY so that it ties into the stock exhaust you are limited by the Vband clamp that connects them. With that said the ID of this connection is ~2.5". That combined with the factory design pipe that has the pipe narrowing down to ~1" causes higher drive pressure and heat. That is just why I stated before that in order to use the MATH YOU HAVE TO USE IT PROPERLY! For the record the VE of a Duramax at 30 psi boost is ~132%. Real measured numbers in an engine dyno cell. IF you leave out the problems that the factory pipe has the math is going to give you the wrong answer, as it should. I can tell you that if you TEST a stock exhaust with no muffler you will be able to measure ~ 5psi of back pressure in it with a stock turbocharger and stock tuning. Again a fact, because it was measured! Then going to a 4" from the downpipe back dropped that to ~ 3 psi. Replace the downpipe with a TTS kit and a 4" exhaust and the measured pressure was <1 psi. The test point was drilled and tapped into the exit of the turbocharger so it never had to be removed during any of the test.

Then start adding power to over and above stock and all the numbers begin to rise in stock trim where as the TTS system stays about the same up to ~ 550 RwHp. Now as for the TTS kit your getting the front pipe as well so that is an added cost but what good would it be to supply the downpipe and not be able to have the customer hook it up? What good would it be to supply a downpipe then close it down to ~2.5"? Go price a downpipe and then add to it the cost of the 4" front pipe that you can buy today and see what that cost. Then understand by doing that you still have the factory Vband clamp connection at ~ 2.5".
 
Hell, I just wanna see the dyno sheets and data.

Let's just say I'm from Missouri......Show Me. Better yet, show the OP that originally had the question.

Manufacturer's always make the claim, but show me the supporting data to go with it. I know you represent TTS, so you should rightfully be defending the product, I don't have issue with that....just show me the data and the dyno sheets.

It's one thing to claim, it's another to prove. And for $700, it would have to be proven, not claimed.

Hell, I have a BONE STOCK '04 (except the 4" front pipe back exhaust) that I'll be glad to throw on our DynoJet 224xLC and see what it puts to the wheels....not on the engine stand, to the wheels.
 
steve, it is still not justified in spending that kinda money to lower drive pressures by 4psi. i will concede that on a tuned truck the pressures are much higher do to the amount of heat produced on full throttle runs, but you havent provided numbers to see what effect the down pipe plus exhaust has made under those conditions. also 9 years into the duramax and there have been minimal issues relating to bigger tunes and stock down pipes. i am not convinced the cost/work to results ratio is justifiable. especially with the advent of the vvt and efi live. i have full control of my turbo vains and even a on the fly dial switch to adjust them if i wanted. again building a race truck is a different animal. the op was not and wanted an answer to justify the cost and time involved.
 
I've never tried to tell anyone its CHEAP. I've said , it's not for everyone. You need to compare apples to apples when doing your research so you truely know what your getting. It's a bitch to get in there and work on it but what I have done is try and correct some of the BS going on in this thread. I've never gone out and run test with every possible combination out there so I only can speak for what was done. While I know its a gain and have seen it first hand it's not huge on a stock application but as the power increases so do the benefits. As for having control over the turbocharger that has nothing to do with it as this is all piping after the turbocharger.

What I can share with you all is a ratio of back pressure in turbocharged applications, "after the turbocharger pressure versus the pressure prior to the turbocharger". This is a general set of numbers that has been proven time and time again over the years so it's not something we discovered here but something we were taught and it has proven again to be true. The ratio is ~2.5:1 What this means is that for every psi you drop after the turbocharger the drive pressure will drop about 2.5 psi. So with this information you can begin to see why the pressure in the exhaust is so important.
 
Diesel Tech said:
I've never tried to tell anyone its CHEAP. I've said , it's not for everyone. You need to compare apples to apples when doing your research so you truely know what your getting. It's a bitch to get in there and work on it but what I have done is try and correct some of the BS going on in this thread. I've never gone out and run test with every possible combination out there so I only can speak for what was done. While I know its a gain and have seen it first hand it's not huge on a stock application but as the power increases so do the benefits. As for having control over the turbocharger that has nothing to do with it as this is all piping after the turbocharger.

What I can share with you all is a ratio of back pressure in turbocharged applications, "after the turbocharger pressure versus the pressure prior to the turbocharger". This is a general set of numbers that has been proven time and time again over the years so it's not something we discovered here but something we were taught and it has proven again to be true. The ratio is ~2.5:1 What this means is that for every psi you drop after the turbocharger the drive pressure will drop about 2.5 psi. So with this information you can begin to see why the pressure in the exhaust is so important.
Click to expand...
thank you. that was my point the whole time. there are better ways to spend money and make power than the down pipe.
 
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