labree dp's?
06-01-2010, 05:31 PM
#1
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labree dp's?
Anyone have any input on labree's split downpipes? I have a stage2 s4 and want to get it ready for stage 3. ive had it stage2 for 5 years and it's time to upgrade. Don't want to get rid of it because the new s4's don't measure up. Any stage 3 guys got any advice for me???
06-03-2010, 03:31 PM
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Anyone have any input on labree's split downpipes? I have a stage2 s4 and want to get it ready for stage 3. ive had it stage2 for 5 years and it's time to upgrade. Don't want to get rid of it because the new s4's don't measure up. Any stage 3 guys got any advice for me???
The more boost you run, the less volume you are passing through the wastegate, by a very substantial amount. You're also then passing a _lot_ more exhaust through the turbine side of the turbo. On a split downpipe like this that means you're basically forcing the turbo/engine to force all the gas out these tiny ~2" pipes, while there's next to nothing going through the wastegate tube.
We typically see 40+ whp increases when removing those pipes and installing 'normal' 3" downpipes on stage 3 cars, with no other changes.
If you really, really, really still want a set, and logic has fallen off the decision making boat, I've got a set here we'd be happy to be rid of!
06-06-2010, 10:26 AM
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Labrees are awesome! ...
Labrees are split 1 1/2" and 1 3/4". That's 3 1/4 inches total. They're designed to prevent the exhaust gases from mixing until further down the system. The workmanship is impressive and the flow is absolutely fantastic. If you can afford them, get them.
http://www.labreemotorsports.com/ima...ownpipes_2.jpg
Last edited by .357; 06-06-2010 at 10:31 AM.
06-06-2010, 12:10 PM
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adding diameters means squat
As an engineer, and car nut, when looking at fluid flow you have to consider pipe volumes. So you have to calculate cross sectional area and multiply by length.
The labree pipes have a total cross sectional area of 4.17 square inches.
A 3" downpipe will have a cross section of 7.07 square inches.
A 3" downpipe is a sewer line compared to the Labree. Heck a lousy 2.5" downpipe is going to have 4.91 square inches of area.
Now let's assume all downpipes are roughly the same length since they go from the same point (turbos) to same point midpipe / catback.
Nate is actually probably being generous in reality.
Just because a part is shiny and well made, doesn't mean it's worth the price being asked.
Remember not all modifications really make your car faster or add power..... kind of like Slick 50, Splitfire plugs, the Tornado and K&N air filters.
And just because someone can weld pretty and uses stainless steel, that doesn't make them a good exhaust system designer.
The labree pipes have a total cross sectional area of 4.17 square inches.
A 3" downpipe will have a cross section of 7.07 square inches.
A 3" downpipe is a sewer line compared to the Labree. Heck a lousy 2.5" downpipe is going to have 4.91 square inches of area.
Now let's assume all downpipes are roughly the same length since they go from the same point (turbos) to same point midpipe / catback.
Nate is actually probably being generous in reality.
Just because a part is shiny and well made, doesn't mean it's worth the price being asked.
Remember not all modifications really make your car faster or add power..... kind of like Slick 50, Splitfire plugs, the Tornado and K&N air filters.
And just because someone can weld pretty and uses stainless steel, that doesn't make them a good exhaust system designer.
06-07-2010, 09:31 AM
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wow
So who's high, you or your dyno?
Can you post a dyno and ECUX from the car that you gained 40+WHP.
I've done over and over dyno pulls back when ko3s were still hot: ) 2002-2003 I invested $$ and found that with the right tune, Splits do spool faster and make good power, even more power than avg open mouth DPs on the market.
Later once ko4s were tuned and we started pushing them over 25psi, The splits lost power over 5k rpms vs open mouth DPs, but it was never 40WHP.
Based on a few ecux logs from a few good running ko4 cars, splits or open mouths make the same power up to 5k.
I sold over 200 sets of splits and currently sell only open mouths from FI since we build many rs6 tubo'd based S4s and do push the ko4s more now vs 5 years ago.
Splits work great on ko3 cars and much easier to work around the vehicle.
Just my $.02
Can you post a dyno and ECUX from the car that you gained 40+WHP.
I've done over and over dyno pulls back when ko3s were still hot: ) 2002-2003 I invested $$ and found that with the right tune, Splits do spool faster and make good power, even more power than avg open mouth DPs on the market.
Later once ko4s were tuned and we started pushing them over 25psi, The splits lost power over 5k rpms vs open mouth DPs, but it was never 40WHP.
Based on a few ecux logs from a few good running ko4 cars, splits or open mouths make the same power up to 5k.
I sold over 200 sets of splits and currently sell only open mouths from FI since we build many rs6 tubo'd based S4s and do push the ko4s more now vs 5 years ago.
Splits work great on ko3 cars and much easier to work around the vehicle.
Just my $.02
06-07-2010, 07:50 PM
#7
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Go to any major university, any of them with an engineering program. Find the mechanical engineering department. Go to the class on fluid flow, and try to convince them that putting all exhaust gases through a 1.75" diameter tube (wastegate shut, making max boost under full throttle) will make more horsepower than putting the same exhaust gases into a 3" pipe....
Oh wait, you'll put more gas through the 3" pipe due to high reduced back pressure.
If you dare to mail me a set of split downpipes, and 3" downpipes. I'll pay for the dyno testing myself, but I get to keep the pipes that test better. Do we have a deal?
I'll be sure to test the split pipes first, because I don't want to waste time with labor.
I'll test them on my car, same dyno on the same day using the same instrumentation etc.
Oh wait, you'll put more gas through the 3" pipe due to high reduced back pressure.
If you dare to mail me a set of split downpipes, and 3" downpipes. I'll pay for the dyno testing myself, but I get to keep the pipes that test better. Do we have a deal?
I'll be sure to test the split pipes first, because I don't want to waste time with labor.
I'll test them on my car, same dyno on the same day using the same instrumentation etc.
So who's high, you or your dyno?
Can you post a dyno and ECUX from the car that you gained 40+WHP.
I've done over and over dyno pulls back when ko3s were still hot: ) 2002-2003 I invested $$ and found that with the right tune, Splits do spool faster and make good power, even more power than avg open mouth DPs on the market.
Later once ko4s were tuned and we started pushing them over 25psi, The splits lost power over 5k rpms vs open mouth DPs, but it was never 40WHP.
Based on a few ecux logs from a few good running ko4 cars, splits or open mouths make the same power up to 5k.
I sold over 200 sets of splits and currently sell only open mouths from FI since we build many rs6 tubo'd based S4s and do push the ko4s more now vs 5 years ago.
Splits work great on ko3 cars and much easier to work around the vehicle.
Just my $.02
Can you post a dyno and ECUX from the car that you gained 40+WHP.
I've done over and over dyno pulls back when ko3s were still hot: ) 2002-2003 I invested $$ and found that with the right tune, Splits do spool faster and make good power, even more power than avg open mouth DPs on the market.
Later once ko4s were tuned and we started pushing them over 25psi, The splits lost power over 5k rpms vs open mouth DPs, but it was never 40WHP.
Based on a few ecux logs from a few good running ko4 cars, splits or open mouths make the same power up to 5k.
I sold over 200 sets of splits and currently sell only open mouths from FI since we build many rs6 tubo'd based S4s and do push the ko4s more now vs 5 years ago.
Splits work great on ko3 cars and much easier to work around the vehicle.
Just my $.02
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06-08-2010, 03:05 PM
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I heard a one issue with the splits is possible overspooling. Considering the main tube is so close to the turbine and about the same size, it can keep the exhaust spinning a little bit. At least more than an open mouth DP will. So I am running a MBC along with the N75 to cap boost spikes.
So that could equate to more power earlier. It certainly feels like it in my car at least. One instructor at a driving event had a hard time believing I didn't have K04's. My car makes a lot of torque, especially at 4500 feet above sea level.
If anyone wants dyno proof just paypal me. I can put my stock DPs back on and have both cats and test pipes for my LeBree splits for comparison...
So that could equate to more power earlier. It certainly feels like it in my car at least. One instructor at a driving event had a hard time believing I didn't have K04's. My car makes a lot of torque, especially at 4500 feet above sea level.
If anyone wants dyno proof just paypal me. I can put my stock DPs back on and have both cats and test pipes for my LeBree splits for comparison...
06-08-2010, 05:09 PM
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I heard a one issue with the splits is possible overspooling. Considering the main tube is so close to the turbine and about the same size, it can keep the exhaust spinning a little bit. At least more than an open mouth DP will. So I am running a MBC along with the N75 to cap boost spikes.
So that could equate to more power earlier. It certainly feels like it in my car at least. One instructor at a driving event had a hard time believing I didn't have K04's. My car makes a lot of torque, especially at 4500 feet above sea level.
If anyone wants dyno proof just paypal me. I can put my stock DPs back on and have both cats and test pipes for my LeBree splits for comparison...
So that could equate to more power earlier. It certainly feels like it in my car at least. One instructor at a driving event had a hard time believing I didn't have K04's. My car makes a lot of torque, especially at 4500 feet above sea level.
If anyone wants dyno proof just paypal me. I can put my stock DPs back on and have both cats and test pipes for my LeBree splits for comparison...
