GT35R over GT37R
So the only 8sec Evo's in the States use what? I'll give you a hint GT42. What type of housings do GT42's use?
Hint. 42r only comes in twin scroll. how do you know it performs better than single scroll? And even if it did and the twin performed better how do you know then that it wasnt just gitting the right A/R for the setup that was making it outperform? The reality is there is no one who has done a back to back that really proves the point. there is just a huge variance in results of turbo setups regaurdless of whether twin or single scroll is being used.
Maybe not worth the effort to drag racers who care more about upper rpm power, and will never see rpm below 6K, but the people asking these questions drive their cars on the street where the difference is very pronounced from my experience.
You could test three different single scroll 35r setups on same car and get three very pronounced results. The whole point of a twin scroll is to ensure the pulses arrive evenly at low rpms. At high rpms they are too close together and an open scroll will always outperform. A single scroll setup can produce the same spool as a twin scroll when the pulses happen to stay very well divided by nature of manifold design and about 100 other aspects of setup.
Comparing anything that Curt Brown does to a normal or even exception car builder/racer is not a good comparison. He is apparently an allien sent here to make us earthlings realize our ineptitude
.
With that exception I've never seen an Evo3 turbo come close to the Evo8 turbo - especially in regards to pump gas hp. Using your example, one could easily say that his 10.59 in a heavy Evo plattform on the Evo8 turbo is a good arguement for the twin scroll.
Hint. 42r only comes in twin scroll. how do you know it performs better than single scroll? And even if it did and the twin performed better how do you know then that it wasnt just gitting the right A/R for the setup that was making it outperform? The reality is there is no one who has done a back to back that really proves the point. there is just a huge variance in results of turbo setups regaurdless of whether twin or single scroll is being used.
Maybe not worth the effort to drag racers who care more about upper rpm power, and will never see rpm below 6K, but the people asking these questions drive their cars on the street where the difference is very pronounced from my experience.
You could test three different single scroll 35r setups on same car and get three very pronounced results. The whole point of a twin scroll is to ensure the pulses arrive evenly at low rpms. At high rpms they are too close together and an open scroll will always outperform. A single scroll setup can produce the same spool as a twin scroll when the pulses happen to stay very well divided by nature of manifold design and about 100 other aspects of setup.
Comparing anything that Curt Brown does to a normal or even exception car builder/racer is not a good comparison. He is apparently an allien sent here to make us earthlings realize our ineptitude
. With that exception I've never seen an Evo3 turbo come close to the Evo8 turbo - especially in regards to pump gas hp. Using your example, one could easily say that his 10.59 in a heavy Evo plattform on the Evo8 turbo is a good arguement for the twin scroll.
I wonder why?
No one? Are you sure?
So, does this mean Geoff's testing is bunk?
So, does this mean Geoff's testing is bunk?
The only real good twin scroll setup has results posted on here is simon norris car. There is a video posted of how fast and responsive it is Yet you can freeze frame the video and show that it doesn't reach full boost till 5800 or higher. same as any well setup single scroll. I would love to see some real proof, so far there isn't any as far as I can tell. This arguement is same as saying you cant make big power on a small .48 hotside. yet there is track proof all over the place showing the theory is just that.
I am done here. In closing I say a 37r and streetcar dont belong in the same sentence. I also believe tubular manifold doesnt belong on a streetcar.
I am done here. In closing I say a 37r and streetcar dont belong in the same sentence. I also believe tubular manifold doesnt belong on a streetcar.
Last edited by 94AWDcoupe; Jul 18, 2007 at 08:27 AM.
The only real good twin scroll setup has results posted on here is simon norris car. There is a video posted of how fast and responsive it is Yet you can freeze frame the video and show that it doesn't reach full boost till 5800 or higher. same as any well setup single scroll. I would love to see some real proof, so far there isn't any as far as I can tell. This arguement is same as saying you cant make big power on a small .48 hotside. yet there is track proof all over the place showing the theory is just that.
I am done here. In closing I say a 37r and streetcar dont belong in the same sentence. I also dont believe tubular manifold doesnt belong on a streetcar.
I am done here. In closing I say a 37r and streetcar dont belong in the same sentence. I also dont believe tubular manifold doesnt belong on a streetcar.
I used to think you contributed to this forum positively, I was obviously wrong.
Scorke
scorke, seroiusly dude geoffs back to back includes dyno comparrison of two different cars!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! thats so far from a back to back I dont even know where to start.
Last edited by 94AWDcoupe; Jul 18, 2007 at 08:33 AM.
Do you believe that Geoff is lying about his results?
Scorke
your just missing my points. I was building turbo cars when most of you were in diapers. Over the years I have met some extremely smart turbo guys. Guys that build fast turbo setups (4-5 second 1/8ths) for breakfast. You only have to ask these guys if twin scroll is the way to go. Its not some new technology. It very old news. geoff is very smart guy and builds awesome parts.
One last time there is no such thing as back to back. if you change the exhaust manifold you have changed the back to back. the only way to get close to proving it works is to take an extremely fast single scroll setup and then add the twin scroll setup to the car and see if performance improves. That has yet to be done.
One last time there is no such thing as back to back. if you change the exhaust manifold you have changed the back to back. the only way to get close to proving it works is to take an extremely fast single scroll setup and then add the twin scroll setup to the car and see if performance improves. That has yet to be done.
I thought you said you were done here
One last time there is no such thing as back to back. if you change the exhaust manifold you have changed the back to back. the only way to get close to proving it works is to take an extremely fast single scroll setup and then add the twin scroll setup to the car and see if performance improves. That has yet to be done.
Geoff, and Drifto have gone from single scroll setups ( why they have to be extremely fast I don't know?) to twin scroll (changing only manfold/housing) and have found that performance improves, I do not understand how you can possibly fail to see, that this means that there is an increase inperformance when using a twin scroll setup vs a single scroll one.
I am not missing your point, your just not making any.
Scorke
The thesis test scorke is referring to was the ideal situation. We changed manifolds and ONLY manifolds within 40 minutes of one another on the dyno. The setups were fullly fabricated and all bugs worked out before we went on the dyno. The engine was a fully built 1.9L B series Honda engine with a GT4088R .95 A/R. We tested
1) single scroll manifold with 12" runners
2) single scroll manifold with 16" runners (white line on the dyno)
3) twinscroll manifold with 16" runners. (purple line)
Identical downpipe, identical everything.
we went from single scroll short runner to single scroll long runner to twinscroll long runner. That was the ONLY change. We didnt pull the car off the dyno, and we all burned our hands.
This is the only graph i have right now, but it is from the test. I wont be able to respond until friday anyway (i fly to AZ tomorrow) but when i get back ill happily provide more data.
You might of been building turbo cars for a long time, and you might know people with fast cars, but that still doesn't mean that you know **** about this topic. If youre so smart why isn't your eclipse breaking some records or running something faster than a 10.....
Dude, the manifold HAS to change in order to change the exhaust housings, of course there is noway to compare "back to back" but swapping out manifolds and housings while leaving the rest the same is the only way to do a "back to back" test as the divided housing necessitates a divided manifold.
Geoff, and Drifto have gone from single scroll setups ( why they have to be extremely fast I don't know?) to twin scroll (changing only manfold/housing) and have found that performance improves, I do not understand how you can possibly fail to see, that this means that there is an increase inperformance when using a twin scroll setup vs a single scroll one.
I am not missing your point, your just not making any.
Scorke
Dude, the manifold HAS to change in order to change the exhaust housings, of course there is noway to compare "back to back" but swapping out manifolds and housings while leaving the rest the same is the only way to do a "back to back" test as the divided housing necessitates a divided manifold.
Geoff, and Drifto have gone from single scroll setups ( why they have to be extremely fast I don't know?) to twin scroll (changing only manfold/housing) and have found that performance improves, I do not understand how you can possibly fail to see, that this means that there is an increase inperformance when using a twin scroll setup vs a single scroll one.
I am not missing your point, your just not making any.
Scorke
The manifold does not have to change to do a back to back. You can use the twinscroll mani for both exhaust housings. But this test has never been done. And you have to use a really well setup single scroll to eliminate the possibilty that you can make the same improvement with another better design single scroll setup. You are smart. I dont understand how you dont see that.
There is well documented data on NABR about turbo setups not improving by swapping from .63 to .82 on some setups. It only increases lag time and greatly reduces drivabilty and low rpm crispness.
I am well aware of driftos swap as well. The dyno graph does not show any big improvemnt. If he got an increase in low rpm feel it could have came from increased velocity of the new exhaust mani. or from going to a effectively smaller a/r and not necessarily from a change from single to twin scroll.
Geoff, the graphs you just posted indicates the single scroll 12 inch runner outperformed the twin scroll setup? that supports what I would be saying. Also you still cant do a back to back if you are changing manifolds. Plain and simple the manifolds can be accountable for the change. When you change manifold volume you are changing A/R of the setup. The 12 inch runner may have made the A/R smaller and thats why it performed the best. Cant believe even you dont get this.