prove to me a divorced downpipe is better then a regular 3"

[supraguy@aol]

I have a have a divorced DP with is recirculated back in at the curve out to the Cat. I call it a separated DP as opposed to divorced- The turbine exhaust and the wastegate cause turbulence together, so they part company, and once they've smoothed everything out in the own personal lives, they get back together, and get along much more tranquilly.
:biglaugh:

But anyway- the turbine pipe is 3" all the way to the muffler, and the wg pipe is 1 1/4 ". I'm quite happy with the turbo response.

 

[IJ.]

OP Seems to be hung up on the 3" pipe thing.....

LOOK at the area between the Turbine exit and the turbine wheel including the exit's diameter, it's MUCH less than 3".

A "system" will only flow as much as the point of it's greatest restriction.

Turbulant flow can help off the turbine housing ie: A cone from the turbine exit diameter to the DP diameter as long as the flow can continue to rotate in the spiral that the turbine promotes.

The wide mouth style DP elbow prevent this happening so you get less power, the Group A inspired DDP/divider retains this effect, being recirculated should have minimal effect as long as the exhaust downstream isn't overly restrictive.

 

[becauseican]

Alright, I just saw this thread here..... I personally did the dyno testing of the two downpipes. The runs were done on Dons car "Van Supra" here on SM, it was a 90 mk3, stock turbo, 5 speed car with only a K&N intake, manual boost controller, 3" exhaust, test pipe and standard BIC 3" DP at 10 psi. I did three baseline pulls with the BIC DP and made 255HP. Then the DDP was swapped in while it was still strapped down to the dyno, yes I do have the burns on my arm to prove it. There were no other changes othen than the downpipe, yes the boost went up about 1 psi, so part of the power gains were from that, due to the higer flow and efficiancy of the DDP. The boost controller was not touched between runs!!. From my experience 1 psi boost on the stock turbo is about a 9-10 HP gain. The end result was a power gain of 28 rwhp more. I couldnt belive it either so we did a few more pulls to confirm the numbers.

Here is some FACTS about the BIC DP and DDP:

1. The DDP is a full 3" pipe, yes the hole flange at the turbo outlet is 2.5", BUT the turbo housing is only 2.5" at the turbine wheel, you cannot put a larger hole as the gasket would be blocking the flow. The flange follows the exact shape as the gasket.

2. The DDP uses a 1.5" dump pipe...add that to a full 3" pipe and you have way more flow area than a single 3" DP, the BIC standard DP included.

3. The Re-routed / Recirculated DDP has the wg pipe seperate for about 11" before re-entering the main 3" pipe. The WG pipe re enters the main pipe at a smooth 45 degree angle.

4. The vented DDP made 28 whp more than the standard BIC 3" DP. I will find the numeric print out of the runs and post the info.

5. The BIC DP's are hand made here in Canada in my shop.

Sorry about the grainy pic, I will try to rescan it
The proof!!!!>>>>

 

[buldozr]

^ that last post just sold another pipe, cant wait for christmas

 

[Rennat]

a 3'' exhaust, and a ct-26 at 11psi puts out 280WHP?!?!?!!?! godddd damn! i need to start saving and working!

 

[ms07s]

Yea, now imagine that with 550s Lex afm and a 57 trim.:evil2:

...almost there...

 

[Poodles]

Makes me wonder what my car puts down...

 

[Grimsta]

If it wasnt for the fact I'll be switching to a 2JZ with a completely different turbo I would get one as well

 

[easternguy2005]

Just like you pressurize the air in, the hybrid turbo Sup' would be a electrical vacuum pump to vacuum the exhaust out.


done hijacking.....

 

[teamslow]

Relax... this is what happens when you change your parameters half way through the debate. The guys are still replying to the posts in the first half of the thread!

.

reread post #1

 

[teamslow]

even more simple than that........by applying some very simple fluid mechanics principles( so hopefully all can follow/numbers usually inspire/prolong more debate):


less turbulence (by either dumping or prolonged recirculation) = higher net fluid velocity


higher fluid velocity within a constant cross-section of area = lower contained pressure


lower contained pressure after the turbo = higher potential for pressure difference before and after the turbine wheel


=faster spool/higher wheel rpm achievable

........hope that helps

thanks! i'll check my fluid mechanics book at home this weekend when i get a chance.

 

[teamslow]

does any have a pro/E or a solidworks model of both the regular 3" downpipe and the recirculated divorced ("separate") downpipe. I dont have the time right now to make it myself. If somone can give that to me then i'll run the analysis on ANSYSworkbench CFD myself and post the result here.

 

[NashMan]

well there has be many divorest threads made here is some facts on my testing on dyno and diffent ideas i have though of over the years

divided = faster spool and creeping thus given more power

mega mouth = slower spool great top end no creep ( hks) made this along time ago but only in 2.5 not 3 inc found on nowaday's cars why most likely to keep some turq and bring up spool

now i have made a bunch of down pipes for diffent cars and a bunch of supra's

and i thought of an idea how can i get the best of both worlds yet not get shitty crappy creep issue's cause like exuast leak sounding car waste gate sticking ect ect

so i gots a thinking why not take a mouth type flange weld in a divider plate form the waste gate to the turbine out let

you will see this done in many bunch of turbo in the exhuast side casting

so i tried and you know what i was pretty glad i did

cause this is what i got

my spool/truq back at low rpm
no creep what so ever
my top end nice and good
no exhuast leak sound's

and the best part is my car gained a bunch of power and boost level stayed the same


oh yae dyno don't really record creep to well dyno dynamicks have hard time doing it dyno jets don't even do it at all

so the 1 psi thing is not ture this was told to me by the dyno installer and tec from dyno namic's when they installed the dyno at the other shop


feel free to use this idea in any way you wonte loose any thing but gain more

and easy as hell to do

 

[ATL88Supra]

Why bother with checking a book ? just get one they are better.

 

[Rennat]

i think its rather retarded... randy posted up a back to back dyno graph... wtf else do you want! its a DOWNPIPE. its not cylinder flow through the intake and exhaust valves... this is serisouly dumb. go make up the solid works model for the head, at least thats useful.

 

[supradjza80]

well there has be many divorest threads made here is some facts on my testing on dyno and diffent ideas i have though of over the years

divided = faster spool and creeping thus given more power

mega mouth = slower spool great top end no creep ( hks) made this along time ago but only in 2.5 not 3 inc found on nowaday's cars why most likely to keep some turq and bring up spool

now i have made a bunch of down pipes for diffent cars and a bunch of supra's

and i thought of an idea how can i get the best of both worlds yet not get shitty crappy creep issue's cause like exuast leak sounding car waste gate sticking ect ect

so i gots a thinking why not take a mouth type flange weld in a divider plate form the waste gate to the turbine out let

you will see this done in many bunch of turbo in the exhuast side casting

so i tried and you know what i was pretty glad i did

cause this is what i got

my spool/truq back at low rpm
no creep what so ever
my top end nice and good
no exhuast leak sound's

and the best part is my car gained a bunch of power and boost level stayed the same


oh yae dyno don't really record creep to well dyno dynamicks have hard time doing it dyno jets don't even do it at all

so the 1 psi thing is not ture this was told to me by the dyno installer and tec from dyno namic's when they installed the dyno at the other shop


feel free to use this idea in any way you wonte loose any thing but gain more

and easy as hell to do

duh duh deeerrrrr. this is so funny to me... Nice post and good luck, I would bet a DDP causes more creep then a standard DP. Think about it and get back to me on how this makes sense.

Also for what it is worth, A Divorced DP will make more torque, more power, and alleviate creep more than any other comparable DP for any car.

DUh Duh Deeeerrrrr

 

[gaboonviper85]

duh duh deeerrrrr. this is so funny to me... Nice post and good luck, I would bet a DDP causes more creep then a standard DP. Think about it and get back to me on how this makes sense.

Also for what it is worth, A Divorced DP will make more torque, more power, and alleviate creep more than any other comparable DP for any car.

DUh Duh Deeeerrrrr

hey asshole.....yeah you!.......the dude you are mocking suffers from dyslexia (sp)....fucking cunt.....he also happens to be a very respected member here who is a very good mechanic/fabricator....now who's the retard!

You should be banned you fucking cock jockey.

 

[ATL88Supra]

hey asshole.....yeah you!.......the dude you are mocking suffers from dyslexia (sp)....fucking cunt.....he also happens to be a very respected member here who is a very good mechanic/fabricator....now who's the retard!

You should be banned you fucking cock jockey.

while i agree with you i also suffer from dyslexia, tone it down a little
no need to insult the guy the admins will make everything better.

 

[IJ.]

This has gotten out of hand, enough...! :nono: