Downpipe and their design
02-24-03, 12:36 AM
#1
I wish I was driving!
Thread Starter
Downpipe and their design
I was porting an S5 wastegate tonight, and started thinking about how poorly designed this was.
Those who have seen the turbo will understand what I mean.
On the back of the exhaust side is a cover that goes over the wastegate and creates the hole for the downpipe. Between this cover and the turbo is a gasket, and a gasket between this cover and the downpipe.
The wastegate flapper door is limited as to how far it opens by this cover. (and perhaps wastegate actuator arm travel, unsure on that yet). Regardless, the air flow out of the wastegate has to make a complete 90 degree turn before heading out into the downpipe. Doesn't seem to make much sense.
Why do aftermarket downpipes just not remove the cover? It eliminates a gasket, and gives and extra 1/2" of room to play with. Plus, you could make the wastegate flow directly into the exhaust path.
I made some shitty paint jpeg's, but I keep getting error messages trying to post them.
Those who have seen the turbo will understand what I mean.
On the back of the exhaust side is a cover that goes over the wastegate and creates the hole for the downpipe. Between this cover and the turbo is a gasket, and a gasket between this cover and the downpipe.
The wastegate flapper door is limited as to how far it opens by this cover. (and perhaps wastegate actuator arm travel, unsure on that yet). Regardless, the air flow out of the wastegate has to make a complete 90 degree turn before heading out into the downpipe. Doesn't seem to make much sense.
Why do aftermarket downpipes just not remove the cover? It eliminates a gasket, and gives and extra 1/2" of room to play with. Plus, you could make the wastegate flow directly into the exhaust path.
I made some shitty paint jpeg's, but I keep getting error messages trying to post them.
02-24-03, 01:33 AM
#3
I wish I was driving!
Thread Starter
Originally posted by astrochild7
i 2nd that opinion.. do some thing like a second pipe off the plate that sites over the wastegate. i'v seen them vent out the quater pannels before. or you could run a duel, y'ed in later down the exhaust that would flow well.
i 2nd that opinion.. do some thing like a second pipe off the plate that sites over the wastegate. i'v seen them vent out the quater pannels before. or you could run a duel, y'ed in later down the exhaust that would flow well.
I know exactly why this isn't done: It is cheap and easy to make a pipe, and hard and more expensive to make a collector like that.
Money matters over a fantastic product.
It wouldn;t be that hard to make, either.
02-24-03, 02:21 AM
#4
I'm a boost creep...
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Just like this one for a WRX:
I plan to do this to mine, or I might even do two seperate pipes.
Curing boost creep means improving wastegate flow through the the whole turbo, not just the port. As well as eliminating the twisted path the wastegate flow normally takes, seperating the turbine and wastegate flows significantly reduces turbulance caused by the two flows mixing, which increases flow.
With an S4 turbo a much bigger flap can be used so you can bore the port much bigger. The S5 flap would be much harder to replace but the ports can still be enlarged. Combined with the better downpipe design I think boost can be properly controlled.
I plan to do this to mine, or I might even do two seperate pipes.
Curing boost creep means improving wastegate flow through the the whole turbo, not just the port. As well as eliminating the twisted path the wastegate flow normally takes, seperating the turbine and wastegate flows significantly reduces turbulance caused by the two flows mixing, which increases flow.
With an S4 turbo a much bigger flap can be used so you can bore the port much bigger. The S5 flap would be much harder to replace but the ports can still be enlarged. Combined with the better downpipe design I think boost can be properly controlled.
Last edited by NZConvertible; 02-24-03 at 02:24 AM.
02-24-03, 02:35 AM
#5
I wish I was driving!
Thread Starter
Originally posted by NZConvertible
Just like this one for a WRX:
I plan to do this to mine, or I might even do two seperate pipes.
Curing boost creep means improving wastegate flow through the the whole turbo, not just the port. As well as eliminating the twisted path the wastegate flow normally takes, seperating the turbine and wastegate flows significantly reduces turbulance caused by the two flows mixing, which increases flow.
With an S4 turbo a much bigger flap can be used so you can bore the port much bigger. The S5 flap would be much harder to replace but the ports can still be enlarged. Combined with the better downpipe design I think boost can be properly controlled.
Just like this one for a WRX:
I plan to do this to mine, or I might even do two seperate pipes.
Curing boost creep means improving wastegate flow through the the whole turbo, not just the port. As well as eliminating the twisted path the wastegate flow normally takes, seperating the turbine and wastegate flows significantly reduces turbulance caused by the two flows mixing, which increases flow.
With an S4 turbo a much bigger flap can be used so you can bore the port much bigger. The S5 flap would be much harder to replace but the ports can still be enlarged. Combined with the better downpipe design I think boost can be properly controlled.
The S5 watsgates can be taken to 30mm and 25mm without swapping the flapper door. The only issue is getting the flapper door to open up to 90 degrees.
I'm going to fiddle with some stuff.
Honestly, though, why can't we get a product like that? B/c our manufacturer's are lazy!
SO... I'm on the right track, then, NZ?
02-24-03, 04:13 AM
#7
Your Opinion is Wrong
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Thats the FIRST thing I thought when I put my replacement turbo on.
Hell, I bet even an S4 gate would be controlable with some porting and a seperated wastegate pipe (that could or could not be brought back into the downpipe down the exhuast path)
Hell, I bet even an S4 gate would be controlable with some porting and a seperated wastegate pipe (that could or could not be brought back into the downpipe down the exhuast path)
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02-24-03, 06:12 AM
#8
This is a GOOD idea in my opinion, specially if you already have the downpipe.
And here is the thread:
https://www.rx7club.com/forum/showth...hreadid=155100
And here is the thread:
https://www.rx7club.com/forum/showth...hreadid=155100
02-24-03, 01:38 PM
#9
Lives on the Forum
Yes, it's a good idea.  Are you willing to pay $250+ for it?  Last time I checked, only a few Japan shops (i.e. KSP?) were offering such a beast.  A 3" downpipe can be had for a little over $100.
-Ted
-Ted
02-24-03, 02:10 PM
#10
Originally posted by RETed
Yes, it's a good idea.  Are you willing to pay $250+ for it?  Last time I checked, only a few Japan shops (i.e. KSP?) were offering such a beast.  A 3" downpipe can be had for a little over $100.
-Ted
Yes, it's a good idea.  Are you willing to pay $250+ for it?  Last time I checked, only a few Japan shops (i.e. KSP?) were offering such a beast.  A 3" downpipe can be had for a little over $100.
-Ted
I believe the downpipe in the pic is a RB one with a custom west gate tube. I believe his total welding cost was like $35. SO that's a heck of downpipe for $160!!
02-24-03, 07:19 PM
#13
SOLD THE RX-7!
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not worth the time and money to me. cause if you really need to go that far. you're probably also at the stage of wanted a TO4 
here's another one that was made
here's another one that was made
02-24-03, 09:00 PM
#14
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This is my set-up : cut a hole in stock TurboII manifold , weld on pipe , buy used Audi 5000 turbo wastegate at junkyard for $25 and install. before I had my TO4E I just closed off the stock internal wastegate on the factory turbo. pics are here BTW works way better than I thought it would.
http://www.hpphoto.com/servlet/LinkPhoto?GUID=444f[img]27da-1452-53ba-2ec4-4ad63a856adc&size=lg[/img]
http://www.hpphoto.com/servlet/LinkPhoto?GUID=444f[img]27da-1452-53ba-2ec4-4ad63a856adc&size=lg[/img]
02-24-03, 09:14 PM
#15
Originally posted by Scott 89t2
not worth the time and money to me. cause if you really need to go that far. you're probably also at the stage of wanted a TO4
here's another one that was made
not worth the time and money to me. cause if you really need to go that far. you're probably also at the stage of wanted a TO4
here's another one that was made
hey knonfs could you give us some more pictures and info about that? and hell, somebody find us someone that will manufacture these things
02-24-03, 10:22 PM
#17
Originally posted by RETed
Yes, it's a good idea.  Are you willing to pay $250+ for it?  Last time I checked, only a few Japan shops (i.e. KSP?) were offering such a beast.  A 3" downpipe can be had for a little over $100.
-Ted
Yes, it's a good idea.  Are you willing to pay $250+ for it?  Last time I checked, only a few Japan shops (i.e. KSP?) were offering such a beast.  A 3" downpipe can be had for a little over $100.
-Ted
I can take some pictures of the DP and adapter plate if anyone wants to see it.
02-24-03, 11:34 PM
#19
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02-25-03, 01:11 AM
#20
I'm a boost creep...
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Originally posted by RETed
Yes, it's a good idea.  Are you willing to pay $250+ for it?  Last time I checked, only a few Japan shops (i.e. KSP?) were offering such a beast.
Yes, it's a good idea.  Are you willing to pay $250+ for it?  Last time I checked, only a few Japan shops (i.e. KSP?) were offering such a beast.
A 3" downpipe can be had for a little over $100.
02-25-03, 01:18 AM
#21
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Originally posted by Scott 89t2
not worth the time and money to me. cause if you really need to go that far. you're probably also at the stage of wanted a TO4
not worth the time and money to me. cause if you really need to go that far. you're probably also at the stage of wanted a TO4
02-25-03, 06:27 AM
#22
Originally posted by RETed
Nice!  You willing to offer this resource to all the members for that price?
-Ted
Nice!  You willing to offer this resource to all the members for that price?
-Ted
The last sentence on my post was:And here is the thread:
https://www.rx7club.com/forum/showth...threadid=155100
But I will do mine like that once I get my T2 running, I'm sure it will cost me around $200 bucks, since I'm paying $145 for the RB donwpipe alone.
02-25-03, 06:28 AM
#23
Originally posted by jacobcartmill
hey knonfs could you give us some more pictures and info about that? and hell, somebody find us someone that will manufacture these things
hey knonfs could you give us some more pictures and info about that? and hell, somebody find us someone that will manufacture these things
And here is the thread:
https://www.rx7club.com/forum/showth...threadid=155100
02-25-03, 09:11 AM
#24
Round&Round not Up&Down
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02-25-03, 09:23 AM
#25
Originally posted by jimmyv13
What happened to this thread?
What happened to this thread?
https://www.rx7club.com/forum/showth...hreadid=155100