twin turbo fc help
01-06-08, 09:33 PM
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twin turbo fc help
i need some ideas on how to make a manifold for a twin set up using the stock s4 turbos with external waste gate any ideas appreciated thanks
01-07-08, 02:15 AM
#3
I'll run with your suggestion, though it's unlikely you'll pull this off.
You'd want one rotor spooling each turbo right? and you'd probably want S5 turbos because the hotside twin scrolls are equally sized (although you could grind out part of the hotside to make it like the s5). the unequal twin scroll of the s4 is pointless if you don't have a working twin scroll system. 2" runners are common on single turbo manifolds, so try that size. You could position one turbo near the stock location and one say 10" forward of that, where an HKS cast manifold would put them.
you'd also have to weld the wastegate shut on the turbos and probaly run dual Tial 38's coming off the runners. Then I think you could use a v band flange on the back of the turbo. I think you can ttake off the 5 bolt backplate and get one of the v band 5 bolt backplates. see www.atpturbo.com. For exhaust I'd run true duals with open vented wastegates.
Block off the coolant lines to simplify plumbing. The front turbo could run the oil lines off the stock locations on the front cover using AN fittings. For the rear turbo, tap the oil pan for the return line and get a racing beat oil pedestel adapter and use that as an oil feed source.
and I hope you realize that two HT-18's would be really nasty. the stock HT-12's on FDs can do 330-350 to the wheels reliably... I would think two HT-18's should flow 450-500. If you could do all the fabrication yourself you could have the power potential of a GT40 with possibly more spool and less expense. You will need to fabricate Y pipe for the intercooler piping, preferably right near the turbo outlet, but it will be tough to do all that and have the hood still close.
Now that I think about it, this wouldn't be THAT hard if you can work out the tight clearances. Also remember you have a coolant heater hardline that will likely need to be relocated. For intakes you will have to use that small *** filters that go right on the inlets of the turbo, and obviously you will need a standalone, full fuel system, and cooling system mods, etc.
You'd want one rotor spooling each turbo right? and you'd probably want S5 turbos because the hotside twin scrolls are equally sized (although you could grind out part of the hotside to make it like the s5). the unequal twin scroll of the s4 is pointless if you don't have a working twin scroll system. 2" runners are common on single turbo manifolds, so try that size. You could position one turbo near the stock location and one say 10" forward of that, where an HKS cast manifold would put them.
you'd also have to weld the wastegate shut on the turbos and probaly run dual Tial 38's coming off the runners. Then I think you could use a v band flange on the back of the turbo. I think you can ttake off the 5 bolt backplate and get one of the v band 5 bolt backplates. see www.atpturbo.com. For exhaust I'd run true duals with open vented wastegates.
Block off the coolant lines to simplify plumbing. The front turbo could run the oil lines off the stock locations on the front cover using AN fittings. For the rear turbo, tap the oil pan for the return line and get a racing beat oil pedestel adapter and use that as an oil feed source.
and I hope you realize that two HT-18's would be really nasty. the stock HT-12's on FDs can do 330-350 to the wheels reliably... I would think two HT-18's should flow 450-500. If you could do all the fabrication yourself you could have the power potential of a GT40 with possibly more spool and less expense. You will need to fabricate Y pipe for the intercooler piping, preferably right near the turbo outlet, but it will be tough to do all that and have the hood still close.
Now that I think about it, this wouldn't be THAT hard if you can work out the tight clearances. Also remember you have a coolant heater hardline that will likely need to be relocated. For intakes you will have to use that small *** filters that go right on the inlets of the turbo, and obviously you will need a standalone, full fuel system, and cooling system mods, etc.
Last edited by arghx; 01-07-08 at 02:24 AM.
01-07-08, 02:47 AM
#5
^ yes but a brand new GT40 would cost you like $1500 alone... I dunno, for the power levels he must be shooting for it doesn't seem like it would be much more expensive than a big single given that good condition s4 turbos aren't that hard to find.
if you have the fabrication resources it would be a sick project. You know that Re-Amemiya had a twin 16G kit for the FC? Somebody posted it for sale a while back... it's possibly to make this all fit.
if you have the fabrication resources it would be a sick project. You know that Re-Amemiya had a twin 16G kit for the FC? Somebody posted it for sale a while back... it's possibly to make this all fit.
01-07-08, 10:03 AM
#8
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The GT40R does not lag when properly set up. I have problems keeping out of boost at 2K on the highway....I would suspect two S4/S5 turbos to be substantially slower to respond.
As for the original poster, here's how to make a manifold:
http://www.aaroncake.net/rx-7/projec...jun52007-1.htm
http://www.aaroncake.net/rx-7/projec...ul182007-1.htm
As for the original poster, here's how to make a manifold:
http://www.aaroncake.net/rx-7/projec...jun52007-1.htm
http://www.aaroncake.net/rx-7/projec...ul182007-1.htm
01-07-08, 11:15 AM
#9
GT40 is a good turbo, no doubt. But if you're just looking to do something different (not necessarily 'optimal') then twin s4 turbos would be sweet.
nobody has really done a big single vs big twins comparison (unless you're talking FD hybrid twins vs big single) so we can't be really sure.
nobody has really done a big single vs big twins comparison (unless you're talking FD hybrid twins vs big single) so we can't be really sure.
Last edited by arghx; 01-07-08 at 11:23 AM.
01-07-08, 01:08 PM
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for fuel i have a sds stand alone bosch inline pump, also 4/750 injectors for ignition i have 2/6al boxes,2msd coils and a 1985 distributor locked. i just wanted some advice on how to make it work. what mods should i do to the turbos to make it a efficient set up?. either with volvo turbos or the stock s4 turbos i rather go with the s4 cause i have 2 of them already so why not? im not looking for specific numbers i just want more efficient power to kick some more ***. every body thinks you need a huge turbo when all you really need is to match everything up by numbers right now with the set up i have im taking new mustang gt`s g35`s, any honda that crosses my path camaros just line it up im pretty sure ill spank it lol .
01-07-08, 01:16 PM
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nobody has really done a big single vs big twins comparison (unless you're talking FD hybrid twins vs big single) so we can't be really sure.
for fuel i have a sds stand alone bosch inline pump, also 4/750 injectors for ignition i have 2/6al boxes,2msd coils and a 1985 distributor locked. i just wanted some advice on how to make it work. what mods should i do to the turbos to make it a efficient set up?. either with volvo turbos or the stock s4 turbos i rather go with the s4 cause i have 2 of them already so why not? im not looking for specific numbers i just want more efficient power to kick some more ***.
Ignore "Volvo turbos" and stock S4 turbos unless you REALLY WANT to fabricate a manifold.
every body thinks you need a huge turbo when all you really need is to match everything up by numbers right now with the set up i have im taking new mustang gt`s g35`s, any honda that crosses my path camaros just line it up im pretty sure ill spank it lol .
01-07-08, 04:04 PM
#15
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This project has FAIL written all over it.
It sounds like the OP wants to do something fancy / rare with very little money.
Uh...
NO.
Your 4 x 750 injectors are only good for about 350hp at the wheels.
Even if you do get that piece-of-**** SDS running, your locked distributor is only going to hold you back.
-Ted
It sounds like the OP wants to do something fancy / rare with very little money.
Uh...
NO.
Your 4 x 750 injectors are only good for about 350hp at the wheels.
Even if you do get that piece-of-**** SDS running, your locked distributor is only going to hold you back.
-Ted
01-07-08, 06:27 PM
#16
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I'm sure you probably know this, but for the benefit of others who might not get the sarcasm...
The wastegate generally has very little do with how responsive the turbo is to build boost. The wastegate only really begins to open as boost pressure on the diaphragm approaches the spring pressure in the wastegate actuator. While the wastegate will start to open before it's set pressure (springs are analog), the wastegate will not be open during off-boost driving unless it's leaking and thus won't effect something like this.
Yes, but it requires a spacer.
Bridgeport doesn't hurt either...
Ah, come on. Maybe he has the special rotary version of the SDS. 
It's rotary because it supports staged injection (only if you run secondaries which are the same size of the primaries) yet still requires a distributor for ignition. It's a great ECU choice...if this was 1987. 
The wastegate generally has very little do with how responsive the turbo is to build boost. The wastegate only really begins to open as boost pressure on the diaphragm approaches the spring pressure in the wastegate actuator. While the wastegate will start to open before it's set pressure (springs are analog), the wastegate will not be open during off-boost driving unless it's leaking and thus won't effect something like this.
I think that's got alot to do with the n/a block. Mine is spooling up at 2500 rpm with a stock s5 turbo on it.
It's rotary because it supports staged injection (only if you run secondaries which are the same size of the primaries) yet still requires a distributor for ignition. It's a great ECU choice...if this was 1987.
01-07-08, 07:32 PM
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my sds is running just fine idles beautiful builds up through the rpms no misfiring just plain ol GREAT the only problems it gives me is that when i use 87 it runs like **** ,89 runs ok but still has some misfiring but when i use 93 forget it all misses are gone more torque and hp is felt due to it burning correctly
01-07-08 05:04 PM
RETed This project has FAIL written all over it.
It sounds like the OP wants to do something fancy / rare with very little money.
Uh...
NO.
Your 4 x 750 injectors are only good for about 350hp at the wheels.
Even if you do get that piece-of-**** SDS running, your locked distributor is only going to hold you back.
-Ted
so my piece of **** sds that so you call is not so as you think. i know that there`s better ecu`s. but when you come to my house install,tune a different ecu of your liking and have it run daily with no problems. you are welcome to do so .so don`t hate just because im trying to do something different/unique. and just because your escapades with sds din`t turn out how you like
that`s not my problem so 
:so keep your hating *** out of my post if you dont have anything that`s going to help me and my twin turbo fc of becoming one
01-07-08 05:04 PM
RETed This project has FAIL written all over it.
It sounds like the OP wants to do something fancy / rare with very little money.
Uh...
NO.
Your 4 x 750 injectors are only good for about 350hp at the wheels.
Even if you do get that piece-of-**** SDS running, your locked distributor is only going to hold you back.
-Ted
so my piece of **** sds that so you call is not so as you think. i know that there`s better ecu`s. but when you come to my house install,tune a different ecu of your liking and have it run daily with no problems. you are welcome to do so .so don`t hate just because im trying to do something different/unique. and just because your escapades with sds din`t turn out how you like
that`s not my problem so :so keep your hating *** out of my post if you dont have anything that`s going to help me and my twin turbo fc of becoming one
01-07-08, 07:41 PM
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Custom.
Also rather pointless.
Hm, sounds like you have a tuning issue there...What timing is your dizzy locked at?
The SDS was an acceptable ECU in it's time. However with no rotary specific features and the necessity to run a distributor, it's a poor choice nowadays. Even the base model Megasquirt, when run on a distributor, would be a far better choice and much cheaper as well. A few upgrades to the 'Squirt and it will run FC ignition.
That said, did you read my page on making a manifold? It covers the manifold I built for my car and while not twin turbo, the principle is the same. It will provide you a considerable amount of help. The SDS website also has a tutorial on how to make a turbo manifold at http://www.sdsefi.com/techheader.htm
Keep in mind that the stock turbos don't have generic flanges; they are proprietary to Mazda. You'll therefore have to cut your own flanges if you intend to use the stock turbos. Using the stock turbos is not something I would recommend. You would have an unacceptable amount of lag if the engine is running stock ports, and the stock turbos are old and inefficient compared to modern units.
Also rather pointless.
my sds is running just fine idles beautiful builds up through the rpms no misfiring just plain ol GREAT the only problems it gives me is that when i use 87 it runs like **** ,89 runs ok but still has some misfiring but when i use 93 forget it all misses are gone more torque and hp is felt due to it burning correctly
so my piece of **** sds that so you call is not so as you think. i know that there`s better ecu`s. but when you come to my house install,tune a different ecu of your liking and have it run daily with no problems. you are welcome to do so .so don`t hate just because im trying to do something different/unique. and just because your escapades with sds din`t turn out how you like that`s not my problem so :so keep your hating *** out of my post if you dont have anything that`s going to help me and my twin turbo fc of becoming one
that`s not my problem so :so keep your hating *** out of my post if you dont have anything that`s going to help me and my twin turbo fc of becoming one
That said, did you read my page on making a manifold? It covers the manifold I built for my car and while not twin turbo, the principle is the same. It will provide you a considerable amount of help. The SDS website also has a tutorial on how to make a turbo manifold at http://www.sdsefi.com/techheader.htm
Keep in mind that the stock turbos don't have generic flanges; they are proprietary to Mazda. You'll therefore have to cut your own flanges if you intend to use the stock turbos. Using the stock turbos is not something I would recommend. You would have an unacceptable amount of lag if the engine is running stock ports, and the stock turbos are old and inefficient compared to modern units.
01-07-08, 08:17 PM
#20
Banned. I got OWNED!!!
Regarding Ted - see sig
Regarding your project - here are my thoughts take them as you will
This sounds like you are trying to do something very unique and unique and on the cheap generally don't go well together. Disregarding the fact that the older turbo's are not efficient, you would need your own intakes and you would need to build everything yourself it seems to me that this isn't something you would want to cut corners on. Assuming you can't weld your own mani - I would really abandon this project or find a pre-fabbed kit out there. The cost alone to get a custom mani like that I would thing would be ridiculous.
Aside from that though..... I like the idea of twins, doing a pair myself but they are sequential. Top-end wasn't a concern for me and if I see 375is RWHP which I expect - I'll be more than happy I'm sure - my primary concern was drivability. Regardless - here are a few links and pics to tickle your fancy. Notice the shitton of fab work done on that monstrosity of an exhaust mani. THINK about how long that took to make and multiply that by whatever going metal work rates are. $98/hr last I checked so assume that a custom mani is going to cost about what both kits sold for and then think about the benefits of using old internally gated turbos.
https://www.rx7club.com/showthread.php?t=703600
[
Regarding your project - here are my thoughts take them as you will
This sounds like you are trying to do something very unique and unique and on the cheap generally don't go well together. Disregarding the fact that the older turbo's are not efficient, you would need your own intakes and you would need to build everything yourself it seems to me that this isn't something you would want to cut corners on. Assuming you can't weld your own mani - I would really abandon this project or find a pre-fabbed kit out there. The cost alone to get a custom mani like that I would thing would be ridiculous.
Aside from that though..... I like the idea of twins, doing a pair myself but they are sequential. Top-end wasn't a concern for me and if I see 375is RWHP which I expect - I'll be more than happy I'm sure - my primary concern was drivability. Regardless - here are a few links and pics to tickle your fancy. Notice the shitton of fab work done on that monstrosity of an exhaust mani. THINK about how long that took to make and multiply that by whatever going metal work rates are. $98/hr last I checked so assume that a custom mani is going to cost about what both kits sold for and then think about the benefits of using old internally gated turbos.
https://www.rx7club.com/showthread.php?t=703600
[
01-07-08, 08:53 PM
#22
Banned. I got OWNED!!!
Anyone with a chop saw a mig welder & a call to Racing beat for some flanges. However - look at the clearance here WITHOUT a spacer in my FC bay. Not to mention unless you plan on spending thousands of dollars to run them sequentially - the lag will be silly. Most FD owners regret going non-sequential and quickly dump it and go single. Not to mention you would need to add a drain into the pan, coolan lines, intercooler piping requiring more welding. Here's a few pics - unless you're planning on running them sequentially - I think it's a complete waste of time and if you need to ask about welding a space - sorry - I think you should look into something else.
FD twins & DP
Cutting the y-pipe to build a flange becuase the stock x-over pipe is totally wrong
And from the top
LOTS of work and certainly not a bolt on deal with an adapter. The adapter is one of a gazillion little things not to mention severe notching of the framerail
FD twins & DP
Cutting the y-pipe to build a flange becuase the stock x-over pipe is totally wrong
And from the top
LOTS of work and certainly not a bolt on deal with an adapter. The adapter is one of a gazillion little things not to mention severe notching of the framerail
01-07-08, 09:12 PM
#23
Lives on the Forum
Ah, come on. Maybe he has the special rotary version of the SDS. It's rotary because it supports staged injection (only if you run secondaries which are the same size of the primaries) yet still requires a distributor for ignition. It's a great ECU choice...if this was 1987.
It's rotary because it supports staged injection (only if you run secondaries which are the same size of the primaries) yet still requires a distributor for ignition. It's a great ECU choice...if this was 1987. -Ted
01-07-08, 09:17 PM
#24
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my sds is running just fine idles beautiful builds up through the rpms no misfiring just plain ol GREAT the only problems it gives me is that when i use 87 it runs like **** ,89 runs ok but still has some misfiring but when i use 93 forget it all misses are gone more torque and hp is felt due to it burning correctly
Either something is really wrong with the gas you use, or you don't know how to tune properly.
so my piece of **** sds that so you call is not so as you think. i know that there`s better ecu`s. but when you come to my house install,tune a different ecu of your liking and have it run daily with no problems. you are welcome to do so .so don`t hate just because im trying to do something different/unique. and just because your escapades with sds din`t turn out how you like that`s not my problem so :so keep your hating *** out of my post if you dont have anything that`s going to help me and my twin turbo fc of becoming one
that`s not my problem so :so keep your hating *** out of my post if you dont have anything that`s going to help me and my twin turbo fc of becoming one
Better resolution, more outputs, uses the stock CAS unmolested, able to pull it throw it into any car with a few keystrokes...
After seeing what you wrote above, don't be insulted if I don't consult you for tuning tips...
Man, you bipolar or something?
First you tell me I'm welcome to come to your house, and then you tell me to get out of your thread?
You forgot you medication today?
-Ted
01-07-08, 09:17 PM
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Anyone with a chop saw a mig welder & a call to Racing beat for some flanges. However - look at the clearance here WITHOUT a spacer in my FC bay. Not to mention unless you plan on spending thousands of dollars to run them sequentially - the lag will be silly. Most FD owners regret going non-sequential and quickly dump it and go single. Not to mention you would need to add a drain into the pan, coolan lines, intercooler piping requiring more welding. Here's a few pics - unless you're planning on running them sequentially - I think it's a complete waste of time and if you need to ask about welding a space - sorry - I think you should look into something else.
FD twins & DP
LOTS of work and certainly not a bolt on deal with an adapter. The adapter is one of a gazillion little things not to mention severe notching of the framerail
FD twins & DP
LOTS of work and certainly not a bolt on deal with an adapter. The adapter is one of a gazillion little things not to mention severe notching of the framerail