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FD's with S5 turbos

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Old 06-01-08, 08:35 PM
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FD's with S5 turbos

Hey all.
Would like to hear from any one running S5 turbo on there fd. I have a 93' jdm fd and recently fitted a S5 fc turbo i had lying around and i must say i was impressed with how it ran! The kit was inexpensive to put together aswell.Had interesting reading there when i ran a search on it in these forums too.
So as always i decided i needed more HP so last weekend i fitted a T04 front to standard fc turbo but not quite sure on the static fuel pressure to run. Bear in mind that here in Ireland we use 95 RON fuel.
Also has there been many people fitted external wastegates to a S5 ex manifold?? So far my car has
Large Autobann fmic
bosch 040 fuel pump
sard 66mm dia f,p,r
full 3in exhaust system
radiator with extra core thick
a/c and air pump removed
greddy boost controller
new innovate wideband
I hope to crank her up tomorrow but really unsure how safe she gonna be fuel wise and how boost i can run before i get her tuned?
Old 06-01-08, 09:47 PM
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95 RON is a bit like 91 (R+M/2) California **** gas.

s5 turbo is good to 250whp on an FC, your hybrid might do 300 all the way up to 350 depending how you built it. For your purposes there's no major differences between the s5 and the s6 setups except you have bigger injectors stock. What is your fuel management system? Haltech, Power FC?

a few people have done external wastegates, search the 2nd gen forum. Given the availability of FD turbo upgrade parts (better manifolds etc) there's probably no point in you doing this if you can't do it cheap.

Since you have a wideband, just see how it runs as far as the AFR's go. Stock FD injectors should be enough for an s5 hybrid unless it is one of the 60-1 hybrids running high boost. Now a stock turbo holds 6-8psi to redline. With the bigger wheel it all depends... maybe 10-12 would be ok for you before the turbo runs out of breath due to the restrictive hotside, but once again it all depends what wheel you put in. You will probably have some boost creep problems. If you don't do the external wastegate you will have to port that wastegate very extensively, to the point of welding on a new flapper door. I had a small port job on my s5 turbo (up to the edge of the flapper door) and it still creeped pretty bad in cold weather.

set your base pressure to either 36psi (whatever that is in metric, that is the stock pressure I think) at atmospheric or 40psi
Old 06-01-08, 11:12 PM
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a friend of mine did that a few years ago, its almost a bolt on, and it runs nice, but i think twins with a downpipe make about the same power
Old 06-02-08, 05:57 AM
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re

Yeah cheers guys.
My twins where well shot so thats why i decided to go single. I also own a UK spec 89' fc fitted with a full 3in system chipped ecu etc and it suffers from boost creep quite a bit. but straight away the fd using an fc turbo is a very different beast compared to my fc. Spools far faster and seems to hit harder but tails off sooner too. Some fun to drive though .
Im near sure its a 60-1 compressor fitted now. The ecu im running is a hks f-con v. Would love to end up with 300whp from this setup but its not that popular so hard to know.
Old 06-02-08, 07:39 AM
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^ oh yeah, the s5 turbo with the boost turned up gives you almost a v8 powerband. Torque hits hard by like 3000rpm (harder than stock twins) and then power starts dropping off around 5500-6000, whereas stock twins feel less torquey but the curve is flatter and boost doesn't drop off.

I think you can do 300whp, but a lot of people port the turbine housing to reduce backpressure.
Old 06-05-08, 05:41 AM
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It's a littlebit of topic..

But I have an S5 FC with hybrid, with the Knightsports big compressor kit.. when installed last year, dynod 280rwhp.. spoolup was good at 3000-3500rpm, sometimes it had some boostcreep..

Now I suddenly I noticed the spoolup was gone, turbo spooled only at 5k rpm anymore, I removed the turbo and wastegade is seized in the "open" postion, after some heating and struggeling I got it back moving..

I was now goign to port the wasteagte to minimize boostcreep somewhat..

What can be done so the wastegade doesn't seize anymore? turbo was overhauled 2000 km ago, shaft play is perfect, no oil consumption or whatsoever..

Also where to port the turbine housing to reduce backpressure somewhat?

Thanks!
Old 06-05-08, 07:54 PM
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Yeah i would be very interested in finding out more in the porting of the standard s5 turbine housing too!
The shaft in my s5 wastegate is slightly wore so the top flap sit sllightly open wen closed so thats all the more reason for me going external! . Even with this the car suffered boost creep with the standard s5 turbo but a 1 1/2in dump pipe and wastegate work sorted this. But the problem is back now wen i fitted the larger compressor housing.
I was planning to fit a large 50mm external that i have and was wondering is it too big for my small turbo? Is there such thing as having a wastegate too big??
Old 06-05-08, 09:01 PM
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I started out with a BNR stage 4 that was a 60-1 HiFi compressor section and a T04 "O" trim exhaust wheel in a S5 turbo housing/manifold w/ mild ported wastegates.

It had boost creep by 3,000rpm, so I ported the wastegates some more and the exhaust wheel got a clip. Still had boost creep.

I open air vented the stock wastegates through the backplate and had it built w/ a larger "P" trim wheel as well as grinding the scroll slots wider and shaped more toward the turbine wheel. It still had boost creep above ~5,000rpm.

Clipped the "P" trim 15 deg and ported out the wastegates as far as the housing would allow and put a HKS 60mm external wastegate on it. Still had boost creep after 6,000rpm.

Finally, I ported the velocity stacks down quite a bit in the exhaust manifold and ported the turbine housing to match up to the wastegate runners to reduce the velocity so the exhaust favored wastegate flow over turbine flow. This fixed the boost creep, though it made 1,000-3,000rpm boost response a little more sluggish.

Still gets boost off idle, ~2psi by 2,000rpm, ~7psi till 3,000rpm and full 14psi boost ~ 3,400rpm in 5th. Spins street tires through 4th gear had to switch to race tires on the street. 720cc primary and 1600cc 2ndary injectors at high duty clycle...
















That wastegate divider to keep the manifold truely pulse divided didn't work out. The exhaust energy tore the thick stainless in half twice.

First time (after ~3,000mile) I though it was from thermal expansion and breaking the welds so I welded it at the back plate and made that ring at the end so it could slide as it expanded. It tore the even thicker stainless sheet in half again (after ~12,000? Miles and lots of racing) right where it bends in the elbow section and the "tang" was left welded to the backplate.

It lacks the divider now, but the difference is barely noticeable.
Old 06-06-08, 05:31 AM
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Nice turbo!

I have an audi RS2 wastegate lying around, but I think it will be too small for this application..

Maybe it isn't a bad Idea to use 2 gt28r ball bearing cartidges..
Old 11-21-08, 07:20 PM
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Requesting more info on running an S5 turbo on an FD. I'm VERY tired of the problems with the twins and i have this laying around. Not looking to make big power. Just keep me happy until i can afford the gt35r setup with twin wastegates



Old 11-21-08, 08:32 PM
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Save your money for the 35r. You will be much happier.
Old 11-21-08, 08:50 PM
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Yeah thats what i'm doing but its going to be a while and i'd like to be able to drive my FD, you know, between now and then without problems?
Old 11-23-08, 05:33 AM
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No input?
Old 11-23-08, 04:04 PM
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what are your "problems"? go non-seq
Old 11-23-08, 05:18 PM
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biggest problem with the stock turbos and hybrids are boost control as has been mentioned before. but that's a problem with all the Rx-7 stock turbos. it probably would be easier to just run full non sequential.
Old 11-23-08, 10:34 PM
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Originally Posted by staticguitar313
Requesting more info on running an S5 turbo on an FD. I'm VERY tired of the problems with the twins and i have this laying around. Not looking to make big power. Just keep me happy until i can afford the gt35r setup with twin wastegates



any info on this turbo??? PM me.
Old 11-29-08, 03:44 AM
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its funny i have been looking for someone else that has done this to there FD before and now that i have my setup almost done i find a post about it lol. But i have a stock rebuilt REW that i am doing a S5 turbo on. The only issue i have came across with the installation of this turbo is the fact that the twins front oil return line flange on the front cover is smaller and farther away that it is on S5 front plate. but for the time being i am just cutting the old return lines a few inches up on both the S5 return line and extension piece that bolts to the S6 front cover and using hydralic hose for that. the other issue is the outside coolant line that normally bolts to the lower intake manifold on the S5 doesn't bolt to S6 so my dad is cutting the pipe and twisting it around and re welding it together to put it closer to the water pump return line. I also had my plate for the backside of the turbine housing machened down about 3/16th off an inch to help with wastegate flow for the time being. i also bent up the arm for the wastegate flapper so it has clearance to open a lil bit further. im only really using this turbo setup because i hate how complicated and how much wiring is needed to run the twins. and i will only be running this till i can afford my TO4R in a few months. but its going to be awhile till i can play with the boost anyways because i have to break it in smooth so i wont really kno how it will react till i get it broke it. ill post pics once i have the whole motor together and when i also put it in the car. if anyone has any suggestions for me im game to see what you have to say.
Old 12-06-08, 01:56 AM
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heres my pics of mine on the motor.
Attached Thumbnails FD's with S5 turbos-1202080002.jpg   FD's with S5 turbos-custom-oil-drain-line.jpg   FD's with S5 turbos-s5-turbo.jpg   FD's with S5 turbos-top-oil-coolant-lines.jpg   FD's with S5 turbos-new-rew-3.jpg  

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