krazy_karl

Hey guys I have a few questions. Before I start I have spent countless hours searching both this forum and the net in general and have gleaned some information but not enough to decide on a direction as yet.

1) Turbo Information

First of I have a S5 turbo with a AiResearch TO4 compressor on it. I want to find out more details on the compressor and have been having a lot of trouble. Shown below are two crappy pics of it taken with my camera phone, sorry about quality.




The only numbers I have managed to find on it are TO4B80 with 4006596 directly underneath there is also a M11 on the front of it. There is also 09. in the compressor outlet and 16 in the compressor inlet. Does anyone know what A/R this turbo could be and possibly, and what trim etc I can't find any info about it at all. The only other thing I can think of doing is what is outlined here http://fc3spro.com/TECH/TURBO/tmodels.html

2) Boost Creep

The next issue is I want to elimanate the boost creep I have been getting with this setup. I have a S4 engine with a S5 manifold and the turbo as described above. The wastegate is not ported and as far as I know the actuator has a standard spring.

I am going to port the wastegate as described here http://fc3spro.com/TECH/HOWTO/KWG/kwg.html but I dont think this will be enough to stop it. I was getting around 1 Bar of boost WOT in 3rd and 4th gear with boost controller wound all the way down. I want to change the downpipe etc to help reduce boost creep. The two options I have found are:



The above one I am not sure on as the wastegate flapper door does not open very wide in the stock S5 turbo exhaust housing, consequently the gas tends to flow into the side of the turbine housing and along into the downpipe. The dividing plate in the photo will help stop this but surely it to will hamper the flow.



The second downpipe I think may be the way to go, but I have seen no downpipes like this on a rx7. Does anyone see any potential issues with this and do you think it will help me cure my boost creep issue.

3) Exhaust coatings

From what I have read the best compromise between affordability and performance is to get the exhaust manifold coated with a ceramic coating, get a blanket for the turbo exhaust housing and heat wrap the downpipe. Is this the consensus in general?

4) Downpipe fastening

Lastly, the 3 bolts securing the downpipe to the exhaust housing of the turbo are a b***h to get to and undo due to having 3" downpipe. Has anyone managed to cut the dump pipe off really short and then put a V-Band clamp in so that then the stubby section of dumpipe can be bolted to the turbo out of the car and then installed with the turbo and the remaining exhaust hooked up using the V- Band clamp?

Any help appreciated,
Karl

coolmike711

iTrader: (7)

Where do you find these pictures. Are you trying to put a Subaru WRX down pipe on your S5?

ifryrice

1) Identifying how they went about the hybrid is going to be difficult. You'll need to probably remove the compressor and measure the wheel. There's a few different ways of doing it, some just modify the compressor housing to work with the original wheel, and others will replace both the wheel and the compressor.

2) With some proper porting, and if you can, welding on a larger flapper should get you some pretty solid boost control without having to modify the exhaust housing at all.

3) Ceramic coating is some wonderful stuff, as is heat wrapping. It goes a long way to reducing underhood temps. It's not really a requirement, nor will you likely see a performance gain from it. It's usually just preventative for reliability sake.

4) I never had much trouble getting to the downpipe bolts with my RB 3" header, do you have any shields in the way? Granted, it usually required an open ended wrench but usually wasn't very time consuming. I've seen people build a short lead pipe with a V-band on it, but i figured it's more trouble to go that route than it is to deal with it. Especially since the RB will have a resale value if you ever decide to go full turbo upgrade.

Jimmy2222

iTrader: (3)

Don't wrap your exhaust, there's an article I read somewhere (somebody else might have it) and it proves that heat wrap reduces the longivity of your exhaust. Ceramic coating works though.

Nick_d_TII

iTrader: (6)

Please site credible references to your claim. Sounds like a ceramic coating sales pitch to me. I don't buy it.

I agree with ifryrice.

I ported my s5 WG pretty far out, but it still creeps a little, but pretty minor. If you port the shiz out of it and have a new flapper welded on, you'll be golden, without the need of hacking and rewelding the Down pipe.

I wrapped my DP and it keeps some of the heat out of the engine bay, I used to have the stock turbo shields on which kept temps even lower(hand thermometer). Wrapping the DP and Turbo is pretty common, and I would assume it keeps radiant heat to a minimum.

I find the three bolts on the DP easy to remove. Just use a 14mm wrench. Apply antiseize when installing them and any other nuts and bolts on the exhaust.

I really appreciate you taking the time to write a clear post and with pictures and references.

krazy_karl

No I don't plan on putting a WRX exhaust on my car it is a representation of what I want to do with my downpipe potentially.

And ifryrice I was told that both the wheel and cover where changed, I am going to take it into work today and measure the diameters.

Does anyone have any pictures of the larger flapper door they welded on? The S5 flapper is already pretty large and I am worried about making the exhaust housing to thin if I port the wastegate out a lot. I dont want it to blow through and/or crack on me.

Yea I have never seen any cold hard evidence of wrap rapidly destroying a downpipe either. And has anyone see a turbo blanket that will work with a internal wastegate?

And no I dont have any heat sheiling at the moment but the downpipe steps up from the exhaust outlet of the turbo to 3" fairly quickly and it is the weld etc that gets in the way. I'll take a pic of my downpipe and you will see what I mean.

ifryrice

It's probably a pretty standard 60-1, as that's the most common for a full wheel/cover replacement. Is your hotside clipped at all? I don't have any pictures, it was a long time ago. I can't remember if it was NZ or someone else, but they had quite a good wastegate porting thread. I'm sure you can find a lot of info just searching for wastegate porting in the 2nd gen area.

krazy_karl

From what I can see the hotside isn't clipped. I am just looking for corners missing off the turbine right?

And yea I read a thread by NZ but none of the pics still work. I PM'd him about getting some pics or details on how he did it but havn't got a reply.

Nick_d_TII

iTrader: (6)

https://www.rx7club.com/showthread.p...ting+wastegate

Here's mine. It only has creep of 1-2 psi in 3rd ,4th ,5th gears at WOT. Just went out to the edge of the flapper, could have back cut it more had I had a longer bit. Works for me tho. it was creeping up to +14psi on my stock turbo.

https://www.rx7club.com/showthread.p...reep+wastegate

Good luck!

RockLobster

iTrader: (7)

What most people find out with the S5 turbos is the wastegate and door itself is not the problem but the flange on the back side of the turbo is. It limits how much the gate opens and also sees a ton of backpressure from the way the waste gasses flow perpendicular into the main exhaust gasses.

I have an S5 turbo with a simple roughly 5/8" spacer between the turbine housing and the backing plate flange. This both allows the door to open more and provides a larger cross sectional area where the two gas streams meet, reducing backpressure on the wastegate. Unless it is 40 deg or lower ambient i see no boost creep at all (and my wastegate is otherwise stock). I would imagine it might be different if i were to upgrade to a hybrid.

If i were you i would do something along the lines of your second (SR20 part) pic. Have a collector made that is basically a short wide mouth pipe that is about the size and shape of the stock backing plate and bolts to the turbine housing (eliminating the stock backing plate). Then it should collect in a rough cone shape down to a 3" v-band connection. I would imagine this piece would work just fine being 4-6" long. This way you eliminate all your problems at once. You get very free flowing wastegate and eliminate any non metalic gaskets near the turbo. You will obviously need to modify or get a new downpipe.

Turbo II Rotor

iTrader: (2)

It's a fact both will reduce the service life of the metal they are applied over. More heat in the exhaust leads to more heat degradation of the metal but quicker spool and cooler bay temps.

RockLobster

iTrader: (7)

Oh and btw. If you dont do what i suggested above, but you still have ABS. Ditch that **** and you will have no problem getting at those 14mm nuts....

coolmike711

iTrader: (7)

I wrapped my downpipe and also used a blanket on the turbo. It works fine for me, have it on the car for 6 months now.
this is what i used on the turbo. It's a S4 BNR Stage 2 turbo
http://www.jegs.com/i/Thermo+Tec/893/15003/10002/-1

mort2002

iTrader: (1)

Ugh i wish i had a pic, i have a S5 hotside, that has the turbine separated from the waste gate, and than there is a hole in the cover where you can bolt a flange to it to external dump the waste gate, i was gonna try it but never got around to putting it on and building a flange for the waste gate, that might be an idea for you to try to separate your exhaust and your waste gate and provide better flow for the waste gate.

Nick_d_TII

iTrader: (6)

Not just cause you say so. Prove it! I want to see clear, concise, credible information with cited references reiterating what you have stated.

Turbo II Rotor

iTrader: (2)

You really can't see the link between trapping more heat in a material (higher temp) and accelerated heat degradation from that? My word is fact so don't think I need to explain further.

Why don't you try to prove me wrong?

misterstyx69

iTrader: (142)

compare your turbo to the pics on here. http://www.bnrturbos.com/2ndGen.htm Similar??

krazy_karl

Wow, getting some good replys!

And yes I noticed the backplate issue today. I am going to mill a hole in the plate to allow the flapper to open more and weld a pipe on back into the dump pipe. Or If an exhaust shop believes they can make me a collector to cover the whole rear of the turbo I might do that like SR20 type collector I show in the original post. There is a large area to cover on the back of the S5 turbo so I am not sure if this is possible or not.

The only way to really get the wastegate flapper to open more would be to change the arm so that it was shorter therefore increasing the distance moved. The actuator only moves a certain amount which limits how much it will open. It was interesting reading the threads Nick D TII posted above where they took a notch out of the backplate did this help the flapper open more?

I tested my actuator as well today with the boost controller in the line still. It started to open at 7PSI and reached full extension at 12PSI so I think this could also be causing my problem as it should really fully open at a lower PSI surely. I pulled apart the boost controller and just found out it is a flow restriction type one not a pressure relief type. Does anyone have experience with either a better mechanical boost controller or EBC? I am thinking I might just splash out and get some sort of closed loop EBC....

krazy_karl

And Turbo II Rotor, heat will break down steel slowly over time yes. But whether or not the wrap will accelerate the wear much... I don't think so. The heat generated has to pass through the exhaust tubing and radiate out into the engine bay whether you have wrap or not.

If you wrap the downpipe it does slow the release of heat into the engine bay as it is not as the wrap itself is not as conductive as steel therefore keeping the heat inside of the pipe and in the gas itself. Do you have measurements on how hot the steel in a unwrapped downpipe gets and conversely how hot the steel gets in a wrapped downpipe? I don't think there will be a massive difference, but I have not seen any cold hard figures.

krazy_karl

And yes it is similar to those S5 turbos. I manged to find the words A/R 60 on the compressor housing they were pretty faint though and quite hard to read. Is this a pretty standard turbo for a near stock motor? And what sort of power max do you think I could get out of it?

Turbo II Rotor

iTrader: (2)

Don't listen to me, take the manufacturers word for it.

http://www.designengineering.com/ima...ast%20Wrap.pdf

Nick_d_TII

iTrader: (6)

I'm not the one that made a claim about 'accelerated heat degradation' but, we will assume that most DP's are constructed from Stainless Steel 304 (jp SUS304).

http://shop.ebay.com/i.html?_nkw=sus...pipe&_osacat=0

"Type 304 stainless steel has lower carbon to minimize carbide precipitation. It is less heat sensitive than other 18:8 steels. Used in high-temperature applications. Machinability - 45%. Drawing or stamping - very good. Welding - very good, tough welds."

http://www.ssina.com/composition/temperature.html

"A further problem that some stainless steels have in high temperature applications is the formation of sigma phase. The formation of sigma phase in austenitic steels is dependent on both time and temperature and is different for each type of steel. In general Grade 304 stainless steel is practically immune to sigma phase formation... Sigma phase embrittlement refers to the formation of a precipitate in the steel microstructure over a long period of time within this particular temperature range. The effect of the formation of this phase is to make the steel extremely brittle and failure can occur because of brittle fracture."

http://www.espimetals.com/tech/stainlesssteel.pdf

http://www.azom.com/details.asp?ArticleID=1175

I'll notify you on this forum in +10 years when my DP rots out from being wrapped. If the wrap gets contaminated from road salt I could see a problem, but heat, I doubt it.

I agree with the OP, and let's not stray off topic...

I'm just going to throw it out there; you could get +300rwhp possibly... add meth +350???

Turbo II Rotor

iTrader: (2)

You're letting your objectivity cloud your judgment. You're telling me that 2 exact motors running 2 exact downpipes(one wrapped, one not) after 50k of heat cycles those downpipes will be in the same exact condition? The wrapped one won't show even the slightest bit of accelerated heat degradation? I'm not saying your down pipe is gonna crack in half, I'm saying it ages quicker and if you believe it doesn't than you're ignorant. Next you're gonna tell me stainless will never rust, right?

prof

Regarding your're boost creep:

I run a turbo II vert with a hybrid turbo - similar to yours. I had the wastgate holes ported about as large as you can go, and then a spacer plate on the back of the turbo assembly - cut from an old wrecked turbine housing - giving another 1cm of space for the flapper to open and for the exhaust to mix before hitting the large 3" downpipe. The system works well - but the only issue I did come across was that the stock wastegate actuator wasn't man enough to keep the flapper shut at higher boosts and tended to leak off after 9-10 psi - an HKS actuator resolved this problem

A friend of mine had a 'bellmouth' downpipe to fit over the entire rear section of the turbo housing - similar to your divorced downpipe system in one of your pics - it works really well - but again he's having the same boost drop issue with the stock actuator. Incidentally - he's running a stock turbo with ported wastegates and 360 bearings - but not a hybrid.

Both cars are series 5 FC Turbo II.

Hope that helps.

krazy_karl

Has anyone ever tried one of these actuators http://www.treadstoneperformance.com...egate+actuator it looks like it works sort of like the actuator in a external wastegate. Do you think this would be any better than a HKS style actuator? If you preload your spring using the adjustment in the actuator rod on the HKS actuator doesn't that then mean that you shorten the travel of the actuator itself? I want my wastegate to stay shut as long as possible and to open a long way fast so that it flows lots quickly so I can get a better boost curve.

I am going to draw up my exhaust housing (with wastegate flapper), and that backplate in CAD and figure out the size hole I need to cover the whole wastegate and allow the flapper to open as mush as possible. I noticed as well there is a flat on my wastegate flapper where it has been hitting the backplate, must have been opening pretty hard!

I am still trying to decide also whether to get a EBC or a better mechanical boost controller to better control the flapper also. I was getting problems with the wastegate opening early before the boost pressure I wanted as well so want to make sure I get it right this time. Anyone have suggestions for the best controller to keep the wastegate shut for as long as possible to build boost properly?