What turbo and manifold for future upgrade?
 

Hi y'all!

I am considering getting myself a bigger turbo and a new manifold with external wastegate for future upgrade to standalone, since this is the cheaper way around since my closest professional tuning shop that know rotaries is 500 miles away. And the fact that standalones are 1200$++.

Anyways, I would guess undivided T4-flange is the way to go, so I need a good manifold with that, a turbo with, guess what, T4-flange. I am running the REV TII exhaust, I wouldnt wanna mod it too much to make it all fit, other than welding a flange on the turbo or v-band on the downpipe, as far as this is possible.

As for spoolup, I would prefer something that is usable on the road. I will be having the stock 9psi~ for four years, so I would need a rather low A/R, but again, I want a turbo that can get me a bit up on the BHP as well when I go that route.

As for BHP I am not going higher than 350-450 on this car and this engine, so that would be what I would need optimaly, a turbo that can handle that but not much more, but can also give me some usable boost early on when running stock as now.

As for the undivided/divided stuff, I read up a bit on it, and fast spool seems to be the result of undivided, as well as simplicity and ease to find manifolds that fit.

Supposedly a BNR stage 4 will get you around 400 whp. If you want to go with a completely different turbo, go with a divided t4 manifold, and for that hp a GT35 would probably be sufficient.

A divided manifold and turbo will get you faster spool. That's why the S5 doesn't need the twin scroll system

Ah okay, I was mistaken, thought it was opposite.

Well, any good/okay manifolds i should look for?

Also, how is it modifying the downpipe/turbo to fit? What is the best route to go? As I understood v-band doesn't need gaskets at all, so that is a problem eliminated for good just there, just weld the v-bnad flange on the downpipe, smack it on and drive really. I hate gaskets, they always break, they just have to.

How would the spool be on that turbo compared to the stock S5 one? The stock one is pretty quick, and as far as I see it all that hinders it from charging more is the T3-design which should stay in the 80s.

ebay turbomanifold? but its undivided

Hey I have a complete BNR Stage 3 I'm looking to get rid of...if you are interested. Real quick spool, around 2700 to 3200 rpm, and I've run it up to 15lbs of boost with no creep and or drop. I have everything from manifold to DP. I was really happy with the turbo and I'm now turning my car into a drag car, so I'm going BWS366. I think I may have put a total of 500 miles on the turbo since I put it on the car, car has been sitting for a little while, but this is due to a Haltech problem. Anyways PM me if your interested.

Having an undivided manifold on a divided housing kinda defeats the purpose of having it divided I guess :P

Is the T4 flange the right way to go? There are so many flanges, what is T04 for instance? YOu also got T25, T6, T31 and so on.

I am not sure BNR is the way to go, at least not stage 3. I will be aiming a bit higher with my turbo than what I will go for in the start, I might end up with 500bhp for all I know.

Also, 15psi wouldn't/shouldn't give more than 300bhp max, if my math is working as it should. What i have seen on the FC S5 is that you would get approx 20hp per 0.1 bar more, and since my 0,4 bar and 170bhp theory feels right compared to my stock 0,7 200bhp, and other peoples numbers, I would say I am not too far from the truth to a certain point.

when you say 9psi for 4 years, are you thinking you will get by with the stock ECU on a much larger turbo? think of a turbo as airflow and not a set psi figure, more air requires more fuel.

The stock fuel cut is on what, 8.7psi? It is not even 0.6 bar just there. The stock exhaust manages the 0.6 bar-ish, the REV TII flows so much better you get more hp without doing anything.

I am not doing anything, it should be okay with just the exhaust.

you're not understanding, you can't slap on a much bigger turbo and think that everything will be fine so long as you keep it below fuel cut level. you will wind up bricking the motor.

Turbo's flow different CFM at the same psi depending on its specs. That is what Karack is saying.

But if you install a wideband lambda and watch the AFR's you should be able to set the boost up to a safe level, right?

depends on the turbo, IMO the turbo fuel system is already a bit on the lean/unsafe side.

At least my S4 TII was very safe when it was stock. Had round about AFR 10.5 when i floored the pedal.:scratch:

Are S5 TII models that different?

Th0m4s, are you running the stock turbo?

Either way OP, upgraded turbo (no matter what the psi) requires you to upgrade your fuel system. This means bigger injectors, fpr and a better pump. At that point you'll need some sort of engine management system.

Not anymore. I'm running a T04b turbo together with an external wastegate, an emanage blue, upgraded fuel system and so on.

Dont shoot me if I'm wrong but if I have say 3 feet of 2" piping, blocked off. I put on the stock turbo and charges up to 9psi. Then I take a bigger turbo and charge up to 9psi. Where is the difference? Nowhere. It is the same amount of space, so unless I am increasing the pressure, the turbo can't put in more air without putting more pressure on it as well.

9psi is 9psi no matter what turbo you are using. And also I still say the stock ECU should be able to cope with fuel-cut boost level and a tad above without going lean, mine is running rich no, just by the sound of it, I would bet maybe around 11 AFR, I will know exactly when I get my paycheck the 10th, ordering a wideband and gauge.

As for the CFM, it CAN put out more, but it doesn't have to. Linked to the PSI I tell it to go to. If a turbo can blow 300CFM as an example, it charges to 6psi. Now a bigger turbo can do 1200CFM, giving up to 24psi. But if the wastegate opens at 6psi, the turbo slows down so the CFM is only 300, but because of the size of the turbo compared to the other, the blades go slower and still put out the same amount of air.

i am not an expert on this but the people commented to ur question knows what the hell they r talking about. u should listen to them and not blow up the engine lol :D

Well, the logic behind what they said is non-existant.

I will ask some math heads (not meth lol) to tell me how this is, and I can come back and tell who is right, because it makes no sense to me that a bigger turbo gives more air at the same level of pressure. If pressure is a set level, so is the amount of air pumped into the engine.

do what you want and believe what you want, you have been warned.

Your logic is non-existant. As long as the wastegate adjusts the speed of the turbo, the CFM will be the same if you set it to the same PSI, as you can't get more air into the same area without increasing the compression of the air, which is the PSI.

EDIT: I will when time and money says yes, prove my point. I will do it with this method:

Stock turbo:
First three gears I will film the AFR and boost gauges with a pre-desided boost level, for example 8psi. Then I will run the same at 6psi and 10psi.

When I get the new turbo, with no other changes (if I change anything else it is still valid as long as I run the test with the stock turbo with those upgrades), I do the exact same thing.

And I promise you, as long as the turbo gives the same amount of boost, the AFR will stay the same, because the amount of air pumped out by the bigger turbo is the exact same because of the size of the compressor wheel, which is bigger, is turned slower to get the same amount of boost level, and since the volume which is pressurized by the turbo is always the same, the CFM will stay the same for the two turbos.

is it? stock turbo makes ~200whp@8psi, GT35r makes about 350whp@8psi, Bw s475 makes about 450whp@8psi. why do you think that is? and now to complete the question, how would stock injectors support a borg warner s475 pushing that power at even a modest 8psi? pressure does not directly relate to airflow and CFM because air molecules do not always react the same in different conditions. in a nutshell you can't even do a simple hybrid turbo without adding more fuel, somehow. nor can you upgrade the airflow and pressure drop via a much larger intercooler without again compensating for it. yes, i have personally seen engines pop just from upgrading intercoolers.

The engine popped because when you swap intercooler the air molecules are colder, and can be pressed more together, so to get the same amount of boost you need more air molecules.

But I am talking in a static enviroment. Stock 2" piping, stock intercooler, if the new turbo developes the exact same amount of heat, the numbers stay the same.

If I get less heat from it, I will get more air into at the same psi. If I get 2,5" intake I get more air into the the engine at the same PSI.

BUt not when those are static.

Also, halfway back to the topic.

My turbo now only charges to 0,4bar, 0,6 is stock I think. 0,7 is fuel cut.

Now this is not the solenoid as I have taken the hose to the solenoid and connected it straight to the pre-turbo intake, like stock but without the solenoid. So now it should in theory get the 0,6 bar, right? Nope.

So the actuator arm, how can it fail on me? Can it be adjusted on the stock turbo? Or is it something like the FD that the C-clip falls off?

Get your head out of your ass.

Stealth 316 - Turbocharger Compressor Flow Maps

There's some compressor maps on that page in CFM. take a look at a few different ones.

Different turbo's flow a different CFM at the same PSI.

removing the wastegate solenoid and venting it back into the intake pipe results in no pressure building to open the wastegate actuator and an overboost condition. plug the line off and you should be seeing roughly stock boost. if not then your intake systems is leaky, intake/exhaust restricted or turbo itself is having issues like worn journal bearings/worn wastegate bushing allowing exhaust to push the wastegate open via backpressure.

Don't think of it as a defined volume with a compressor on one end.... because that's not what the system is.

Keep in mind there's an engine that still consumes this air. So if the stock turbo makes x.x psi at x.x rpm under x.x load condition, the engine will consume what it can out of the turbo. A larger turbocharger will allow the engine to consume more air. However, because there is still an inherent restriction in the system, that will explain why there's a pressure. It's not just static pressure when talking about compressors, it's pressure, volume, density, and velocity. There are multiple factors you're not taking into consideration.

So in a nutshell, the larger turbo will allow the engine to consume more air at a faster rate, expelling more air (exhaust), making room for more air, faster, which will increase the HP, and at the same time prevent the pressure from building up inside the engine. More flow rate means you will need more fuel to keep the air/fuel ratios the same. So the pressure DOES NOT MEAN ANYTHING without a flow rate. Stock injectors will not work for almost anything other than a stock turbo.

There's also a point at which a turbocharger no longer pumps air efficiently. With the stock turbo, going above 10-12 psi it won't flow more air, but instead superheats the incoming air, making it so much more susceptible to knock, or detonation. This is deadly for an engine.

That is the problem. I don't see more boost. 0.4 bar... 1 bar is 14.7, no overboost at all. Intake is not leaky the vacuum is fine.

Is the actuator arm adjustable at all on this turbo? Can I feel the slack if the diaphragm is very bad, for instance? That is the two main things I can think of right now. Wouldn't bad bearings often show signs with blue smoke and oil consumption?

The turbo can when the wastegate is not connected give over 10psi, tested it once last week and once today, it peaks even higher than 10psi, maybe 12 (watching the road, don't wanna die). Connected the wastegate vac line, and same thing as before, 0,4 bar, whatever that is in PSI. So I'd say it's probably not the bearings, probably not anything else but something with the actuator arm, or the actuator itself.

Just been out driving, so the turbo is too hot to handle right now, so I gotta wait till later tonight or tomorrow before I do any feeling of the arm (sounds nasty)

Also

I found this line very interesting in the bottom of the page, in the summary:
Which is kinda what I said here. If it is 9psi, 20 degrees celcius, and 6000rpm, I got X amount of air going into the engine with the stock turbo. With the bigger turbo, it is still X.

.4 bar is 5.8psi.

check the wastegate arm for slack, it should be tight and difficult to move by hand. sounds like your bushing is worn and allowing exhaust to bypass lowering boost and dropping too much when the actuator is moving the arm.


not going to argue the turbo differences anymore.

Is that bushing replaceable, and/or can it make that amount of exhaust to bypass through the wastegate?

And that quote I gave was from the link Molotovman gave. Funny, isn't it, giving me the one sentence that says I'm right, when trying to prove I'm not?

Okay, the actuator arm seems fine. No slack in it, so bushing is okay I guess.

However, holding the hood up with my neck, pulling in the arm with my left hand(right handed), I could pull the actuator arm out without any real trouble, so with the right hand I would probably pull it without any effort at all.

Is this normally doable? I have never touched the arm so I don't know at all.

it shouldn't be that easy to pull, no.

for the other comment, as i mentioned many posts ago: do what you want, it's just advice. but when you see AFRs start to spike and can't explain it. *shrug*

The compressor maps say it all, and the information is in the article. I just did a quick google search and found that.

Since you can't get your head out of your ass and trust others who have experience, do it yourself. Put a larger turbo on, keep it at 8 PSI or whatever you want, blow you engine. We won't have to say "we told you so" and rub in your ignorance. You'll be doing that to yourself when you have an expensive rebuild.

I will prove you wrong. But as RotaryEvolution said, he is done, and so am I. It's word against word.

So, back to my current turbo. Actuator and arm (I guess), is this hard to swap if I fetch a HKS uprated actuator, holding 0,6 which is the stock level anyways? A clip and some bolts I would guess, without having taken a real good look on it yet.

Is maybe that something I take when I get my new exhaust, just taking the turbo off and doing it then?

Key word. Temperature.