jimmydanny

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.

jimmydanny

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.

AGreen

iTrader: (11)

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.

AGreen

iTrader: (11)

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

jimmydanny

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.

R-X-R

iTrader: (9)

ebay turbomanifold? but its undivided

Holton713BRE

iTrader: (4)

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.

jimmydanny

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.

jimmydanny

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.

RotaryEvolution

iTrader: (30)

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.

jimmydanny

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.

RotaryEvolution

iTrader: (30)

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.

Molotovman

iTrader: (49)

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

Th0m4s

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?

RotaryEvolution

iTrader: (30)

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

Th0m4s

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

Are S5 TII models that different?

brian_skotch

iTrader: (6)

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.

Th0m4s

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

jimmydanny

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.

R-X-R

iTrader: (9)

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

jimmydanny

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.

RotaryEvolution

iTrader: (30)

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

jimmydanny

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.

RotaryEvolution

iTrader: (30)

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.

jimmydanny

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.