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Questions for Justin...

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You don't need a huge exhaust housing to push a 35 lb/min turbo to the max on a 2.0 4-cylinder. Keep in mind this thing's only slightly larger than a 14B....anything larger than a stock-sized turbine housing is going to add lag without providing any gain in flow.
 
Hi Justin,

I've bought myself a Borg Warner S362 ETT FMW turbo. I asked for a T4 .88 A/R housing, however my manifold is a T3. I'm honestly thinking about going T4 instead of keeping the T3 flange and using a BEP housing as all options I've been looking for a larger turbo seem to fit better in a T4.

My question is, I currently have a GT3582R on T3 A/R .82, I don't bother "the lag" of it, my car is a 2.0L 5cyl and revs to 8500rpm, but a bit concerned about going T4 and how would that affect response. The Holset and BW ETT have the best journal bearing response/spool in category, but being the turbine a lot bigger and the compressor slightly bigger on a larger T4 inlet as well, I'm curious how that is going to perform. I've seen the A/R .70 and was fine with it, but would a T4 inlet and slightly larger A/R cause much of a difference in lag?

Thanks.
 
Hi Justin,

I've bought myself a Borg Warner S362 ETT FMW turbo. I asked for a T4 .88 A/R housing, however my manifold is a T3. I'm honestly thinking about going T4 instead of keeping the T3 flange and using a BEP housing as all options I've been looking for a larger turbo seem to fit better in a T4.

My question is, I currently have a GT3582R on T3 A/R .82, I don't bother "the lag" of it, my car is a 2.0L 5cyl and revs to 8500rpm, but a bit concerned about going T4 and how would that affect response. The Holset and BW ETT have the best journal bearing response/spool in category, but being the turbine a lot bigger and the compressor slightly bigger on a larger T4 inlet as well, I'm curious how that is going to perform. I've seen the A/R .70 and was fine with it, but would a T4 inlet and slightly larger A/R cause much of a difference in lag?

Thanks.
The larger inlet changes things a bit by reducing overall backpressure due to the physical size of the volute. You must consider the size difference between a T3 flange, a T4 flange, and a T6 flange- no matter what the a/r, it's going to require more exhaust energy to fill the volute of the housing.

Although something else to consider is most guys do not jump platforms when they're perfectly happy with how their current turbine housing configuration is flowing on a certain turbo. This means that they're already willing to trade a little spool time to gain some critical turbine flow.

That in mind- jump from T3 single scroll to a true twin-scroll T4 setup with a similar a/r on the turbine housing, and you may not notice any additional lag but still gain critical flow. Jump to a single-scroll T4 setup or bolt a twin-scroll housing to a single-scroll manifold and the lag may potentially be unbearable. Hard to say, honestly.

Havent found alot of information about the HX30 turbo except is close to a 20g. I was wondering if the bep housing will bolt up to the HX30?

There are no Bullseye housings available for HX30's.
 
The larger inlet changes things a bit by reducing overall backpressure due to the physical size of the volute. You must consider the size difference between a T3 flange, a T4 flange, and a T6 flange- no matter what the a/r, it's going to require more exhaust energy to fill the volute of the housing.

Although something else to consider is most guys do not jump platforms when they're perfectly happy with how their current turbine housing configuration is flowing on a certain turbo. This means that they're already willing to trade a little spool time to gain some critical turbine flow.

That in mind- jump from T3 single scroll to a true twin-scroll T4 setup with a similar a/r on the turbine housing, and you may not notice any additional lag but still gain critical flow. Jump to a single-scroll T4 setup or bolt a twin-scroll housing to a single-scroll manifold and the lag may potentially be unbearable. Hard to say, honestly.

Awesome, I'll keep you guys posted with the results. Unfortunately since I'm on a 5cylinder platform, I cannot go Twin Scroll, only single scroll. I compared the inlet sizes, huge difference, but hopefully the ETT and BW center section will assist in the spool up.

I chose to go this route because it seems every bigger turbo I look I get the feeling that they will be choking on a T3. B/W also does not offer T3 for the S300SX series and the A/R .70 T3 Bullseye sells seems to be too small for the size of the turbine wheels of that series. I know it works well, I seen it, but I'm sure there should be a penalty up high boost/high rpm wise.

Another question Justin, do you think there is a certain whereabouts in the amount of horsepower where you would recommend switching T3 to T4 or that's not relevant at all?

Thanks.
 
...hopefully the ETT and BW center section will assist in the spool up.
Extended tip versus non will have nothing to do with spool. If anything you could hope to gain spool with a BatMoWheel compressor due to better aerodynamics, but back-to-back ETT vs. non-ETT wheels should spool identically.

Another question Justin, do you think there is a certain whereabouts in the amount of horsepower where you would recommend switching T3 to T4 or that's not relevant at all?
Has to do with engine displacement and total airflow produced by the engine. You'll know if you're running into a restriction if your airflow tapers off well short of the compressor's potential based on the map. If your airflow is tapering off a few lb/min short of the map's peak but comes back after going to a larger housing you'll know you had a turbine housing restriction.

In a case like this, going to a larger housing almost always gains horsepower but it can come at the expense of some torque numbers depending on how much lag it adds. You're picking up peak airflow, but if you add too much lag it can move you too far away from that magic number of 5250rpms on the dyno charts where torque and horsepower are the same. If the turbo is way lazy you'll see like 700hp/400 tq, where a system that is working in good balance will be like 550hp/500tq.
 
Extended tip versus non will have nothing to do with spool. If anything you could hope to gain spool with a BatMoWheel compressor due to better aerodynamics, but back-to-back ETT vs. non-ETT wheels should spool identically.

Thanks, I wrongfully associated it with spool considering results witnessed with ETT compressores VS. other regular journal bearing. Now, thanks clarification I did a little research of ETT and found out really the purpose really is to broaden the compressor map.

Things start to make sense now, no wonder the ETT turbos work well with a lot more boost, not to mention the turbine wheels are almost always larger. Good Stuff.

Has to do with engine displacement and total airflow produced by the engine. You'll know if you're running into a restriction if your airflow tapers off well short of the compressor's potential based on the map. If your airflow is tapering off a few lb/min short of the map's peak but comes back after going to a larger housing you'll know you had a turbine housing restriction.

In a case like this, going to a larger housing almost always gains horsepower but it can come at the expense of some torque numbers depending on how much lag it adds. You're picking up peak airflow, but if you add too much lag it can move you too far away from that magic number of 5250rpms on the dyno charts where torque and horsepower are the same. If the turbo is way lazy you'll see like 700hp/400 tq, where a system that is working in good balance will be like 550hp/500tq.

Hmm... my original question was about the inlet of T3 vs. T4, not the housing size. Does a bigger inlet has the same effect of a larger turbine housing, is that what you're saying? Because there are similar sizes, such as Garrett T3 A/R .82 (which I use) and B/W T4 A/R .88, which is what I am looking to upgrade to.

Let me see if I got this right, so the fact of the T4 inlet will provide less restriction just as if it were a larger housing? The housing itself is not that much larger .82 vs .88, but the larger inlet should bring additional lag, but with better "breathing" top end to compensate. Does that sound right?

I guess my main question is I'm trying to separate the Inlet size VS. A/R Size and what difference do they make it for performance, but perhaps they are the same? I know it's kinda stupid but I look at that T3 opening and think of it as too small when you're looking to make high horsepower & airflow coming at that inlet.

As for "Lazy" turbo, I honestly prefer them that way, less torque means less harm to the drivetrain which always seem to be what gives up first, so if the torque in smaller numbers but comes up high, that's great IMO.
 
Justin, I just have a quick noobish question. I have a 14b I just now finished boost leak testing. If I plug the outlet of the compressor housing and pressurize just the housing with my tester attached to the inlet, I can hear bubbling at the end of the oil drain at the pan. This is with only a few psi... If I was running 15 to 20 psi previously, have I been blowing oil out of the bearing and potentially ruining this turbo? It doesn't smoke, and still boosts pretty fast and hard, but not quite as hard as when I first started running it a couple months ago. I only tested it today because I put a supra ic in and one of the lower pipes was whistling on boost... I am wondering if I should immediately remove the turbo, put my old t25 back on, and order a rebuild kit asap? Or if I leave it in place until I can get the kit (week, maybe 2) am I doing more damage than a rebuild kit would fix?

I have it stripped down and the radiator out right now, so based on what you say, I'll do it immediately. Thanks.
 
Hmm... my original question was about the inlet of T3 vs. T4, not the housing size. Does a bigger inlet has the same effect of a larger turbine housing, is that what you're saying? Because there are similar sizes, such as Garrett T3 A/R .82 (which I use) and B/W T4 A/R .88, which is what I am looking to upgrade to.

Let me see if I got this right, so the fact of the T4 inlet will provide less restriction just as if it were a larger housing? The housing itself is not that much larger .82 vs .88, but the larger inlet should bring additional lag, but with better "breathing" top end to compensate. Does that sound right?

I guess my main question is I'm trying to separate the Inlet size VS. A/R Size and what difference do they make it for performance, but perhaps they are the same? I know it's kinda stupid but I look at that T3 opening and think of it as too small when you're looking to make high horsepower & airflow coming at that inlet.
If it were possible to buy two identical a/r housings, one T3 and one T4, and run them back-to-back...the T4 will still be laggier because of physical size of the flange and entrance of the housing even though the nozzle area of the housing (at the turbine wheel) will be nearly the same spec.

Bullseye actually made a few .55 a/r DSM housings that fit our o2 housing flange but had a T4 inlet; you can see how much larger the inlet is than the DSM bolt-on flange we're used to seeing:

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Total turbine flow and spool is a delicate balance of flange size, housing a/r, and turbine wheel spec. Compare turbine flow of the HX35 and HX40 both in Bullseye .55 housings...the HX35 stops around 52-54lb/min while the HX40 is a full 12+lb/min more just because of the larger turbine wheel.

Justin, I just have a quick noobish question. I have a 14b I just now finished boost leak testing. If I plug the outlet of the compressor housing and pressurize just the housing with my tester attached to the inlet, I can hear bubbling at the end of the oil drain at the pan. This is with only a few psi... If I was running 15 to 20 psi previously, have I been blowing oil out of the bearing and potentially ruining this turbo? It doesn't smoke, and still boosts pretty fast and hard, but not quite as hard as when I first started running it a couple months ago. I only tested it today because I put a supra ic in and one of the lower pipes was whistling on boost... I am wondering if I should immediately remove the turbo, put my old t25 back on, and order a rebuild kit asap? Or if I leave it in place until I can get the kit (week, maybe 2) am I doing more damage than a rebuild kit would fix?

I have it stripped down and the radiator out right now, so based on what you say, I'll do it immediately. Thanks.
I'd run it until you can rebuild it. It's not uncommon for higher-mileage 14B's to have sealing issues, especially if you're feeding unrestricted from the filter housing.
 
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Nevermind. I answered my own question. I popped it open and can see the seal on MHI compressor side isn't designed to be directly pressurized like that. This is the first MHI I've owned and its a little different than my last. I'm still going to rebuild it though, so I know what I'm working with.
 
whats the max boost you can run an fp green ?? is 35 psi too much ??
Study the map and see for yourself.

Pr = (14.7 + Boost) / 14.7, so plot 3.38 on the left of the map:

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Notice at that boost level, you're almost off the map. It may move air, but it's going to be very, very hot air that your intercooler and engine are not going to like. The map shows this compressor's sweet-spot to be around 23-25psi.
 
Study the map and see for yourself.

Pr = (14.7 + Boost) / 14.7, so plot 3.38 on the left of the map:

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Notice at that boost level, you're almost off the map. It may move air, but it's going to be very, very hot air that your intercooler and engine are not going to like. The map shows this compressor's sweet-spot to be around 23-25psi.
im boosting 30 on E85 i was concerned if i squeeze NO2 the boost will creap a bit
 
I was recently rebuilding my TDO6 MHI 20G and came across this on the compressor wheel. Any explanation as to why the wheel is like this? There is no visual scoring on the compressor housing and everything else looks good. The marks appear to be exactly the same on each fin also. I have a slight understanding of turbo clipping, but I was under the impression this was done on the exhaust wheel and not the intake side and I would think should be smoother than what I have. Any insight would be great. Thanks.

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I was recently rebuilding my TDO6 MHI 20G and came across this on the compressor wheel. Any explanation as to why the wheel is like this? There is no visual scoring on the compressor housing and everything else looks good. The marks appear to be exactly the same on each fin also.
Thrust wear caused the wheel to rub the cover at some point. If you have ANY in/out play, damage like this is possible. The wheel-to-cover clearance for thrust wear is less than .015" in most cases, so you don't have much tolerance before wheel damage occurs. This is why excessive in/out play is the worst type to have.

You do not have a clipped wheel- you have a damaged wheel.
 
Thanks for the explanation. Would you happen to know if Gpopshop sells just the compressor wheel off the top of your head? That is if you deal with them, as this is who I ordered the rebuild kit from and was happy with their shipping time, parts quality, and cost seemed fair. I'm going to take an educated guess and say I need a new wheel being it's damaged and more then likely will eat any new parts if it is reassembled from being out of balance? Just trying to further educate my self on turbos. Thank you again.
 
You can buy a new compressor from G-Pop, and they'll most likely want the rest of the rotating assembly to do the balance work as well.

You may be fine running it as-is....just sucks that you weren't able to catch this at the time of the rebuild so you wouldn't have to disassemble it again.
 
I may try and run it but keep an eye out to make sure it doesn't develop any play until I can locate a spare turbo, then disassemble the 20g again (practice makes perfect) and call G-pop up and see what they need from me. If you don't mind any suggestions on what else to watch for if I try and run the turbo other then shaft play? On a side note your turbo rebuild write up was very helpful.
 
I may try and run it but keep an eye out to make sure it doesn't develop any play until I can locate a spare turbo, then disassemble the 20g again (practice makes perfect) and call G-pop up and see what they need from me. If you don't mind any suggestions on what else to watch for if I try and run the turbo other then shaft play? On a side note your turbo rebuild write up was very helpful.

If you're going to run it i would at least take some sand paper and get rid of nay o the metla that' rubbed off partially that may be able to come loose and get to the engines combustio chambers and do harm. won't hurt balanace nay more than the wear from housing contact already has
 
If you're going to run it i would at least take some sand paper and get rid of nay o the metla that' rubbed off partially that may be able to come loose and get to the engines combustio chambers and do harm. won't hurt balanace nay more than the wear from housing contact already has

Will do. I have no idea how long the car had the 20g on it in the current condidtion but not to long ago I had pulled the head and there didn't appear to be any out of place nicks or marks on the piston tops, aside from where the valves had kissed them :ohdamn:, but best to prepare for the future and smooth the edges for the hopefully short time the turbo is on before replacing the wheel.
 
SkyGrowsCold.. If you could see the 57 trim i ran on for over a year and the shape it's comp wheel was in you'd feel great about your turbo,and i made 438hp in the shape it was in..matter of fact i'm going to get you a pic of it now) This was from 100k + miles of abuse, the bearings NEVER went bad or even showed signs of wear btu one winter i hit a snow bank sliding out of control during a bad storm and lost the low mounted filter and since this was about the time of my disability starting i never looked or thought abut the filter being taken off but the turbo had a tube sucking up road salt/sand into the turbo for a few weeks before i causght it (thank god i put a new engine in that next year but the old one was stil good on compression some how LOL)

Anyway, the wear from the contact is only incresing the blade to housing clearanc which although important, isn't absolutely cruicial (you loose more from a ported housing or what some people calll an "anti-surge" housing)

I've seen custom turbos built many times as i was being trained in it back in 2001'ish (god what a long time ago LOL) and although we would machine and smooth 7-12 angles into the comp housin to match the wheel there was a good deal of "wiggle room" from what i saw at majestic turbo (although you want only .020-.030 at max unless other conditions call for more)

so run it, enjoy it, fix it when ya can..but the sooner the better

Anyway..here's the wheel that from a 49+ lb/min turbo made 438hp at 30-31psi on my setup (i've since replaced it with a DBB PTE6776RS

im boosting 30 on E85 i was concerned if i squeeze NO2 the boost will creap a bit

well, n20 (nitrouse) will cause creep.. it spooled my 57 trim like it was a t25 on a 2.3 liter, but it also would over boost a bit too so i had to set the n20 to turn off a few psi earlier when using it to spool... OR when using it on a full gear pull i set the wastegate to open several psi lower (set it at 26 and with n20 it wuld run 29-30) or set at 30 it would spike my gauge to the peg (only 30psi gauge ihave)

but the real answer to it lies in the size of your wastegate (bigger is better for n20 ) the size of the exhaust wheel and housing )again bigger = better to avoid creep/spike) and where thewastegate leaks air from (mine pulls from one runner only) having it at the collector or on the actual turbine housing it's self would be much more effective from what i've seen, tuned, and played with in DSM 's withnirouse oxide
 

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I must say Mr. Turboglenn after seeing that photo I feel MUCH better about the condition of my wheel. Very confidence inspiring right there.
 
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