crxracer2

Is a 46mm V band precision wastegate too big for my set up? Its a pretty much basic b20/vtec turbo. B20 bottom end, b16 head. Both top and bottom are stock. And ive got a t3/t4 turbo. Im thinking of running around 10 psi max. And later building the b18 bottom end i have in storage. I see the 46mm precision turbo gets lots of good reviews, and is cheaper then the 44mm tial and turbosmart 45mm. But are they too big for me to daily at psi?

TheShodan

iTrader: (14)

Not necessarily. 2mm here or there means very little in the grand scheme of things. It depends upon the cfm (lbs/min) of your "t3/t4. Give a specific size of the turbocharger, and we may be able to provide more info.

There is a reason why those units are less expensive than the TiAL or Turbosmart.

1HGEJ2

iTrader: (1)

Bigger wg have less boost creep. And less stress/problems. Smaller wg on the wrong places produce Incredible boost creep.

TheShodan

iTrader: (14)

Very true, to a degree. But specifics need to be given before that premise can have "weight" to it.
it's not that simple

crxracer2

Thanks guys. Ill get specs here soon just woke up. BTW, TheShodan, i believe i recognize your name from an article i used before switching to this turbo last year. Did you do a huge write up on greddy turbos and how to get more power out of them in the past?

crxracer2

T3/t4 garrett turbo, A/R .60 and hotside .63

TheShodan

iTrader: (14)

Anything more than this? Inducer /Exducer wheels? .......even a photo?

I've done countless write-ups. Which one were you specially looking at?

For this, 46mm isn't too large, but even a 38mm won't "creep" when applied properly

crxracer2

Are you reffering to a photo without the housing on? I was trying to get the car up and running again due to the fact i dont have a running car right now. I was avoiding opening it up, but i noticed it was burning a little oil on the turbine side. Not sure if i wanna rebuild it yet or invest in a nicer turbo yet. (My daily driver snapped a timing belt, with only 10,000 on the belt. :/ b20 with the 84.5mm type R pistons. Might have bent some valves). Ill try to find the write up, it might have even just been you dropping some good knowledge. It was talking about the elbow restricting the greddy td05 turbo, and using a bigger custom downpipe. Ill look for it.

crxracer2

TheShodan

iTrader: (14)

Yes. that's me, alright. Even a photo of the housings on w/ a plate (S/N number if possible) or even just a shot of it from the compressor inlet. The oil in the turbine may NOT necessarily mean it needs a rebuild. you have to narrow that down to a diagnosis, because there are several ways oil leaks can occur in the turbine housing/CHRA area.

crxracer2

I admire your knowledge. I do have a shot of the plate, i took some today. Let me see if i got a good picture.(it was pretty sunny today.)

crxracer2

SN#
Comp.
Comp. Housing
Turbine.
Turbine housing.

JRCivic1

Shodan, I wasn't aware that a waste gate could be "too big". Can you offer a practical explanation that would illustrate this phenomenon ???

TheShodan

iTrader: (14)

Well, in the drag racing world, the idea of something being "too large" really doesn't come into the common thought process. That's like a drag racer saying .. "there's no such thing as too much power..". There really is such a thing, but the threshold is rather high in that type of motorsport before that logic comes into play. Because most drag racers are using larger turbochargers in which a wastegate larger than most street applications are used, (which thereby equates to the wastegate venting more than enough excess exhaust gases than the driver requires), I can see where the idea of a wastegate being too large doesn't really come into mind.

I'll give this a try. I may not be successful in explaining it without making a video, (which I don't have time for), so ,please ask subsequent questions if needed.. ok? Also, you'll see some internal edits for clarity of explanation, and the ability to post additional content as I get this together. so, please be patient for me.

Sizing a wastegate really has more to do with which size turbocharger is associated with its wastegate valve size, in addition to the boost pressure used in relation to the size of the turbocharger for the driver. The purpose (as usual) is most important, we have to really remember what a wastage is being used for; to control excess exhaust gas energy in order to control the amount of converted airflow that is entering into the combustion chamber.. Not just "boost".

But, before I attempt to create a simpler correlation, I'll first establish a few definitions that I'll be using to establish the general relationship associated between a turbocharger and its wastegate

"Low boost" - Generally a boost pressure range of about 1Bar (14.7psi or 2.05PR) or lower

"High boost" - Generally a boost pressure range of about 1Bar (14.7psi or 2.05PR) or above

"Large Wastegate" - A wastegate with an opening valve size of about 44mm -68mm or above, designed to vent larger amounts of exhaust gasses. (This includes the TiAL 44mm, TiAL MV-R, PTE 46mm, Turbonetics 45mm, and Turbosmart Hypergate 45mm and larger)

"Small Wastegate" - A wastegate with an opening valve size of about 28mm - 41mm or below, designed to vent lower amounts of exhaust gasses relative to the turbocharger's ability to process. (This includes the TiAL 38mm, TiAL MV-S (which is actually 40mm) , PTE 38mm, Turbonetics 35mm (actually 40mm), the Turbosmart UItragate 38mm, Turbosmart Compgate 40mm, and all internal gates based upon the size of the turbine housing's opening)

"Large Turbocharger" - Turbochargers that are considered to be mid-framed to large-framed turbochargers that have airflow rates over 60lbs/min or larger. (This includes GTX3576R, GT3582R and larger)

"Small Turbocharger" - Turbochargers that are considered to be OEM-sized or smaller-framed to mid-framed turbochargers that have airflow rates of 60lbs/min or lower (This includes anything GTX3071R and smaller to the OEM-sized applications.)

Now, When it comes to the ability of a wastegate to control excess turbine exhaust energy, (as a practical matter in normal use and main forms of motorsport), you want to size the wastegate so that it is large enough to vent excess pressure in-between shifts properly to where you don't experience boost "creep" or boost "spikes" (I'm describing this without getting into the realm of solenoids or other boost control methodology... That's for another discussion), and at the same time retain high-boost recovery in-between shifts with the valve closed.

If you go too large of a valve with a relatively smaller turbocharger, you now have actually created a condition in which possibly excess boost pressure as been vented, slowing boost-recovery time in-between shifts and the turbo's behaviour becomes undesirable. Go too small, and you experience boost creep and spikes relative to ignition timing, and you can easily effect the solenoids ability to regulate valve motion when it needs it most.

Full drag-racing cars utilizing full-throttle shifting, 2-step controls (one type of anti-lag ignition timing control) and other devices need not worry about going too large, mainly because of the purpose of the car; high acceleration, larger mid-framed or large-framed turbocharger, with little need to vent excess exhaust turbine energy. Cars in other motorsports that utilize more partial-throttle control and have more requirements to assist with maintaining traction in possible more than 2 wheels, with higher torque expectations, have more to worry about than the drag racer.

For the drag racer, in some cases, they are running so much boost pressure with such a large turbo, the car will have an additional wastegate to act as a blow off valve, because no Blow-off valve spring can handle the high boost pressure numbers that the car may be experiencing.. (i.e. 3.7BAR or more)

So, in the end, here's the correlation:

Large Turbo + Low Boost Pressure ---> Uses large Wastegate Valve or two smaller valves
Large Turbo + High Boost Pressure ---> Uses large Wastegate
Small Turbo + Low Boost pressure ---> Smaller wastegate valve
Small Turbo + High Boost Pressure ---> Slightly larger wastegate valve (Ventilating to the atmosphere vs. recirculation of the dumptube helps with boost-recovery , also.)

So, basically, wastegates are sized for the power output of the engine and turbocharger used. For the OP's example in which they're using a 52lbs/min turbo such as a T3/T04E 60 "trim" using a 58mm inducer/76mm exducer & 64.73mm Inducer exhaust wheel, 46mm shouldn't be to bad at all, as long as you don't keep boost pressure too low (i.e. less than about 10-14psi) otherwise, you may experience a bit more lag between shifts. This phenomenon can be offset with a good manual or electronic boost controller.

Now, here's where going cheap hurts. If the coil spring in the wastegate is compromised, or the exhaust gas pressure contaminates the metal in the valve itself (usually from an ethanol or ethyl-alcohol based fuel.. If the valve's metal isn't treated at the molecular level with an anti-corrosive). If that valve is compromised, it could seize shut, causing an immediate spike and cause destruction to the engine the turbo or both in a split second. No boost control safety or rev-limiter will prohibit the spike. Higher end valves (that yes, usually cost more) have higher tolerances and better valve treatments than the cheapos. That means they last longer and have less of a chance of destroying your engine. Is a PTE 46mm considered "cheap?".... Well, some say yes, while others say no. I don't know if I can answer that with any impartiality. So, I don't, and stick with TiAL, Turbosmart, or Garrett for my wastegates.

TheShodan

iTrader: (14)

BTW, that turbine looks as though it may be improperly draining due to location /orientation of the drain line, and/or the hardware used to connect to it. If the oil sealing rings are compromised, it can be rebuilt, but not without incurring more cost than you may be ready for. I'd have to see the turbocharger hooked up to the car to determine anything else.



Like I said, you have a T3/T04E 60 "Trim" turbocharger using Garrett 466159-5004S.

Compressor :
58.16mm inducer
74.9 Exducer
CHRA
Oil-cooled only #4457
Turbine
Inducer/Wheel Diameter - 65mm
Exducer -56.6mm



About 430whp realistically at over 22psi (1.49Bar)

crxracer2

Thats a huge amount of good info. I got confused on a couple parts. I think you meant to write small on a couple parts that were meant to be large. So would it be better to go with a 44mm Tial wastegate? Go-autoworks sells it a little cheaper then the precision 46mm. I do have a stock block b20 bottom end so i think i'd be running max 8 to 10 PSI max to be on the safe side. Thats until i build the b18 block i have in my storage and crank the boost for that.

TheShodan

iTrader: (14)

Nope. I typed exactly what I intended to type. But, yes, I'd go with the TiAL MV-R (44mm) if you're using the same flange.

crxracer2

Did i end up asking.if a 8lbs. Spring would be good on that Tial MV-R. A (.06 bar spring)?

TheShodan

iTrader: (14)

Depends upon what boost pressure you're ultimately going to. If over 22psi, no. If under that, sure...

crxracer2

Im gonna be low boost, due to having a fulling stock block b20. Then ill upgrade spring rates when i finish building my b18 block i have in the storage.

TheShodan

iTrader: (14)

You'll need to change turbochargers by then, anyway.