144 replies to this topic

[lookforjoe]

Trying to decide what if anything I can do about the EBP I see with my current setup, since it's all coming apart for the bottom end rebuild.

Ben & I started having a conversation about back pressure & what to do about optimizing flow, given that any changes are always a compromise between spool time, etc.

What I'm specifically trying to determine is where the 'choke point' is with a given setup; I would assume that it is in the turbine wheel sizing & the chamber needed to support it - but maybe not. In looking for potential alternate turbos, there are plenty that use impellers no bigger than my TD05H (56mm Major) in smaller A/R housings, that are rated for over 500HP.

I am also unclear on "trim".

Maybe I'm confusing the A/R.

For reference, my setup is: Short runner Intake. Ported '03 head. Enem 9.6mm lift cams. LG Speed header, feeding the TD05H 10cm2 (.73 A/R) 56mm impeller, 59/76mm compressor (Garrett 60-1) Exhaust is all 3", with 1.25" WG dump pipe feeding back into main pipe

The problem I see (now that I can measure EBP @ the collector) is that the pressure rises to 1 bar over IBP under higher rpm (5600-8200) WOT conditions.

I'm trying to determine if:

1)a larger A/R housing would alleviate that

2)if the exhaust impeller just needs to be larger, say 65mm (TD06) Link to my impeller

3)or if porting the wastegate opening & dump chamber would help.

I already did this (ugly, perhaps, but functional):



Originally, the WG dump was closed off, and all the flow had to make a sharp turn into the main outlet. What I have has to be an improvement, but since I never measured EBP before I installed the header, I have no idea how bad it was before. I don't experience boost creep or drop off, so I don't see how modding the WG is really going to make any difference.

[GP850T]

i have no idea what would be the best option for you, but i have to say everytime you post a new thread i always have to take a moment and read the positive ideas and creative thinking you give to this community.

[boxpin]

GP850T, on 26 January 2012 - 02:20 PM, said:

i have no idea what would be the best option for you, but i have to say everytime you post a new thread i always have to take a moment and read the positive ideas and creative thinking you give to this community.

He is definitely a Performance Pioneer.

[BlackT5]

Have you thought of going to an extrnal gate? Do they even make housings for that turbo with no internal flapper?

[fischmama]

I agree with BlackT5, a different housing that does not have a flapper and utilizes an external wastegate but also shortens the distance from the wheel to the actual end of the housing. I think the sooner it goes to the 3" exhaust the better. On my turbo, there is only about 1/2" from the wheel to the exhaust flange.

For example...this housing you can see that the exhaust opens up even in the housing...and you see that with most turbos where the distance from the wheel to the flange is more than a one inch.

Edited by fischmama, 26 January 2012 - 04:00 PM.

[lookforjoe]

BlackT5, on 26 January 2012 - 03:23 PM, said:

Have you thought of going to an extrnal gate? Do they even make housings for that turbo with no internal flapper?

They do. The question still is, is that what is causing the excessive back pressure, or is it the impeller sizing?



vband adaptor

[lookforjoe]

fischmama, on 26 January 2012 - 03:33 PM, said:

I agree with BlackT5, a different housing that does not have a flapper and utilizes an external wastegate but also shortens the distance from the wheel to the actual end of the housing. I think the sooner it goes to the 3" exhaust the better. On my turbo, there is only about 1/2" from the wheel to the exhaust flange.

For example...this housing you can see that the exhaust opens up even in the housing...and you see that with most turbos where the distance from the wheel to the flange is more than a one inch.

Found this 25g (TD06H, .73 A/R)



Looks closer to what you are suggesting

Justus, where did you find that housing listed? I'd really prefer to stick with Int. WG

[550]

lookforjoe, on 26 January 2012 - 04:22 PM, said:

Justus, where did you find that housing listed? I'd really prefer to stick with Int. WG

Justus was telling me you didn't want to go external due to the manifold you already have made, and while I understand your concerns, I really think with the gials that you are trying to attain that external is the way to go now.

I can't recall the design of your current header, but I would figure a decent shop should be able to modify it accordingly to accommodate an EWG. Unless you are running a pulse paired setup in which you would need two gates. But I don't think your turbo is setup that way IIRC.

[dublin14]

Hussein I have a brandnew 63ar T3 external hot side if you are interested? If it is of any interest, LMK before I ship the HG.

[lookforjoe]

550, on 26 January 2012 - 04:28 PM, said:

Justus was telling me you didn't want to go external due to the manifold you already have made, and while I understand your concerns, I really think with the gials that you are trying to attain that external is the way to go now.

I can't recall the design of your current header, but I would figure a decent shop should be able to modify it accordingly to accommodate an EWG. Unless you are running a pulse paired setup in which you would need two gates. But I don't think your turbo is setup that way IIRC.

This is my header/dp



So the EWG could go right angle off the header, with the dump straight down into the dump I made...

..it would have to stay close to the header, not much room in the bay



It all comes back to whether or not this is the choke point - if a external WG would reduce EBP vs. IWG, then it makes sense, otherwise it's major reworking for unknown possible gain.

I wish someone else on here actually measured their EBP.

LG Speed did sell a EWG version of the header, so I could copy that layout, if it comes to that. Boost control then becomes another issue, as the Apexi AVC-R states that it's not intended for EWG...

dublin14, on 26 January 2012 - 04:38 PM, said:

Hussein I have a brandnew 63ar T3 external hot side if you are interested? If it is of any interest, LMK before I ship the HG.

Hi Gary

I think .63 is too small....

[fischmama]

lookforjoe, on 26 January 2012 - 04:54 PM, said:

It all comes back to whether or not this is the choke point - if a external WG would reduce EBP vs. IWG, then it makes sense, otherwise it's major reworking for unknown possible gain.

I wish someone else on here actually measured their EBP.

LG Speed did sell a EWG version of the header, so I could copy that layout, if it comes to that. Boost control then becomes another issue, as the Apexi AVC-R states that it's not intended for EWG...

I will run an external shortly with the APexi. I know they say its not recommended but from the research I've done online numerous people where running EWG with it.

The housing I posted was for a GT3076R, not for a TD05H.

EDIT: Shoot me a txt or PM with the setup needed to measure EBP and if its not too expensive I may get it so we have some data to compare.

Edited by fischmama, 26 January 2012 - 05:00 PM.

[JCviggen]

lookforjoe, on 26 January 2012 - 04:54 PM, said:

I think .63 is too small....

For a T3 housing it really isn't. Going larger than .63 does have benefits but you get a pretty substantial increase in lag. If you have a pretty sizeable turbine wheel (TD05/TD06) .63 is the sweet spot for a car you drive everyday imho.

You do see people (like the nissans 2.0 litres) with .82 and larger but more often than not they're on T25 housings which changes the math.

Edited by JCviggen, 26 January 2012 - 05:02 PM.

[lookforjoe]

Justus - sent you a PM

JCviggen, on 26 January 2012 - 05:01 PM, said:

For a T3 housing it really isn't. Going larger than .63 does have benefits but you get a pretty substantial increase in lag. If you have a pretty sizeable turbine wheel (TD05/TD06) .63 is the sweet spot for a car you drive everyday imho.

You do see people (like the nissans 2.0 litres) with .82 and larger but more often than not they're on T25 housings which changes the math.

OK. So this comes back to where the choke point is in the exhaust housing - from what you're saying, this will still flow OK in the 6600-8200 rpm range? I don't have a stock intake, so flow is not restricted up top - I need to make sure the exhaust housing is not going to be the problem.

As you say, everything is a tradeoff. My current housing is .73 A/R, but the turbine is only 56mm major, vs the typical wheel (58/67mm) that would be matched to my compressor... The spool now is perfect for DD, but top end EBP is nuts..

[EricF]

I think this all comes down to compressor-turbine wheel sizing. I would suggest either a mild clipping of your current turbine wheel, or trying out the TD06 wheel. You could always jump ship and get on the Garrett-based families of turbos so you will have more easily comparable data to others on our platform.

Another thing to keep in mind is that the more ignition timing advance you are running, the less combustion energy is going to end up going past the exhaust valves. I have always thought your setup 'seemed' to lack top end timing, but you have been very thorough in your attempts to accurately document your live timing so I cannot really say that as a serious suggestion

Another aspect of combustion energy getting past the exhaust valves is your exhaust cam opening angle, and perhaps retarding your exhaust cam timing a little will help keep the combustion event in the cylinder where it belongs. What cam timing are you running currently? I'm guessing the higher duration Enem cams will open sooner than stock, I wonder how much more so?

Just some food for thought and possibly trying to open up the scope of this discussion a little

[550]

Damnit... I had a whole reply ... and then it was wiped out. I'll try again. :-/

lookforjoe, on 26 January 2012 - 04:54 PM, said:

This is my header/dp



So the EWG could go right angle off the header, with the dump straight down into the dump I made...

..it would have to stay close to the header, not much room in the bay



It all comes back to whether or not this is the choke point - if a external WG would reduce EBP vs. IWG, then it makes sense, otherwise it's major reworking for unknown possible gain.

I wish someone else on here actually measured their EBP.

LG Speed did sell a EWG version of the header, so I could copy that layout, if it comes to that. Boost control then becomes another issue, as the Apexi AVC-R states that it's not intended for EWG...



Hi Gary

I think .63 is too small....

Yeah you really are running on SUPER limited room. Really the thing to have to figure is the design of the collector. And at what point the 5 dump into the 1 and you can then figure out where you can place the EWG.

I cant say for sure that your EBP will decrease either. But I know once you start looking for higher HP ranges most of the turbos don't even consider IWG setups anymore. I do admit though, your housing is pretty well divorced as way of the majority of IWG setups are. Do you measure EBP before the DUMP of the gate?

What are you HP goals now with the new engine plans and all?

JCviggen, on 26 January 2012 - 05:01 PM, said:

For a T3 housing it really isn't. Going larger than .63 does have benefits but you get a pretty substantial increase in lag. If you have a pretty sizeable turbine wheel (TD05/TD06) .63 is the sweet spot for a car you drive everyday imho.

You do see people (like the nissans 2.0 litres) with .82 and larger but more often than not they're on T25 housings which changes the math.

I know what you mean, but depending on HP goals, .63 is not going to cut it.


Isn't Ben running a .83 how is his lag, Hussein? ( IIRC I saw a video of you driving his car)

EricF, on 26 January 2012 - 05:14 PM, said:

I think this all comes down to compressor-turbine wheel sizing. I would suggest either a mild clipping of your current turbine wheel, or trying out the TD06 wheel. You could always jump ship and get on the Garrett-based families of turbos so you will have more easily comparable data to others on our platform.

Another thing to keep in mind is that the more ignition timing advance you are running, the less combustion energy is going to end up going past the exhaust valves. I have always thought your setup 'seemed' to lack top end timing, but you have been very thorough in your attempts to accurately document your live timing so I cannot really say that as a serious suggestion

Another aspect of combustion energy getting past the exhaust valves is your exhaust cam opening angle, and perhaps retarding your exhaust cam timing a little will help keep the combustion event in the cylinder where it belongs. What cam timing are you running currently? I'm guessing the higher duration Enem cams will open sooner than stock, I wonder how much more so?

Just some food for thought and possibly trying to open up the scope of this discussion a little

I thought he was running into knock event pulled timing for a while up top, and that may be why it's lower.

[lookforjoe]

550, on 26 January 2012 - 05:16 PM, said:

Damnit... I had a whole reply ... and then it was wiped out. I'll try again. :-/

Yeah you really are running on SUPER limited room. Really the thing to have to figure is the design of the collector. And at what point the 5 dump into the 1 and you can then figure out where you can place the EWG.

I cant say for sure that your EBP will decrease either. But I know once you start looking for higher HP ranges most of the turbos don't even consider IWG setups anymore. I do admit though, your housing is pretty well divorced as way of the majority of IWG setups are. Do you measure EBP before the DUMP of the gate?

What are you HP goals now with the new engine plans and all?

I know what you mean, but depending on HP goals, .63 is not going to cut it.

Isn't Ben running a .83 how is his lag, Hussein? ( IIRC I saw a video of you driving his car)

I thought he was running into knock event pulled timing for a while up top, and that may be why it's lower.

Still only looking for around 400AWHP (I say that now)
EBP is measured at the colllector.

The lag in Ben's was not bad, but definitely later than mine - pretty sure I see full boost by 4K

I added much more timing to the map, and lowered boost. Sustains pretty good timing as a result. Adding the header & Intake allowed me to raise boost again somewhat (about 20psi) before timing drops below 10ºBTDC. Pretty sure the high EBP is causing issues in that area, though - since I never seem to get the performance I should, given the hardware...

EricF, on 26 January 2012 - 05:14 PM, said:

I think this all comes down to compressor-turbine wheel sizing. I would suggest either a mild clipping of your current turbine wheel, or trying out the TD06 wheel. You could always jump ship and get on the Garrett-based families of turbos so you will have more easily comparable data to others on our platform.

Another aspect of combustion energy getting past the exhaust valves is your exhaust cam opening angle, and perhaps retarding your exhaust cam timing a little will help keep the combustion event in the cylinder where it belongs. What cam timing are you running currently? I'm guessing the higher duration Enem cams will open sooner than stock, I wonder how much more so?

Just some food for thought and possibly trying to open up the scope of this discussion a little

I'm wondering if I can get my housing machined to accept the TD06H wheel, it's about 10mm larger OD - don't know if that can be done, if there's enough meat in the housing, etc..

Cams are set by lift - @ true TDC: 1.5mm Int. opening, 1.2mm Exh before closing. Really have no way to translate that into degrees, I'm no mathmatician (sp?)

Enem strongly advised against changing the cam timing, he said get a bigger exhaust housing...

[Fishey]

This thread makes me LOL...

[JCviggen]

550, on 26 January 2012 - 05:16 PM, said:

I know what you mean, but depending on HP goals, .63 is not going to cut it.

Turbine wheel is a big factor really. I made a lot of power once on the stock engine with a .48 AR T3 stageIII wheel. Way, waaaay better at high revs than any similar AR volvo oem turbo. I then made what probably would count for 400 american whp with a .63 GT2871 and the 28 is a pretty small wheel. Get a GT35 with .63AR and you could do 500+ no sweat, at least the turbo could, the head and cams become more of an issue once you start going really high.
My personal (somewhat limited) experience a larger turbine wheel with a modest AR felt better to drive than a smaller wheel with a large AR.

[fischmama]

Fishey, on 26 January 2012 - 06:33 PM, said:

This thread makes me LOL...

Feel free to add to this... It seems that you have much more expirence with this than we do.

[550]

JCviggen, on 26 January 2012 - 06:38 PM, said:

Turbine wheel is a big factor really. I made a lot of power once on the stock engine with a .48 AR T3 stageIII wheel. Way, waaaay better at high revs than any similar AR volvo oem turbo. I then made what probably would count for 400 american whp with a .63 GT2871 and the 28 is a pretty small wheel. Get a GT35 with .63AR and you could do 500+ no sweat, at least the turbo could, the head and cams become more of an issue once you start going really high.
My personal (somewhat limited) experience a larger turbine wheel with a modest AR felt better to drive than a smaller wheel with a large AR.

Interesting.

I do agree that a smaller .AR would be better for daily driven, and .63 can already be called "laggy" by some.

I wonder if going with a larger exhaust housing, counteracts what limitations may be seen at the head.. may not be much though.