Short Runner T4 TS GTX3076R Experiment
Nov 3, 2011, 07:54 PM
#32
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You will have higher back pressure on the one cylinder that is NOT being relieved by the waste gate (because of its placement....) and lower back pressure on the cylinder that IS being relieved by the entire waste gate. I don't know exactly how much that will affect your AFRs for those two cylinders but one will be rich, and the other lean. ....With the geometry of your recirculation setup....expect....a lot of turbulence across the exhaust flow out of the turbine when the waste gates are open.... if those effects could be measured...
Last edited by sparky; Nov 3, 2011 at 07:56 PM.
Nov 3, 2011, 08:06 PM
#33
x2 I don't understand how the air flow mixture can be altered on the exhaust side. It is hard to believe the affect will be as drastic on a twin scroll set up with two separate gates compared to if he did one runner on a single scroll. This is all hypothetical but three out of four runners might be all it needs to control boost properly. I for one am very interested to see the results.
Nov 3, 2011, 08:48 PM
#34
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With respect to the AFR's being impacted by the exhaust side, I think that he's talking about differing levels of exhaust back pressure for each individual cylinder, due to each cylinder's exhaust valve not being equidistant with respect to WG placement on the manifold. Different levels of exhaust gas reversion and different exhaust scavenging efficiencies in each of the four individual cylinders and the resulting differing levels of exhaust gas contamination of the intake mixture on each individual cylinder's intake stroke. Toxicfab had already touched on this earlier in post number 15. No one can estimate with any level of certainty how much of an issue this will be though in actuality.
Last edited by sparky; Nov 3, 2011 at 09:12 PM.
Nov 3, 2011, 08:54 PM
#35
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I agree with you on this one Revmoto. I don't think that as a practical matter his WG placement will be an issue. He is pretty much overgated in the way that the relatively large dual gates are setup for a 30R in this particular application on a 2 Liter(It is a 2L. mill isn't it?). I am figuring this setup will spool up really fast and control boost rock steady. Nice job OP!
Last edited by sparky; Nov 3, 2011 at 09:07 PM.
Nov 3, 2011, 09:10 PM
#36
I'm with CO_VR4 on the wastegate placement being less then ideal and it potentially having a negative impact.
However, I think that's the point really. He's built a manifold around the idea of minimizing runner length while still having a decent collector. This should keep lots of energy available to the turbine wheel. There will be reversion problems, but get rid of the overlap in the cams and turn up the boost...
However, I think that's the point really. He's built a manifold around the idea of minimizing runner length while still having a decent collector. This should keep lots of energy available to the turbine wheel. There will be reversion problems, but get rid of the overlap in the cams and turn up the boost...
Nov 3, 2011, 09:29 PM
#38
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Yeah accepted, 03whitegsr! Specific location is far from ideal for the 1 & 4 WG flange, as was aptly pointed out by CO_VR4.
Last edited by sparky; Nov 3, 2011 at 10:06 PM.
Nov 3, 2011, 09:54 PM
#39
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I more or less understand what CO_VR4 is talking about with respect to potential AFR differences in the cylinders due to differing levels of exhaust backpressure as a result of uneven WG placement on the manifold. I can grasp this.
I look forward to CO_VR4 expanding on his view that the merge tube locations might have a negative impact on turbine outlet flow. This, at least from my perspective, might be a bit more difficult to verify and place into quantifiable terms.
I look forward to CO_VR4 expanding on his view that the merge tube locations might have a negative impact on turbine outlet flow. This, at least from my perspective, might be a bit more difficult to verify and place into quantifiable terms.
Last edited by sparky; Nov 3, 2011 at 10:04 PM.
Nov 4, 2011, 09:09 PM
#41
WOW, I am impressed with the initial results. I did not change anything on the tune and just ran the setup as it was with old tune running the 0.63 a/r t3 housing. So what where the results?
~400rpm increase in spool with the new 1.06 a/r T4 twinscroll.
3.5krpm
+21hp/+29ft/lbs/
4krpm
+56hp/+65ft/lbs
5krpm
+50hp/+51ft/lbs
6krpm
+36hp/+31ft/lbs
7krpm
+25hp/+13ft/lbs
I need to give Tom a chance to work his magic before posting any graphs, but with no change in tune(timing) the car makes 24.4psi at ~4000rpm and previously made 24.5psi at ~4400rpm.
~400rpm increase in spool with the new 1.06 a/r T4 twinscroll.
3.5krpm
+21hp/+29ft/lbs/
4krpm
+56hp/+65ft/lbs
5krpm
+50hp/+51ft/lbs
6krpm
+36hp/+31ft/lbs
7krpm
+25hp/+13ft/lbs
I need to give Tom a chance to work his magic before posting any graphs, but with no change in tune(timing) the car makes 24.4psi at ~4000rpm and previously made 24.5psi at ~4400rpm.
Nov 5, 2011, 05:56 AM
#44
As you can see the larger T4 TS outspools the old setup.
Keep in mind this is stock motor, stock cams, stock intake, and stock tb.
Last edited by 240Z TwinTurbo; Nov 5, 2011 at 05:59 AM.