Got ya! I figured it was for a good reason. {thumbup}

Huh?:crap:

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.

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.

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!

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...

That came out pretty nice man. Nice work.

Yeah accepted, 03whitegsr! Specific location is far from ideal for the 1 & 4 WG flange, as was aptly pointed out by CO_VR4.

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.

im looking forward to hearing how the vacuum test went with the downpipe.. if its a big difference from the intake (turbo source vacuum) then i will tap my can into the downpipe. :)

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.:beer:

Oh, and I don't have boost creep{thumbup}

Sweet setup man. I'm surprised you picked up spool with that large hot side, but I suppose the short mani helped. I can't wait to see the final results.

In all honesty I was also surprised. Knowing that timing and fuel tuning will only make spool better I am happy with the results. The pic below is the .63 a/r T3 OS vs. 1.06 a/r T4 TS untuned. Also, keep in mind this is the RevHard Cast Manifold vs. Short Runner Tubular manifold.

As you can see the larger T4 TS outspools the old setup. :beer::beer::beer:
Keep in mind this is stock motor, stock cams, stock intake, and stock tb.

http://www.eng.fsu.edu/~jthagard/EVO...Twinscroll.jpg

I guess that I missed it, but could you tell us what size Tial WG's you are using? And also, are you still on the stock DV?