worth porting a 10.5 housing?
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OP: I used to think that by boring out the turbine bypass port, that is eliminating the center wall in the bypass port passage, I could improve flow out through the bypass port.
However, I learned here on EvoM that this wouldn't be a very good idea at all. Since the 16G turbo is a twinscroll design which divorces exhaust gas pulsations. By eliminating the divisory wall in the turbine housing's wastegate bypass port you would be defeating the twinscroll design concept by creating exhaust gas reversion from one side across into the other.
The most you can do to improve exhaust gas flow out though the turbine bypass port is to open up the entrances to the bypass port by easing the tight radius into the bypass port in the turbine inlet area of the housing. You can't really increase the diameter of the port at the wastegate puck because it is already pretty much optimized as cast and you would risk leakage because the flapper valve has a bit of horizontal play across the seat.
However, I learned here on EvoM that this wouldn't be a very good idea at all. Since the 16G turbo is a twinscroll design which divorces exhaust gas pulsations. By eliminating the divisory wall in the turbine housing's wastegate bypass port you would be defeating the twinscroll design concept by creating exhaust gas reversion from one side across into the other.
The most you can do to improve exhaust gas flow out though the turbine bypass port is to open up the entrances to the bypass port by easing the tight radius into the bypass port in the turbine inlet area of the housing. You can't really increase the diameter of the port at the wastegate puck because it is already pretty much optimized as cast and you would risk leakage because the flapper valve has a bit of horizontal play across the seat.
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Yeah, if the WG side as he calls it flows better, then it follows that turbine bypass flow should improve. Yes, the WG's sole job is to"reduce" turbine rotational velocity by bleeding off exhaust gases before they hit the turbine blades. The resultant reduction in shaft speed slows the compressor wheel thus reducing boost pressure.
So, he hasn't really reinvented the wheel. When the wastegate opens, it is supposed to "reduce boost", duh.
So, he hasn't really reinvented the wheel. When the wastegate opens, it is supposed to "reduce boost", duh.
so now the WG port flows a little easier (when ported) to correct the change so my boost levels are the same some ebc duty cycle would be lowered=job done but no gain yet.
now when at full chat and on the onset of creep the ebc (if you have set it like this) will be getting to full duty cycle to try to control your set boost which its now going past because the amount of exhaust gas cannot get out of the wastegate hole fast enough so its directed ever more to the wheel and voila "creep" thats where a better wastegate hole size would help maybe even cure creep. thats my opinion btw.
and thats why external gates don't have this problem and control boost excellently.
I switched over to a IX turbo just last week, i picked up another manifold for cheap so i gasket matched the manifold outlet to the turbo inlet and the outlet of the turbine to the ebay O2 housing. I don't have any raw numbers but this setup seems to spool much quicker than my 9.8 Evo VIII turbo did. That should tell you something right there. Granted i did add the O2 housing with the turbo so i'm sure that helped a bit but i think it's worth your time. I will be tunning on 30psi and E85 in 2 weeks so we'll see how she does.
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I switched over to a IX turbo just last week, i picked up another manifold for cheap so i gasket matched the manifold outlet to the turbo inlet and the outlet of the turbine to the ebay O2 housing. I don't have any raw numbers but this setup seems to spool much quicker than my 9.8 Evo VIII turbo did. That should tell you something right there. Granted i did add the O2 housing with the turbo so i'm sure that helped a bit but i think it's worth your time. I will be tunning on 30psi and E85 in 2 weeks so we'll see how she does.
I switched over to a IX turbo just last week, i picked up another manifold for cheap so i gasket matched the manifold outlet to the turbo inlet and the outlet of the turbine to the ebay O2 housing. I don't have any raw numbers but this setup seems to spool much quicker than my 9.8 Evo VIII turbo did. That should tell you something right there. Granted i did add the O2 housing with the turbo so i'm sure that helped a bit but i think it's worth your time. I will be tunning on 30psi and E85 in 2 weeks so we'll see how she does.
-E
No. Evoscan measure the IAT before the turbo (at the MAF). The important one is before the intake. There are ways to do it with the stock ECU but it is not straightforward. You need to add a GM IAT, tap the IC Piping before the intake and modify your ROM.
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ah right yes seem to remember now! is it usdm specific 8/9 what about jdm 9 they have this stock right?
^yes, it's boost & rpm plotted against time.
what doesnt make sense?
i just wanted to show the time delay of the e9 vs grn. + you get to see that the grn makes more power once boost comes up by the steeper slope of the rpm trace.
what doesnt make sense?
i just wanted to show the time delay of the e9 vs grn. + you get to see that the grn makes more power once boost comes up by the steeper slope of the rpm trace.
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I switched over to a IX turbo just last week, i picked up another manifold for cheap so i gasket matched the manifold outlet to the turbo inlet and the outlet of the turbine to the ebay O2 housing. I don't have any raw numbers but this setup seems to spool much quicker than my 9.8 Evo VIII turbo did. That should tell you something right there. Granted i did add the O2 housing with the turbo so i'm sure that helped a bit but i think it's worth your time. I will be tunning on 30psi and E85 in 2 weeks so we'll see how she does.
Also Sparky's comments are very much the case,it's better if you leave the wastegate port as it is,you can thinner the inner section in an effort to control boost creep better but you risk getting it cracked through time,especially if you over do it,but do not mess with enlarging the inner diameter of the w/g port itself,if you get what i mean, because as Sparky mentioned you are very much risking to make it leak due to it's horizontal play. My advice is do not touch the w/g port .
There is this guy on your MLR forum,that knows his stuff,he is greak I think, he was the guy who helped me out on converting my stock turbo to an externally wastegate one.
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You don't need to actually port the exhaust housing to match the O2 housing since it's an aftermaket one and it is bigger at it's entries than the stock housing's outlet,since the gasses are not hitting any sort of wall on their way out then there is no problem. But you do need to to match the exhaust manifold outlet to the turbine housing inlet,it helps spool quite a bit