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BoxxerSix BoxxerSix is offline
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Join Date: Jun 2006
Location: Ballston Spa, NY
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Originally Posted by mb911 View Post
interested in your suggestions I like seeing thoughts explained. I recently developed a collector for the 993 heat exchangers and it was so confined that it makes it hard to get 2"X2 into a t3 flange but It worked out well

Sure thing, not a problem Just remember you opened the floods gates to my long winded posts here, hahahaha!

I have seen these pictures of the setups you make and by just visualization the quality is far better than that of OBX. Just note that none of this in here is directed against the quality or function of your product as all, just straight line facts for reference for those interested here in this thread.

For reference TS = twin scroll in this post

Is this a true TS setup add-on you offer for the 993 HE's, or just a 2x2 merge collection into a standard single volute(scroll) t3 flange?

I only ask because a t3 TS flange is a bit different in how you end up welding the primaries to it(they don't actually merger before the flange). You can take a T3 single volute flange and add a divider plate to make a "t3 divided flange", but the openings are still going to be physically different in some aspects and create overhangs on the turbine housing flange itself that face into the oncoming flow. If you purchase a true t3 TS and overlay it to a standard t3 flange(non ported) you'll see the slight difference in port configuration + the divider.

Non-ported true t3 TS flange and "merge" setup(supra manifold)

Merge collectors into a standard t3 single volute flange

You can see the difference in port and primary spacing leading into the laser cut t3 TS flange there, and the volute inlet on the t3 TS turbine housing matches that exactly so any sloppy hand cut/overly ported TS flange, or standard T3 flange converted to TS use, is going to cause flow issues into the volutes on the turbine housing itself.

The whole point of using a TS setup is to isolate exhaust pulses and concentrate their energy to the turbine wheel. Any small disruption or induced reversion before that happens and you just start to negate the benefits of the setup.

This is why I'm such an advocate of using the proper flanges on TS system. If you're going for response on a mid size motor(under 3.5L) you're probably using the T3 flanged setup. Running 2" primaries into that TS flange on tight radii can be difficult as you've seen but if you can't do it to a true TS flange without porting the openings then you're better of ramping down to a smaller primary size.(see notation below) Yes that will limit total flow a small bit but the benefits of using the proper flange far outweigh it and remember, you're using a T3 flange so top end flow isn't your concern. Now if flow and maximum power are what you're after then you're better off stepping up the a T4 flanged housing as that will facilitate easier fitment of larger primaries into the volute opening on the flange without distortion or porting. GT3582R's are offered in a T4 TS option from a few places(ATP for example) in a 1.06 a/r sizing.

Note.....if you're REALLY good with porting and have a good steady hand, or have a CNC, you can perform a taper port of the t3TS flange on the leading side(primary side) with a step recess that will allow you use a slightly larger primary than normal and still have a good flow transition. You don't want to go nuts with this, no more than a 10% taper per inch of port length.

I love TS systems for what they're worth. It's just my thought and opinion that if you're going to build and use this type of system that you'll want to maximize all it's benefits and minimize the draw backs of it as well(flow restrictions up top vs single volute)

Another little trick for you while we are on this subject of your 993HE pipes here...... looking at your picture there with the wastegate pipes leading off the primaries T-ing into the primaries at 90 degree works, but can create some turbulence and flow/choke issue at high flow rates. Now I haven't done what you've done here for the 993's and I don't know the space constraints that you've been working with but what I would do(or at least attempt) is to merge the wastegate lead pipes into the primaries at a minimum of a 45 degree into the flow. In fab terms, instead of a 90 bend I'd use a full tight radius 180 and begin the flow transition into the wastegate lead pipes right at the HE flanges, wrapping back around an terminating in the same fashion as you now have them. This promotes better flow into the gates at higher flow rates(higher RPMS). It doesn't make a big difference to most until you start messing with EBC electronic boost ramps and then the benefit comes out. It allows you to ramp up the crack pressure rate on the EBC much higher, without boost spikes and boost creep from showing it's ugly head. As with the exahust flowing itno the merge collectors, you want the flow transition going into the wastegates to be as smooth as possibly

That last topic is discussed in detail in Corky Bells Maximum Boost book as well if you need more info on it Nothing you MUST do. would certainly add a bit more cost and complexity to the fabrication of the system. Maybe offer it as an option to your setups though in the future. Most systems for cars don't do this though just because if space and fitment issues.

Post is getting long, I'll stop here for now
Adam Hennessy
Old 02-21-2009, 06:07 AM
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