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if your wanting to run a divided setup to get the max pulse out of the system there really is no other route. i was gonna get a custom manifold made running twin tial 38mm but i ended up going an alternate route for now. maybe if i change my manifold again i can comment on the difference seen for spool and actual control vs. the single i have now. from what i was told though it is a bit harder to setup but you will have greater boost control. not that setting up a wastegate is hard but some people have problems.
my 2c
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To answer your original question -- I'm one person running dual WGs. I'm using a pair of TiAL 44s. I changed to a dual WG setup and changed from a 60-1 to an A-Spec GT35R both at the same time, so I don't know what the individual contibutions were. But my full boost RPM dropped from about 5200 RPM to 3100, and the time from pedal down to kick in the backside seems quicker, even at say 6K. Here are some pics.
I have run both setups with the same turbo and exhaust setup. With only one 44 I was no where near able to control boost. The new twin setup is a nightmare fabrication and installation wise, but its a dream on the car.. Super responsive and can control boost 100%.
Thanks for the picture. I don't plan on boosting the single above 15 psi as my power goals are minimal but I want to be maximizing response and boost control definitively.
Aaron,
Are there advantages to having the wastegates so close to the piping or could I put them further away. I ask because I wanted to continue to use my M2 CF Intake and SMIC but with the length of those runners doesn't look like it would be possible.
I have run both setups with the same turbo and exhaust setup. With only one 44 I was no where near able to control boost. The new twin setup is a nightmare fabrication and installation wise, but its a dream on the car.. Super responsive and can control boost 100%.
This is discouraging. I am switching from an FC HKS undivided log manifold with HKS 40mm wastegate to a Feed long runner divided manifold (very similar to the Greddy) with a Tial 44 and a T04R. I'm hoping the single 44 will be able to hold the 13psi spring pressure consistently and at higher boost I'll be able to crack the wastegate pretty close to the target pressure.
Single 44mm should be fine. Issues you may see depending on port work and placement will mean either it should hold fine or will hold within 3psi usually. Ie a 13lb spring will get you a solid 15-16lbs. Alcohol can change that though as well. We found single 44mm gates were much harder to get them to do what we wanted when running a methanol car.
If your wastegate doesn't creep at 13PSI, it won't at higher boost levels. Do you have any pics of your setup for the non-FD crew?
not at this point because I am waiting to get the motor together. I have a friend who is helping me (first motor I've ever done) and he has been very busy for the holidays so I've got a pile of parts just sitting in my garage.
Did different EBC's show different results when having difficulties with single WG's or Meth Sean??
I'm assuming your meaning one versus another showing better results? Not really, you can always tweak one more lets say to get what the other did with less tweaking. Things that can effect flow on the 44mm gates are how things are rerouted, 4" dp versus 3" dp etc. With meth I'm referring to methanol as the only fuel source.
This is discouraging. I am switching from an FC HKS undivided log manifold with HKS 40mm wastegate to a Feed long runner divided manifold (very similar to the Greddy) with a Tial 44 and a T04R. I'm hoping the single 44 will be able to hold the 13psi spring pressure consistently and at higher boost I'll be able to crack the wastegate pretty close to the target pressure.
I should have mentioned my motor has quite extensive port work, rerouted wastegate (w/ single as well) and full 4" exhaust, so creep may not be nearly as big of an issue on your setup.
besides total wastegate piston area there are enough other controlling factors re WG performance that you could end up w a small book. near the top of the list is manifold design.
IMO you need to think about twin scroll vs not twin scroll. Those are the pros and cons to single or twin gate. its the whole system, not the gates themselves
The above manfold, even though it has a divided flange is not a real twin scroll manifold
We're big believers in twin scroll, twin gates. But like already mentioned, wastegate position is incredibly important. The biggest complaint we hear from our customer service about their old setups is over boosting.
My first set up was an ebay Meagan racing style single gate manifold with a Tial 44. On E85 this manifold would creep to 20psi right after peak torque. Honestly shoot to 20psi is a better description. Switching to a Turblown twin gate manifold solved this issue and increased response quite a bit. I am sure there are really good single gate manifolds out there but if you are going to run a divided manifold and cost is not a issue, just do a twin gate manifold and be done with it. You can't go wrong.
Single 44 seems a bit small though. If i had to do it all again id probably ditch the twins and go a big, flow prioritised single with a divider butting into the piston if i decided to stay split pulse.
12-17-08, 02:15 AM
