Twin Scroll; Making all Existing Turbo Kits Obsolete?
Well if it has the SAME topend as AMS and better mid range, they just might. Trouble is the AMS evo is geared at 5000+RPM's so the turbo is spooled bu then and I don't see an advantage of a twin scroll there.
Evolving Member
Joined: Nov 2006
Posts: 116
Likes: 0
From: JHB
I often quote Abraham Lincon to those seeking advice and to my customers - "you can not please all of the people all of the time" Point is decide what you want from the car before moding it!
Speaking from a turbo kit perspective only (ignoring all else for simlicity of discusson), what makes for a very a good drag /large track car will not work equaly well for a gymkhana/timeattack chasing cones on a tight circuit. Decide what your application is and follow that to the max, instead of wating the car to be able to do "everything" under the sun. In the abscence of more significant displacement to cover low end torque, there is little one can do to plug all gaps.
I have considered both AMS and Full Race TS designs in practice and both have strong points and improvement areas, (admitedly or not - just my obesrvation as a R&D designer of exhaust) but it's mighty unfair to compare the two products with one application/test. Rather see it as variety to choose from.
Anyway....good thread........bordering on applied-engeneering talk which im sure has lost a few readers along the way! LOL
A
Speaking from a turbo kit perspective only (ignoring all else for simlicity of discusson), what makes for a very a good drag /large track car will not work equaly well for a gymkhana/timeattack chasing cones on a tight circuit. Decide what your application is and follow that to the max, instead of wating the car to be able to do "everything" under the sun. In the abscence of more significant displacement to cover low end torque, there is little one can do to plug all gaps.
I have considered both AMS and Full Race TS designs in practice and both have strong points and improvement areas, (admitedly or not - just my obesrvation as a R&D designer of exhaust) but it's mighty unfair to compare the two products with one application/test. Rather see it as variety to choose from.
Anyway....good thread........bordering on applied-engeneering talk which im sure has lost a few readers along the way! LOL
A
I am glad that at least somebody understands torque curve v gearing. I just wish you wouldnt insist that this only benefits the drag racer.
If people want to spend their time and money chasing better spool so they have a higher peak TQ number to brag about or get that sledgehammer feeling for half a second when they hit the gas, thats fine... I just hope they arent too upset when they get smoked in the 1/4, out accelerated coming out of a corner and down the straightaway, or blown off the highway by the guy that spent his time and money increasing upper RPM TQ.
If people want to spend their time and money chasing better spool so they have a higher peak TQ number to brag about or get that sledgehammer feeling for half a second when they hit the gas, thats fine... I just hope they arent too upset when they get smoked in the 1/4, out accelerated coming out of a corner and down the straightaway, or blown off the highway by the guy that spent his time and money increasing upper RPM TQ.
I explained it very poorly...when running a twin scroll properly imagine you divide the motor into two...as you have essentially split the exhaust housing into two.
Now each half works seperately from the other as to its effect and pressure build on the turbine wheel as one side effectively has a larger A/R than the other.
Now to control the exhaust pressure as best you can, you dont want to bleed pressure from the lower pressure side (bigger half of the exhaust housing) as it is still not effecting reversion and is still trying to spool hit its target pressure.
The small side is now at its pressure and bleeding off...
when you run a regular ewg do you want to pull all the exhaust pressure from one runner? no...you want to evening pull the pressure to keep the pulse strengths as even as you can.
I really suck at explaining things but hope I helped clear it up some.
Now each half works seperately from the other as to its effect and pressure build on the turbine wheel as one side effectively has a larger A/R than the other.
Now to control the exhaust pressure as best you can, you dont want to bleed pressure from the lower pressure side (bigger half of the exhaust housing) as it is still not effecting reversion and is still trying to spool hit its target pressure.
The small side is now at its pressure and bleeding off...
when you run a regular ewg do you want to pull all the exhaust pressure from one runner? no...you want to evening pull the pressure to keep the pulse strengths as even as you can.
I really suck at explaining things but hope I helped clear it up some.
Evolving Member
Joined: Aug 2005
Posts: 282
Likes: 0
From: Mooresville, NC
If I have misunderstood what you mean by wg from the turbine, please elaborate a bit more...not sure if you mean the cast turbine housing or what...?...
Wow, a lot of different discussions going on.
I'll say that for a drag car, you don't want a twin scroll/divided housing. A divided housing is less efficient than a regular housing because it has more surface area, so more flow resistance. If you want max power, stick with the regular housing.
The benefits of a the divided housing are less reversion, and it obviously helps spool the turbo more quickly. In terms of reliability, you can get cracking at the divider, but as long as the crack doesn't make it to the outer surface of the housing, it's probably okay.
Internal wastegates are great for packaging reasons, not so good for power production. As mentioned before, the location of the port in the turbine housing can disrupt the flow going to the turbine wheel. Also, on really big turbos trying to run an internal gate, it might not flow enough exhaust out the wastegate leading to boost creep. Also, in high HP apps, you may end up wastegating as much flow as going through the turbine wheel, so an external gate can allow for better flow.
Like someone said before, running a divided housing is sorta like running two turbos, or two motors even. You want to have a wastegate for each side to better control the flow and keep things relatively 'even' between each side.
Anyways, enough rambling from me
I think most of what I said is right...
I'll say that for a drag car, you don't want a twin scroll/divided housing. A divided housing is less efficient than a regular housing because it has more surface area, so more flow resistance. If you want max power, stick with the regular housing.
The benefits of a the divided housing are less reversion, and it obviously helps spool the turbo more quickly. In terms of reliability, you can get cracking at the divider, but as long as the crack doesn't make it to the outer surface of the housing, it's probably okay.
Internal wastegates are great for packaging reasons, not so good for power production. As mentioned before, the location of the port in the turbine housing can disrupt the flow going to the turbine wheel. Also, on really big turbos trying to run an internal gate, it might not flow enough exhaust out the wastegate leading to boost creep. Also, in high HP apps, you may end up wastegating as much flow as going through the turbine wheel, so an external gate can allow for better flow.
Like someone said before, running a divided housing is sorta like running two turbos, or two motors even. You want to have a wastegate for each side to better control the flow and keep things relatively 'even' between each side.
Anyways, enough rambling from me
I think most of what I said is right...
no, you can wg from the turbine...internal wastegate...down side is the balance of controlling the flow without causing turbulence and killing velocity just prior to the exhaust hitting the turbine.
If I have misunderstood what you mean by wg from the turbine, please elaborate a bit more...not sure if you mean the cast turbine housing or what...?...
If I have misunderstood what you mean by wg from the turbine, please elaborate a bit more...not sure if you mean the cast turbine housing or what...?...
Evolving Member
Joined: Aug 2005
Posts: 282
Likes: 0
From: Mooresville, NC
ok, I had a feeling you were reffereing to that. I've seen pictures of setups where they use a normally external gate on the turbine housing but have never messed with them myself. I would imagine that it would cause turbulence but would also yield the most immediate boost pressure response for not overboosting when rapidly spooling that is.
i heard the setups were desireable for the boost pressure regulation reason... i thought that might be an appropriate application for this setup because it would save money on an extra gate and some complete *** welding and packaging.... amiwrong?
Evolving Member
Joined: Sep 2004
Posts: 381
Likes: 0
From: In my house
Question on TIAL housing
What AMS's thoughts on the new TIAL exhaust housings? Have you guys tried out their 35R housing yet? Any chance you can revise your existing header to fit the new TIAL 35R exhaust housing?
Any thoughts or input here would be helpful.
Thanks-Big Boost
Former Sponsor
Joined: Sep 2005
Posts: 984
Likes: 0
From: Chicagoland
At this point, the only car running a Tial housing is our drag car. I have not personally seen the smaller T3 housings but if they are anything like the T4 housing we have on the drag car, it would not be compatible with our Evo kit.
Our Evo kit uses a Precision Turbo housing that has a WG feed hole in it. We machine and hand port each housing to work with our O2 housing. Using a housing with no feed hole and no real way to put one in it would require us to take the feed for the WG off the collector and re-design the O2 housing. I dont foresee this as happening.
On the other hand.... Our 240sx KA turbo kit, we have the WG off the collector.... Maybe Chris wouldnt mind purchasing another turbo.. LOL
Our Evo kit uses a Precision Turbo housing that has a WG feed hole in it. We machine and hand port each housing to work with our O2 housing. Using a housing with no feed hole and no real way to put one in it would require us to take the feed for the WG off the collector and re-design the O2 housing. I dont foresee this as happening.
On the other hand.... Our 240sx KA turbo kit, we have the WG off the collector.... Maybe Chris wouldnt mind purchasing another turbo.. LOL
Evolving Member
Joined: Sep 2004
Posts: 381
Likes: 0
From: In my house
At this point, the only car running a Tial housing is our drag car. I have not personally seen the smaller T3 housings but if they are anything like the T4 housing we have on the drag car, it would not be compatible with our Evo kit.
Our Evo kit uses a Precision Turbo housing that has a WG feed hole in it. We machine and hand port each housing to work with our O2 housing. Using a housing with no feed hole and no real way to put one in it would require us to take the feed for the WG off the collector and re-design the O2 housing. I dont foresee this as happening.
On the other hand.... Our 240sx KA turbo kit, we have the WG off the collector.... Maybe Chris wouldnt mind purchasing another turbo.. LOL
Our Evo kit uses a Precision Turbo housing that has a WG feed hole in it. We machine and hand port each housing to work with our O2 housing. Using a housing with no feed hole and no real way to put one in it would require us to take the feed for the WG off the collector and re-design the O2 housing. I dont foresee this as happening.
On the other hand.... Our 240sx KA turbo kit, we have the WG off the collector.... Maybe Chris wouldnt mind purchasing another turbo.. LOL
Thanks for the quick response, as it is greatly appreciated.
So from this, can we assume you will not offer this as an option for your 35R kits due to the amount of re-design needed?
Former Sponsor
Joined: Sep 2005
Posts: 984
Likes: 0
From: Chicagoland
I am one of the mechanics at the shop. I do not make those type of decisions. Although its my opinion that a redesign of the turbo kit is unlikely.
Well if you guys (AMS or Buschur) do a TS 35r, please let us know. Not when it's done, but when you plan to have it for sale. I'm in the market to step up from a 3076 to a 35r. If something breaks as far as news on kits, I'd like to know ahead of time before I drop the cash.
