Twin-Charging and Compound Turbo Charging
10-05-2010, 03:26 AM
#142
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Hi all!
Sorry for not owning 350Z, but i found this topic one of the most useful in internet. As i have same problem with KKK29 turbocharger - spooling up at 4000-5000RPM on 2ltr engine. Initial idea was to follow boostlogic sequental turbo setup, but imo even huge wastegate between turbochargers will reduce top-end performance. I'am really agree with madmac that the positive difference between intake and exhaust pressure will give lots of benefits - lower backpressure and EGT, higher VE and excellent purge of combustion chamber during valve overlapping.
Question to madmac - as i understood SC in your setup always revving till 8000RPM (no electromuff), so rev ratio for SC and crank is 2 or lower?
Sorry for not owning 350Z, but i found this topic one of the most useful in internet. As i have same problem with KKK29 turbocharger - spooling up at 4000-5000RPM on 2ltr engine. Initial idea was to follow boostlogic sequental turbo setup, but imo even huge wastegate between turbochargers will reduce top-end performance. I'am really agree with madmac that the positive difference between intake and exhaust pressure will give lots of benefits - lower backpressure and EGT, higher VE and excellent purge of combustion chamber during valve overlapping.
Question to madmac - as i understood SC in your setup always revving till 8000RPM (no electromuff), so rev ratio for SC and crank is 2 or lower?
10-18-2010, 01:44 PM
#143
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I recently just got my 350z. I want to purchase a good Supercharger/TT, but I don't know which would be right. I've seen videos on the HKS, Greddy, and the STS. Any additional info I should look at to know which is the perfect one for me?
10-18-2010, 03:45 PM
#144
I had a Greddy TT system, and it worked great. It does not use water-cooling, and relies on oil cooling alone. For street and 1/4 mi. use, I think it is a great kit. For road racing, water-cooled turbos seem to have some benefits. There are a lot of good water-cooled TT systems out there. JWT, APS, PE, and custom systems from Speed Force Racing and Sound Performance racing also look good. I have a GTM TT kit, and will post my results when I have my car back together, which hopefully will be within the next couple of months.
Do yourself a favor and do some research on the subject. Start here:
https://my350z.com/forum/forced-indu...for-noobs.html
10-19-2010, 07:22 AM
#145
Eliminate the SC.
Go two very small turbos from say a JWT kit or even smaller...instant boost but not enough to keep going.
DROP a bigazz huge turbo (REMOUNT) to take you home!
Problem solved.
I have been researching this for about 3 years, I had cardboard mock ups and everything. You can do this but you wont find HUGE hp out of the set up because the only way to get boost off the line is to go with a Stillen SC which still has a build up issue before full boost although I think its about 2800 RPMS... then you run into the root SC being restrictive as the huge twin turbos or single turbo can yeild more airflow than the SC can digest effectively.
450-500hp all day....good luck getting anything more, for the money and fab work, its not really worth the drama.
Go two very small turbos from say a JWT kit or even smaller...instant boost but not enough to keep going.
DROP a bigazz huge turbo (REMOUNT) to take you home!
Problem solved.
I have been researching this for about 3 years, I had cardboard mock ups and everything. You can do this but you wont find HUGE hp out of the set up because the only way to get boost off the line is to go with a Stillen SC which still has a build up issue before full boost although I think its about 2800 RPMS... then you run into the root SC being restrictive as the huge twin turbos or single turbo can yeild more airflow than the SC can digest effectively.
450-500hp all day....good luck getting anything more, for the money and fab work, its not really worth the drama.
10-19-2010, 07:23 AM
#146
Also the twin sc and twin turbo GTR uses HKS SCs they claim full factory boost at 1800 rpms
another thing you all are forgeting is that all boost is combined so all components work together and this is not a fair estimate of power vs boost levels.
another thing you all are forgeting is that all boost is combined so all components work together and this is not a fair estimate of power vs boost levels.
Last edited by 4SHIZZIL; 10-19-2010 at 07:25 AM.
10-19-2010, 08:01 AM
#147
This is pointless. If you want to have a true "twin charge" setup you must use a roots type blower. Using any type of centrifical blower, and you might as well use small turbos.
Roots is the only blower with INSTANT displacement/boost.
That GTR is for show only, and those superchargers are not helping much, if anything at all.
Roots is the only blower with INSTANT displacement/boost.
That GTR is for show only, and those superchargers are not helping much, if anything at all.
10-19-2010, 09:12 AM
#148
This is pointless. If you want to have a true "twin charge" setup you must use a roots type blower. Using any type of centrifical blower, and you might as well use small turbos.
Roots is the only blower with INSTANT displacement/boost.
That GTR is for show only, and those superchargers are not helping much, if anything at all.
Roots is the only blower with INSTANT displacement/boost.
That GTR is for show only, and those superchargers are not helping much, if anything at all.
The goal of this car was to make INSTANT boost, not huge HP (The GTR above), yes higher HP came with the results but the BOOST is instant. Its not true twin charge but its using two diff FI Set Ups, which is twin charging.
Straight from Japan on the Wangan, this "twin charged" Nissan Skyline GT-R by Power Enterprise is a representative of the highest automotive technology in the world using two forced induction systems working together as one in mechanical perfection. What is Wangan? See here. Typically, a car is either turbocharged or supercharged. It is very rare to see these two systems working together. The turbos feed the procharger style supercharger boosted air that is made from energy used out of the exhaust system. That extra force of air keeps the lag minimal as it forces air into the supercharger spline. This helps push the compressor in the direction of creating boost which in return eliminates turbo lag by providing extra air pressure during low RPM. Almost instantaneous boost can be achieved by using a twin charged forced induction system.
If I recall from the first article full OEM boost was had at 1800 rpms... then they went well above and beyond that point to drop down 700 wheel.
like I said
go really small turbos that can be nearly full boost at idle, like off the new BMW 335i (9psi at idle on my buddies auto) 18psi max, with freggin BMW warrantee.... then add yourself some huge Turbos or one huge on the rear or midmount section of the car.
Like I also stated. I have been doing research on this for about 3 years with various shops.
I almost did a Twin SC with GTM using the Rotrex aka HKS blowers.
pointless....I think not, your post maybe.
when twin charging....1 plus 1 is not 3.... 1 plus 1 is about 4.5...so the forced feed SCs go faster, along with everything else... you have to be sure not to bottleneck the intake side, in a TRADITIONAL twin charge situation would be had with a restrictive blower sitting ontop of the motor... unless you retrofit something bigger than a M90 to sit ontop. Maybe a Mustang Kenny Bell...and thats a maybe and good luck finding a hood that doesnt look 1970's to fit ontop of it.
Last edited by 4SHIZZIL; 10-19-2010 at 09:20 AM.
10-19-2010, 09:25 AM
#149
Also Open Deck Engines vs Closed Deck Engines also plays a part in this too!
SC and twin turbo mustang Cobra
One area that needs to be addressed in this test is the intake manifold. After running the HP twin-turbo kit on the supercharged combination, the blower was replaced with an intake manifold from an '01 (normally aspirated) Cobra. This is important, as the intake itself offered a performance gain over that employed by the supercharger. The factory '04 intake manifold used with the supercharger offered very short runners and a large open plenum. This design was chosen primarily for fitment, as packaging the blower, air-to-water intercooler, and intake manifold between the Four-Valve heads and under the factory hood clearance all but eliminated any chance of additional runner length. The short runners employed on the supercharger (and compound) combination actually reduced power production up through 6,000 rpm compared to the factory '01 NA Cobra intake. The runner length offered by the '01 intake was responsible for some of the additional power offered by the turbo-only combination compared to the compound and supercharged-only combos. Despite what you may have heard, runner length has a decided tuning effect on the power curve, even with the presence of boost. The additional runner length is no substitution for the instantaneous boost offered by the blower, but it certainly helped the turbo combination.
What this test boils down to is that when it comes to forced induction, the Roots-style blower offers plenty of low-speed boost response and torque production, but it's actually low man on the proverbial totem pole when it comes to power per pound of boost. Topping our power pole are the turbos, especially a system like the one employed from HP Performance. The turbos alone produced the highest peak power and torque numbers and even outpowered the compound system, despite a difference in boost of nearly 9 psi in favor of the compound system.
If the turbos are tops and the blowers are bottoms, where does this leave the compound system? By combining the less efficient Roots-style blower with the more efficient turbos, the compound system occupies the ever-popular middle ground. Just how close the compound system is to either side depends on how much boost is supplied by the blower and how much is supplied by the turbos. The slower the blower speed and the greater the turbo speed, the more the curves will resemble that of the turbos alone. Of course, the reverse is also true if we speed up the blower and slow down the turbos.
In the end, it all comes down to individual preference and how much emphasis you place on the cool factor of having a twin-charged motor.
full articel here!
http://www.musclemustangfastfords.co...bra/index.html
SC and twin turbo mustang Cobra
One area that needs to be addressed in this test is the intake manifold. After running the HP twin-turbo kit on the supercharged combination, the blower was replaced with an intake manifold from an '01 (normally aspirated) Cobra. This is important, as the intake itself offered a performance gain over that employed by the supercharger. The factory '04 intake manifold used with the supercharger offered very short runners and a large open plenum. This design was chosen primarily for fitment, as packaging the blower, air-to-water intercooler, and intake manifold between the Four-Valve heads and under the factory hood clearance all but eliminated any chance of additional runner length. The short runners employed on the supercharger (and compound) combination actually reduced power production up through 6,000 rpm compared to the factory '01 NA Cobra intake. The runner length offered by the '01 intake was responsible for some of the additional power offered by the turbo-only combination compared to the compound and supercharged-only combos. Despite what you may have heard, runner length has a decided tuning effect on the power curve, even with the presence of boost. The additional runner length is no substitution for the instantaneous boost offered by the blower, but it certainly helped the turbo combination.
What this test boils down to is that when it comes to forced induction, the Roots-style blower offers plenty of low-speed boost response and torque production, but it's actually low man on the proverbial totem pole when it comes to power per pound of boost. Topping our power pole are the turbos, especially a system like the one employed from HP Performance. The turbos alone produced the highest peak power and torque numbers and even outpowered the compound system, despite a difference in boost of nearly 9 psi in favor of the compound system.
If the turbos are tops and the blowers are bottoms, where does this leave the compound system? By combining the less efficient Roots-style blower with the more efficient turbos, the compound system occupies the ever-popular middle ground. Just how close the compound system is to either side depends on how much boost is supplied by the blower and how much is supplied by the turbos. The slower the blower speed and the greater the turbo speed, the more the curves will resemble that of the turbos alone. Of course, the reverse is also true if we speed up the blower and slow down the turbos.
In the end, it all comes down to individual preference and how much emphasis you place on the cool factor of having a twin-charged motor.
full articel here!
http://www.musclemustangfastfords.co...bra/index.html
10-19-2010, 09:30 AM
#150
wow,
please describe to us the kind of blowers top fuel dragsters use and how they are "actually low man on the proverbial totem pole when it comes to power per pound of boost"
and your last article just supports what BP said and why the GTR is a show car. YOu use roots blowers with turbos, not centrifugal type chargers which are just belt driven turbos..
please describe to us the kind of blowers top fuel dragsters use and how they are "actually low man on the proverbial totem pole when it comes to power per pound of boost"
and your last article just supports what BP said and why the GTR is a show car. YOu use roots blowers with turbos, not centrifugal type chargers which are just belt driven turbos..
Last edited by str8dum1; 10-19-2010 at 09:34 AM.
10-19-2010, 09:30 AM
#151
like I stated 1 plus 1 is not 2.
It's important to note that the boost pressure supplied by the turbos never varied by less than 0.5 psi, but the boost pressure from the blower dropped in both the supercharged and compound combinations. The result of adding 7 psi from the turbos to the already supercharged motor was a peak power reading of 625 hp and 651 lb-ft of torque. We'd certainly welcome any motor that produced 625 hp at just 7 psi from the turbos, but the reality is that this motor was making 625 wheel horsepower at roughly 20 psi (at the power peak). While 625 wheel horsepower is nothing to sneeze at, testing has shown that it shouldn't require 20 psi to achieve it on this '04 Cobra motor.
20 psi of SC boost 625 vs adding 7psi of turbo boost with 11 psi SC boost made the same results
It's important to note that the boost pressure supplied by the turbos never varied by less than 0.5 psi, but the boost pressure from the blower dropped in both the supercharged and compound combinations. The result of adding 7 psi from the turbos to the already supercharged motor was a peak power reading of 625 hp and 651 lb-ft of torque. We'd certainly welcome any motor that produced 625 hp at just 7 psi from the turbos, but the reality is that this motor was making 625 wheel horsepower at roughly 20 psi (at the power peak). While 625 wheel horsepower is nothing to sneeze at, testing has shown that it shouldn't require 20 psi to achieve it on this '04 Cobra motor.
20 psi of SC boost 625 vs adding 7psi of turbo boost with 11 psi SC boost made the same results
10-19-2010, 09:32 AM
#152
I have 3 years of research on this topic...you?
unlike most feggin claimed experts on here I dont just diss people's post. I ask quesitons. I am no expert but at the same time you cant tell me that GTR was POINTLESS and didnt make instant boost with centrifugal blowers.
It does, bottom line, his responce to my post was not cool and lacked the researched before he typed and hit the enter button.
I am ready and willing to admit my error if someone can find one.
unlike most feggin claimed experts on here I dont just diss people's post. I ask quesitons. I am no expert but at the same time you cant tell me that GTR was POINTLESS and didnt make instant boost with centrifugal blowers.
It does, bottom line, his responce to my post was not cool and lacked the researched before he typed and hit the enter button.
I am ready and willing to admit my error if someone can find one.
Last edited by 4SHIZZIL; 10-19-2010 at 09:39 AM.
10-19-2010, 10:18 AM
#153
I have 3 years of research on this topic...you?
unlike most feggin claimed experts on here I dont just diss people's post. I ask quesitons. I am no expert but at the same time you cant tell me that GTR was POINTLESS and didnt make instant boost with centrifugal blowers.
It does, bottom line, his responce to my post was not cool and lacked the researched before he typed and hit the enter button.
I am ready and willing to admit my error if someone can find one.
unlike most feggin claimed experts on here I dont just diss people's post. I ask quesitons. I am no expert but at the same time you cant tell me that GTR was POINTLESS and didnt make instant boost with centrifugal blowers.
It does, bottom line, his responce to my post was not cool and lacked the researched before he typed and hit the enter button.
I am ready and willing to admit my error if someone can find one.
As I build turbo kits for the 350z now, I have also built S/C kits for other platforms. So I can say that I have hands on experience with both, turbos and superchargers.
On that note, I used an Eaton M62 roots type blower for the S/C kit I mentioned. When I say instant boost, I am talking under 1000rpm. There is no centrifugal supercharger out there that can do that.
Have a look at the boost curve of the HKS kit, the Procharger kit and Vortech. When do you see max boost? Also, have a look at the torque curve of a roots blower compared to a centrifugal...again, have a look at the torque.
Now compare that to a roots type blower.
Now, because the roots blower starts to move air instantly it is ideal for twin charging. It pre spools the turbo as it is sucking air through the compressor housing, while the exhaust gas is speeding up the turbine, hence speeding up the compressor wheel.
Last edited by Boosted Performance; 10-19-2010 at 10:21 AM.
10-19-2010, 11:09 AM
#155
As I build turbo kits for the 350z now, I have also built S/C kits for other platforms. So I can say that I have hands on experience with both, turbos and superchargers.
On that note, I used an Eaton M62 roots type blower for the S/C kit I mentioned. When I say instant boost, I am talking under 1000rpm. There is no centrifugal supercharger out there that can do that.
Have a look at the boost curve of the HKS kit, the Procharger kit and Vortech. When do you see max boost? Also, have a look at the torque curve of a roots blower compared to a centrifugal...again, have a look at the torque.
Now compare that to a roots type blower.
Now, because the roots blower starts to move air instantly it is ideal for twin charging. It pre spools the turbo as it is sucking air through the compressor housing, while the exhaust gas is speeding up the turbine, hence speeding up the compressor wheel.
On that note, I used an Eaton M62 roots type blower for the S/C kit I mentioned. When I say instant boost, I am talking under 1000rpm. There is no centrifugal supercharger out there that can do that.
Have a look at the boost curve of the HKS kit, the Procharger kit and Vortech. When do you see max boost? Also, have a look at the torque curve of a roots blower compared to a centrifugal...again, have a look at the torque.
Now compare that to a roots type blower.
Now, because the roots blower starts to move air instantly it is ideal for twin charging. It pre spools the turbo as it is sucking air through the compressor housing, while the exhaust gas is speeding up the turbine, hence speeding up the compressor wheel.
I am in 100% agreement, however when combined with the twin turbos on the GTR the OEM GTR boost level was achieved at 1800 RPM.
thats all I am saying...
My solution that I have been working on included a smaller version of the M93 (basically the stillen type or M90) due to cost and avalibility... and twin, single or rear turbo.
I agree the roots style is more instant than a centrifugul...I just didnt want the OP to rule out the centrifugal because when you combine the two...you get 4.5ish. lol
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The blower doesnt have to suck air in because it being pushed, the turbos dont have as much resistence because they are being pulled by the SC (somewhat at idle) together, even with a centrifugal the boost should come on faster than any single FI application alone... as proof with that GTR twin turbo, twin SC set up.
I personally would run the Turbo through an IC before the SC, then back through a secondary IC...might be over kill but looking at this you are blower VERY hot gas into the SC. I guess with a huge IC you can cut down inlet temps, but I see damage to the blowers over time with this set up.
Last edited by 4SHIZZIL; 10-19-2010 at 11:19 AM.
10-19-2010, 11:28 AM
#156
And for the record before all the drama kings and queens way in. I think that the BP turbo kit is very impressive. Its about time someone did it right. I hope this isnt offensive, but its right up there with Powerlabs as far as price and HP/boost level.
I think I may do a twincharged set up one day on my stock block becaus as I see it thats all the HP I can get out of COTS products. I dont have the energy to make something one off anymore.
I think I may do a twincharged set up one day on my stock block becaus as I see it thats all the HP I can get out of COTS products. I dont have the energy to make something one off anymore.
10-20-2010, 04:47 PM
#157
This link gives an overview of how the variable geometry works:
http://porsche911-hq.com/porsche-mis...ned-and-video/
With variable vane geometry, the vanes have a high incident angle with respect to the exhaust gas flow at low rpms, thereby allowing the turbos to spool quickly, and provide significant boost in the low rpm range. As the rpms increase, reversion would normally be an issue due to increased back pressure as the exhaust gas volume increases. With variable geometry, however, the vanes open up as the rpms increase. This keeps the exhaust back pressure in check to minimize the effects of reversion, which allows the engine to breath at high rpms. In short, the variable vane geometry allows the turbos to operate like small turbos in the low rpm range, and operate like large turbos in the high rpm range.
A compound turbo system seeks to accomplish the same result, but variable vane geometry seems to be a cleaner and more compact way of achieving this. I have not researched the patents that Porche holds and/or has licenced for the variable vane geometry technology, but assuming that the technology is adequately protected, I would not expect the technology to become common place until such patents expire.
10-20-2010, 05:40 PM
#158
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Not to get off topic but the late 80s RX-7 turbos had this type of turbo (some sort of expanding vane technology). Hence the name Turbo II. I had one back in the day but it was prolly more to give the rotary engine some torque. Just to throw in my 2 cents on this topic. I think it has been established that a supercharger after a turbo may be restrictive. How about bypassing some of the boost off the turbos around the supercharger right into the manifold?
10-20-2010, 07:26 PM
#159
If anything, I can envision a SC creating a small time delay in a sharp increase of boost from the turbo(s), but the time delay should be minimal, especially if using a SC that is relatively close to the intake runners.
If having the SC after a turbo is an issue, that would seem to be a good solution.
Last edited by ttg35fort; 10-20-2010 at 07:38 PM.
10-21-2010, 03:18 AM
#160
^ just like a radiator or intercooler or a simple fan at home. the designs has a max CFM or flow rate it can handle. Thats why BP used the bigger M93 over the M90 due to the amount of volume the blower can physically digest.
if you add the turbo before the SC you do not get the compound interest affect. The SC is stuck having to pull its air vs being pushed. They do work together in the SC after turbo, dont get me wrong, but if you can combine them SC after turbo and keep the inlet temps down that would be a more effecient option of using the two.
if you add the turbo before the SC you do not get the compound interest affect. The SC is stuck having to pull its air vs being pushed. They do work together in the SC after turbo, dont get me wrong, but if you can combine them SC after turbo and keep the inlet temps down that would be a more effecient option of using the two.