roots vs twin screw
06-24-2009, 07:50 PM
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roots vs twin screw Twin screw fans always have tons of fancy graphs and efficiency stats that "prove" they are better than roots type blowers. However, roots seems to be the primary choice for oem blowers. Is one really that much different/better than the other?
06-24-2009, 08:33 PM
#3
That's a simple one - Roots are cheaper to product and the OEM's like cheap and reliable. The complex curves of the male and female twinscrew rotors make it much more expensive to produce. But when a Cobra wants a hefty upgrade, they switch to a KB or Whipple twinscrew, usually bigger, but for the efficiency as well. Twinscrews actually are compressors where Roots (including the newest Eaton TVS) is only an air mover. That gives the twinscrew a leg up on the efficiency curve which translates to less heat at a given boost level.
Jim
Jim
06-24-2009, 09:36 PM
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Manufacturers go with the HEaton because it's FAR cheaper to mass produce. You would add 3-5k to the price if you added a twin screw. Most manufacturers shy away from that kind of hike for fear of losing customers.
Last edited by Z28usmc; 06-25-2009 at 11:49 AM.
06-24-2009, 10:37 PM
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How about this for proof: Take an 03 Cobra. It comes with a roots style Eaton M112 from the factory. If you put full boltons, port the SC and tune it within an anch of it's life you MIGHT get to 550 RWHP. However- if you bolt on a twin screw KB or Whipple you ROUTINELY see RWHP #'s 600-800 depending on supporting mods and size of blower. The proff really is in the numbers- you can believe them or not believe them- your choice.
Manufacturers go with the HEaton because it's FAR cheaper to mass produce. You would add 3-5k to the price if you added a twin screw. Most manufacturers shy away from that kind of hike for fear of losing customers.
Manufacturers go with the HEaton because it's FAR cheaper to mass produce. You would add 3-5k to the price if you added a twin screw. Most manufacturers shy away from that kind of hike for fear of losing customers.
06-24-2009, 11:10 PM
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The lingenfelter zr1 is making 740 wheel with the stock TVS. This matches or exceeds larger whipple blowers on ford gts and gt500s. That's why I am questioning twin screw superiority. In addition, I don't see why ford would have cared about an extra $3-5k when building their ultimate super car back before the tvs generation was available.
I'm not trying to be a smart *** here- why are you so skeptical of the numbers? I know you aren't a Ford guy but they have the most recent experience with bigger blowers from the manufacturer as well as a crazy aftermarket with them. Ask some of these other Ford guys if you don't believe me or KB/Whipple. They can SHOW you the difference between the dyno numbers.
06-25-2009, 12:07 AM
#7
How about this for proof: Take an 03 Cobra. It comes with a roots style Eaton M112 from the factory. If you put full boltons, port the SC and tune it within an anch of it's life you MIGHT get to 550 RWHP. However- if you bolt on a twin screw KB or Whipple you ROUTINELY see RWHP #'s 600-800 depending on supporting mods and size of blower. The proff really is in the numbers- you can believe them or not believe them- your choice.
Manufacturers go with the HEaton because it's FAR cheaper to mass produce. You would add 3-5k to the price if you added a twin screw. Most manufacturers shy away from that kind of hike for fear of losing customers.
Manufacturers go with the HEaton because it's FAR cheaper to mass produce. You would add 3-5k to the price if you added a twin screw. Most manufacturers shy away from that kind of hike for fear of losing customers.
If you insist on a PD system, TVS is the way to go. Period!
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06-25-2009, 01:16 AM
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Z28usmc your also forgetting, a big reason why the kbs and whipples make more power than a ported stock eaton has to do with the fact that they are also much bigger. Your making an unfair comparison
06-25-2009, 11:32 AM
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I would suggest that that math doesn't add up. Do a comparo between the numbers PERCENTAGE wise between the HEaton and the Twin screws. Twin screws still make more HP statistically speaking.
I see you have done some homework, however show me a KB powered LSx car making 800rwhp. The Magnuson MP/Eaton TVS product is making the #'s on the LSx engines. I have spent some significant time tuning and logging a 2.8l KB 402 and am not impressed with the #'s all. If efficiency was so high, then tell me why the IAT's are so high. This is even after fixing KB's engineering failure of an IAT setup. With a Magnuson MP112 and spinning the crap out of it, IAT's were 160 degrees at the end of the 1/4 mile. With the KB, they're 250 plus. If you're wondering about my tuning, don't bother. He took it to LMR for a retune because I sent him home to fix some issues and he wanted "the best" They did their best and that car isn't making over 600rwhp. Mustangs may like them, but LSx engines don't. Forget about reading. This is real world. I've seen it many times now and the crappy #'s keep coming from those not too embarrassed to post them.
If you insist on a PD system, TVS is the way to go. Period!
If you insist on a PD system, TVS is the way to go. Period!
I will say this though. From what I know regardless of application twin screws flow better, run cooler and are more efficient than roots style blowers. Does that make roots style blowers bad? Of course not- but from all the empirical evidence I've seen first hand and read about Twin screws are the way to go for positive displacement blowers. That's not to say YOUR experience is wrong- maybe you got a bad blower- it happens. I don't know because I wasn't there. But I've personally seen KB's and Whipples make MUCH better numbers percentage wise over the roots blower.
Here is another example. Take the GT500 SuperSnake. There are 3 versions. 1 Heaton, 1 TVS, 1 KB- They each stepped up in HP in that order. Why the results aren't the same with LSX's I couldn't tell you.
Last edited by Z28usmc; 06-25-2009 at 11:51 AM.
06-25-2009, 11:56 AM
#10
The lingenfelter zr1 is making 740 wheel with the stock TVS. This matches or exceeds larger whipple blowers on ford gts and gt500s. That's why I am questioning twin screw superiority. In addition, I don't see why ford would have cared about an extra $3-5k when building their ultimate super car back before the tvs generation was available.
06-25-2009, 12:58 PM
#11
That's 680HP at the crank after their tune and pulley.
This is the latest Lingenfelter ZR1 Chassis Dyno that they have posted (stock vs. pullied/injectors/tuned):
Not quite as impressive as you make it out to be...
And let's not forget that the ZR1 makes it damn hard to convert to any other system without adding a 3" cowl hood and a total engine reconfig. They integrated that TVS so deep into the manifold that it will be a while before you see blower changes.
Look at the Ford GT - the highest power package out there now has a Whipple 3.4HPR strapped to the top, but that engine compartment has plenty of room. Part of the LSx problem is the engine setback and cowl issues that make some blowers very difficult to fit.
UPDATE: Just found this: "This Lingenfelter ZR1 has the latest version of our second level of supercharger upgrades and produces an impressive 739 RWHP & 720 RWTQ. The Lingenfelter supercharger upgrades included our pulley upgrade, air intake modifications, intercooler improvements and tuning."
Jim
This is the latest Lingenfelter ZR1 Chassis Dyno that they have posted (stock vs. pullied/injectors/tuned):
Not quite as impressive as you make it out to be...
And let's not forget that the ZR1 makes it damn hard to convert to any other system without adding a 3" cowl hood and a total engine reconfig. They integrated that TVS so deep into the manifold that it will be a while before you see blower changes.
Look at the Ford GT - the highest power package out there now has a Whipple 3.4HPR strapped to the top, but that engine compartment has plenty of room. Part of the LSx problem is the engine setback and cowl issues that make some blowers very difficult to fit.
UPDATE: Just found this: "This Lingenfelter ZR1 has the latest version of our second level of supercharger upgrades and produces an impressive 739 RWHP & 720 RWTQ. The Lingenfelter supercharger upgrades included our pulley upgrade, air intake modifications, intercooler improvements and tuning."
Jim
Last edited by DeltaT; 06-25-2009 at 01:09 PM.
06-25-2009, 01:32 PM
#12
I think the Kenne Bell works great on the LS engine. It does not care what its on top of for the most part. I tuned a Stock C5 Z06 a couple weeks ago with the 2.6l unit on it. Through stock manifolds it made over 530 to the tires with out even trying. I know a 112 would not do that with a 2.8" pulley on it. The temps were 110-120 at the start of the runs and 150 or so at the end. About the same as a 112 making 480 to the tires. It was making another 12-14hp per degree of timing I added at that point, I still quit at 18 for safety.
06-25-2009, 05:49 PM
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I see you have done some homework, however show me a KB powered LSx car making 800rwhp. The Magnuson MP/Eaton TVS product is making the #'s on the LSx engines. I have spent some significant time tuning and logging a 2.8l KB 402 and am not impressed with the #'s all. If efficiency was so high, then tell me why the IAT's are so high. This is even after fixing KB's engineering failure of an IAT setup. With a Magnuson MP112 and spinning the crap out of it, IAT's were 160 degrees at the end of the 1/4 mile. With the KB, they're 250 plus. If you're wondering about my tuning, don't bother. He took it to LMR for a retune because I sent him home to fix some issues and he wanted "the best" They did their best and that car isn't making over 600rwhp. Mustangs may like them, but LSx engines don't. Forget about reading. This is real world. I've seen it many times now and the crappy #'s keep coming from those not too embarrassed to post them.
If you insist on a PD system, TVS is the way to go. Period!
If you insist on a PD system, TVS is the way to go. Period!
The harder you spin a blower, the less effecient it'll be. Spin it within its effeciency range and temps will obviously stay in check, given the cooling system is working properly. I wouldn't pin this car's issues on the KB being an ineffecient blower - and I'm not much of a KB fan.
06-25-2009, 05:53 PM
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You are absolutely correct. The 2.8H that was run on the lightning and made 1200rwhp, is the EXACT same as the 2.8H run on the LSx
Couple other differences though. As other members know in this thread, yet they just feel necessary to keep the info back cause it doesnt make their claims sound near as bad. The inlet manifold SUCKS. On a good day, you get roughlt 1067cfm out of it. If the 2.8H flows over 1500cfm (it actually flows more than that), yet the inlet feeding it only flows 1000cfm, it doesnt take a rocket scientist to calculate how much air will be fed to the motor.
IAT's... Again, anyone worth their salt in tuning knows that IAT's are DIRECTLY related to airflow and air compression. If your anemic on air, then you try to compress it, your temps WILL go up. This will be a non issue within the next 3 weeks. Although the IAT's will always be higher than other forms of F/I, they will be more than manageable. The member with 250* IAT's... The poster must have forgotten that the member had his damned cooling system ran backwards.. I have personally installed more KB's on LS platforms than anyone in the country, and I can say from first hand experience, we have NEVER had IAT's that high. Even in 117* ambient temps.
We already have 2 new inlet manifolds. One is flowing 1550cfm, but it needs a large TB (around 110mm) The other one flows a tad less, but will allow for a 90mm.
Twin Screws in general are significantly more efficient than roots style blowers. The reason OEM's use roots is for 1 reason, and 1 reason only. Its 3 times cheaper to manufacturer a roots blower.
Also, there have been 800+rwhp KB LS vehicles for 3 years now. Its nothing new. But this is a debate that will continue until the new inlet is released. Until then, it is very difficult to make the power. But it has NOTHING to do with the blower itself.
Couple other differences though. As other members know in this thread, yet they just feel necessary to keep the info back cause it doesnt make their claims sound near as bad. The inlet manifold SUCKS. On a good day, you get roughlt 1067cfm out of it. If the 2.8H flows over 1500cfm (it actually flows more than that), yet the inlet feeding it only flows 1000cfm, it doesnt take a rocket scientist to calculate how much air will be fed to the motor.
IAT's... Again, anyone worth their salt in tuning knows that IAT's are DIRECTLY related to airflow and air compression. If your anemic on air, then you try to compress it, your temps WILL go up. This will be a non issue within the next 3 weeks. Although the IAT's will always be higher than other forms of F/I, they will be more than manageable. The member with 250* IAT's... The poster must have forgotten that the member had his damned cooling system ran backwards.. I have personally installed more KB's on LS platforms than anyone in the country, and I can say from first hand experience, we have NEVER had IAT's that high. Even in 117* ambient temps.
We already have 2 new inlet manifolds. One is flowing 1550cfm, but it needs a large TB (around 110mm) The other one flows a tad less, but will allow for a 90mm.
Twin Screws in general are significantly more efficient than roots style blowers. The reason OEM's use roots is for 1 reason, and 1 reason only. Its 3 times cheaper to manufacturer a roots blower.
Also, there have been 800+rwhp KB LS vehicles for 3 years now. Its nothing new. But this is a debate that will continue until the new inlet is released. Until then, it is very difficult to make the power. But it has NOTHING to do with the blower itself.
06-26-2009, 12:56 AM
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Whipple is a twin screw. Both Whipple and Kenne Bell got their start working for Lysholm over in Scandinavia- Finland if I'm not mistaken. Lysholm still makes twin screw superchargers- hell, they developed the technology. Up until the mid to late 90's Lysholm still supplied many internal componants to both Whipple and KB.
06-26-2009, 03:22 PM
#20
Hey Andrew... I FINALLY got a few prototype inlets..
When will your motor be up and running? I want to send you one to test. We did back to back testing on our SF 1020 today, and the results are freaking unreal. I cant wait to have a couple guys run these.. Im dying to see what the excuses for not buying one will be then..
Also, what size is your TB so I can have the flange cut right. Do you want methanol bungs in it?
When will your motor be up and running? I want to send you one to test. We did back to back testing on our SF 1020 today, and the results are freaking unreal. I cant wait to have a couple guys run these.. Im dying to see what the excuses for not buying one will be then..
Also, what size is your TB so I can have the flange cut right. Do you want methanol bungs in it?