Turbo vs Supercharger
#76
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I prefer a supercharger to a turbo.
I just dont like having to wait for power when I get on/off/on the throttle. I know the Turbo will almost always make more HP when setup in a comparable enviroment but thats not extremly important to me. I do think a good solution to this problem is adding water injection + N20 for a higher RPM window (3500-6500rpm). However I am sure that the turbo owners could also add N20 and see even better gains.
I just dont like having to wait for power when I get on/off/on the throttle. I know the Turbo will almost always make more HP when setup in a comparable enviroment but thats not extremly important to me. I do think a good solution to this problem is adding water injection + N20 for a higher RPM window (3500-6500rpm). However I am sure that the turbo owners could also add N20 and see even better gains.
#77
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Fishey,
I agree - us having 16V 944's also puts us in the category of wanting more low end power.
One point to this I don't think has been brought up yet is overall design simplicity. I know the turbo side argument will be a properly setup turbo should not have lag with today's turbo's, computers etc... problem is our cars are NOT turbo cars from Porsche. We do not have their team of engineers, decades of on track testing etc..... so from a simplistic point of view the SC will always win over a turbo just because it is 100x's easer for the average joe to install. The redesign of exhaust manifold alone puts a turbo setup way over the top vs a supercharger. The 944 is lucky to be able to borrow a 944 turbo header - the S and S2 don't have this luxury, neither does the 928.
I love John's design - it's beautiful motor (post that pic!!) but the complexity of that setup is far greater than the SC kits Tim and Andy offer. That is why a lot of people run superchargers over a turbo. I run with a F-body club at Road America - superchargers out number turbo's with this group at least 10 - 1. I'd be willing to bet simplicity was the #1 factor.
I agree - us having 16V 944's also puts us in the category of wanting more low end power.
One point to this I don't think has been brought up yet is overall design simplicity. I know the turbo side argument will be a properly setup turbo should not have lag with today's turbo's, computers etc... problem is our cars are NOT turbo cars from Porsche. We do not have their team of engineers, decades of on track testing etc..... so from a simplistic point of view the SC will always win over a turbo just because it is 100x's easer for the average joe to install. The redesign of exhaust manifold alone puts a turbo setup way over the top vs a supercharger. The 944 is lucky to be able to borrow a 944 turbo header - the S and S2 don't have this luxury, neither does the 928.
I love John's design - it's beautiful motor (post that pic!!) but the complexity of that setup is far greater than the SC kits Tim and Andy offer. That is why a lot of people run superchargers over a turbo. I run with a F-body club at Road America - superchargers out number turbo's with this group at least 10 - 1. I'd be willing to bet simplicity was the #1 factor.
#79
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Originally Posted by 944J
Like I said, I'm just learning here, but from the above data it seems like the absolute fastest cars use superchargers and the lower cost smaller cars use nitrous and turbo chargers. Why? Thats up to the experts out there. I only need 2,000 HP not 8,000, however ![Smilie](https://rennlist.com/forums/images/smilies/smile.gif)
![Smilie](https://rennlist.com/forums/images/smilies/smile.gif)
Top fuel cars use superchargers because turbos are illegal.
#80
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The cost to make a turbo not have lag is extreme and even so they still have lag.
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I've driven supercharged cars before and I like them as well as turbo'd cars. My plan is to someday get a 928S4 as well and put that new supercharger kit on it.
That way I'd have the best of both worlds!
Either way, you gotta admit, Forced Induction, turbo or Super, is a great way to make more power!
#81
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Originally Posted by Hacker-Pschorr
One point to this I don't think has been brought up yet is overall design simplicity. I know the turbo side argument will be a properly setup turbo should not have lag with today's turbo's, computers etc... problem is our cars are NOT turbo cars from Porsche. We do not have their team of engineers, decades of on track testing etc..... so from a simplistic point of view the SC will always win over a turbo just because it is 100x's easer for the average joe to install. The redesign of exhaust manifold alone puts a turbo setup way over the top vs a supercharger. The 944 is lucky to be able to borrow a 944 turbo header - the S and S2 don't have this luxury, neither does the 928.
#82
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Originally Posted by Fishey
The cost to make a turbo not have lag is extreme and even so they still have lag.
#83
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Originally Posted by Got Me a Porsha
But the boost is NOT constant...as the BOV (blow off valve) releases the boost until a predetermined decrease in engine vacuum dictates it should close.
#85
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Originally Posted by Geo
So tell me again how there is no lag in a supercharger?
You get *PARTIAL BOOST* instantly since the supercharger is belt driven, but you don't get *FULL BOOST* until redline. That's the nature of the beast.
With a turbo, you get *NO BOOST* instantly because it's waiting on exhaust gases, but you get *FULL BOOST* from 3000 RPM 'til redline. Again, nature of the beast.
Proper shifting will keep any car > 3000 rpm and in prime turbo territory, but that rpm range isn't where superchargers shine.
It's all about personal preference, driving style, and race type.
You may now return to your regularly scheduled cat fight.
#86
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Originally Posted by Geo
This is really funny. Lot's of kids running around today with better engineered turbo set-ups than a 951, especially when you consider the cross-over set-up and 20 year old technology. Exhaust manifolds are simple to make.
Care to list how many companies make turbo kist for Honda Civic's (I know this is the market your talking about)
Care to list how many companies make turbo kits for NA 944's?
Apple's to oranges and you know it.
Ever change the exhaust manifold on a 928? I have
Ever design a set of headers for a 928? I know people that have - simple would not be the word they use. Even John has been quoted time and time again about the "fun" he had getting a set of headers to fit with the turbo.
Anything can be easy to make. Midas can weld up some headers if I ask them to, will they be quality units like a factory turbo header? I doubt it.
There is no comparison, a SC intall is easier to install and design than a TT setup. Even more so when you throw the 928 into the ring.
#88
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Originally Posted by Rich Sandor
"easier" does not = "better"
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but I'm basing all of my comments on the 928 side of things. Tim Murphy and Quick Carl's setup is cost effective - solid as a rock - and easy to install. I'm saying that no way any turbo setup will ever equal the simplicity of Tim's SC kit (or Andy's, but I've never installed one of his so I cannot say).
"better" is relative, always will be, so not a good term to use anyway.
EDIT -
If it makes you happy, replace "easy" with "simple" in my last post. Im my opinion, making somthing more simple is always better if it does not sacrifice quality. Tim, Andy, and Carl's kits to just that.
The only known produced turbo "kit" was Calloway's for the 928 - ever see one? How about his 944 kit? How reliable were those? Tim has already sold 4 - 5 times as many SC kits as Calloway did. All running strong.
#89
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Originally Posted by Z
Yes, any car including a supercharged one will have some exhaust backpressure. The amount is nowhere near the same though. A supercharged car with an adequately sized exhaust will have very, very little backpressure. On the other hand, a turbocharged car will have substantial backpressure if it's making a good amount of boost. In his post above, nine-44 mentioned that he'd read on multiple occasions that the backpressure between the head and the hot inlet of the turbo shouldn't exceed more than 2-3 times the boost pressure in reguards to efficiency.
Originally Posted by Z
I know some of you have removed cats from cars and installed "offroad" or "test" pipes in their place, and noticed a performance improvement. That's with cats being responsible for causing a less than 1psi backpressure in the exhaust.
Originally Posted by Z
Anybody with a normally aspirated car want to restrict their exhaust to the point of where it has 24psi of backpressure at full power and tell us how the power felt compared to when it had almost no backpressure?
Originally Posted by Z
Exactly. It's defined by how much the supercharger or turbo increases the temperature of the incoming air during the course of compressing it. It does not take into account higher air temperatures that may very well be going into or being created in the turbo initially due to high underhood temperatures from close proximity to hot exhaust plumbing, confined engine compartments, or from close proximity to the hot exhaust side of the turbo.
Originally Posted by Z
The book it's from was published in 2002. The Porsche test data is obviously older
Originally Posted by Z
Even on the track, it's not necessarily a clear cut choice though. Did any of you see the Acura NSX with the centrifugal supercharger that was racing in the SpeedVision series? When I saw it race in the SpeedVision race up at Road America, I think it was the only supercharged car in the field. It came in I believe third place, ahead of a good number of turbocharged cars.
Originally Posted by Z
A good question to ask might be why are the majority of cars that Porsche has sold NOT turbocharged?
Originally Posted by Z
I don't know about the 944 cams, but at least the later 928 cams have zero overlap. There is never any point where the intake and exhaust valves would be open at the same time for positive manifold pressure to move the exhaust gasses out. That also means that none of that pressurized fresh air/fuel charge is being blown out past open exhaust valves. As has already been stated, the exhaust backpressure on a turbo will be significantly higher than the boost pressure in the intake. If both valves are open at the same time for very long at all, which way do you think that the gasses are going to want to flow?
Originally Posted by Z
There is no constant boost with a supercharger. During normal part throttle driving there's vacuum in the intake like with any other car.
#90
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Originally Posted by Hacker-Pschorr
Now I know your just trying to be difficult - plain and simple.
Care to list how many companies make turbo kist for Honda Civic's (I know this is the market your talking about)
Care to list how many companies make turbo kits for NA 944's?
Apple's to oranges and you know it.
Care to list how many companies make turbo kist for Honda Civic's (I know this is the market your talking about)
Care to list how many companies make turbo kits for NA 944's?
Apple's to oranges and you know it.
There is no reason there cannot be a turbo kit for a NA 944. But nobody has put forth the effort. And that is just one of the differences between the 944/951 community and the rest of the import community. I'm not dissing anyone or the 944/951 community. Just pointing out a fact.