Big decision: Supercharge the 996 C4 Cabrio or buy a 996 Turbo Coupe....
#31
Sorry, regardless of what the article says (haven't read it nor do I intend to) there is no loss of power or performance at any time, or at any engine rpm with a centrifuge compressor on the 996. That's just a fact. More power than stock at 1000 rpm and more power than stock at 7000 rpm. There is little parasitic drag at low rpm.
On boost or off boost, you will never have less power than you did before your 996 was supercharged.
Therefore, your statement "..... it's possible to actually lose horsepower until the benefits of compressed air into the cylinder starts to take hold" remains a ridiculas one.
On boost or off boost, you will never have less power than you did before your 996 was supercharged.
Therefore, your statement "..... it's possible to actually lose horsepower until the benefits of compressed air into the cylinder starts to take hold" remains a ridiculas one.
you can be happy with your faith-based belief in SCs and i'll stick to my view which is supported by facts and physics.
#32
Three Wheelin'
I understand that, in theory, you will experience a parasitic loss from any supercharger, just like you would from turning on your AC compressor. In actuality, I would take what 99 and Redridge say as gospel....they both have SCs on their 996s.
#33
Welcome to Rennlist, gotta have thick skin here.
#34
actually, i wouldn't be surprised if the debate has been going on since francis roots patented forced induction sometime in the 1860s according to wikipedia.
#35
I only care about the fact that what you stated is not true and never has been with a centrifuge compressor. Don't care about anything else the article says. Show me a car that loses power at any engine speed after installing a centrifuge compressor and I'll show you an incompetent installer.
#36
Lets be realistic, $$$ wise I dont think the SC and the turbo is the same price at all . A good turbo will be at least $10K+ over a SC... Thats a full blown moton suspension, control arms, sways... the works. Ever see the prices on modding a TT... like 2x-3x more than a carreras' price.
If you want a fast cab... theres only 2 ways to do. A turbo or a SC. Like the OP says, a cab turbo is $25K more and a SC cab is $15k (though with a group buy and installation $12K)
#37
I only care about the fact that what you stated is not true and never has been with a centrifuge compressor. Don't care about anything else the article says. Show me a car that loses power at any engine speed after installing a centrifuge compressor and I'll show you an incompetent installer.
this is why with equivalent PSI and air and fuel, a SC engine produces less (net) HP than a TC engine (again, all things being equal).
of course any forced induction will produce more HP (net) than a non forced induction engine. i'm claiming in the brief time that an SC is not spinning at full RPM (around 9k for most) there can be a net loss of HP at the wheels because energy (work) is being spent spinning the TC before the TC is producing optimum forced air into the engine.
it's similar to turbo-lag. except there is a parasitic effect (because the crank or belt is being driven by the engine and not by exhaust gas) and the period in which it lasts is much shorter than in turbos.
so i can't "show" you an engine that produces less HP (net) than non-forced induction.
but if you look here: http://i62.photobucket.com/albums/h90/slc92/dyno011.jpg
it shows a dyno measurement (before and after).
you can see that between 2500-3000 RPM the non-forced induction engine produces more HP and torque than the same engine after getting fitted with a Vortech SC. all things being equal there is a very brief period of parasitic power loss (but it's only for 500RPM).
i'm sure that isn't enough proof for you or you'll argue the SC wasn't installed correctly, etc. but you'll find all SC engines have a similar result (but smaller RPM band of loss if using a smaller SC) of around 2-500 RPM of parasitic power loss due to the engine working to spin the SC before the SC gives enough air to the engine for a net power gain.
ultimately under equal PSI (on the engine and fuel mix), TCs don't give the 0-60 times of SCs (because turbo-lag is longer than the time it takes for the engine to spin to 3000 RPM), but TCs do have higher top speeds because the PSI is given to the engine with less penalty. again, all things being equal.
but you and others are correct, the ROI on TC vs. SC makes the math easy. SC gives more bang for the buck, apparently.
Last edited by yasuro; 04-15-2008 at 10:25 PM.
#38
yasuro quit the mumbo jumbo.
i had an s2000 with a comptech sc... never once ever in the 15K miles i logged on it did i ever feel like i had less power than sans sc.
no lag, all power, all reliable for $6K installed. was great stuff.
i had an s2000 with a comptech sc... never once ever in the 15K miles i logged on it did i ever feel like i had less power than sans sc.
no lag, all power, all reliable for $6K installed. was great stuff.
#39
i don't claim a TC is better or worse than SC. it depends on what you want, that's what drives the mods we perform for a given amount of money.
#40
yas, but i'm referring specifically to my supercharged setup, not turbo charged to which you were debating with the others in earlier posts in this very thread.
the comptech sc added 80HP to the wheels. and it was felt. all of it.
the comptech sc added 80HP to the wheels. and it was felt. all of it.
#41
uhhhh didn't read anything except the title so this might be a BIG enzo....
but, a 996TT has an air cooled block and the heads are water cooled. thats why they are much better cars. supercharge your water cooled aluminum 996 and it won't last very long....
but, a 996TT has an air cooled block and the heads are water cooled. thats why they are much better cars. supercharge your water cooled aluminum 996 and it won't last very long....
#42
I see you have a new engine in your 99 (for sale)... was it ever SC?
#43
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From: Aurora, CO
Thanks everyone. I have to wait for some money coming in and bills going bye-bye, but this will happen. I am concerned about the engine difference (my biggest concern actually) as I'm planning on keeping the car, for good, either way. So, how it holds up over the next 10yrs/120,000 miles is critical. However, I also saw some had as much as 60,000 miles on an SC without an engine blowing up. I've heard a turbo engine is $20,000 vs. $10,000 for a n/a 996 engine. Between those two costs I could still replace my engine twice for the cost of one turbo engine (including the cost to "upgrade" to a TT coupe). Please correct me if my math is way off. Plus, it sounds like the SC is quicker on the power and holds its own vs a stock TT, especially at lower speeds (where I drive it most the time) like 0-60. I really appreciate the input, I'll be talking to Orin at Eurosports Ltd here in the next few days (a very reputable installer
#44
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BTW, since it will probably be the end of summer by the time I do the mods (later if I trade in to a TT), I will post/repost my results, costs, findings, etc for all. I did hear you Raisedina911! I appreciate what eveyone here on rennlist is doing... great people, great site!
#45
w=f*d (work=force * distance). so if you increase (f) with all things being the same, you increase the work. work for an engine is measured in horsepower. the increase in force required to turn the engine comes from the added mass of turning the SC (if this wasn't so, lighter fly wheels wouldn't help. lowering mass in all engine components wouldn't help). so early in the RPM (and further on) there is less horsepower produced at the wheels for a given air and fuel in the engine.
this is why with equivalent PSI and air and fuel, a SC engine produces less (net) HP than a TC engine (again, all things being equal).
of course any forced induction will produce more HP (net) than a non forced induction engine. i'm claiming in the brief time that an SC is not spinning at full RPM (around 9k for most) there can be a net loss of HP at the wheels because energy (work) is being spent spinning the TC before the TC is producing optimum forced air into the engine.
it's similar to turbo-lag. except there is a parasitic effect (because the crank or belt is being driven by the engine and not by exhaust gas) and the period in which it lasts is much shorter than in turbos.
so i can't "show" you an engine that produces less HP (net) than non-forced induction.
but if you look here: http://i62.photobucket.com/albums/h90/slc92/dyno011.jpg
it shows a dyno measurement (before and after).
you can see that between 2500-3000 RPM the non-forced induction engine produces more HP and torque than the same engine after getting fitted with a Vortech SC. all things being equal there is a very brief period of parasitic power loss (but it's only for 500RPM).
i'm sure that isn't enough proof for you or you'll argue the SC wasn't installed correctly, etc. but you'll find all SC engines have a similar result (but smaller RPM band of loss if using a smaller SC) of around 2-500 RPM of parasitic power loss due to the engine working to spin the SC before the SC gives enough air to the engine for a net power gain.
ultimately under equal PSI (on the engine and fuel mix), TCs don't give the 0-60 times of SCs (because turbo-lag is longer than the time it takes for the engine to spin to 3000 RPM), but TCs do have higher top speeds because the PSI is given to the engine with less penalty. again, all things being equal.
but you and others are correct, the ROI on TC vs. SC makes the math easy. SC gives more bang for the buck, apparently.
this is why with equivalent PSI and air and fuel, a SC engine produces less (net) HP than a TC engine (again, all things being equal).
of course any forced induction will produce more HP (net) than a non forced induction engine. i'm claiming in the brief time that an SC is not spinning at full RPM (around 9k for most) there can be a net loss of HP at the wheels because energy (work) is being spent spinning the TC before the TC is producing optimum forced air into the engine.
it's similar to turbo-lag. except there is a parasitic effect (because the crank or belt is being driven by the engine and not by exhaust gas) and the period in which it lasts is much shorter than in turbos.
so i can't "show" you an engine that produces less HP (net) than non-forced induction.
but if you look here: http://i62.photobucket.com/albums/h90/slc92/dyno011.jpg
it shows a dyno measurement (before and after).
you can see that between 2500-3000 RPM the non-forced induction engine produces more HP and torque than the same engine after getting fitted with a Vortech SC. all things being equal there is a very brief period of parasitic power loss (but it's only for 500RPM).
i'm sure that isn't enough proof for you or you'll argue the SC wasn't installed correctly, etc. but you'll find all SC engines have a similar result (but smaller RPM band of loss if using a smaller SC) of around 2-500 RPM of parasitic power loss due to the engine working to spin the SC before the SC gives enough air to the engine for a net power gain.
ultimately under equal PSI (on the engine and fuel mix), TCs don't give the 0-60 times of SCs (because turbo-lag is longer than the time it takes for the engine to spin to 3000 RPM), but TCs do have higher top speeds because the PSI is given to the engine with less penalty. again, all things being equal.
but you and others are correct, the ROI on TC vs. SC makes the math easy. SC gives more bang for the buck, apparently.
What do you mean "all thngs being equal"? All things ARE NOT equal. A stock TT will always produce less power than an otherwise stock 996 that is running a centrifuge compressor when both cars run the same amount of boost. It doesn't matter whether they run 3 psi or 7 psi. It doesn't matter what the engine speed is. The 996 will always have an effectively larger displacement and will therefore perform better than the TT when boost is equal.
As for your dyno, if in fact that was a centrifuge compressor, there was an install problem, or god forgive me for thinking this......but, maybe the dyno wasn't accurate?
Last edited by 1999Porsche911; 04-16-2008 at 01:04 AM.