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YOUR RESEARCHSupercharger Installation Cost
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Install properly, there are no reliability problems
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Installed properly, there are no reliability problems with the VF system.
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A new intercooled supercharger kit is being tested now, its nothing like anything presently on the market..
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Suggestion
I havent changed my comment that I disagree with the statement above and said the higher boost/lower CR motor in your example would make more power vs the higher CR/lower boost.
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Suggestion
You're not trying to change the debate to something else again, are you?
Run 12:1 static/base/native compression ratio rather than 10:1
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Suggestion
Basically this is also why the new Porsche DFI engine can run a 12:1 static/base/native compression ratio rather than 10:1 for SFI.
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I havent changed my comment that I disagree with the statement above and said the higher boost/lower CR motor in your example would make more power vs the higher CR/lower boost.
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Suggestion
My point is/was that if the engine CR is already close to optimum, and what Porsche engine isn't, there isn't much "room" for an increased dynamic CR using Boost even with an intercooler.
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Suggestion
The latest designs use extended VVT-i to obtain an "effective" equal to static CR of 13:1 for low throttle openings and only switch to delayed intake valve closing mode under moderate to high throttle openings.
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Everything else being equal, it make no difference whether you have low compression high boost or high compression low boost.
How much did it cost you to get your VF Engineering Supercharger installed? Did they have to do anything else after installation?
http://www.vf-engineering.com/kit_porsche_996_36.php
But I think it takes less than 8 hours for someone who knows that they're doing right?
So maybe shoot for $1200, 8 hours x $150, or maybe even less....
Did you already buy a kit?
I was under the impression it was around $1200 but that was awhile back. I would hate to see them charge by the hour, but by the job which should include the flash. If I had to reinstall mine again I would allow 2 days to make sure everything was right and tested.
Do a thorough search. Some people have had nightmares with their systems, mostly oil leaks. Most haven't had problems though I think. It's way important to have someone that really knows what they're doing for the install. I'm surprised anyone is still buying these kits considering they cost 1/3 to 1/2 the value of the car. Who knows, maybe that is the reason. Lot's of cash left after a fresh purchase?
What good would a SuperCharger be absent lowering the static compression ratio(***) to take optimum advantage of the BOOST pressure, intercooled BOOST pressure presumiably. Same with TurboCharging but much more important.
I can't imagine that doing it correctly would cost anything less than 6-8,000 dollars.
*** double head gaskets or thicker ones.
I guess you have never experienced driving a high compreesion engine that is boosted. Night and Day compared to a low compression setup. High compression engine is much more powerful at low rpm than is the same setup on a lower compression engine.
My point is/was that if the engine CR is already close to optimum, and what Porsche engine isn't, there isn't much "room" for an increased dynamic CR using Boost even with an intercooler.
It's not the dynamic CR we are interested in. It's the boosted compression ratio. At a ratio greater that 17:1, I find it quite rewarding. The substatial increase in the effective compression ratio is just as rewarding.
Maintaining high CR in an engine maximizes performance in off boost driving.
A higher CR engine with boost will make more down low power, at the compromise of the capability to run higher boost...
The ability to drop CR slightly (1 point) with the usage of our head gasket shims is a possibility. I like to keep moderate CR with boost for the best mix of reliability/performance/longevity/safety.
A new intercooled supercharger kit is being tested now, its nothing like anything presently on the market.. The biggest handicap of a supercharged set up is elevated intake temps that reduce output and increase the chances of detonation.
I am finishing a boost specific engine combination now... Slightly less CR (through custom pistons), head work, enhanced valve train and a set of boost specific cams, etc.. But I prefer a Turbo. :-)
Everything else being equal, it make no difference whether you have low compression high boost or high compression low boost. If boosted compression ratio is the same, the risks and rewards at maximum boost are the same. However, the engine with the higher CR will overall, out perform the one with lower CR.
Boosting a 9.6:1 engine with 13.5 lbs of boost is no safer than boosting a 11.3:1 engine with 9 lbs of boost.
Yes, we do know. The maximum power will be virtually EQUAL with a slight edge to the car with the lower boost due to less heat generation. Furthermore, the car with the lower maximum boost will have more power off boost and at low boost, so overall performance goes to the car with the higher static CR and lower boost.
Phil had a problem with the output hose (about 2-1/2 in diameter) sucking down upon itself and some fuel starvation issues. One shop was trying to sort out whether the s/c was a factor or not. The owner is now seriously reconsidering his choice to s/c the 9974S in the first place as it has loads of torque of hp to start with (355 PS). I suggested that he learn to drive what he has now before he worries about adding another 100 hp. He's new to the 911 concept.
I disagree on this point. Putting more air into a motor will make more power than squeezing the air more.
Unless you have far exceeded the impellers efficiency and are trying to achieve more boost once out of its range, then I agree.
The other point, If you mean that the overall torque/hp curve is flatter with the higher compression/lower boost, I buy that but I like big hp #'s.
The inlet hose can collapse but not the outlet. Fuel starvation is not the kits fault either.
Starving a forced inducted motor is very detrimental. I've lost many from it.
The only way I predict he was starving for fuel and knowing this was the car was cutting out. Running lean will just start melting things like the head gaskets or pistons.
You ALWAYS disagree with me which, by definition, makes you wrong.
What I stated is absolutely true on paper and in practice. There is no "unless" since we agreed on "all things being equal".
Boost, effective CR increase, that is provided externally can be intercooled whereas pure piston CR cannot. Look at what would happen if ALL compression pressure could be intercooled.
So the more BOOST provided via external intercooled methods the better.
Cool. So I'm going to lower my static CR to 1:1 and pump in 60 psi of boost. My car will be the bomb at the strip. It won't matter that the ingested air will be 500+F.
Ok, I got the numbers for my car from Protomotive (Carrera 3.2).
9.5 CR - 10.5 lbs boost - ~16.5 Effective CR =
400 hp
8.8 CR - 12.75 lbs boost - ~17:1 Effective CR =
485 hp
Dyno results of my car
8.0 CR - 15 lbs boost ~16 Effective CR =
514 hp
These are real world results and all things equal.
Compression went down, boost went up, HP went up in all 3 examples.
What is it about "all things being equal" don't you understand? First of all, "effective CR can only be changed with internal mechanic mods and is slightly effected by VE. I never mentioned effective CR.
Other than a few hp difference from the all accurate dyno runs, my statement stands correct even based on your 3 examples. As boost compression ratio rises, so does power, regardless (all else being equal) of what portion of the boost compression comes from static of induction.
Nice try tho. Back to your research.
All things equal mean, CI, turbo size in my example, IC, etc etc from the same company.
Effective CR is static CR with boost for a total CR.
Boost compression ratio? You mean Effective CR?
Let's accept your incorrect difinition of "effective" CR. Why are the engines with a higher effective CR producing more power?
Because they should. Which is exactly what I stated.
How does this fact and your example above challenge what I stated? You're not trying to change the debate to something else again, are you? Here is a reminder of what I stated, found on the previous page.
Everything else being equal, it make no difference whether you have low compression high boost or high compression low boost. If boosted compression ratio is the same, the risks and rewards at maximum boost are the same. However, the engine with the higher CR will overall, out perform the one with lower CR.
I think you have the wrong definition.
There are tons of "effective CR" calculators out there for calculating after boost CR.
Try this site and look at the "compression ratio calculator plus". It talks about calculating "effective CR".
http://performancetrends.com/Compres...lator_V2.3.htm
No Im not, you said the higher CR/lower boost motor will make slightly higher power than the lower CR/higher boost engine.
I gave real world results even with mine.
Wait, stay on subject. Using your example of the 2 3.2 engines:
9.5 CR - 10.5 lbs boost - ~16.5 Effective CR = 400 hp
8.8 CR - 12.75 lbs boost - ~17:1 Effective CR = 485 hp
How does this differ from my statement?
I never veered off.
You said the slight
HP
advantage would go to the
higher CR/lower boost
vs. the
lower CR/higher boost motor
.
I showed you with real world examples (same company, motor, and dyno) that I disagree.
Hell, I threw in the "Effective CR" for ***** and giggles to show they are fairly close.
We both know 0.5:1 compression bump (in Effective CR) did not account for the 85hp gain above, it was
BOOST
.
Like I posted before.....
boost ftw
Disagree about what? Do you even know what we are debating? Your example shows an engine with higher effective Cr is more powerful. Really? I didn't know anyone ever stated otherwise.
Why don't you reread this thread slowly and see if you can get a handle on what we are discussing.
I'll let you debate this new subject with yourself. I'm tired of responding to you about something I am not even talking about.
Let me start from the beginning.
You were talking about safety of an engine with the above stats.
Then, I threw in the joke of which one would make
more power
.
Then you stated this above.
I havent changed my comment that I disagree with the statement above and said the higher boost/lower CR motor in your example would make more power vs the higher CR/lower boost.
I then backed it up with a real world, apples to apples comparison reinforcing my point that I beat to death.
Yes, missing the POINT entirely.
The more compression that is subject to intercooling the HIGHER the effective compression can become without the potential for encurring engine damage from detonation.
Basically this is also why the new Porsche DFI engine can run a 12:1 static/base/native compression ratio rather than 10:1 for SFI. Fuel depressurization/atomization/vaporization with SFI serves primarily to cool the intake runner, intake valve, and intake airflow, whereas DFI primarily COOLS the just previously compressed (and thereby HEATED) air.
DFI requires another new intake valve design beyond non-leaded gas..??
Toyota HSD Atkinson cycle engines have a static/base/native compression ratio of 13:1, reduced to an EFFECTIVE CR of 10:1 via delaying the intake valve closing. The latest designs use extended VVT-i to obtain an "effective" equal to static CR of 13:1 for low throttle openings and only switch to delayed intake valve closing mode under moderate to high throttle openings.
Shame they didn't yet "discover" DFI , 15:1 static, 12:1 effective.
How much is a Liter of LOX..??
If DFI allows CR to be increased from 10:1 to 12:1 what do you suppose LOX, LIQUID oxygen, injected, vaporized, directly into the combustion chamber would allow....??
