ilko

Seriously, whoever's looking to charge you all this money in labor better explain exactly what the hell they are doing. I'd like them to itemize the procedure and show me exactly why it would cost so much. The install is pretty straight-forward:

Remove stock intake
Remove pulleys
Remove engine carrier
Install TPC intake
Install roller on engine carrier
Reinstall carrier
Modify throttle cable
Install TPC pulleys
Install TPC supercharger
Connect wiring
Test.

A Porsche mechanic familiar with our cars should have no problem taking care of this in more than a day and a half.

BlueHeeler

Porsche 911s are designed as road race cars not drag cars. Nitrous does not make as much sense on a road race car.

Sure you could add nitrous and do well at the main street stop light grand prix, but then you are missing the point of a 911, NA 964 especially.

raspberryroadster

actually I kind of agree with you NA 964 with its high compression engine-high torque is very decent drive indeed (25hp more at the wheels would be nice tho').

i was simply responding to the posting re discussion between turbos/sc's, and there is no reason not to add into the mix a discussion on NOS. Which for a fraction of the cost does what a forced induction installation will do, add extreme power for a limited time usually under WOT.
...instead of forcing oxygen into the engine via a blower or a turbine - oxygen is created chemically, principle is the same (more air, matched with more fuel). as far i know there is no difference in terms of engine stress...(altho of all power adders i believe sc generally runs coolest.

964speed

So doing a NOS on a Porsche is a good idea? What are the risks? I gather you'd be wise to use a low HP Hole shot brust, as to not blow up your motor under extreme stress.

Has anyone done this before?

ilko

A turbocharger is driven by exhaust gasses. Last time I checked, they are generally hot. On top of that a turbocharger compresses air in order to stuff more of it in the combustion chamber. That creates even more heat. Add all the plumbing around the engine bay and you get even more heat.

The supercharger on the other hand only compresses air coming from the intake, which is 12 inches away, at the top of the engine where it's cooler. At the end, the air is hotter, but not nearly as hot as in a turbo.

The hot air can cause detonation in lower boost levels on a high compression engine that is turbocharged, versus a supercharged engine. Google it if you don't believe me.

That's why Porsche uses intercoolers on their turbocharged cars, along with lower compression.

raspberryroadster

my view anytime you are dealing with a compression ratio of 11:1 power adders are a bit of an issue.
the only nos installations i have found are boxsters, 944 series and newer 911's.
there are kits that will bolt onto 964 engines, but they will certainly detract from value. additionally i am not sure NOS is 50 state legal.

it certainly can be "trackable" (there are applications for motorcycle racers and motocross) but would certainly not meet the regs., so any application would be street use only (likely same issue may hit forced induction power adders).

be good for some engineers to chime in - and comment as to whether a short shot of nitrous would add more heat than a low boost forced induction installation (all reading i have done says no).

likely best power adder for supercharged / turbo'd cars "with engine capability" is NOS

964speed

DING DING DING ...we have a winner! I like it! NOS on my 3.6 say 500hp hole shot! Man oh Man...LOL

Seriously that would be cool if it doesn't blow up the motor

wellcraft290

Ilko a turbo or s/c both compress air to make more horsepower. one blows one sucks. turbos don't blow in teh exhaust air but uses it to spin the turbo. Also not sure what area of the car is hotter the area near the exhaust or by the motor. The exhaust is caused by the motor so would only be as hot as some part of the motor. I don't think one system is better then the other for the motor just you can make more HP with a turbo.

Love to see your proof that on an exact same boost the air on a turbo is hotter then a SC. Who said that TPC? You guys just fight for your SC were I honestly don't think one is better or worse just know what is cheaper more proven and equals more power.

BlueHeeler

Nitrous does not add heat to the intake charge like forced induction because you are not trying to compress the intake charge. Actually the liquid to gas phase change of nitrous has an over all cooling effect and a more dense charge. The problem is nitrous adds oxygen and must have corresponding fuel to prevent the engine running lean and detonating. A/F ratio is critical to keep cool.

I do no know how long a bottle lasts, but in a drag race scenario you are looking at a few seconds at WOT. In a 20min trackday session you will be WOT for a significantly longer period than that.

BlueHeeler

It is simple mechanics. Have you seen a glowing hot turbo? This is why it is customary to run an intercooler (aftercooler actually) for a turbo and not as important on a supercharger.

The plus for a turbo is it is more efficient. IIRC spinning a sc in high rpms is ~30 hp depending on 1000 different other factors, but it does explain why Ilko's car has tons of low end stomp and not so much top end.

Lag is the next question for turbo. Non issue on a sc. On a properly sized turbo this is not a big problem depending on what the driver expects, full boost should be available below 3K rpms.

Aside - Porsche in the 930 fitted a larger than optimal turbo hence it is famous for lag. The benefit of a larger turbo is cooler intake charge and more available top end hp. Porsche had to do this to get the big hp numbers and keep the aircooled engine cool.

Proof? Again read Maximum Boost by Corky Bell. He has forgotten more about turbos than you, I, or anyone on this forum will know.

raspberryroadster

thanks, confirms - all info i have seen. agree heavy fuel usage (& hi-octane) but as is the case with forced induction.
so upside, install costs are like cheap-but need seriously good pro tuner, kits are cheap (double ZEX bottle set up and all the fittings are what - less than $900).
excellent point bottles go dry (altho in your example -drag usage is set for very heavy spray-typically power added of 150% of engine HP is not uncommon)....for porsche engine spray would have to be exceedingly mild -power added of about 20-30%.
perhaps for the track - not suited, but seems a viable power adder for street-highway, prudent use....
do you Agree?

BlueHeeler

I agree mechanically, but not philosophically.
For the street-highway fun nitrous could be a very cost effective and safe power adder if you are a 100% your A/F ratio is good if not slightly rich. The 964 has knock sensors, but I would not bet my engine on them. Philosophically if I wanted something that goes silly fast in a straight line considering budget, 964 would not be my choice. The 964 engine is already tuned. So the margin of error is less than a stock Mustang if you lean on it.

High fuel usage for a forced induction setup is a function of having an improperly tuned setup for efficiency. Three variables come into play. Basically you cannot increase one without decreasing the other two: Response, Economy, Ultimate bhp.

Turbos and superchargers are mechanical devices that have an efficiency range. You can look up the graphs. They cannot have an increased efficiency from 1.5K-7K rpms. Either they will be inefficient on the top or bottom. There is always sacrifice for ‘free power’.

I am not anti sc, turbo, or nitrous. I have used them all. They all have merit.

raspberryroadster

....well put. whatever power adder you choose - with a compression ratio of plus 11:1 the engine is dependent on a failsafe mechanism....which if it fails results in "rebuild time"...matters not whether its forced induction or nitrous.

more i ride this auto, more i respect that its torquey engine responds well to weight reduction - perhaps suspension/chassis enhancements.

but actually apart from cup pipe/drilled airbox/new audio system (stock audio sucks)....stock - gotta love it!!

MPB993

9m in the UK installed a tpc sc on my 993 in 2001 so I thought I would add a perspective. I'm running a non-intercooled kit and 60k miles later I'm still smiling. You do get used to the flat torque curve.
Mark.

ilko

We keep showing you proof over and over in every turbo thread you started but you fail to see it. And it's just common sense at the end. One is hotter than the other. That's why it's recommended you run an intercooler with a turbo, which also adds extra power.

BTW, I've spoken to TPC once since I bought the car 2 years ago. It was over the winter and I asked them where in their opinion would be the best place to tap into the plumbing for a boost gauge. So yeah, apparently I have a lot at stake.

Cheaper and more power is relative. There is one guy I know on these boards with a Promotive turbo. He's currently selling the kit since his engine blew up. Unrelated apparently.