Nitrous question

[Evans, Marv]

+1 on what Harry said.
I must have gotten screwed on the system I bought, although it had everything including the Porsche intake manifold plumbed with everything it needed to go with.
Another thing you might consider if you go the nitrous route is thermal barrier coatings. I did that on an engine I built, along with dry film lubricants on a bunch of stuff. Haven't tried the engine yet in my car since it's still in the process on being put back together. I had the piston tops, combustion chambers, valve faces, and exhaust ports coated. I wasn't planning on nitrous, but trying to do some things to make the engine last.
The added oil cooler is a good idea too.
Go for it.

[Steve@Rennsport]

I've done a nitrous system on a carbureted 911 and one of the biggest problems is pulling out timing as the solenoids actuate.

Personally, I think this stuff is best left to the water-cooled engine crowd where they have more than 4 simple studs holding down each cylinder and MUCH better control of cylinder head temps.

[JFairman]

I put a wet nitrous system on a '79 3.5 liter BMW engine some years ago.
There are universal wet kits that would be easy to install.
I used one from Nitrousworks that would add about 75hp depending on how big you went with the fuel and nitrous jets in the injector nozzle.
The injector nozzle is mounted just upstream of the throttle body after the air flow meter.
I had the bottle on the floor of the passenger side rear seat, so I could just reach back and turn the knb when I wanted to use it.
I used the origonal front fog light switch to turn the system on or off.
The nitrous and fuel solenoid are hooked up to a multipin 12 volt relay that is triggered by the origonal throttle body L-jetronic full throttle microswitch.

Having multiple pins on the relay let me connect the wire that was on the throttle body to the relay instead so it was still functional even if the nitrous was turned off.
Setting ignition spark retard while nitrous flowing was easy too.
I did two things to control that.
I had an MSD Digital 6 ignition that has adjustable spark retard built in and that is triggered by the relay hooked up to the throttle body switch. So spark is retarded when at full throttle with nitrous is on.
I also hooked up a small vacuum solenoid from a salvage yard into the vacuum advance line so vacuum advance to the distributer is bled off when nitrous comes on.
You have to do this to control detonation when nitrous comes on using street gas.
I could also control fuel enrichment from the dashboard by installing a 10,000 ohm linear taper potentiometer inline with the coolant temperature sensor wire going to the L-jetronic brain.
Those temp sensors worked by varying resistance. Higher resistance = richer mixture.
At 10,000 ohms the brain thinks it's 30 below out and the injectors pretty much stay open... So if I heard any detonantio i just turned the potentiometer to the right and richened up the fuel mixture and the detonation would go away. Turning it farther you would see black smoke out the exhaust because you were then running too rich.

As the bottle ran down on nitrous you would start running too rich because there was less nitrous pressure, so I installed a small switch to take the fuel solenoid out of the loop and I'd only use the potentiometer in the coolant twmp circut to richen the mixture until the bottle was empty.

ZEX made a system that would monitor bottle presssure and then put some of that pressure into the vauum port of the fuel presure regulator for fuel enrichment. It is a dry system. I don't know how well that system worked.

In the end my set up worked very well and didn't add any moving parts that wear out other than the solenoids.
It did speed up the wear and tear on everything from the clutch on back especially the rubber guibo connection on the driveshaft.
I kept a dark towel over the bottle so it wasn't so visible if I got pulled over...

good luck!

[stevej37]

Not sure if it's the same as the Holley NOS, but I currently use the a Zex dry kit in my Honda Prelude. The Zex kit is supposedly one of the safest to use because it adjusts A/F ratio with changes in bottle pressure. Mine is a 75 hp shot and I've used it often over the last 3 years with no problems at all. A bottle heater will keep your pressure up to max until it is almost empty.

[84porsche9113.2]

Originally Posted by 911Blast

However, the "turbo" referrals (just because they were added by the Porsche factory in the mid-seventies) reeked of elitist conformity. A lot of talk, but dead end, at best.

I disagree with the above. The only reason I mentioned that if you want more speed, one should stick with a factory turbo (vs. aftermarket supercharger), is because of resale value and investment reasons.

I think someone is more likely to recoup their investment (if they had to sell their car), if the $30k they spent on their car is for a pristine factory turbo. On the other hand, if you spend $20k on a carrera and spend another $10k to add a supercharger, it's unlikely someone is going to be willing to spend $30k for something that's been modified in someone's backyard or another garage. You may even have a hard time selling a modified car. I think a factory turbo is easier to sell at a higher price than a highly customized carrera with an aftermarket supercharger on it. The reason is that what is "nice" to you, is not neccesarily nice to everyone. And it's also hard to quantify the value of a highly customized car because there's no standardized "blue book" value for it. I think people who customize their cars probably get a lot less than they spent, as opposed to someone who just restores a factory vehicle to original condition.

That's just my take on it. I could be wrong. But I don't think there was anything "elitist" about what I said. I was more or less looking at it as an investment decision as well as a way to get more speed at the same time. Personally (after learing the hard way myself) I wouldn't just want more speed and loose $ or make a bad investment in the process.

If you never sell your car then you wouldn't have that problem. But then again, even if you think you'd never sell your car, there's still the very small chance you might, and it's nice to have more options and be able to get more of your $ spent than less. I'd still say if you can have both the speed and power AND a good investment at the same time, I would tend to think that's better than having only one of the two...

If $ is no object and you don't care about investments, then what I said is truly irrelevant in your decision making process (but who can afford not to think about $ at all?)

[Cornpanzer]

Head temps should not be an issue as the evaporation of the nitrogen cools the intake charge.

The big concern would be detonation. In the VW world, nitrous systems can be tricky to tune when you start getting greedy because the engines are air cooled and use reletively thin cylinder walls. If you go lean, you wont hear the detonation, just the puffing of a cracked cylinder or pulled head stud.

That being said, a 50 shot should be pretty safe. I would guess that a large chunk of your increase from a dry shot would be the cooling effect in the intake charge combined with the extra oxygen.

[TerryBPP]

How about I build you a cheap turbo kit? 6-7 psi would be a snitch. Too bad your in LA.

[911Blast]

I agree that I am also not happy that I am currently located in Louisiana. However, If anyone wnats updates, with pics, of my "Phillip Patek" WET NOS system, I'll be happy to post them as my project progresses.

Sorry...but as I posted earlier, I've gone as far a twin turbos, cubic inches and a F.A.S.T. system can produce. I am just having fun now with a regular 3.0....................

Whoooopeeee!!!!