Why not NOS?
 

A buddy of mine just got a custom nitrous system for his 70ish Buick Skylark GS. He said "I bet you could get your Boxster sprayed for about $500" which piqued my curiosity. I searched this forum and found a thread from about 3 years ago where someone said Toolpants had sent him a pic of a Box with a nitrous tank in the trunk, but no technical details. Obviously, nitrous is not something you need in the twisties, and okay, it does seem a little juvenile on a car like the Box, but for cheap, straight line horsepower, why not? Is it doable, or is there something about the engine that makes it a nonstarter?

No it's plain dumb.

Hey, thanks. That's just the kind of insightful, technically competent and thorough explanation I was seeking.

I don't think I'd do it to my boxster because it could blow the engine.

It could blow any engine in any car, but replacing the motor might cost $2k or less for a rebuilt one... whereas a rebuilt boxster engine is $7k plus installation, right?

It seems to come down to risk.

I do wish someone would do it though.... and it should be YOU.

Get busy and come back to this thread with pix and video of it in action. We have a need for speed! :dance:

And that's why I fully support your decision to do it. Ha!

I too have always wondered about juicing a Boxster. Most people, I find, have little to no experience with Nitrous. That's why you hear cries of caution when approaching the idea. They don't know much about it or have had little experience with it. (People fear what they don't know -who said that, Batman?)

In my several years of participating on this forum, I have never come across an individual who has juiced their Boxster. You'd be a pioneer!

I think it's something I would do to mine. I'd go SMALL though, nothing more than a 50 shot. I don't think I'd trust a $500 job though. I'd track down a Nitrous expert and some one that knows Porsches. Ask the right people the right question.

Anyway, go for it and post your results. You shall be the 986forum guinea pig!

"I don't think I'd do it to my boxster because it could blow the engine."

But WHY could it blow the engine? What does that mean? The crux of my original post was, what are the technical limitations of the engine, what would the failure mechanism be?

Sorry Jeph, I haven't bought into this idea yet-I just said my curiosity was piqued. After all, Boxster drivers typically say that on the track they can carry equal or better speed through the corners compared to 911s, but they lose time in the straightaways, which is where the juice could be used.

But would it be practical to use NOS on a track when you're doing multiple laps? I thought NOS was more for single sprint runs for 1/4 mile races and such.

In the early days of being "on the bottle", novice individuals gave the concept a black eye by not properly metering the squirt. To much gas tends to get a little to hot and things that are suppose to move will become welded together.

Current systems are pretty much full proof. They come with jets that meter the correct amount of fuel and fog and solenoids that will shut down if pressures aren't enough. I wouldn't worry much about blowing the motor, then again I wouldn't go putting in a 300 shot and expect my bottom end to hold together unless I strengthen it. Any car should be safe up to a 150 squeeze.

Mr. Cutter, that settles it. You have no excuses.

We want to see a juiced boxster ASAP and it should be your car!

(See how easily I appointed you instead of me?)

Spraying a car that is used reguarly just does not sound like a good idea. I have heard some horror stories about using nitrous (one involves the crank coming out of the block).

What I do know about nitrous is that it adds oxygen to the fuel/air (for those that know chem N02) mixture which creates a more intense explosion plus the release of the bonds from the no2 mixture. This in turn creates power (which we all love). But it effects the parts of the engine. I assume its like putting a turbo in that adds the same amount of power. The seals get worn, the bottom end gets tested and the engine gets worn out because when it comes down to it the engine isn't meant to take much more power than what it puts out.

I think asking, "what happens to the engine when you spray it," is like asking the same question for turbos/super chargers. The engine isn't meant to put out 50% more power than it does normally. If it was, it would probably put it out stock.

As much as I would love to see someone spray their car, I would cringe just as much. If you want more power just get a turbo. Its more expensive, but I would argue that its not as bad and you don't have to refill a tank. Or if you have the $$ just get a bigger motor.

I personally have no need for more power. I raced an m3 today on the highway and I kept up with him from 65 to 130 (neck and neck). Granted he would dust me from a stand still, but I could have bought an m3 instead if I cared that much about traffic light racing....

What picture....

if it's done properly, it's pretty safe. probably more so than turbo or supercharge boost since the charge is cooled & has a cooling effect on the motor. it's important that it's done right for two reasons: first, not enough fuel = lean mix = detonation = bad. you have to add larger or extra injectors. usually an extra injector is wired in just aft of the throttle that just dumps fuel when the bottle's on.

the other thing to be wary of are the cylinder pressures. we already run 11:1 compression. this is why if we turbo/supercharge our cars, we can only ad a LITTLE boost. if the cylinder pressures get too high, things start to break. a properly engineered system would be fine in any car.

NOS on the Boxster would be a lot more than $500. For around $500, most of the kits are plate or fogger systems to be used with wet intake manifolds (ie, carburetors). This is what you see on Chevys and Fords. It's a plate sandwiched between the carb and the intake. It's plumbed with the nitrous and fuel, which usually has it's own dedicated fuel pump. During combustion, things get hot enough to release the extra O2 molecules from the nitrous. The extra fuel helps to slow the burn and cool things down. Without the extra fuel, things get lean and temperatures skyrocket. The problem with the Boxster (and most modern cars) is that we've got fuel injection with a dry manifold. You can't just put a plate in after the throttle body. To add nitrous, you would have to put nitrous injectors and solenoids in each intake runner as close to the fuel injectors as possible. Then, you would need to either enlarge each of the injectors to flow enough fuel to get the correct ratio with the nitrous (likely resulting in a very rich condition when the nitrous is not flowing), or you would need to add another set of dedicated fuel injectors to work with the nitrous, which would make for some very crowded intake runners. Along with the injectors, you would probably need to plumb a dedicated fuel line and add a fuel pump. The stock system would not be able to handle the added load. To top things off, you would need to reprogram the ECU to, at the very least, retard timing during the nitrous application. Whew!!

And with all of that said and done, the only place you'd be allowed to do any competition would be the drag strip. PCA and SCCA prohibit use of nitrous in all classes, as do most other AX/track organizations. The folks at he drag strip would be happy to take your cash, being that lots of those cars are in the 1000+ HP range. I used to have a 71 Camaro (no nitrous, but I've worked with others who had it). It was like getting shot out of a cannon.

Simply think s Nitrous as liquid forced induction. Would you add a turbo, or a supercharger to your car? If the answer is no, then there you go. As for the $500 system, go for it. I make very good money cleaning up after the people who like to cut corners. A proper system with the correct DME reprogramming would be ok but when you start dropping $$$$$ on bottle refills you will come to realize that it isn't cheep.
We, just for kicks installed a 250 shot on my sons Eagle Tallon, (it was on it's last legs anyway) Man that was a fun 150 miles. :D
The car is yours, the choice is yours, the results are yours too. I wouldn't do it to my car, but that is just me, and I would be staying in the "nause" cause I am a speed freak. :)

I suggest you peruse the IMS posts on this board. Given that their is a structural flaw that allows engines to greanade, personally, I would be loathe to experiment with MY engine.

Of course, we are happy to have you try it and report back.

Good luck and go with God.

:)

I have no intention of being a guinea pig. Since the car has been out, what, 11 years, I thought somewhere someone must have given that idea some thought and I wanted to know the nuts and bolts of why it couldn't be done. I figured $500 was overly optimistic because nothing can be done cheaply to a P car. The key, as many have pointed out, is a properly designed system and it doesn't look like there is such an animal available off the shelf. I would prefer a turbo because I know that's been done and it would be usable on a daily basis.

http://www.andysautosport.com/porsche/1997_2004_boxster/performance/nitrous_oxide/nitrous_oxide_kits/nos/

I'd prefer a turbo too. It's just 10x more $$$. However, it's under your right foot any time you want it and there's no bottle to refill.

I will be working on it within the next month or so :cool:

Well. Looks like you've found your kit. The questions now are, where do you put the fogger? Where do you get a TPS signal? Where do you mount the bottle? Etc..

Surely this motor can support a 75HP shot. ( a honda civic can) If the bottom end can support 75 HP from a turbo or SC then this would be no different. The cool thing about EFI is that if the jets for the nitrous are slightly rich or lean the system will make up the difference in a matter of milliseconds. Another cool thing is that the engine likely has a knock sensor and can retard the timing if that should prove to be an issue.

You seem certain that the Box can deal with the NOS hit. I am curious as to why you believe this?

:)

Can the bottom end handle 75 HP from a turbo or supercharger?? What would the difference be???

That Tool Pants and his pictures....

It seems the IMS is the weak link in the Box engine. How might that be effected by a boost from either a Turbo or NOS.

It is interesting that Porsche has never offered up a Turbo on the Box. This is kind of out of character for them, as they have put them on many past models.

That could be coincidence or not. I guess I never thought of that before?

:D

More pictures wanted from Tool Pants!

Putting a turbo on the Box would put the Box in 911 territory which is a big no-no cause when the guys who pay the big bucks for a 911 realize that a Boxster can be faster than them they will get kinda mad. This is also the reason why our engines are so muffled.

and on the above picture: I want to know what kinda shift kit that guy has!

ok, well here is the deal..

A turbo or supercharger takes air,(19% oxygen), and compresses it.. The fuel injection system can keep the air/fuel ratio at about 14.7 to 1 even with the extra oxygen & air from the turbo or supercharger.

With NOS, you are injecting liquid Nitrous Oxide into the engine, about 200 times more oxygen than the fuel ingection system can handle. If left to it's self, this would lean out the mixture & act like a blow torch and melt down a cylinder head.. this is why a NOS system has an additional fuel nozzle with the NOS nozzle.

Here is the real problem: getting the mixture right

I know the companies who make the systems say its all good, but if you are off on the mixture by even a little bit, your 10k boxster engine will turn into a boat anchor in about 25 seconds...

Now back in the day when I was building air cooled Porsche engines, NOS was a BIG NO NO.. just due to the fact that the extra HP brought along with it alot of extra heat that an air cooled engine could not get rid of fast enough..

The biggest problem is the F&F ruined the reputation of Nitrous. But this is not a limited discussion. The 944 line has been out for 26 years and adding nitrous brings up the same kind of debate. There are some very sophisticated systems now that plug into the OBDII and meter based on injector duty, RPM and so forth. A well done system has no more risk than any other bolt on mod. It will be cheaper initially but you do have to refill the tank. is it worth it? Thats your own decision. I am sure people have added nitrous, I have heard of it on other boards. If you are interested I would do the research with nitrous guys, they may tell you its not worth it for your car. But I would inquire with someone who is neither selling a product, or bent on maintaining a strictly OEM car.

Just my .02 while sitting in an airport at 5am.

While researching something else recently, I think it was 3.6 swaps, I recall seeing and IMS upgrade/replacement or something such as that on a site. If the IMS is the weak link since they changed the design, can shaft bearings be replaced/upgraded to handle additional power?

Be careful.... 75 HP shot? 150 HP shot? NOPE, ain't gonna happen. The issue is not what the engine can "take" as in how strong the crank, pistons, connecting rods, etc. are. That is not the issue at all as I am sure the bottom end is more than strong enough to handle the extra power of a mild NOS shot. The problem is DETONATION.

Plain and simple it's detonation that causes an engine to blow. Sure you can get detonation from a poor mixture of nitrous and fuel, but as stated previously most modern systems are pretty good at getting the right ratio into the engine and for a mild shot you would do fine with the stock fuel system without needing a separate pump or tank, simply T-ing off of the stock system and stock fuel pressure.

The big problem with our cars and why they can't run a simple 75 shot like a Honduh is that this is already a high performance engine from the factory. The stock high compression ratio (11:1) is the main issue here. If squeezing even a very mild shot of nitrous into a high compression engine like this you run a real risk of detonation and destroying your engine. The same goes for adding on a turbo or supercharger where only mild levels of boost can be tolerated. That's why most turbo engines are around an 8:1 compression ratio.

A couple of sources I've researched this in the past with are this book by A. Graham Bell:

http://www.amazon.com/Induction-Performance-Practical-Supercharging-Turbocharging/dp/1859606911/ref=pd_bbs_1?ie=UTF8&s=books&qid=1218481199&sr=8-1

If you want to do ANY kind of forced induction with your car BUY THIS BOOK!!! It is an excellent resource and I've read it a couple of times now just for fun.

Another resource I have is an excellent review of nitrous use that Sport Compact Car did around 1999 or 2000.

Both of these sources STRONGLY recommend NOT using nitrous on anything around 11:1 or higher compression ratio with a simple NOS system (like the ZEX setups). Sport Compact Car said that even a 50 HP shot of nitrous was pushing it at 11:1. About the only thing you could do for $500 would be a 25 HP shot that would probably be safe, but it may be difficult to find the proper fuel and nitrous jets to get that small of a shot.

To go with a higher nitrous shot you'd have to either rebuild the bottom end with lower compression pistons or put together a "safer" system than what you can buy for $500. What would I do if I were building a safer system?

1. I'd get a Knock Link or other form of detonation detection and display. I've got one in my car from a previous turbo WRX. Photos are in my thread in the Show and Tell forum.

2. I'd get nitrous pressure and fuel pressure gauges.

3. I'd get the appropriate window switches to make sure the nitrous doesn't kick in too low or stay on until red line. MSD and NOS sell these.

4. You'd have to pull ignition timing with a bigger shot of nitrous. No, you would not reprogram the DME. If you did that, then you'd be driving around with retarded timing all of the time, even when you're not on the juice, which is retarded. Instead, you would need to switch the ignition system over to one of the MSD (or equivalent, there are other options) ignition systems with controllable timing and set it up to only retard the timing when you're hitting the NOS.

5. Colder spark plugs.

6. Lots of prayer. I'm sure there's more that I'm missing... Of course a dedicated fuel pump and tank with high octane fuel wouldn't hurt, although it probably would not be compatible with your O2 sensors and catalytic converters.

With all of that in place... maybe you could run a 50 shot of nitrous. Maybe more if you really want to push it. What's the point then??? :p

Kirk

This is Kelvin Ho's car from Southern California.... I think somewhere in the LA area. He had his nitrous system up for sale on eBay a couple of times this last winter. I don't know if he ever sold it, but it was like $450, used....

Here's a 996 with a front trunk mount...

Another... not sure who's this is, but it looks like it's in a Box

And my favorite, two nawz bottles mounted on the speedster humps... :rolleyes:

Kirk. Would not the vast majority of things you listed also have to be done with any forced induction setup?? Are the turbo, and supercharger setups addressing all of these issues or are they just keeping the boost down low and hoping the knock sensors will retard the timing enough to save the engine??

Another issuse would be traction control. Another member mentioned a "traction control swith", and I thought "why". Then it occured to me. Engine management cuts fuel to some cylinders.. That wouldn't work.

I feel compelled to rat Jay out now that he's joined and is posting. HE is the one who instigated all this. :matchup:

Yes, with any forced induction setup you'll have to pull timing as the boost pressure increases and it would be wise to have the gauges, etc. (although I would use EGT, boost, and a wide band O2). But with a turbo or supercharger you're pretty much running forced induction all of the time, unlike nitrous, which is just temporary. So with a turbo or supercharger you would re-map the DME or use a piggyback system to control the fueling and timing. You need that any way as you'll need more fuel out of the injectors. With nitrous you don't need a new fuel map as you can simply provide the additional fuel with the nitrous.

Still, even with remapping the DME, you'll have to run at a fairly low boost pressure. It's tough. People get greedy (just as with nitrous) and end up turning it up to get more.... As a result you see a lot of people who buy the turbo or supercharger kits and then suddenly want to sell their cars within 6 months... ;) Obviously there are a couple exceptions on this board where boost has worked well for them, over the long haul.

Hoping the knock sensors will retard the timing is a big hope. I personally wouldn't count on it. Even the Knock Link is wishful thinking. The problem is that once detonation hits, if it hits hard enough, fast enough, it may be too late to react whether it's by lifting the throttle when you see knock on a Knock Link or whether it's by the DME pulling timing.

Kirk

And, we've all learned something.. Hopefully Kirk will tell us more. He seems to know alot more than "it'll blow it up"..

It does seem to be a difficult engine to get much more performance out of.

I'm not sure there's really anything in particular about this engine that makes it more "difficult". The high compression ratio is great for a naturally aspirated engine. It's only when you try some form of induction that it's a problem. The lack of improvement from headers, exhausts, and intakes on performance just tells me that Porsche makes a good, highly tuned product from the factory that is already pretty much at the peak.

The tight packaging is a bit of an issue though. Where do you even put a supercharger, turbo, or intercooler? The engine bay is really tight, which makes these issues more difficult to overcome.

But back to the engine... again I don't think it's so much "difficult" as it's just underdeveloped. If you could buy some pistons that would drop the compression ratio to 8:1, a forged crankshaft, forged connecting rods, etc., then you could rebuild the bottom end for not 4 psi of boost but more like 14 psi of boost and run that all day long with no problems. But nobody out there is really developing these kinds of parts for the Boxster engine. That's a shame... but for the same money or less people would just rather drop in a 911 engine, which makes a lot of sense.

I talked to Marc at Turbowerx a lot when he was developing the kit for the 3.2 and he said he could do a monster build with low compression pistons and such and run high boost and get around 500 hp. He estimated the cost would be about what most people are talking about for a 3.6 transplant. I would really worry about that much power being tractable, though...last year on the TOD in the rain my PSM kicked in a few times. Twice the stock power would be pretty hairy unless I kept it about 2 gears high and below the powerband.

It wouldn't be usable power in the first couple gears since boxsters don't have an LSD. You would have to budget in an aftermarket limited slipper if you did something like that.