EFI safety switch
 

Not sure if this is what I should be looking for to safe guard my nitrous set up. I'm planning to install it off the fuel tap. http://www.amazon.com/Nitrous-Expres...=ATVPDKIKX0DER
If not can you point me in the right direction. Thanks:tiphat:

You really don't need a new thread for every option.

I couldn't find the electrical specs for the switch but it looks like it's what you want. You'll need some way to set the switch (calibrated pressure source) - you might be better off with a non-adjustable switch.

Sorry about that. Just thought I'd get more exposure.

Thanks. NOS has them adjustable, but come factory preset to 50. I'm searching what our cars run at. Sorry for the extra post.

Somebody with more experience with nitrous may have a better answer but, in general, if you are only guarding against catastrophic loss of fuel pressure (eg, pump craps out) then the setting will not be critical. If losing a few pounds of pressure is the problem, you will need to be more accurate.

Normal fuel pressure range should be in the FSM.

I just looked over the FSM and couldn't find anything that pertains to fuel pressure. Being a newbie to nitrous myself, I'm not really sure what is most important. I'm thinking a few pound loss but like I said, at this point I'm just guessing.

A safety check valve to shut it down is a good idea... if you are really serious, and plan on running nitrous a lot, something that independently monitors knock and pulls timing is also worth considering (I know you can set uprev to do that with the protuner, otherwise you need something like this J&S Electronics SafeGuard Indivdual Cylinder Knock Control ).

1 or 2 step colder spark plugs are advisable as well.

Related notes: I glanced over a few of your older posts, but couldn't find clear reference to how you will handle fueling needs.

Do you have uprev? You WILL need to add a lot of extra fuel to keep in-cylinder temps in check, You'll probably need to pull a few degrees of ignition advance too. Just spraying without extra fuel (or something with a very high octane) and a bit less advance is not a great idea...

I would absolutely tune for your shot on a dyno and have someone who knows what they're doing handle it.

Anyway, with an uprev tune, before you spray, you would just switch to your nitrous tune with the cruise control, and you're set to destroy the rear tires.

Another option is to add a water/meth injection kit -- the shot and the W/M Injection could all be set on the same progressive controller/window switch, or at least run in tandem -- for maximum safety.

If you go with adding a W/M kit, I'd consider porting directly into the IM with high atomization injectors. I can offer more tips and details on W/M injection if you decide to go that route; I have a good bit of experience with that.

In short, to do this right and minimize the chance of detonation, you should treat this like any other FI set up, with the exception of worrying about intercooling.

If all this is old news to you -- sorry to clog up the thread, and looking forward to the track or dyno results! :tup:

According to page EC-608 of the 2009 FSM:
At idling : Approximately 350 kPa (3.57 kg/cm2, 51 psi)

A note on fuel pressure: Boost pressure fights fuel pressure, but I don't know if the psi difference from a nitrous bottle is really a major issue -- all the power comes from adding a ton of extra oxygen to the mixture (much more than the in same quantity of ambient air!), but not so much through compression of the charge, meaning lower charge pressures, at least as I understand it (someone correct me here if I'm wrong).

Anyway, even if it causes a slight drop in pressure, it's really the increased oxygen concentration you have to worry about, and without adding more fuel you can run very, very lean.

Now, although the nitrous itself will cool the charge as it enters the IM (it's cold! The IM may feel frosty), but the benefits of the temp drop going in is at odds with the lean burn in-cylinder if fueling is insufficient. This may create hot spots on the piston crown and can cause flame kernels to flare along it, resulting in preigntion and knock... also, the greater pressure wave created during combustion can cause autoignition of the fuel, also resulting in detonation and knock (i.e., un-timed/unplanned combustion events -- engines don't generally like that).

Sooo... long story short, fuel pressure drops shouldn't really be the big issue to contend with (maybe for motors that run adjustable FPR's?). It's making sure your injectors can handle the fueling needs, tuning them to have increased duty cycles when spraying, and retarding ignition advance and using "colder" plugs, making you less prone to preignition events.

Actually, with enough of a pressure wave, you can crack a ringland without any detonation -- the force alone can break it on the compression stroke. I doubt you have to worry about that considering motors are holding together making tons of torque (although more gradually with turbines, whereas N2O hits full force all at once...)

And/or, like I said, a safety device that can shut it down/pull tons of timing at the first sign of knock or water/meth injection are also good additions.

Just spraying and playing, which lots of folks do, isn't a great idea for engine longevity, and although the motor may never have a problem during the course of your ownership, the second owner might wonder why s/he has spun a rod at < 100K...

Anyway, it sounds like you are doing a lot of research and planning rather than just bolting it on and hoping for the best, so you should be having fun (and safely) before you know it :tup:

Thanks, I probably wasn't looking in the right section. Just starting to get familiar with it.:tiphat:

Hey Jordo,
Thanks for the info. I do have uprev and my shop of choice will be RAD or Vinny Ten Racing.
So I shouldn't worry about a fuel pressure safety switch. One less thing I have to wire.
I'm taking my time and trying to get as educated as I can during the process. The car is away for the winter, unless there are some odd warm days, I don't think the car will see the road after the tune and dyno.
I don't plan on spraying all over town, so use will be on the low side. I'm not sure of the average amount of shots you get from a 10lb bottle.
I'm sure I'm getting on the annoying side with all my post, but I don't want to have a catastrophic failure.
What I would like is to be able to skip first and second gear, I know there is a way to do it so if any one has some insight on that I would really appreciate it.:tiphat:

Dump all the PDFs into a folder then tell your reader to search all documents in that folder. In Adobe Reader it's Edit:Advanced Search. I did that and used "fuel pressure" as the search string.

Okay -- that's good! If you have seasoned guys with protuner cables and a dyno, you are set other than maybe colder plugs.

Unless they strongly urge you to use the shut off valve, I'd just see if they can have your "nitrous tune" aggressively pull timing if there's any sign of knock.

If knock sensor response gets too sensitive, you can always dial less sensitivity in (hell, you can probably have a "regular", "sensitive knock detect" and "ultra sensitive knock detect" map, the latter two for, say winter vs. summer.

As to the gear issue -- are you looking to start in a higher gear for traction? Have you looked into a launch controller?

I would like to set it so that the system is active but won't spray until I reach 3rd gear and beyond.

I think you can approximate that by load if they can't access a gear dependent map -- the ECU monitors gear if you have either SRM or AT. They might be able to set it up if there's an ECU wire they can tap.

If not, you'd need something like this -- maybe exactly this: http://www.jegs.com/InstallationInst.../249-82085.pdf.

Tommy - how much spray are you planning to run?

Like most, starting at 75.

Ok, I understand, which is a miracle in itself when it comes to wiring. The Zex unit would have been ideal, but they don't make it anymore and I searched for days and couldn't even find a used one, so I went with the MSD rpm switch.

Huh. That sucks :(

Actually, now that I think about it, load (or TPS), engine speed, road speed, and knowledge of how that breaks down for each gear will give you the values to plug into whatever window switch device you use, so this can definitely be done with the right controller :tup:

Zex window switch just counts the number of times rpm hits ur upper shut off rpm before it will engage at lower limit 3rd gear spray would be upper limit reached twice then its on does mad not make a "skip shift"?

Boy I wish I could get my hands on one of those Zex switches!:shakes head:

Are you sure no one has any in stock?

I got a bunch of hits googling the p/n -- it might be worth calling around to see if anyone has it in their inventory.

http://www.summitracing.com/parts/zex-82085

ZEX Traction Control Window Switch (79-12 All) at AmericanMuscle.com - Discontinued

ZEX Nitrous Systems Free Shipping on all Zex Nitrous Kits

Hey Jordo,
I called and searched everywhere and the only guy that has one is RPM outlet and wants $400.00 for it:shakes head:. I'm not so desperate that I'm willing to pay double. I do appreciate the help!:tiphat:
Figures, they were the only one I DIDN'T call because of the price, they have two!!! Now I sit here trying to decide, send back the MSD digital and bite the bullet and succumb to their demands!

Does it have to be a ZEX? A quick web search shows that MSD and NOS make one.

Those are both good choices, there in line with the MSD that I'm planning on using. http://www.msdignition.com/Products/...ow_Switch.aspx
The problem is, I'm looking for a skip shift function. The Zex allows you to do that. I can have it set on the line but won't spray until second gear.
I just called RPM Outlet again and tried to talk him down, no chance! They specialize in finding out of stock items and then mark them up for a huge profit. I'm all for making a profit but.....
SH!T this sucks, do I spend another $250.00 for that option. That's my AFR gauge out the window!

Do you have any friends/acquaintances that could build one for you or modify one of the existing units? It should be a fairly simple analog circuit - comparators for the window function and a counter for the skip-shift. Digital should be just as easy to design/build ( but more expensive) and have the benefit of a decent UI.

Edit: If the MT knows what gear it is in, you may be able to tap into that, but that would probably involve an OBD interface.

I may be able to reach out to some members on another forum that I belong to, there always making control boards and usb devices, I'll give them a shot.

The skip-shift thing sounds like a pretty great feature.

I think if you can't get the Zex one at a reasonable price (or at all) I think definitely see if you can find or build another traction control type device to use and then just return or sell off the standard controller you have now.

Hey Jordo and South, I reached out to Randy at Leash Electronics and asked him to try and duplicate it. No go, he also thought it was a great feature. No response from the other forum. So I guess I'm going to bite the bullet and drop the $400.00 for it, it's killing me :shakes head: to do it, but it's exactly what I'm looking for in a simple solution.

That sucks. I also only just realized its "not available" at summit :shakes head:

I would do a quick search to make sure it wasn't discontinued because it doesn't work very well...

If it works well, and does what you need, and you can't find it anywhere else, I say go for it.

By AFR gauge, did you mean that shut-off switch or a separate one for purposes of external monitoring/datalogging?

You may not need either if your tuner has a pro cable -- he can set the ECU to be extra aggressive in pulling timing at the first hint of knock, which should stave off catastrophe.

Plus, the ECU will still have a tuned target map to reference, so keeping AFR's in check shouldn't be something that needs constant attention.

That's great news. You just saved me the cost of the gauge, yes it was just going to be used for external monitoring. Yep I'm calling tomorrow to have it overnighted. I will google and check on its reliability.

Sorry to hear you had to go the expensive route. Keep us posted on how it works out.

After searching until my eyes started bleeding, I was able to find one sight that I hadn't seen before. There selling it for $180.00 if they have it, I won't know till tomorrow. Keeping my fingers crossed.

Well I've made my last call trying to find the Zex and it's just not there. So I'm going to bite the bullet and spend the $400.00.:shakes head: