boostmotorsport

So I installed a NX wet kit in my 87 T2 today. I installed the fogger 2" from the TB. It was a 50 shot, with the fuel t'd from the fuel inlet line between the filter and metal pipe by the oil filter. I was running it off a button so I could have it only in 3rd and 4th gear for a brief shot. After fixing the fuel leaks after the fuel solenoid I made the maiden run. The most relevant mods are intake, exhaust, 800 sec.'s, safc, pump, ported WG, man. boost controller tuned down to 6LBS for the N2O(still creeped to 10).
So for the first ( and only) run I hit the button in 2nd gear at 3K WOT and held it till 7K. When I let off the throttle and button, the engine just died out. Fortunately I could coast back into my driveway. I heard a hiss coming from the engine bay for about 2 seconds then it faded away. So I went to start the car and BOOM! Apparently puddled fuel combusted in my manifold!!!! it blew about 5 vac lines free, and my PVC TID blew apart at the seam!!!! Also the fogger and entire throttle body was frozen and covered in frost. After reparing all the leaks amazingly enough the engine started up fine and held the same vacuum and steady idle as normal!! My turbo seems to have a lil more wobble than it use to though. What a relief that the engine survived though. At this point I plan on getting rid of the kit.

So my Q's are this-

1. What the hell went wrong?
2. Why did that explosion occur?
3. If it was puddled fuel why did that happen?
4. Why did my car die out when I let off the throttle/NOS?
5. What would you do?


All input will be appreciated.

Rxmfn7

iTrader: (4)

Im not expert, but it may have been possible for some N20 to still be spraying after you let off the throttle. If you dont have any electroninic management systems for the N20, such as a rev-limiter or a cutoff or something, even after you let off the button a small amount may have still been spraying. Once you let off the throttle, you were still at like 7rpms, and maybe some spray, which could of led to one helluva detonation. Its just a thought though, as I have very little experience with N20.

fastrotaries

That's a nitrous hiccup and that's what you get for not using a window switch. You should keep it from spraying above 7k and only at wide open throttle.

fastrotaries

Next time it dies like that. pull the injector fuse out and crank the car over, like you were unflooding it.

Roy James

hhmm... what the hell? I have never heard of anything like that. Fastrotaries, care to explain what you mean by "window switch"? Thanks

pp13bnos

iTrader: (1)

It was just the button sticking. I had the same exact thing happen to me with my old 74 repu. CJ

Suds

"At this point I plan on getting rid of the kit. "


I am interested!

Megaspeed7

How much you want for it?

My big question is...HOW FAST WAS IT?

Patrick

fc3s.org

One thing I can think of was where you T'd into the fuel line. When you do it that way, you are taking away from the main fuel feed to the injectors. It is recommended to T into the fuel source AFTER the secondaires. T into the fuel line in the return line to the fuel tank. You also need to have the system setup so it will NOT engage unless you are at WOT.

Barwick

nitrous in a rotary? are you crazy? They run hot enough already, and the apex seals aren't exactly able to handle even one mishap with detonation

Gene

iTrader: (1)

The reason the injector was frozen up is because it was spraying for an extended period, gasses get cold when they expand. The reason it was spraying constantly is probably like the guy mentioned above with the switch...

emagdnim

This is why Confucious say "Always use kit with toggle switch." (Zex owns all)

amemiya

it's best to run a progresive setup

Poppinrex7

hot enough already? nitrous is very very cold....it is just another way of forcing air into your engine but in this case very cold....

Poppinrex7

although, i would NOT do it on stock seals....

NZConvertible

Please don't spread more rotary/nitous misinformation. Nitrous is as safe on a rotary as it is on a piston engine, as long as it's set up right.

Boostmotorsport, the whole botton thing scares me. In fact, until I came here, I'd never even heard of nitrous beting activated by one button! All the systems I've seen here and in Oz use a master switch on the dash and a WOT switch on the carb/TB or under the accelerator pedal (old kickdown switches are good). So as soon as you lift off, no gas.

scathcart

Nitrous hiccup would be about the closest... but horrible terminology.
My guess is a nitrous backfire, commonly associated with a wet system. Perhaps a momentarily stuck fuel solenoid, but more than likely just the placement of the nozzle or mis-installation. How did you install the fogger? Also, if you kept the button on even momentarily after you let off the throttle, this would cause the pooling of the fuel. Try installing a micro-switch inline with your button so that the system can only operate at WOT. If you need more info on this, I can get you a wiring diaghram tomorrow morning.

The frost is normal and should appear. There's water vapour in your engine bay, and nitrous comes out at -167 F.

A window siwtch would not have helped here. Fuel cut-out is 8000, and he didn't spray above it.

A window switch is a switch that only opens the circuits between a programmed rpm. For a Turbo rotary, between 3000 rpm and 7500 rpm is optimum. The window switch keeps the circuit from being operated at too low an rpm (which brings about nitrous backfire), and keeps the engine off of the fuel cut limiter. Since fuel cut wasn't until 7800 rpm, this wasn't a problem.
MSD makes a window siwtch, as does NOS brand.

Nitrous is fine to run on a rotary. I run an extra 200 horsepower in dual stages (80+120) in my S5 TII, gone through plenty of bottles, all is fine.

As for it coming out colder... kind of true. Yes, it lowers intake temps since it comes out at -167 F, but you're also making more horsepower and thus more heat...

Amemiya seems to have the best idea in here, but often a $500 computer on a $500 kit is not the most economical option, especially since most people using nitrous use it since it is the cheapest hp/buck.

Why not do it on stock seals? HP is HP, how you get it won't make a difference. Detonation will. If you build a system with the right amount of retard (via a retard unit) and the right amount of fuel (from a big pump), stock seals are fine.
What else would you use? Detonation would still kill 3mm.

Lots of nitrous ignorance and rumour in here...

And 200 hp hit together is VERY fast for the person who asked...

amemiya

you can buy a jacobs progresive controler from jeg's for $225. my friend has that one and it's pretty nice.

scathcart

Really?? Hmm... that's a hell of a lot better than the $499 for the NOS brand one I was looking at. Any idea how it compares?

stinkfist

WTF are you talking about? I'm sure you don't know.


Mike

boostmotorsport

Well the fogger was 1.75" in front of the secondary butterfly valves in the TB. I want it on a button so I only have it for short bursts in only 3rd and 4th gear down the strip. So should I wire it--toggle arm switch to button to hobbs switch? So do you guys think its safe to try it again with a WOT switch after the button or should I just bail on the idea?

boostmotorsport

And the other change that was suggested was to tee it into the fuel return line, which now thinking about it does make much moe sense. After those differences, would you guys try it again?
And to awnser the Q it was fast but not that fast, as I tuned boost down from 12lbs to 7lbs to determine how much it would cause boost to creep so I didnt shoot from 12 to 20lbs! And yes even with a really well ported ser4 WG it still creeped about 3 lbs!

boostmotorsport

What would you guys do, keep the nos kit already 80% installed or ditch it and get a compressor upgrade for the (apprxmt) same price?

fc3s.org

The compressor upgrade is a totally different thing. That will yield more power over all of the gears where as the nitrous will be a bit more restricted in when and where you can use it. I would wire it as follows. You need a WOT switch so that you can only go hot when you are at WOT. Then if you want you can wire in the button so that it only works when the WOT switch is closed (at WOT). The return fuel line is the only place I would and did draw fuel from as to not starve the injectors from volume or pressure that they usually see, especially in a turbo application.

I would just make corrections, and try it again. If you don't like it then, sell it or trade it for an upgraded compressor.

Poindexter10thae

iTrader: (2)

Don't add incorrect input when you don't know what you are talking about