In response to the other thread about the blown motor...and a few other recent stories I have heard....manufacturers recomeneded jetting is just that. A recomendation for a starting point to get you close on Af ratio for a certain size shot.

You guys have to keep in mind that these are just starting points. IMO it is still up to the end user to get on a dyno with a wideband...or use an onboard wideband to check the ACTUAL AF ratio. Many many times you will find tweaking the actual jets will be required. If nitrous manufacturers could control all possible variables they would state with a certainty to use a specific jet under all curcumstances. But there is too many things that can change to have an affect on a combo. So IMO its rule of thumb to check your ACTUAL AF ratio after every install..AS WELL AS regular intervals from time to time....or when you feel its not running right.

IMO this goes for a 50 shot on up. Just dont take the chance. Yes...9 times out of ten youll get away without checking....but who wants to be that tenth guy?

Most here know that..I just wanted to reiterate this point for some of our newer lurkers.

 

True story, every combo is slightly different. Fuel pumps can vary from car to car. Mods done to a car vary from none to many and this will affect your a/f. So, please check a/f, as has been stated the rec jetting is just that, a rec to get you started. But it's up to the end user to check all parameters for ultimate safety. Spray safe out there.
Robert

 

I completly agree with this. Every car is going to be alittle different. I think people should consider buying a wideband a must when setting up a nitrous system. My wideband has saved my *** a few times and, my motor wouldn't still be togethor if I didn't monitor every pass.

 

I think a incar wideband is a necessity now that Ive used one. Ill never go without one again.

Good thread Al.

 

If you cant tune your car then dont install nitrous on it!! I live 4000 feet above sea level, I have never had a Manufacturers recomended jetting be even close to the right jets I need. Too many people just slap a kit on and go. If your going to run nitrous learn a few things about it first. Check your plugs get a wideband, log your runs, upgrade your fuel system. Its better to be safe than sorry. I can believe how many people blow there motors on this forum. This forum has all the info you need to run safe with nitrous. Please if your going to run nitrous learn about it first so you dont make the rest of us nitrous users look bad. Everyone thinks nitrous blows motors it doesnt. Bad tuning kills motors. Just my 2 cents

 

I'd also suggest addressing your fuel system WHENEVER adding nitrous to these cars.

New fuel pump/and or injectors or New MOTOR

 

 

Good points Al , I found out my car was lean up top , so I jetted up the fuel side.

 

Another item to address with the nitrous system is bottle pressure. Jetting and getting your AFR correct @ 950-1000 PSI is fine, but getting greedy and bumping up the PSI to say 1200 or higher with out taking into account the effects, is just as risky.

Vin @ 860 Performance helped set up my two stage system, we started with small jetting and worked our way up testing each system independantly (Wideband in car and the dyno Wideband were used), we discovered my Dry shot was only safe with a 50 shot (75 shot was too Lean), I am very glad we did not drop in the dry 100 or 125 jets and call it good. We had plenty of pump and the wet plate we tested to 150 with no issues. The dry problem was the injectors maxing out (fixed that with replacing the 26's with 42's from HSW a few months later). We ended up with a combined 175 shot, using the 50 dry and a 125 wet AFR under 12.

Dean and Dan @ Dynotune pointed me in the right direction with a Wideband and now I am learning tuning and logging all my shots. I see the importance of monitoring AFR while spraying.

 

i made my post in the other thread.. actually gm switched between 3 or 4 manufacturers for fuel pumps in our cars over the years.. and if you know anything about parts.. defects are evident.. even in brand new parts.. fact is you gotta pay to make HP.. 90% of the people out there don;t even know how to read a spark plug.. you should see the look on there face when i break out the indexer from timie to time.. if you don;t do your research your gunna pay the price.. PERIOD.. i blew 2 up.. now i'm over 700 on the stock bottom end.. its amazing what a little knowledge in what your dealing with can grant you..

Mike

 

Its a necessity and in my opinion should be part of a complete kit. Forget the junk *** FPSS....

 

Definatly evaluate your fuel system when adding nitrous. Get advice from an expert if you are not sure.

However depending on the condition of your fuel system and the size of shot you are running the stock fuel system may be just fine.

The NX recomemded jetting is said to be usually on the rich side. I found it to be much too lean and I am so glad that I sprung for an FJO wide band or I would probably have bought a motor instead.

 

I agree.... but call me weird... I figured it would be cheaper to replace my factory fuel pump with a larger one (less than $300) than replace a motor ($$$$) because I was being cheap and assumed that the stock piece was up to par.

I guess I don't put a price tag on "Piece of mind" :0

 

Depending on the condition of your fuel pump and the HP you added that may have been the right call.

However if you did not need it you spent over 1/2 the cost of an FJO wideband that would really give you peace of mind down the road if your fuel pump ever fails for any reason, fuel filter plugs up, you make a wrong jet change or something else causes a lean situation.

 

so you guys dont think runing a 50 shott untuned would be ok

 

cuz thats what im doing i just installed the kit friday and called my tuner about it and he told me it would be fine with a 50 how it its now....i sprayed a few times using my windwo switch between 3,000 rpm and 6.0rpm and my redline is set at 7000 with the shifts points being around 6,600-6650 and everything seems to be fine the 50 felt pretty good im puting new 42#s in and a racetronix fuel pumo in for the 100. with a tune.

10s or bust..

 

I'd take this one step further - a wideband is good to help establish a baseline but still it is not as accurate as reading the plugs. I've made pulls where the a/f said it was pig rich and then found two cylinders that were lean when I pulled the plugs. Nothing beats reading the plugs when it comes to tuning nitrous.

I hope folks read the information in this thread and we can help defeat the myth.

 

Most definately. Plug reading really should be part of your routine. I know I checked and changed plugs so often I would keep about 60-80 or so on hand. I dont even have my car any longer and I still have about 16 of each heat range 6,7, and 8 laying around the garage...lol.

I know alot of guys that are just gonna run a 100 or a 125 arent going to do plug readings regularly....but IMO you should always start with atleast a wideband check.

 

Please make sticky, this is great information.

 

Sorry, but I we have way to many stickies already and you wouldn't believe it but those are the most ignored threads.