How much can i spray safely?

[pontiac69fb]

I'm wanting to run nitrous on my stock turbo, stock intercooler grand national. My car has a 3" dowpipe, with a dumped test pipe. It also has 36# injectors and a walbro fuel pump, and an electronic boost controller. My car right now runs 12's and my goal is a solid 11 sec pass. My question is how much would I need to spray to reach my goal and how much of the juice can a stock motor handle?

 

[SlickTR]

I'm wanting to run nitrous on my stock turbo, stock intercooler grand national. My car has a 3" dowpipe, with a dumped test pipe. It also has 36# injectors and a walbro fuel pump, and an electronic boost controller. My car right now runs 12's and my goal is a solid 11 sec pass. My question is how much would I need to spray to reach my goal and how much of the juice can a stock motor handle?

Lots of different ways to get to your goal but nitrous is always an option I guess. A stock motor can run a 50 shot to a 200 shot just fine. The only difference is once you knock on the bigger shot your motor goes boom, smaller shots let you get away with more. The key is in the tune, start off small and work your way up in small increments keeping in mind the bigger the shot the greater risk you take. Dont cut corners either be safe as possible. I think most guys that spray through out the whole run dont go above a 50 to 75 shot. Do you have ALKY on it yet, if not you can try ALKY and running a bit more boost and timing to break into the 11's

 

[Black Power]

Hit it with a 75 out of the gate and after you hit 3rd gear let the turbo take over by itself.

 

[pontiac69fb]

Thx for the replies. I plan on spraying throughout the whole run and I don't have alky but I plan on using race gas. I guess the way I see it nitrous is kinda killing two birds with one stones, instead of an intercooler, alky, turbo, and stall, I can have it all with one mod because it'll help me get off the line better. Is nitrous more dangerous than turbo and superchargers if so why?

 

[Black Power]

Thx for the replies. I plan on spraying throughout the whole run and I don't have alky but I plan on using race gas. I guess the way I see it nitrous is kinda killing two birds with one stones, instead of an intercooler, alky, turbo, and stall, I can have it all with one mod because it'll help me get off the line better. Is nitrous more dangerous than turbo and superchargers if so why?

Not more dangerous, it's just different. IMO nitrous and forced induction works well together, you just have to have a good tune on it and keep close watch on what is going on.

Might want to start out with a 35 shot for the full pass, then up it to a 50, then a 75 so you know how it will respond.

It will launch a lot harder and you will be pulling harder up high like you mentioned. Keep an eye on fuel pressure and knock and you should be good to go.

 

[Razor]

Nitrous can overwhelm the exhuast housing and make boost climb way higher. You understand the MAF system on the Buick stops reading at 255 grams.. meaning at 14 PSI it is already maxed out.. so tuning is done through chip injector duty cycle changes and fuel pressure changes.

Watch your tune.. its easy to hit the button and the boost to hit 30 PSI. So as far as a 200 shot being safe.. dont think so on a stock engine.

 

[Chuck Leeper]

Another prospective member of the DOTC club???

 

[Razor]

Another prospective member of the DOTC club???

Nah its the broom and shovel club

200 shot is very safe

 

[SlickTR]

Wasnt saying that a 200 shot was safe to go out and run, I was trying to make the point that the size of the shot isn't the only factor to consider, the tune is very important. With a crappy tune you could blow it up with a 35 shot.

 

[pontiac69fb]

I really don't think my ported stock turbo can hit 30psi. My mostly stock car is putting down somewhere around 300 to the wheels so with a 200 shot I will be in the high 400 to low 500 rwhp range. So is this about the limits for our stock motors?

 

[SlickTR]

I really don't think my ported stock turbo can hit 30psi. My mostly stock car is putting down somewhere around 300 to the wheels so with a 200 shot I will be in the high 400 to low 500 rwhp range. So is this about the limits for our stock motors?

NO, dont spray a 200 shot! I was just trying to say dont get caught up with how big the shot is, it didnt really come out right lol. Start low and tune it to run the spray. Start at a 35 and work your way up to 75. Some guys spray better than 100 shots but that is just off the line not through out the whole run. A 100 wet shot for the whole run might eventually be possible with the right tune on a stock motor but you have to start lower to get your tune right and see how the car reacts. every car is different though yours might not like anything more than a 50.

 

[SlickTR]

I really don't think my ported stock turbo can hit 30psi. My mostly stock car is putting down somewhere around 300 to the wheels so with a 200 shot I will be in the high 400 to low 500 rwhp range. So is this about the limits for our stock motors?

Also keep in mind that you dont need a big shot to reach your goals. On a turbo car a 75 shot will most likely give you more than 75 whp gain, you could see a 100 whp gain from a 75 shot. This is due to the cooling effect being more significant to our turbo motors than a NA motor and you will also see a few more pound of boost on the spray. The last turbo car I had spray on saw over 100 whp gain from a 75 shot

 

[Black Power]

I really don't think my ported stock turbo can hit 30psi.

Wanna bet?

Mine with the PT51 which isn't a big turbo at all made 28 psi with a SEVERELY cracked driver's exhaust manifold. It probably would have made 35 without that

As Razor suggested the n20 can make your boost spike hard and fast, it makes your eyes bug out the first time you look at the boost gauge while you are in the juice

 

[pontiac69fb]

O.k. you guys have givin me a lot to consider. I will take your advice and start out with something small 25-50 ish and work my way up to the perfect tune and combo. I think probably in the end a 100 shot may be the highest I go if I do end up going that far. I will update this thread with the results of spray on a stock motor hopefully we can get a happy ending.

 

[Razor]

Its like boost.. you start low and work your way up. Nitrous isnt any different.

Anyone wanting to start at 30 PSI boost is like starting with a 200 shot. Anyone wanting to start at this level gets what they ask for..

Common sense.. dont use it.. spend a lot of money buying parts. Easy.. It cost's money to go to school.. so you pay for an education.






Bet that stock turbo will pin a 35 boost guage with a 200 shot.. wanna bet.. I say 20 bucks.. get a video camera and prove me wrong

 

[Black Power]

Lol on a 35psi gauge a 200 shot would make the needle do a 360

 

[TurboTR]

Good advice about the limits of the stock controller. But as long as you have the right amount of matching fuel AND matching timing retard (both also taking into account a boost spike as well as the limits of your ECU), a 100 shot is nothing to be skeered of. If you don't have both of the above matching factors properly taken care of, in advance, it won't work as hoped with any significant nitrous shot (or boost increase) and you will break something.

Anyone can plumb a hose system, just like anyone can turn a boost knob. The difference is in understanding and taking care of the matching factors.

TurboTR

 

[Mr.Spool]

i would like to add that those who think that it is only in the tune and if it's tuned right it can't get hurt will find out the hard way nitrous raises the compression of the motor like more boost does and a wideband, egt,scanmaster, cannot measure compression!think your safe at 10.5 on a wideband and no knock?doesn't mean your heads won't lift or push a gasket out.i must say the stuff really works ps a big no no on the 200 shot, a 50 shot on mine was sweet:biggrin:

 

[TurboTR]

Of course it can get hurt even tuned well, and even without nitrous. But without the tune, it will get hurt for sure was the point.

The timing retard aspect is the main control to prevent excessive cylinder pressure, everything else being equal (no abnormal combustion going on). Don't really care about compression, but I do care about peak cylinder pressure. And we can measure that in the cyclinder, in real time, and have. I have WOT cylinder pressure traces from 30 psi boost, 30+ psi boost with 150 nitrous, etc. These traces are pretty rare.

Before taking on a nitrous project (or high boost project for that matter), it really helps to read through the article found on the web, "Nitrous: Naughty and Nice" by Keith Black's piston engineer John Erb. It doesn't tell the whole story, but it's one of the few "true" articles available out there among a sea of untruths. Personally I care about what is true and what is not. Not everyone does though. But this article is unlike the misleading, flashy headline we see everywhere- "Nitrous works by drastically increasing the cyclnder pressure". Misleading at best because yes, it CAN drastically increase the cylinder pressure if you allow it to, which will lead to broken engine parts, stat. And that method for increasing power seems to make intuitive sense at first thought, drastically increasing cylinder pressure is how the engine makes radically more power. But your job is to make sure it does NOT, because the engine structure just can't take it.

The real mechanism that allows radically increased power is not as obvious, but fortunately it allows us to do so without "drastically increasing cylinder pressure" and destroying the engine. If Erb's article isn't enough food for thought, I have WOT cylinder pressure traces that also prove it. The article will help explain why this is. At the very least it will help get the correct mind set. Give it a look.

TurboTR

 

[Alky V6]

Excellent article.