iceblue

Hmm someone should post a referance guid. Of tolerances, temps, retarding degrees, under boost, and foger types and sizes used based upon amount of HP shooting. Be a nice referance for the forum. I was just thinking baout reserching n2o the other day.

midnight_7

a 50shot is more like 50hp and 50ft/lbs of torque...

scathcart

To the tires.

Works out to around 60 ft-lb gain at the flywheel.

RoadRaceJosh

Don't forget about progressive controllers. The Jacobs Electronics Nitrous Master Mind is only $225 and if you have an aftermarket ignition box it can pull timing while spraying too. The biggest benifit though is that you can run a larger shot safer as you don't get such a huge torque increase at lower RPM. It's like a constant torque increase rather than a constant horsepower increase. You can run twice as much nitrous at 6000 RPM than at 3000 RPM. The progressive controller allows you to do just that with a single stage system.

scathcart

I have a very long spreadsheet of this exact kind of data. For each engine, I log:
Fuel jet, nitrous jets, number of foggers, fogger position, octane, timing retard, ECU type, wideband-measured AFR's under WOT, EGT's under WOT, bottle pressures, fuel pressures. EGT's and AFR's in N/A form, change in spool.... and if I built the engine, the seal tolerances, the port job, etc etc etc.

What exactly do you want to know?

Tofuball

It's a different market. The big rigs with turbos are diesel and biult completely different from even your average gasoline car piston engine. They run for litterally millions of miles, and most of them you can swap out the cylenders themselves when they get worn. Diesel turboing is a whole other ballgame, and entirely unrelated to this argument :P

Now, modifying a turbo IS more unreliable then modifying an NA, because the modded turbo is MUCH more prone to detonation.

I'm not saying that there arent any reliable turbos out there, I've seen one with 174,000 miles on the clock with 94psi on all compression faces, and all it had was a RB catback.

N2O sounds fine to me, I wouldnt mind doing it at some point, just that if I ever run lean while spraying, I'm out my daily driver :p

scathcart

Pulling timing on a CDI box on the leading coil results in negative split timing at WOT on a stock ecu, and a blown motor.

Its not really for safety, either... its for traction. If you are running a big enough shot to break the tires loose when you engage the nitrous system, then you should run a progressive controller.

Also, its a progressive controller... it is RPM dependant to engage the system, but after that, it is time-based to full engagement, not rpm based. If you set it to come on at 3000 rpm, and then set a 4 second ramp up time, you would get full nitrous at different rpms for every gear.

There are some better controllers out there as well. Nitrous Express and FJO built a fantastic unit that I have been playing around with lately... much superior to the jacobs.

Tofuball

Do you have a document that covers the ideal timing for both trailing and leading plugs? My ECU allows the control of each seperately. Or at least point me the right way for the theory on such a topic?

scathcart

I was referring to the stock ECU, which runs zero split at WOT.... so if your retard the leadings, you get negative split.

What ECU are you using? What kind of engine? Are you looking for just WOT timing, or what?

RoadRaceJosh

True. I wasn't advocating the system primarily for the timing, but the feature is there. Works a lot better for cars with one coil though.

I disagree. If you push the button on your 100 hp shot you get 100 ft/lbs of torque at 5252 RPM. If you push the button at 3000 RPM you get 175 ft/lbs of torque and a lot more combustion chamber pressure and greater chances for detonation.

The Jacobs system is 100% RPM so the torque increase can be made nearly constant across the RPM range. The NOS system is time based and that sucks.

What do the NX and FJO systems cost?

scathcart

Well.... you either took this link http://www.chevyhiperformance.com/te...48_0208_nitro/
, took the numbers from this article and then divided them both by two and then tried to claim it applied to rotary power curve....

Or you used HP=torque*rpm/5252 and got your values that way....

Either way, its wrong. A 100 hp shot won't give a 100 hp gain across the entire power curve, its a peak gain. If it did, you could launch at idle with 700 ft-lbs of torque. It would also mean that your torque curve decreased throughout the entire rpm range, giving slower acceleration as your rev's increased.

Having pointed out that flaw in your reasoning, should I continue with what's wrong with the detonation-during-engagement theory?

Looked into it, and indeed, it is RPM based. Still not all that useful for anything but a automatic-drag car.... needs to be tunable for each gear to be useful in a standard... that's why the FJO uses gear counting.

What do the NX and FJO systems cost?[/QUOTE]

$600. Made for NX by FJO.

RoadRaceJosh

$600. Made for NX by FJO.[/QUOTE]

I don't read Chevy HP. I do, however, know how horsepower is derived from torque and RPM.

I would love for you to explain how burning 100hp worth of extra fuel and N2O does not make 100hp. If the engine can take it you'll make slightly more power from that fixed amount of fuel and N2O at say 3000 RPM than you would at 6000 RPM due to the lower frictional losses.

I'm saying you cannot add 100hp worth of fuel and N2O at idle as the extreme pressure breaks engines. Heat and pressure cause detonation and the pressure goes sky high if you hit the button at idle. And you pointed out the additional problem of trying to use N2O on a 6 port before the secondary ports open, but that's a manifold air/fuel stagnation problem.

I'm saying that the ADDITIONAL torque with N2O falls off directly with RPM. I fully understand that the rotary has a rising torque curve. The fact that a rotary has such poor low RPM torque and combustion pressure means that it can handle more additional torque from N2O at low RPM than a piston engine with a relatively flat torque curve. As the torque added by the N2O torque falls off the engine naturally makes more torque up to a point where it also falls off.

Injecting 100hp worth of fuel and N2O will have twice the torque GAIN at 3000 RPM as it does at 6000 RPM. This does not mean the engine as a whole puts out half as much torque at 6000 RPM as it does at 3000. A single stage N2O system provides a fixed HP gain, not a fixed torque gain.

RPM proportional N2O is still valid for a manual transmission because of engine strength and detonation limits. Gear dependant N2O is still valid for an automatic because of traction limits.

Tofuball

I'm using a MegaSquirt with the sparknextra code.

I'm only looking for WOT timing under N2O, if it is different then a regular WOT timing, or if I should just retard the whole thing and leave it at zero split.