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Nitrous and megasquirt, anti lag feature...


blake culp

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This is still in the early, early, planning stages but i was reading about how you can set megasquirt n spark extra to trigger a nitrous system between x and y map values in order to spool the turbo faster. Anyone have any info or expierence on this? Im running a t3/t4 50lb comp and stage 3 turbine with a 360deg thrust washer so im pretty sure it can put out all the power i want on the top end, but it seems kind of laggy down low. I am still tuning my MSNS-E so im sure that will get rid of some of my lag, at the same time i have always been intrigued by nitrous. thanks,

Blake

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HA!

Yea Baby! perfect combo don't know the answer but just had to chime in. I've read the same solution for turbo lag...except I would think you would calabrate the NOS systum to do the amount of shot and at what time...could possibly use a rpm index but at take off you would go over said rpm revving up before launch....would think you need to also have it tie in with boost psi?? or time delay after you let out your clutch.....May just have to predetermine the safe amount of shot and use manual button after every shift....

Just thinking out loud...

Have you addressed your MS gremlins you had issues with earlier?

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Len, yes i got all the electrical gremlins solved. Well i think so anyway as i havnt burnt out my gm hei in say the 200miles i have put on it tuning, where before i was frying them in less than 20miles. The megasquirt n spark extra code that i am using already has provisions for nitrous. There are some mods needed to be made to the MS box itself but they seem pretty minimal. It is all described here http://megasquirt.sourceforge.net/extra/nitrous.html

But as i understand it, i can switch to a whole seperate timing table (slightly retard the timing) or retard the timing by a set amount without switching to a new table when the nos is activated. i can even run a seperate fuel table, but i plan on using a wet system so i wouldnt use this feature. Furthermore i can have the nitrous system turned on (simple toggle switch) and activate it by a WOT switch but, the MS will only allow it to spray between two set MAP values. So what i am thinking is to have it turn on at say 85kpa (~-2psi) and turn off at 160kpa (~9psi) and run 12psi-15psi of boost with the turbo alone. When driving all i would have to do is open the bottle, throw the toggle switch, and floor it. MS takes care of the actual activation of the nitrous and fuel solenoids. Depending on how i have it set up i would really only use it for a second or two in first gear at the track... maybe a fraction of a second after each shift, i should be able to keep the turbo spooled and the psi up by shifting quick and my blow off valve.

Another thing that i think is really cool about this feature is that the timing will be completly normal untill the nitrous is actually spraying, The instant MS sprays the nitrous it will also switch tables/retard by set amount. This would keep daily driving the exact same as before, as opposed to sluggish daily driving with the timing pulled a set 5-10 deg just in case you want to use the nitrous, that make sense?

I know the idea of using nirtous to spool a large turbo has been around for a while, but it would be nice if someone has done it using the megasqurit ecu to trigger the nitrous i have been searching msefi and yet to find much info from people actually doing the mod. I like staying more on the cutting edge, not the bleeding edge.

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How do you tune for nitrous?

 

I would probably use this feature and install a dry kit, let MS take care of the extra fueling needs. Can you still use an O2 sensor, or do you need something more elaborate to tune when the car is on nitrous?

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Blake I'm amazed at what you say!...

Personally since I'm not that up on NOS or MS ..I would think the wet kit would be a good idea as just a double safety measure... knowing you WILL have enough fuel at time you spray. I guess you having those larger injectors... dry wouldn't/shouldn't be a problem either.

 

You burn't out a GM HEI distributor every 20 miles??? why? ouch!

 

Again all the versitility of this MS...I'm wondering if I should do the 300 zxt ECU switch afterall...bottom line I just need more time to work on my car.

Maybe since you have the newer model MS not too many people have walked the path you are about to travel...so you can be the GUIDE..your thoughts sound right on....carry on Kemosabie :)

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olie, i have no idea how to tune for nitrous from what i understand with a wet kit the nitrous to fuel mixture is done by the "pills" that which are in the nitrous and fuel lines themself so by the time the fuel and nitrous gets to the jet it is sprayed in the correct proportions. Im sure you would tune with a wideband 02 sensor, keep it rich, and retard a few degrees timing. I dont know much about dry systems, mainly because i always heard wet systems were somewhat safer so thats what i planned on installing. Im really hoping that someone who has put nitrous on a turbo car will chime in with some knowledge from expierence.

Len, i think i was burning out the hei's because of a bad ground or over heating, i went through three of them. (gotta love autozones lifetime warranty though, lol) This last one i ran a extra wire for an even better ground and bolted the thing to my fender well with a lot of "heat paste" seems to have done the trick. I am actually running the older megasquirt its a version 2.2 but the code i have downloaded to the ecu itself is the most recent. Mega squirt and spark is the old code, im running mega squirt and spark EXTRA. Im pretty sure once we meet up either at your place or the drag strip youre going to be hooked on MS, the install is so clean, and ultimately adjustable. The 300zx ecu may keep you happy for a while, but what happens when you max that system out...however, im not sure what the 300zx ecu is capable of.

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A wet nitrous system is tuned using jets that are measured in thousanths , on a simple shot like your talking about a fuel system "T" would be used and a single fogger nozzel would provide the fuel and nitrous.This will spool the turbo INSTANTLY and the intercooling effects of the N20 will be felt as well.Anytime a lean condition on nitrous is experienced bad things will happen , running a wet system is the safe way to go esp. going into unknown territory.

 

http://www.go-fast.org/z28/new_to_nitrous.html

 

http://www.dynotunenitrous.com/store/Scripts/

As source for cheaper solenoids and kits than NOS,NX ect.

 

 

This is a good writeup on how to installl a basic N20 system.

 

The thing to remember about nitrous is that it`s basically compressed air in liquid form.If you are tunning nitrous I would strongly suggest using a wideband and to set fuel settings very rich then to back off the fuel rather than starting lean and using cyl head/piston aluminum as fuel.The cool thing about using a seperate map with a wet system and MS is that you can taylor your fuel and retard settings to compensate for the N20 jetting .Personally, once you start spraying I belive you will want the system on all the time through a 1/4 mile.It`s one of the few upgrades that I have done that literally shocked me at the dyno.Plus turbo`s and N20 go together better than peanut butter and jelly.

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Thanks 510 for your input.....Hot Dam! If I know Blake....your post is going to spool him up faster than the N20 ........with regards to installing it on his Z :)

From what I understand they have 4, 6 and 8 cylinder N20 systums. My question is could a person buy say just one "wet" systum for example a fogger type. Then be able to install it in either 4, 6, 8 cylinder engines? I would think you would need a plate to place under the 4 barrel if being used for a carborated. then say drill and install a jet after the TB (or before I wouldn't know) in our turbos or FI engines.

Then use less of a shot for smaller engine and larger shot for bigger engines?

thanks

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A person could run a single fogger nozzle with a 40HP shot or so just to spool up the turbo.A port nitrous system is more difficult to plumb and really is unnecessary for a small shot just to spool a turbo.Place the fogger nozzle at least a foot away from the TB so the N20/ fuel can atomise properly.I would just leave everthing connected on the motor that the shot is tuned for.There is more to it than just bolting a few things on the car and hitting a button...that would be a really good way to break a motor.PM me if you want a list of everything you really need to be safe.

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