Nitrous fuel pulsewidth question

Tuning concepts, methods, tips etc.

Moderators: muythaibxr, jsmcortina

Nitrous fuel pulsewidth question

Postby Eaallred » Fri Mar 02, 2012 8:02 pm

Hey all,

Getting ready to finish rebuilding my engine and install a dry nitrous system onto it.

Just want to check how to get a rough guess on where to set my additional fuel pulsewidth to.

I am going to be installing much larger injectors and re-tuning it N/A before I start doing nitrous, but using last years tune for example, let me know if I have this right:

My required fuel is 9.5, 2 squirts per cycle, so my ms is 4.75.

A point on my VE table where my car makes 100hp is tuned to a numeric value of 72.

If I were to run a 100hp shot of nitrous, would I multiply 4.75 by 0.72 to get my additional fuel pulsewidth of 3.563, maybe to be safe for the first run multiply it by an additoinal 25% to make up for flywheel hp being higher than the chassis dyno shows, and be a bit rich to be safe? So start at 4.450? I will obviously wait until I dynotune it N/A with the new injectors before looking at what numbers to reference, but is my math right?

Appreciate the help, just want to make sure the first time I hit the button, I don't do something horrible to my engine.
Eaallred
Helpful MS/Extra'er
 
Posts: 90
Joined: Fri Sep 26, 2008 8:39 pm

Re: Nitrous fuel pulsewidth question

Postby Blue93Dakota » Fri Mar 16, 2012 10:07 pm

Seems like it would make sense. Wouldn't you not need to add as much since the injectors are already opening and closing? Therefore you would not need to account for the dead time as well as the open and close time, right? I really don't know, just thinking. Good luck and let us know if your estimate was close.
MS3X, 93 Dodge Dakota, 408 R3, Indy Heads, Twin 66mm Bullseye BatMoWheel Turbos, Tial 44mm Waste Gates, Tial Q50mm BOV
Blue93Dakota
Helpful MS/Extra'er
 
Posts: 46
Joined: Mon Jul 04, 2011 5:45 pm

Re: Nitrous fuel pulsewidth question

Postby Eaallred » Sat Mar 24, 2012 12:41 pm

Good point about dead time and open/close time.

Will be hitting the dyno in the next couple of weeks, will let everyone know how it goes.
Eaallred
Helpful MS/Extra'er
 
Posts: 90
Joined: Fri Sep 26, 2008 8:39 pm

Re: Nitrous fuel pulsewidth question

Postby Blue93Dakota » Mon Apr 02, 2012 3:20 pm

Cool. Be sure to let us know.
MS3X, 93 Dodge Dakota, 408 R3, Indy Heads, Twin 66mm Bullseye BatMoWheel Turbos, Tial 44mm Waste Gates, Tial Q50mm BOV
Blue93Dakota
Helpful MS/Extra'er
 
Posts: 46
Joined: Mon Jul 04, 2011 5:45 pm

Re: Nitrous fuel pulsewidth question

Postby Eaallred » Tue Apr 10, 2012 5:26 am

Getting closer. Got the engine built, but then broke a rocker adjuster which wiped out the rocker arm and found a main bearing squeezing on the crank (found cause of that). Rebuilt engine this weekend, just waiting for rocker arm to get here then will schedule dyno time. I'll be sure to post my results.
Eaallred
Helpful MS/Extra'er
 
Posts: 90
Joined: Fri Sep 26, 2008 8:39 pm

Re: Nitrous fuel pulsewidth question

Postby Eaallred » Sun Apr 29, 2012 7:32 am

Looks to be fairly accurate.

I dyno'd my car on a chassis dyno. For my 87hp shot of nitrous I looked on the dyno at where I made that same HP, looked at the cell and multiplied that by my pulsewidth. It gave me 1.73ms. I made a pass on it last night and it was way rich, which make sense because I took wheel HP and not flywheel HP. But that made it safe to hit the first time. I ended up dropping it to 1.45ms before the night was over.

Hope this helps anyone doing a search for this. MS works great for controlling nitrous! I couldn't be happier with it!
Eaallred
Helpful MS/Extra'er
 
Posts: 90
Joined: Fri Sep 26, 2008 8:39 pm


Return to Tuning

Who is online

Users browsing this forum: No registered users and 2 guests