Hal, the only reason I said Jeeps only is because I suspect our transfer cases have something to do with us being limited.
I did not let off as I was testing to see if the manuel switch would caused the same shifting problems. My 3rd gear was going for sometime and is not related to the shifting problems.
I have window switch set to ...on 3500...off 6000...Do you think I should have it shut down a lil sooner beacuse of 1st gear being about 5950 shift ?
You can try and see but then you have the 2-3 and 3-4 shift that will be running without nitrous from 5900-6300. My theory is the 1-2 shift is still pretty firm on nitrous. Its just the 2-3 and 3-4 shift that are kinda sloppy. I would go with window switch off around 6100 and try that. I need some track results to prove one way is better than the other.
With a window switch, as soon as the rpms drop back into the designated range during the shift, the nitrous turns right back on. So if you are using a window switch, you are spraying during the shifts. Personally, for huge shots I'm completely re-wiring my system so I can turn it off during the shifts.
The above statement was pulled off this thread when I had same concerns. http://www.srtconnection.com/forums/showthread.php?t=3853&page=3 What has Changed since you and Chris discussed this Jmatt ? It seems like a push button breaking ground to the N20 Kit would be a good solution.
What changed was the sheer volume of nitrous I'm pushing. At a 100 shot, just spray through the shift - no problem. At a 175 shot, I never had a problem, but was probably placing a lot of extra wear on my trans. At a 275 shot, the transmission can't shift from 2-3 through all the spray. So yes - a pushbutton to interrupt the RPM signal to the window switches is in order. I'm wiring it so the RPM will read 0 when I push the button. SO as soon as the shift starts, I'll press the button, let the tranny shift, then let loose again. We'll see what happens.
That sounds like it could be pretty inefficient and hard to do consistently and optimally. You'd think the Nitrous companies would have something like that? What you need is a cutoff with a programmable delay. If it's not available some hardware nerd should be able to whip one up. If you can light up a shift light you could use that to trigger the cutoff. Then it stays off for some fixed amount of time (just a little more than the trans takes to shift) and re-arms itself.
Well what we really need and I suspect the LX owners will get before us Jeep owners get is, either find the programming in computer to cut duration time between shifts at WOT or way to boost line pressure(shift kit) to decrease time it takes transmission to mechanically shift. I doubt any electrical guru would build something like you describe because it is only a bandaid to a needed solution. Its also a bandaid that a very limited number of people will need.(In otherwords no sales) No I understand why you arent wanting to spray thru the shifts, I had these concerns months ago and Chris stated that you, he and Dave had come to the conclusion that the N20 was cutting off briefly during shifts. (See above quote) With that statement it is only 1 of 2 things that have now come to surface. 1) N20 is not disarming during shifts or 2) Briefly wastnt defined and its only a split second and not the entire duration of time required to complete the shift. I thought I made it clear in that thread that I wanted to disarm the system all together during shifts and was told that tps has voltage change and system would disarm. Im not throwing stones at you, Im just wanting to know the correct answer because I figured all along that spraying through the shifts, regardless of shot size is bad and eventually going to cause premature failure. Thanks
That one wouldn't take a guru. Most any electrical hobbyist could whip that up. You might have to buy them a shift light to take the trigger off of. "Here's $50. Take the trigger off this light and give me a wire that goes low for x milliseconds on the trigger and high any other time". That should do it. Maybe another $10 for adding a tiny 3 position switch for x, y, z millisecond pause so you could tune it. That should do it. About the TPS voltage dropping during shifts... Don't know if this shows anything but here are two DashHawk logs I took when my car was completely stock. I don't know if the PCM reports everything in the PIDs but it doesn't look like the throttle position changes during shifts. I'm not sure about that 'cause from the second log it's pretty clear that the narrowbands go from full rich (WOT mode fuel enhancement pegs them rich) to full lean during shifts. So maybe the injectors are cut off during that time? I would expect Jeff might know exactly what's happening here?
Ran out and got this one to check. About 2 seconds in you can see closing the throttle causes the MAP to drop so it looks like it's logging those correctly. Map stays pretty solid through the WOT shift so it doesn't look like the throttle plate is doing anything at that point. Does that mean they just chop the fuel during a shift (injectors)? That would explain the narrowbands going full lean. That wouldn't be good if you were spraying through that would it? If I totally missed something here I won't be offended if you tell me to just STFU and quit cluttering up the thread.
Actually your one of the few folks that looks at all this in a logical way trying to understand this all. And it would be a great loss if you decided to not post. Yes the injectors shut off whenever the Microprocessor demands it, and spark will ususally fire anyway because even if there is no fuel, the plugs firing won't hurt a thing during a shift because there is no fuel present. All the computer programming is based around that fact. Chrysler's original "Logic" when designing this operating system never planned to run N2O so as far as the stock programming is being used everythings cool. Now corrupt all the design program logic by adding fuel and Nitrous during the shift, (or even a microsecond late or early before the transmission fully completes it's shifting sequence) and the engines still producing torque. Now thats a huge problem as the TCM "talks" to the PCM on the Can Bus and decides the tell the PCM when to turn the fuel back on because the transmission has fully completed it's shift. When that is overruled by adding fuel and N2O during the shift it is only a matter of time before the trans clutches lunch as the shafts are still producing power (think of it as the old term "Slipping the Clutch" on a standard transmission) it doesn't take long before transmission distress is seen. And it also is made difficult by the fact there is not one good circut to access that can define when you can use an external N20 switch. Actually the best way would be to monitor the Can Bus and "Pick Up" the TCM byte that tells the PCM to put power back in. Jeff
Jeff, again isn't this one of the many things that will be truly helped out by "you" geniuses finally braking the codes? The rpm/shift limit raised, tcm re-adjusted, converter adjustments, and those momentary but crucial split second computer tricks will let our beasts really fly. albeit, parts will suffer damage with too much abuse. Keep hacking, I can hardly wait. 10s as is, are possible !
That's a hard one, as there rally is no good bulletproof circut to tie into. If my good ol buddy JAAK would finish the fuel rail test and we could be assured the fuel pump shuts off at redline, I'd say use the fuel pump relay. You can't use the injector signal as it can fire up to 3 times per each ignition event. For the manufacturer the Can Bus is a beautiful thing for us looking for a trigger signal we are screwed. Barring that somebody would really have to hack into the can bus and read the data then tie that data into a custom built module that would read the rpm and use that data to trigger a relay. I do know some people that could make that sort of box. But it won't be out tomorrow. Maybe a Daskhawk could be hacked as a "trigger box" even the Predator. Jeff
Yes, but as someone noted in that other thread, you're going to be burning an awfully dry shot of n2o while the injectors are off right? How bad is that? (I guess it's not really really bad since not too many have blown?)
For a trigger, how about the voltage drop from the narrowbands? You'd only be a little late. Too late? [edit] (now that I think about it, might not be late at all. You don't have to wait for the narrowband to go very far. In WOT mode there is fuel enrichment so they're very solidly pegged high. Any drop in voltage means that fuel has been cut and they react pretty quickly) You'd need the window switch for the rpm range, the throttle position in case you feathered it (maybe don't want to shut it off if you're feathering the throttle and drop out of WOT mode), and the narrowband to detect when the injectors are off. So your stock n2o setup would handle all cases except: (TPS == full open) && (narrowband voltage < x) --> override active (turns n2o off) (narrowband voltage > x) --> cancel/deactivate override function (note: you need both conditions above to re-activate the override) Both these voltages are available to be tapped into physically so it should be pretty easy?
