Ive been pondering buying some dry nozzles to try and eliminate mess and to be a little more stealth.
Can any body give any insight on where to start w/my
F/A adder % vs .coolant temp in PE if i were to do this?
How do i initially figure out how much to add to get me in the ball park?
And if i do find a ball park figure can i trust a w/b o2 with No2?

 

I've seen a few guys refer to using this table. From what I've read in various "hack"s the real purpose of this table is "start routines". Once the vehicle is warmed up and in closed loop (and please don't say you force your ECM to remain in open loop), you should be looking at the % Fuel Change A/F Ratio vs RPM when you are in PE/WOT.

 

No i don,t force my car to stay open loop LOL,I just figured use that table because I thought would make a global change in PE.
So i figure if i ever get my wot tuned in then i would just add to that table for a No2 prom.

 

So you mean the % F/A change vs. coolant temp table
is useless when car is warmed?
Please excuse me if i misunderstood.

 

Anybody on this subject?
Glenn care to elaborate on you reply?

 

I see you did'nt get clarification so I'll thy and help.Glenn is right,use the % Change f/a Ratio vs RPM for wot tuning.From what I understand the ratio vs coolant temp is for startup/open loop.I have seen No2 kits for honda's.So I think you'll be ok,check some vtec boards though.

 

Thanks again KVU ,
Way to often there are to many statements made but never any claification.
I know i can make a dry system no problem, was just wondering if anybody knew any way to calculate the fuel change for a givin amount of NOS.

 

According to Tunercat Help file:

PE %Change To Fuel/Air Ratio Vs. RPM
This table is percent change to Fuel/Air Ratio used when in power enrichment (PE) mode Vs. RPM.

The values from this table and the PE % Change To Fuel/Air Ratio Vs. Coolant Temperature are summed to arrive at the Power Enrichment Fuel/Air Ratio.

The resulting air / fuel ratio can be calculated as follows:

PE AFR = 14.7 / (1 + %Change vs Cool/100 + %Change vs RPM/100)

You don't say what size injectors you're running but it seems to me it would be hard to get idle/cruise smooth with injectors large enough to just increase these tables so they'll add enough fuel.

I have 30#SVO's running at 62# of fuel pressure with the injector constant set at 30#in my bin. I can't get mine to pulse over 9.03pw/79.4% 5275RPM in first gear. I get 8.70pw/85.2% at 5875RPM at the top of second gear.

I've got a nitrous setup but haven't installed it. I'm sure I'd have to run the fuel nozzle from the fuel rail to keep if from running lean since reading the plugs shows I'm still lean with the above settings.

I doubt I answered your question but these tables are summed .

Edited *after* reading Glenn's post, and testing it myself with Datamaster. Seems these are only summed at startup, after that you need to change the P.E. %Change to Fuel/Air Vs. RPM for WOT tuning.

 

Im running 30 lb injectors also and constants set at 27.6 with fuel pressure @ 44 - currenly my duty cycles at 5700 are 67%
and drivability is not bad at all - I was thinking of lowering FP
some more to get higher duty cycle.
I would think i would have some room for enough fuel.
Wonder how LSI do it?
Thanks for the info on the %vs rpm and coolant,so i was right you can make global changes with % vs coolant?
That conv. says im running 10.08 a/f which im sure has to do w/
inj constants being off from actual size.

 

Yes, when BOTH conditions are met (i.e. in start up mode). In normal closed loop, the coolant table would not be used (on most the hacks I've seen).

It's like the Spark Advances are summed (PE, HMSA, Main Spark) but ONLY when the condition for each table to be active is met. This is why guys have to be careful with HMSA to ensure that they don't have this table engaged when in PE mode.

I strongly suggest reading the $32 hack to clarify when the condition for PE vs Coolant is set and not set so you don't accidentally go lean.

 

Im sorry ,
Not sure if it will make a differance.
I did not specify that i am running a 7730 ecm $8d

 

Well, that didn't take long to test that! I changed ONLY the P.E. %Change to Fuel/Air ratio Vs. RPM to some very high numbers from the stock settings and my pulse widths have increased from 9.20's to 10.20's at WOT. As I said before, I couldn't get the pw any higher and was still lean at WOT, but after reading Glenn's post and editing the *CORRECT* parameters with Tunercat I now believe I can get it to run richer at WOT.

Thanks, Glenn!

Sometimes reading the directions can be mis-leading, (especially with PROM tuning and TC's descriptions of what some of the tables are really doing). I still have a lot to learn.

Now, concerning the thread that started this, I have no idea if this table could add enough fuel to run dry nitrous.

 

If i wanted to run dry nitrous through the computer, i would not try to do it by fiddling with existing functions too much. Nitrous is simpler than that, why make it a complex kludge. You know how much nitrous you're injecting, therefore you know how much fuel you need to add. When you know a value, andf the value is constant, why would you want to try to scale it and superimpose it onto another variable. I'd just hack the code and have some switch trigger a constant adder value of fuel into the fuel calcs. Seems hella easier than the alternatives...

 

I see after 4000rpm the pulse width number signicantly decrease for 92 camaro bin now if I want more pulse width I just a dd a bigger number? and will I hurt anything by doing so.. I am new at this..

Thanks