OK, I've got my dry nitrous system working really well in speed density...much better in fact than running with a MAF. No more lean spikes and very consistent fuel delivery. I have just one question:

Because I'm spraying in my air lid, my IAT sensor will go into the 20-30F degree range during the run. Will big drop in IATs affect fueling or timing in speed density? The only table I can see that it might is in Charge Blending. Most of the other tables are more referenced to ECT and not IAT.

 

2000 didnt have access to the IAT vs. ?????? tables like the 2002 does. I was going to swap to a 02' OS and go from there, but never got around to it.

 

Thanks for responding Charlie. I thought nobody in this section cared. I've gotten 17 replies in the PCM section on the subject. Yes, I'm still using the 2000 OS. I've loaded the '02 OS and even EFI Live OS5, but I still prefer how my car runs with 2000 OS.

 

You are the second person that I've heard of doing this (switching from the 2000 OS to a 2002), and not being happy with it. Kinda weird...

Keep us posted on how it works out.

 

The IAT vs power adder is the only table I know of, but I am no pro tuner. How is it the SD tune eliminates the lean spike and the MAF does not? I have no lean spikes running upto a 250rwhp shot going through the maf. Fuel system is upgraded (pump, reg and return at rails, injectors)(which goes a long way in eliminating spike), and activation of the PE is set to come on below the set on rpm for n2o.
Robert

 

Robert, in my case, there's about a 1 second delay from the nitrous hitting to the fuel ramping up when running a MAF. Lifting throttle on gear changes doesn't help either. With my OLSD setup, I'm at full fueling at 95% TPS and the nitrous engages at 100%. No lag time at all. It hits harder than a wet shot.

 

Sounds good, glad it's working fine, and just another one of many ways to tune a dry hit. Wow, a one second delay, is this upon activation?
Robert

 

Yes, after logging many dry activations with EFI live, it took around 1 second before the MAF started reading grams/cyl in the appropriate range and with the LM1 WB, it took around the same time to get in the 11s for A/F ratio.

With the OLSD, the hit is instantaneous!

 

Patrick, I'm experimenting with a timing tricker that is activated by either a window switch or throttle switch and is plugged in between the IAT sensor, basically a PnP system with a little bit of wiring. During normal operation your car can run an optimal N/A tune and an optimal nitrous tune. The pic below shows the IAT the PCM reads, the total timing and the IAT timing correction.

Myself and another engineer designed the hardware and we are going to put it together hopefully this weekend. I should have some time to play with the fuel this weekend



We did some experimentation with the stock thermistor (IAT sensor) and found the response to be to slow. Even just mapping out the resistance vs temp took time because we had to wait for the thermistor to come to an equilibrium. We checked the temperature reading with a dedicated K-type thermocouple. You can see where we cycled the relay on and off using an independent power source.

This all came about after I found a customer car running lean with a dry shot. Fortunately he had an 02 car so I could adjust a couple of tables for fuel and timing based on the IAT reading. Well the response was too slow and temperature drop not enough were I felt comfortable with the tune. That and the readings weren't extreme enough to keep it in an area that the vehicle would never see in day to day driving so the customer could have the best of both worlds.

I don't know if anybody has done this before, never really bothered to check.

You can do it with an 00' but you can only control timing with the OS. I upgraded mine to an 02 (for a lot of other reasons) and it was nice to find you can control both timing and AFR with IAT.

I'm hoping the reaction to fuel will be just as instant.

I have ordered the connectors and hoping <crosses fingers> they'll be in friday.

 

sscam68, are you also SD tuned?
Robert

 

no i'm not

 

Patrick, when you tried the 02 OS, did you go back thru the tune and alter the additional parameters that are extended, like RAF, where the 02 has more temp columns etc? I know if you simply try swapping over the basic raw values from the 00 to the 02 there are tables that will be left unchecked, unaltered etc and causes problems. Using the IAT Trickers, be it like sscam68's or adjustable pot's are a nifty thrifty way to compensate, but if you can dial in the 02 OS I am thinking that would be the easiest and least "add-ons."

 

Charlie, yes I very painstakingly checked and rechecked all tables to load them up with comparable 2000 values, even where the 2002 OS had higher resolution tables. Hmmm...

Don't know why it didn't run better. Like I said, I even messed with the Roadrunner for a whole weekend trying to get it as good. And when you have real-time tuning, that stuff gets changed FAST!

 

Patrick.... what is the run down of what it takes to put a dry kit on top of a SD tune?? Layman's terms if ya dont mind.

 

You mean you want to get rid of the almight Zex kit? lol

 

With speed density, I made my PE multiplier inactive unless my TPS exceeded 95%. To compensate for a possible lean condition on motor, I added 13% extra fuel to my 90-105KPa VE tables to get them to keep me at 13.0 A/F ratio up to 95% TPS. This mimicked my NA tune as my VE tables were tuned with my PE multiplier being locked in at 1.13. At 95% TPS and above, my PE multiplier is 1.30 (adding 30% more fuel). So under 95% TPS, I'm at 13.0 AFR N/A in my 90-105KPa VE tables, then as soon as I'm at 95% TPS or higher the extra 1.30 PE multiplier kicks in. Basically, the fuel is already there by the time the nitrous hits (at 100% TPS). No delays. It hits harder than a wet shot (since wet shots can have lean spikes too).

Here's how I did it:
Let's say that my NA tune has my VE table peaking at 115% at 100KPa and 103% at 90KPA. Well this is based on my PE multiplier of 1.13. When I zero my PE multiplier for anything below 95%, it leaves the VEs on the lean side from 90KPa and greater. To compensate, I add the 1.13 back to the 90,95, 100, 105 VE numbers. Now my 100KPa VE table peaks at 130% and my 90KPa table peaks at 116%. So now, up to 95% TPS, my tune is exactly like my NA tune.

But when the TPS exceeds 95%, it adds the 1.30 PE multiplier to compensate for the nitrous that hits at 100% TPS. The 1.30 multiplier seems to work well with the .065 jet at 1050 PSI.

Special thanks go out to Geoff from Thunder Racing for giving me the idea.

 

Maybe I don't totally understand the SD tune, but I have a question. How is it that before you zeroed out you PE multiplier under 95% TPS, it was suppling extra fuel? PE multiplier is normally on at 100% TPS, is this a SD thing where you enable it normally at a lower than 100% TPS? But in this case you brought it up to 95% (for dry hit) and needed to find another way to add fuel in the 90/105kpa area? Just trying to fully understand and not trying to bust your *****.
Robert

 

Gosh Robert, I thought I explained it in pretty good detail above. Let's see... normally, to achieve a 13.0 A/F ratio on motor, I have my PE multiplier set to 1.13. This adds 13% fuel to make my 14.63 A/F ratio 13.0:1 at WOT. But since I wanted to add extra fuel for right when the nitrous hit, I set the PE multiplier to 0 for any TPS lower than 95%. To compensate for a possible lean condition at greater loads, I added 13% fuel to my VE tables in the 90-105KPa range. So even with my PE multiplier at 0, I was still at 13.0:1 A/F ratio at heavy loads up to 95% TPS.

Once my TPS exceeded 95%, the PE multiplier kicked in and added the 1.30 (extra 30% fuel) so my fuel was there by the time my nitrous kicked in at 100% TPS. Hope this makes more sense.

 

[QUOTE]...I set the PE multiplier to 0 for any TPS lower than 95%...[/QUOTE]
Ok, I understand the rest of what your saying, your quote in blue is my question. How is it, and why was it, that your PE multiplier was suppling fuel below 100%, or in this case 95%. The WOT PE Multiplier normally only comes into effect at wot or 100% tps, right? So, did you have this set below 95% before you tuned it for the nitrous, for added fuel, that's what it sounds like? Tell me what tables you used. I understand that you state, that you had a 1.13 multipler to change from 14.X to 13.x n/a, but this does not happen at part throttle, only at WOT, right, or am I missing somthing here?
Robert

 

You're missing something. The PE multiplier is based off both TSP and load (MAP reading). The PE multiplier comes in around 85-90KPa and often will come in at throttle positions as low as 30% (think low rpm passing in 5th or 6th gear).

Great news is you can adjust the parameters for either. In my case, I kept PE from coming on until the TPS exceeded 95% and to compensate, I pumped up the VE tables by 1.13 in the 90-105KPa range. As long as I keep my TPS at 95% or lower, my car drives 100% like stock. With a 90mm TB, you can get nearly all your power with 95% TPS or less.