For those who haven't see the IAT vs Timing table here it is. Just log your IAT with NO2 and make the necessary timing reductions...

 

What program uses that display?

 

Thats EFI Live. I'm sure that graph will make more sense when I get my software and start playing with it.

 

So, if I adjust the table to reduce timing in order to run nitrous the PCM will run this reduced timing at every WOT run, correct? So this means when I'm not spraying I will see a small?? hp drop because of the reduced timing and no nitrous? Being FI, I'm only running 18-20* @ WOT anyway. Would I need to turn down even more because of the N2O? What are guys who have actually done this running in that table? 16*?

 

I was making 9-10 psi boost. I ran 20 degrees whether on the track on the street. Whether I was spraying my 50 wet shot didn't influence me at all. Would I recommend do it exactly like I did again... not exactly. I would run a little less timing on the street (16-17 degrees) and maybe 18 or 19 at the track with the nitrous. In other words... I'd run a little bit safer to live a longer happier life

 

running a dry shot on a radix. that's a great way to run lean. if you have a radix that runs hard at all, you're maxing the maf's capable reading to start with. even if you extended the maf's range by descreening it and rescaling it's tables, i think the nitrous would still run you again into maxing that. we discussed this before for a naturally asperated application (Link ), but hadn't tried it yet. as far as putting nitrous through the radix though, a 50 shot has been performed on a SSS with success even with the 2.9" pulley and 10.0:1 compression. i would say on a standard compression setup a 75 shot should be easily done, only on race fuel would i try it though.

 

As a side note.... my IAT's never reflected the drop in air temp that I received from the N2O. So.... if you are thinking about basing timing off a change in IAT I would suggest you consider abandoning that plan. Seriously... a 50 shot showed nothing to the PCM. I would guess this is related to the relatively small ratio of N2O to Air AND the fact that the Radix IAT is located in a big aluminum case that tends to be hot right about time you are hitting the N2O.

It MIGHT show a drop in IAT to the sensor if you ran less boost, but I can't confirm that.

Some may recall the post from John Ulaszek (spelling?) about his tests with that thermocouple inserted into the Radix pressurized cavity giving different readings than the PCM IAT sensor. They were hotter temps that the PCM reported.

I don't doubt for second that the N2O gives a temp drop... but in my experience the IAT wasn't into the airstream far enough to really notice.

 

If you log while spraying you will see a drop in the IAT. Depending on the outside air temp and your boost the actual temp the IAT sensor see's will vary. But log the grams/cylinder and you'll see where to make the adjustments. No if you see a 25c degree drop based on your usual IAT in the Gm/cyl range your seeing during boost then pull timing there. This would probably require you to have a few tunes a couple for hot/warm summer days cool summer/fall days ect.. LOL or you could skip all that and BUY EFI FLASHSCAN... and go to your local GM dealer and buy a 2 bar map and use this table (which comes with EFIFlashscan for Zero 0.00 extra dollars.. ) You'll find you'll really wake up your Radix with a good SD 2 bar tune.

I've run more than 16 degress of timing with NO2 but I've never had a stock engine for more that a month or two. Forged internals are always best when the budget permits. The stock LS1 block and pistons should be good for a 75shot if you don't get carried away with the timing.