Tuning a 93 3.4 Firebird

[robertisaar]

that one flew over my head obviously...

i'm saying normally, the kill value is say 108 and restore is 105. my theory is that if kill is still 108 but restore is above it, like 111, the PCM would still limit speed to 108, but it won't suffer the massive bog down to 105 before the fuel kicks back in.

basically, instead of waiting for the speed to drop, it will maintain it at exactly 108 by alternating between cycles where fuel is injected to speed up and fuel is held to slow it down. a much softer way to limit speed.

[tkoforpresident]

i was datalogging and decided "this seems like a good idea".

so i put foot to floor and quickly found out that the PCM cuts fuel at the limiter... and that my brakes were damn good at one time.

i don't have that log anymore, but i do remember calculating my injector duty cycle from it as well, somewhere in the 70s...

the "110 barrier" might be the speedo inaccuracy, wouldn't surprise me at all. if they meant it just couldn't pull any farther, thats different, but i was still making steam, hit 108, fuel cut so the car slowed down naturally, with my foot to the floor, it got back to the restore MPH, hit the limiter again, then i decided to test the brakes at 100+. Disk/Drum still works good for me!

Awesome! Hey Day!! all righty!!

I was wondering what you meant by putting the reinable speed higher than the kill speed.

[robertisaar]

i was datalogging and decided "this seems like a good idea".

so i put foot to floor and quickly found out that the PCM cuts fuel at the limiter... and that my brakes were damn good at one time.

i don't have that log anymore, but i do remember calculating my injector duty cycle from it as well, somewhere in the 70s...

the "110 barrier" might be the speedo inaccuracy, wouldn't surprise me at all. if they meant it just couldn't pull any farther, thats different, but i was still making steam, hit 108, fuel cut so the car slowed down naturally, with my foot to the floor, it got back to the restore MPH, hit the limiter again, then i decided to test the brakes at 100+. Disk/Drum still works good for me!

[tkoforpresident]

......... i tested the limiter on the monte when it was still 1.5.

pulls all the way to 108 then it cuts fuel...

i have to wonder if it would limit it softer if the re-enable speed was higher than the kill speed...

hmm... what do you mean by that?


I've heard of people hitting the so called "110 mph barrier"

so i knew there was a fuel cut off at some point.

[robertisaar]

......... i tested the limiter on the monte when it was still 1.5.

pulls all the way to 108 then it cuts fuel...

i have to wonder if it would limit it softer if the re-enable speed was higher than the kill speed...

[tkoforpresident]

that would make them 20.37lb/hr injectors.... which is about a 3.14% bump from your number at 47psi...

so yeah, 196 is perfect after rounding.

Cool, thanks for double checking my hw

btw, i just changed the speed limiter kill speed to 255 mph lolz. Never have to worry again.... ( i would never go faster than 80 unless i was on a track)

I doubt i'll ever go past 100, but it's nice to know there's no restriction any more.

[robertisaar]

that would make them 20.37lb/hr injectors.... which is about a 3.14% bump from your number at 47psi...

so yeah, 196 is perfect after rounding.

[tkoforpresident]

lol my bad....


So what the 3.5% increase in psi does is essentially change the injector size to:

19.7495 Lb/HR

which added into isaac's equation (as i have decided to call it)

= 202 BPC with 19lb injectors at 47psi !! (way off from 193)

Now that i have the equation right.... I can decide which psi to run...

what's your opinion Robert? I can run anywhere from 43.5 psi all the way up to 60 with the holley afpr. I'm thinking somewhere around 50 should do.

OK, i've decided to run 50 psi... at least for starters.

I came out with BPC of 196. That makes logical sense right? considering

19lbers @43.5 psi was 210

and

19lbers @ 47psi was 202

so... looks good to me. I'll go change it in the .bin

Like you said Robert, I can always up pressure later.

[tkoforpresident]

Max....

This is driving me insane.... but is there the least little chance that the Brand New Crank (DIS) Sensor you bought and installed...could be bad...? Or would that show up on your Actron Scanner?

Well, technically my 24x Sensor IS bad. (the one behind the HB)

I installed a new one during the build and when i scanned it post build it was throwing a code for the 24x sensor signal loss. But my bro's 3.4 camaro ran with the same code for a long time and only had difficulty on starting the car up from now and then. Also, when i switch over to obd-1 with the swap kit, that sensor will be made irrelevant anyhow, as well as the cam sensor and one of the o2 sensors, etc.

Now if your talking about the more important 3x crank sensor in the side of the block i'm not getting a code for that on my scanner, and i didn't even replace it during the build so there's a good chance that sensor is still fine.

[60dgrzbelow0]

Max....

This is driving me insane.... but is there the least little chance that the Brand New Crank (DIS) Sensor you bought and installed...could be bad...? Or would that show up on your Actron Scanner?

[tkoforpresident]

hahhahahahah^^^

i'm assuming the connectors that will make my pcm kit complete???

[robertisaar]

I did not disable the speed limiter.

Guess what showed up today?

???

[ForcedFirebird]

I did not disable the speed limiter.

Guess what showed up today?

[robertisaar]

in my A1 ADS, there should be a speed/rev limiter catagory, probably near the bottom of the constants...

[tkoforpresident]

i'm guessing there is a cell called "speed limiter" ? or "fuel cut off speed" ?