mstansbury0704

Just wondering what people are street tuning with when using wideband and HPT.

Do you use a throttle position filter? I’ve read people doing it both ways. One argument is to not get decel garbage data in your cruising tables, etc. But what is your preferred way of dialing VE and MAF tuning in? I understand for most people it won’t matter much, but for us big cam guys that idle at 70KPA what is the preferred method?

I usually can get my VE dialed in pretty quickly everywhere except those really low rpm & low load cruising tables and maf areas where sometimes there is transitional on/off throttle I.E. maintaining a 55mph speed limit, is this why?

smokeshow

iTrader: (17)

I filter with my eyeballs for the most part. Filter selection and configuration is almost always application-sensitive, so no single set of HPT filters is going to handle all situations. If I really want to make sense of an issue, I parse and process the data in MATLAB.

How you filter your data depends on the hardware combo and the operating conditions you're looking to filter for. TPS is always a good thing to monitor, but large cams can experience large transients with little change in TPS. So unfortunately, the most accurate answer will be 'it depends'.

mstansbury0704

Yea I just applied the tps filter to some of my logs and it only changed it by a thousandth of a %.
I’m having lean tip in transient issues that I can’t get rid of. Tried the fuel to wall impact by multiplying it by 20%. No change at all.

smokeshow

iTrader: (17)

Yeah, that tends to happen with cams that improve scavenging. The impact factor does compensate for the changes to puddle fuel mass, but not for the fuel that scavenging drags out of the cylinder. The software technically isn't designed to handle that effect, but there are other tables that compensate for that very same thing for different reasons. GM has called it 'stomp compensation', which essentially means that a transient fuel correction is applied when you stomp on the throttle. It's meant for cold engine/warmup conditions since cold engines don't burn their fuel all that well, as it may not be vaporized...so extra fuel is added to compensate. This table can be used to add extra fuel at hot engine temps too to account for fuel lost to scavenging. There may be some tradeoffs, but warmup transient fuel cals have been helpful to me to fix that in the past.

mstansbury0704

do you have any idea what that table would be called in HPT on a 2000 OS? Funny enough I’ve read people talking of the stomp table but I think that’s an efi table.. I don’t see a stomp anything on my vcm editor tab.
best I can figure is I think the fuel impact deal uses some kind of kpa vs kpa increase by % or something.
So maybe I’m not right in multiplying the highest kpa and then interpolating the values in between, as then I don’t think I’m really adding any percentage difference. The issue I think might come Because of my like 17 degrees of overlap..cruising around 1500-2k and light throttle. I usually don’t see too bad of vacuum around 50 kpa I think. And in small tps increase I don’t see very much if any of change in vacuum. I’d have to take a look at my logs again to verify but it’s really a PITA and it’s been wracking my brain for weeks trying to get rid of it

smokeshow

iTrader: (17)

Its called warmup transient fuel correction.

mstansbury0704

Here is a log, you can see Flooring it I get a smaller spike to 14.5 and then settles back to less than 1% AFR error and then on clutch in i have a HUGE rich condition followed by a clutch out and 100% TPS i get another bigger lean spike.
IF what ive been reading and searching is correct.. I need to increase the fuel impact @ 100 KPA to help smooth down the 100% TPS lean tip in.

Then i need to increase the fuel boiling rate for I would assume the lower KPA tables to fix the overly rich tip out. Am I right? or am I way off base or in the wrong tables entirely. MAF and VE are very close. VE dead nuts tuned recently (besides decel regions I try to keep a little richer) using O2 error to 3000rpm and dynamic set to take over at 2400rpm. Maf in the log is slightly trending about 2% lean in the lower HZ and less than 1% rich in all hz above 6250.

Im also getting a small lean out on small throttle changes, I.E. going from 15%-25% and I am hoping getting some of these transients dialed in will help me out.

smokeshow

iTrader: (17)

Yeah that sounds right. If you have different heads, injectors or fuel type compared to stock, transients will almost always need to be addressed. And what can't be accounted for in the impact/evap would need to get shoved into the warmup transients.

mstansbury0704

I have prc 225 heads and 42# injectors. So completely different valve angle and ports and the whole 9 yards.
think you could walk me through the warmup transients?
Also, that is correct about the fuel boiling right? Basically the opposite of the fuel impact? So instead of adding to the 100KPA like the fuel impact I need to add to the 20 KPA on the fuel evap table? Is it just a trial and error to it or is it a good practice to say if I add 25% to the 100 KPA fuel impact I need to also add 25% to the 20 KPA fuel

basically this is the best thing I’ve found

Here

and the close to last post
Here
This first I think is an EFILIVE guy but his graphs are very good.

I just wish there was a good write up about this

here in a few days while the misses is at work(the couch isn’t so fun) I’ll have to spend all day working on this. I’m sure once I get this dialed my entire VE table and MAF curve will need to be touched up. With some more digging for me with a big cam I think my solution is to get my WOT whacks down. Then try to get my part throttle either in the impact factor table and if that throws it all wonky maybe my issue for part throttle transients lies in the gain table.

Also, these are my Injection timings vs stock so I cant think of anything else this can be

mstansbury0704

So I took the car to work today, as an update I added 40% (x1.4) to the 100KPA impact table. I haven’t had a chance to review the log but I noticed now my part throttle transients may be a bit worse just from the drive.. Don’t mind the graph data being a little lean, I think the transient lean spikes are messing with my data a little bit. From the drive it looked like hits from 3000rpm was blipping 11.x AFR on my gauge and then settling to commanded. But I haven’t reviewed the log.
I’ve no idea how to settle this part throttle down. It’s hard to get right, throttle changes have very little change in my KPA except from full decel…
Haven’t had chance to really go through it yet but here is the log. Maybe just putting the transients back to stock and richening up my lower curve of the maf will help with the transients at part throttle? I’m lost at this point. Steady state is mint and wot pulls are really close but I just can’t get the transitions to settle down. In fact, it was better driving when I didn’t even mess with them.

*UPDATE*
Added some more. Here there logged, shut off tried changing the gains, Horrible. Put it back to how it was before.. please someone explain to me how the hell to get this right.