Transient Fuel Stops Working above 3999rpm

[10_SS]

well i dont know, there are other areas that have high FP and have a bit of a spike, but just like my logs, FP fluctuates, on my bench setup I 0,d the FP injector compensation and it clearly stopped at 4000rpm. But now you got me wanting a fast WB like yours.... i know its PLX but what model, or are they all the same? mine is NGK and looks so slow... wonder if its causing tuning problems

[cc-rider]

well i dont know, there are other areas that have high FP and have a bit of a spike, but just like my logs, FP fluctuates, on my bench setup I 0,d the FP injector compensation and it clearly stopped at 4000rpm. But now you got me wanting a fast WB like yours.... i know its PLX but what model, or are they all the same? mine is NGK and looks so slow... wonder if its causing tuning problems

My wideband is the PLX Gen4. It is pretty damn fast. Ive got it installed in the collector of my long tube headers.

[schpenxel]

PLX w/4.9 sensor isn't bad

The new AEM's with CAN bus support are the fastest out there though. Dr.Mike has an update that lets you connect them to the OBD port and then log WB data over the CAN bus in HP Tuners instead of connecting the WB to the HPT interface directly. Not sure if you already knew about that or not, but I thought it was pretty cool.

Faster, and no ground offset issues.

[10_SS]

PLX w/4.9 sensor isn't bad

The new AEM's with CAN bus support are the fastest out there though. Dr.Mike has an update that lets you connect them to the OBD port and then log WB data over the CAN bus in HP Tuners instead of connecting the WB to the HPT interface directly. Not sure if you already knew about that or not, but I thought it was pretty cool.

Faster, and no ground offset issues.

I think either way I need something new, my NGK data looks like massive averaging compared the CC-Riders... I wonder if my sensor is going bad... this one is $189, seems pretty cheap. "The DM-6 + SM-AFR Wideband Gauge Combo - Wideband Air/Fuel Ratio Oxygen Sensor Controller (UEGO) with 2 1/16" touch screen gauge. Combo includes, multi-touch gauge, aluminum controller box, Bosch LSU4.9 sensor, sensor harness, and wire/connector kit."

And, my NGK AFR reading between shifts stays low, though not sure if it is this low, but my 02's do stay around 700mv, so maybe... log snippet attached.
On the first WOT below 3999rpm you can see I get some Injector Spike and matching AFR richness which you want, on the second shift right at ~ 4025rpm you see no injector spike at all, and a slow AFR enriching transition. The 1st Inj Spike is occurring with ~50-psi fuel pressure, the second shift with no spike is ~51psi...

120a lots of WOT SHIFTING SNIPPET.hpl
Camaro2.Charts.xml

[schpenxel]

Yeah, the new ones are way faster. If you can find the thread about the new AEM model there are some test results in there that show reaction times for several common models. PLX was good but a bit noisier than most. AEM's latest and greatest was (surprisingly to me) the best tested

I've been using a PLX for a while, no issues. Same for a few other friends

[10_SS]

Yeah, the new ones are way faster. If you can find the thread about the new AEM model there are some test results in there that show reaction times for several common models. PLX was good but a bit noisier than most. AEM's latest and greatest was (surprisingly to me) the best tested

I've been using a PLX for a while, no issues. Same for a few other friends

Maybe the noise is what I see in CC-Riders PLX that makes me think mine is "averaging" too much. I definitely don't get the sharp on/off AFR that the PLX gets, that's what I really want. Maybe I'll use my NGK for my lawn mower. I updated my post above with a log snippet and chart if you want to see my shifting with NGK (and reduced throttle opening rate, which makes my Whipple MAP/MAF airflow transition look just like CC-RIders (also makes me think something is up with the Whipple setup... others don't appear to cause pressure spikes at tip in).

Good discussion

[10_SS]

Yeah, the new ones are way faster. If you can find the thread about the new AEM model there are some test results in there that show reaction times for several common models. PLX was good but a bit noisier than most. AEM's latest and greatest was (surprisingly to me) the best tested

I've been using a PLX for a while, no issues. Same for a few other friends

here's two links about the comparison. Anyway, there is mention of the AEM 30-0300 gauges needing to be flashed by Dr. Mike to use over CAN with HPT... is this true? They don't just work over CAN out of the box? In post #10 gmtech16450yz says "I've got dual AEM 30-0300's in my LSA Sky now, I'll finally be getting it out of my shop tomorrow or Monday. I sent my gauges to dr.mike to have them reflashed so I am also reading them off the CAN line like the OP described. "

http://www.hptuners.com/forum/showth...k-Afx-wideband
http://www.ctsvowners.com/forum/66-t...omparison.html

[cc-rider]

Maybe the noise is what I see in CC-Riders PLX that makes me think mine is "averaging" too much. I definitely don't get the sharp on/off AFR that the PLX gets, that's what I really want. Maybe I'll use my NGK for my lawn mower. I updated my post above with a log snippet and chart if you want to see my shifting with NGK (and reduced throttle opening rate, which makes my Whipple MAP/MAF airflow transition look just like CC-RIders (also makes me think something is up with the Whipple setup... others don't appear to cause pressure spikes at tip in).

Good discussion

Took a look at your log. Can definitely see a fuel shot on the first tip in to boost. And then its gone. Can you post a log file or pic of the pressure spikes you see when you don't have your throttle open rate slowed down? I'd like to see what that looks like.

[cc-rider]

here's a link to that post, maybe there's one on HPT? Anyway, there is mention of the AEM 30-0300 gauges needing to be flashed by Dr. Mike to use over CAN with HPT... is this true? They don't just work over CAN out of the box? In post #10 gmtech16450yz says "I've got dual AEM 30-0300's in my LSA Sky now, I'll finally be getting it out of my shop tomorrow or Monday. I sent my gauges to dr.mike to have them reflashed so I am also reading them off the CAN line like the OP described. "

http://www.ctsvowners.com/forum/66-t...omparison.html

Another reason why I went with the PLX is because when I am not hooked up to HP Tuners, I can use my iphone to datalog and monitor AFR and boost. It's a pretty slick set up.

I have a PLX kiwi 2 device with their iMFD module attached to it. This allow me to run a serial line from my wideband box (what PLX calls the SM-AFR module) right into the kiwi device. The Kiwi then plugs into the OBD port and creates a local wireless (or Bluetooth) signal inside your car that you wirelessly connect up to your phone. I use an iPhone app called DashCommand. With all this....I can monitor every single PID that the ECU puts out, and also my wideband. And it datalogs as well. You can output everything to excel. And it has an incredible amount of information. But I mainly use it as simply a boost and AFR gauge. It allow my phone to serve as a boost and AFR gauge.

[schpenxel]

here's two links about the comparison. Anyway, there is mention of the AEM 30-0300 gauges needing to be flashed by Dr. Mike to use over CAN with HPT... is this true? They don't just work over CAN out of the box? In post #10 gmtech16450yz says "I've got dual AEM 30-0300's in my LSA Sky now, I'll finally be getting it out of my shop tomorrow or Monday. I sent my gauges to dr.mike to have them reflashed so I am also reading them off the CAN line like the OP described. "

http://www.hptuners.com/forum/showth...k-Afx-wideband
http://www.ctsvowners.com/forum/66-t...omparison.html

Yes, they have to be re-flashed to work over our CAN bus. They're designed to work with some kind of logger box thing that AEM has and Dr.Mike has come up with some kind of update for them to output CAN data over the cars network in a format HPT can see. I don't know enough about CAN protocols to know what he does exactly or what the differences might be. It's free though, so there's that at least.

It still has the regular 0-5V output too

I haven't used one so can't really say much else about it other than dr.mike seems to know more than anyone I've ever seen about WB's and that one has been the best in his tests

Another reason why I went with the PLX is because when I am not hooked up to HP Tuners, I can use my iphone to datalog and monitor AFR and boost. It's a pretty slick set up.

I have a PLX kiwi 2 device with their iMFD module attached to it. This allow me to run a serial line from my wideband box (what PLX calls the SM-AFR module) right into the kiwi device. The Kiwi then plugs into the OBD port and creates a local wireless (or Bluetooth) signal inside your car that you wirelessly connect up to your phone. I use an iPhone app called DashCommand. With all this....I can monitor every single PID that the ECU puts out, and also my wideband. And it datalogs as well. You can output everything to excel. And it has an incredible amount of information. But I mainly use it as simply a boost and AFR gauge. It allow my phone to serve as a boost and AFR gauge.

That's pretty cool, I'm going to look into that more. I have dash command too but didn't know you could get wideband data over to it

[10_SS]

Took a look at your log. Can definitely see a fuel shot on the first tip in to boost. And then its gone. Can you post a log file or pic of the pressure spikes you see when you don't have your throttle open rate slowed down? I'd like to see what that looks like.

Here is one with full TPS rate at low RPM, you can see the MAP jumps up to 210kpa at 2600rpm which should be less than 150kpa, then comes right down to 150kpa at higher rpm after this event. At higher RPM it is way worse, I had some that logged 250kpa at tip in... then look at my narrow band 02's at this point, one shows 48mv at 210kpa... lol, and I have lots of knock here. It was so bad I could hear the knock at tip in, however I only heard this a couple times then immediately reduced the TPS opening rate and this problem went away. Also at this RPM you should have seen Transients, but the stock tune had them basically turned off (this was before I enabled them by using the ZL1 settings).

With these pressure spikes at tip in with the Whipple, I dont think the system could ever respond fast enoough. Pressure spikes like this are different than a normal transient.

2B005g MAP Pressure Burst SNIPPET.hpl

[schpenxel]

Is there some kind of bypass valve issue or something causing a spike by chance? Total guess. Looking at the log I'm not sure that makes sense though? It's like it spikes then drops then starts building but never gets back to where it was. I dunno.

Got a bit of knock it looks like!

[cc-rider]

Wow. You sure do have a hell of pressure spike. It has to be bypass valve slamming shut way too quickly. Its the only thing that can cause that. It must shut at very low vacuum levels which causes that boost to come in before the engine can even start its rev up in rpms and be able to accept and consume that boost. Whipple must have a fairly light bypass spring in their kit. Did you happen to buy your Whipple kit used from a guy who may have used it with a big cam? I know that big cams on PD superchargers require the bypass to sometimes have no spring dampening effect so it can properly run vacuum/boost it needs.

Not a big deal in the end I guess. You seem to have it completely under control with the throttle slowing down a bit. And I can't imagine that slowing the throttle down a bit would hurt anything at all in terms of performance. These PD blowers barrel into boost so damn quick. The throttle response is nuts to begin with.

Got to wonder how many people are running Whipple kits and have a ton of KR on hard throttle/MAP transients and don't even know it. I know after getting into my tune and datalogging...the spark that KB in their canned tune was way too aggressive and I was getting a ton of KR on shifts. I kind of guessed it just by the feel of driving the car last summer. I think some of these canned tunes take advantage of the advanced KR systems that are on these cars. We are lucky to be tuning in this day and age when we can tune without blowing engines. Just log and check out KR and pull some timing back.

[cc-rider]

10_SS...question for you (or anyone who knows)

I'm ready to start playing with the transient section of the tune. Does changing the transient setting affect the VE or MAF fueling at all in steady state modes? Would it throw off everything by a certain % requiring me to go back in and redo the tables? I am going to check anyway. But I'm just curious if you've notice any broader fueling effects occurring when changing the transient tables.

[GHuggins]

My findings showed it can. So if you're all of a sudden having idle air fuel issues you might want to keep that in mind.

[cc-rider]

Thanks for that tid bit GHuggins. I'll keep an eye on the idle fueling.

[10_SS]

10_SS...question for you (or anyone who knows)

I'm ready to start playing with the transient section of the tune. Does changing the transient setting affect the VE or MAF fueling at all in steady state modes? Would it throw off everything by a certain % requiring me to go back in and redo the tables? I am going to check anyway. But I'm just curious if you've notice any broader fueling effects occurring when changing the transient tables.

I have seen strange steady state WOT fueling from changing some of the Transient Settings, I think in the Transient Fuel Mass Gain section, and sometimes I wonder if this is related to some of the "lean/rich spike" some people see shortly after entering WOT/PE. Whatever I did at some point playing with Transients created a long rich condition that lasted the entire time I was at WOT... so when you make changes, pay attention to things like this.

[10_SS]

Wow. You sure do have a hell of pressure spike. It has to be bypass valve slamming shut way too quickly. Its the only thing that can cause that. It must shut at very low vacuum levels which causes that boost to come in before the engine can even start its rev up in rpms and be able to accept and consume that boost. Whipple must have a fairly light bypass spring in their kit. Did you happen to buy your Whipple kit used from a guy who may have used it with a big cam? I know that big cams on PD superchargers require the bypass to sometimes have no spring dampening effect so it can properly run vacuum/boost it needs.

Not a big deal in the end I guess. You seem to have it completely under control with the throttle slowing down a bit. And I can't imagine that slowing the throttle down a bit would hurt anything at all in terms of performance. These PD blowers barrel into boost so damn quick. The throttle response is nuts to begin with.

Got to wonder how many people are running Whipple kits and have a ton of KR on hard throttle/MAP transients and don't even know it. I know after getting into my tune and datalogging...the spark that KB in their canned tune was way too aggressive and I was getting a ton of KR on shifts. I kind of guessed it just by the feel of driving the car last summer. I think some of these canned tunes take advantage of the advanced KR systems that are on these cars. We are lucky to be tuning in this day and age when we can tune without blowing engines. Just log and check out KR and pull some timing back.

YEs, but I also heard if it doesnt close in time, this can destroy this type of supercharger? Or maybe if it doesn't OPEN in time, so maybe it's closed between shifts, high revs, building pressure (or vacuum) since the TPS blade is shut, then opens, ... one of the two, so I've been hesitant to mess with it, though there are no settings for it. This is what I've been dealing with since the beginning of time with this Whipple and why I whine so much about the transients... lol

No I bought it brand new... shipped straight from Whipple. But, I also complain of the boost coming on too early in the TPS... I get a MAP spike from 95-115kpa with steady Pedal and TPS (jumps right from 95-115kpa, part throttle, when the valve closes) and I absolutely cannot get rid of, it's probably a 25-50hp jump in power.. it almost took me out at a road coarse going 80mph in a slight curve, getting on the gas just a bit, just enough to kick me sideways. Then another time getting on the highway on a curve ramp, I may have moved the pedal 1% and was enough to close the valve, BAM, +40HP, sideways I go.. I tuned the Pedal sensitivity way down in that area but it's still annoying when turning in a curve, and it kicks in, kicks me sideways. I've seen this 95-110kpa blip come on with other peoples logs too though.. they just haven't admitted it yet. Of course I dont remember who they are.

Seeing your log, I see no boost spike at all. That kinda makes me wonder if something is messed up with mine. Yep still so many people just throw the kit on and go... dont even log. lol, mine surely would have been blown up by now with all that tip in knock/boost surge.

[schpenxel]

The key is it has to open when you don't want it in boost

http://www.corvetteforum.com/forums/...post1574360715

[cc-rider]

I've got some transients going now. I populated my transient tables with everything from a stock ZL1 tune. Including the manifold volume (which went up significantly). I've now got a nice shot of fuel on tip in which makes me go rich, and then I go lean on the tip out. This is the complete opposite of what I got when I was seeing before. I used to go lean on tip in, and then hang rich on tip out. Here are a couple of pics showing the differences between the 2 (stock SS transients vs ZL1). Both pics show just a basic throttle blip in neutral.

Stock SS transients.jpg

ZL1 transients.jpg


I am going to play around with the manifold volume a bit to see what effect that has. I think its a scaler that determines the size and duration of the fuel shot. I need to figure out what makes me go so lean on tip out too.