RPM data log not smooth? - need Ideas

[JETGSR]

I have noticed with my datalogs that the RPM trace isn't smooth as one would expect.
on a power pull it is eratic on its climb to redline (ie: bumps and troths)

I'm running a sample rate of 100ms E85 4xLS1 coils @ 5.5ms charge rate with a haltech ps1000 (balance shafts removed and fluidamper installed)
I've have decreased the timing right down to 12* but EGT's go threw the roof
leaned up AFR's to 12.2 enriched AFR's to 11.2 still no effect on the trace.
I have also reduced the plug gaps down to .020 not that there was a miss. and changed to a hotter plug (normally run BP8ES now down to BP7ES)
EGT's don't show any strange behavior in the run.

I'm starting to run out of ideas.

The fluctuations can be felt in the cars performance.

The car drives fine under normal driving and in the early stages of boost.
Boost is being held at a constant 22.PSI from 5000 to 7500

My next option is compression test and if that is good I'm stumped.

i've attached a log pic so you can see what i'm talking about.
Could we keep it to educated responses not guessing please - you don't need to keep your post count up with this topic.

Thanks in advanced
Troy

 

[khubner1]

Have you checked or thought about looking at the ignitor sometimes they can send a bad signal

 

[bazeng]

What trigger config on your cas are you running?
Rising or falling trigger?

What about ignition config setup on the ecu?

I would check timing on ecu vs actual with timing light at idle
and at higher rpm.

If trigger setting is incorrect it may not be indicated at idle but as rpms increase and the wave form changes, timing
variation may be note noticeable.

Apart from that, what is your injector timing set as?

Last thing, what about trims/ compensations? Is the ecu doing something differently on cruise vs wot?

Some sort of tps compensations?

 

[JETGSR]

the trigger settings are the same as it has been right from the old E8 days (have posted a shot)

I was thinking possibly CAS? I know my speed sensor input go's a little haywire on a power run and its trace is erratic maybe the CAS is doing the same thing.
So i'm going to log the input and see what that does.

Baz are you talking inj firing angle or dead time? dead times are as of ID2000 specs from their web site (ID2000's installed)

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500 6000 6500 7000 7500 8000 8500 9000
455.0 455.9 459.1 462.2 463.5 464.4 465.2 466.1 467.0 467.8 468.7 449.0 429.2 409.5 389.7 370.0 365.6 361.2 356.9

I've never touched the Injector firing angle? This is another area to look at I guess I have no idea what these should be?
I know what they do but with out a dyno pretty impossible to tune on the road - would these change a lot with a 2.4stroker vs 2ltr


the only trim I have active is a 7% on injector #3 - trying to cool it down as it is about 50-80* hotter at the end of a pull then the rest.

If you look at the first log you can actually see the rpm decrease eg: 6150 6270 6230 6330 6500 6740 6700 6860 <- this just an example

I'll drop more of the other logging data and start logging triggers and inj angles etc and see if we have any strange behavior.

Troy

 

[JETGSR]

just checked a few other maps from other ppl and my inj timing is different especially at the top end.

so I have changed that to same as EVO00X

that could explain why I have a dirty plenum too!! (last time i checked)

also bumped my charge times on my coils from 5.5ms to 7ms LS1 coils apparently can run as much as 8ms with out issues - so i've read....

 

[clone]

what program are you running for your EGT? or does the haltech software have a screen for it ? and whats the input being processed in?

 

[JETGSR]

haltech software processes it
you just set up a new window with what ever gauge you want assign that data to it
so in theory the bigger the screen you have the more dials gauges and sliders you can have and you can move them around the screen to what ever position you want them in.
You can pretty much log any input or output the ECU sees or sends (most decent aftermarket ECU's do this now)

inputs can be configured to look at Volts / Freq or switching
EGT's are volts (they go through an amplifer TC4

 

[bazeng]

What cams do you have?

In order to determine your injector phasing/ timing aka injector end angle, try this.

At idle, start at central value ( 350 or so) change with + button and notice if it stumbles. If not, go down with - button all the way to zero and notice where it stumbles.

Find the stumble point and see if it is repeatable.
The stumble point is where the injector is piling fuel at the back of the valve... you want to ensure fuel is injected before this point.

So if it stumbles at 400, set your injector end time at 300 for your whole table. It should also be the richest point also ( means all the fuel is getting in the cylinder efficiently).

Mine is usually around 350 to 400.

Also 7 percent of a 2000cc injectors is quite a lot! Have you tried moving the injector to another cylinder to see if the hot cylinder followed?

 

[bazeng]

Please do the below:
Lock your timing to 10 deg (either by map or by timing lock in software)
Attach timing gun and check engine timing with light - hopefully 10 deg at idle.
Rev and it should stay the same.
If timing changes, You have a trigger setting problem.
I would change your home trigger to falling and see if that does anything.

 

[JETGSR]

I noticed the inj firing angle is a lot lower in the EVO9 map then what I had
and EVO00X is higher again.
home and trigger count is constant
even with those things changed it still has the trace thing moving up and down.

Am i looking at this wrong? That trace for RPM on a normal log should be smooth right?

Just making sure I'm not chasing my tail.

I will go home and grab my timing light and check the base and for drift.

might drop the EVO9 inj angle map in for logs on the way home.

 

[JETGSR]

cams are kelford 264 inlet 272 exhaust
they do run I think one of the highest lifts.
and I found in the past that my intake runners are always oily looking which would indicate that my inj angle is out.

 

[bazeng]

EVO9 inj timing would be very different due to mivec I would say.

 

[JETGSR]

yep! thought of that but it starts around that 397* and tops out at 480* at 9000rpm

ok Timing is a bit erratic at idle but it is a rough, once you put some rpm into it say 1300 - 6000 (free rev) it is a solid 10*

One other thing I did notice is my fluidamper looks like the V groves do not spin smooth like runout in a rim. (egg shaped)

I'm going to try and measure the run out and check it is bolted nice and firm.

just looking at a new log
BATTERY VOLTAGE ONLY .2 VARIANCE
Did notice idle control motor not shutting under boost holding at 30% (not that this should make any difference but I changed the setting to 0 (it is like a throttle stop) so we will see if it tries to stall now

EGT's still a bit high peaked at 950* so going to add more timing 5500 @ 13.4 to 7500 @ 18.6

I know Tim (brizvr4) is running well over 20* (baby steps grasshopper)

this is evo 9 inj angle 397 397.8 397.8 403.1 410.9 418.6 426.4 434.1 437.0 440.0 443.0 446.0 448.9 451.9 454.1 457.0 460.0 465.0 470.0
.....................................0.......................................................3500......................................................7000..................................9000

 

[EVO-00X]

Have you tuned on E85 before Troy? Or is this your first go at it since converting to E85?

 

[JETGSR]

been playing with e85 for a little bit
was tying to get everything nice before it goes on the dyno and noticed the RPM thing in the logs
it should be smooth but it ain't
was looking at your map for injector timing angle but It seems to make little difference.

I have turned off all O2 input and adjustments so it is purely running of the zero throttle map
then started changing the timing angle it starts a lump at sub 300 and AFR's go up slightly where if i go up to 480 i get the richest AFR @ idle also throttle responce is a little better when you jab it.

Not sure if this is the correct way 480 seems high for 1000 rpm timing angle
evo 9 is like 397 and your tune rob is around 450 Baz is around 350 - 400

I have this across the whole rpm range at the moment - haven't driven it yet

looked at my old E8 map from godzilla motorsport and he had it at 275 which runs with a distinct lump to it.(like monster cams) AFR's are still good
that tune was for 98 PULP

So i'm still confused as hell

I don't think this is the fix to my RPM issue though.

 

[EVO-00X]

Got me stumped man. I would have thought it was just your injectors not spraying properly at low rpm.

 

[JETGSR]

yeah I'm thinking it is mechanical
vibration or something interfering with the overall smoothness of the pull

I'm going to change my fluidamper back to the std harmonic and see if that changes anything?
I don't like the way it has the runout!!

 

[DOUGMO]

if you have reduced the timing and the EGTs have increased you dont have enough timing in it.
if the timing is too low or too high it will raise EGT's (not relevent to your trace but it may help)

to give you an idea my EGT sits on around 600-630 on the track

 

[JETGSR]

just did another log EGT's through the roof tipping on 950 -1000*
what timing are you running dougmo do you have a screen shot of your IGN map? and what boost are you running?

I'm convinced this is now a mechanical thing! nothing I have tried makes 1 bit of difference

but with these temps i'm just waiting for the thing to melt.

Doug check these temps vs timing what are your thoughts?

something i did notice the injector duty cycle is only 50% but it is not smooth neither.

 

[bazeng]

just a thought, can you disable your boost controller and do a run?

simply use spring pressure on your gate.
advise on rpm log after please.