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Serious KR at part throttle only

97AutoXVette

97AutoXVette

New member
Morning everyone. Here's the scoop:

2002 GTP Sedan

New build mods include:
3" C-less DP
P-LOG
180 T-stat
Ported outlet/inlet Gen3
Ported Stage 2 ZZP Throttle Body
ZZP 9" open cone intake
1.8 Yella Terra Roller Rockers
New stock heat range plugs
3.3 Modular Pulley
60# Deka injectors

I just got the top end put back together and have been doing some tuning and scanning with HP-Tuners.. My issue:

Under part throttle ONLY, I get HUGE KR spikes.. this mainly happens when cruising in 4th gear and then gradually getting on the throttle. See snapshot of log screen below. Note that it does not happen when I really get on the throttle from a dig or off the line, etc. I have been up to 90%+ throttle on side streets from a standstill boosting up to 10 psi thus far with minimal to no KR (less than 1* or so).

Log%20file_zpszoslrxiq.png


I have currently set PE mode to come in around 32% throttle across the board. As you can see above, I am not even in boost yet and am seeing 5* of KR at 24% throttle....

Anyone know what I am should be doing next? Should I make PE come in even sooner to try and add fuel where I am seeing this KR? (PE mode at 20% TPS sounds crazy to me.. but not positive)

is the 3.3" pulley too much for my current mods?? (if it is, I will do E85 on my next tank :))

let the thoughts/suggestions start flowing please!
 
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id say 3.3 is def too small on pump gas. im sure besides the kr spikes i bet the timing isnt very high.
do you know what the timing is on the 3.3 setup right now?

with rockers 60s and e85 you should be able to run 3.3 or 3.2 even.

id run a bigger pulley on the junk gas
 
I hear ya... I figured I was getting too ambitious with the 3.3.. Timing tables are currently stock. I had my best luck on E85 with stock timing tables in the past, and since I planned on going E85 again with these 60# injectors, I haven't touched the timing tables yet.

However though, still don't know why I would get that KR under no boost to very little boost, and not at higher boost/RPM/throttle positions in lower gears pulling much harder...
 
cant see the screen shot. how are the trims? got a wideband? did you tune the new injectors? if they are off you can run rich or lean.
 
Updated the pic above Scotty. I have tuned for the new injectors and I am monitoring fuel via wideband. My trims are not ideal (still tweaking MAF tables for new stage 2 throttle body) but AFRs are reading very close to my targets via normal and PE commanded values.
 
your just cruising along with 20% throttle and bam kr at 1800 rpm? ltft are a bit rich too. take the sc belt off, see if you still get kr.

your old e85 timing will likely be to high for pump gas. when guys end up where they may have to swap back and fourth between gas and corn they have 2 tuned pcm's one for corn, one for gas, and a pulley for each tune.

try stock timing for your car, see if that changes anything, if theres no kr sc belt off, id blame the supercharger.
 


Thx for the feedback. To be clear, I am actually currently running completely stock timing tables on my setup (including the log file ran this morning above)

I'll make another MAF tweak tonight to try and get fuel trims a bit more in check. Just this part throttle only KR has my head spinning. I feel like if I am getting it at only 20% throttle, I'd see it at higher throttle/boost levels as well
 
i was just tuning a locals car, he had 2.2 kr revved in park. up to 7-8 when he got on it. no kr sc belt off. this was on the stock pulley still. 3.4 changed nothing kr wise.

i went as far as to take 3 degrees wot timing out and it spiked at 9º kr lol was like wtf is going on here????? then found it had kr in park.

hes gen 5 swapping now.
 
Haha.. It's stuff like your headache above, and my experience that has me ready to go E85 again within the week.. It's just so much more forgiving and gets rid of a lot of these KR bugs...

I'll prob pull the SC belt tonight to see if it eliminates it (I am fairly optimistic that it will)
 


104's would be better i think. i just bought a set of plugs on line at advanceauto, cost 11 bucks after a 20% off code.
 
The reason you are getting kr is due to the torque converter lockup at that low of a rpm with higher load. I've dealt with this a lot since we have lots of hills around here.

You can either pull timing back in those cells where it is knocking, or unlock the torque converter sooner. Or both.

If you shift into 3rd and drive like you normally would instead of D, I bet your kr is gone.
 
GTPpower said:
The reason you are getting kr is due to the torque converter lockup at that low of a rpm with higher load. I've dealt with this a lot since we have lots of hills around here.

You can either pull timing back in those cells where it is knocking, or unlock the torque converter sooner. Or both.

If you shift into 3rd and drive like you normally would instead of D, I bet your kr is gone.
Click to expand...

you are def. correct regarding 3rd gear. I did modify my Trans table to drop from 4-3 easier, and when I blip the throttle quickly in 4th and drop to 3rd, the KR is pretty much gone when pulling in 3rd.

Any adverse effects to unlocking the converter sooner? I'll need to check out how I control that in HP-Tuners this evening. I have not experimented with the converter settings much at all
 
GTPpower said:
The reason you are getting kr is due to the torque converter lockup at that low of a rpm with higher load. I've dealt with this a lot since we have lots of hills around here.

You can either pull timing back in those cells where it is knocking, or unlock the torque converter sooner. Or both.

If you shift into 3rd and drive like you normally would instead of D, I bet your kr is gone.
Click to expand...
You beat me to it. I was just going to say converter lockup.
 
Fuel mileage will drop, and you may notice a slight increase in trans fluid temps.

I would do a mixture of both TC unlock and reduced timing. A little kr is OK without boost. If you get it down to 1ish, I'd leave it and let the computer do the work.
 


GTPpower said:
Fuel mileage will drop, and you may notice a slight increase in trans fluid temps.

I would do a mixture of both TC unlock and reduced timing. A little kr is OK without boost. If you get it down to 1ish, I'd leave it and let the computer do the work.
Click to expand...

Will give it a try asap. May need to ask a few questions regarding tables in the tune when I take a look to make sure I don't screw anything up. Stay tuned folks!
 
Late to the party about the TCC being engaged. You set it to release with less throttle % instead of allowing you to "dig" into the throttle before it releases.
I also dumped the lock up in 3rd. Meh. Who needs it
 
I got rid of the lockup in 3rd gear. been reading multiple threads on people doing it without issues (here and on HP-Tuners forum).

Anyone have 4th gear apply/release values they wouldn't mind sharing?? I am not quite sure how I should begin modifying those exactly without causing trans or other issues. Note: I have a 2002 with no performance shift mode, so only working in the "normal" apply/release speed table.
 
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