Pulling time on WOT but wideband shows neither too rich or lean

So its been quite sometime (sad to see sirius is not with us as he helped a lot)

Over the winter I've installed a set of heads and cam on the car. Heads are AI TFS 215 cc heads for the lt1, and the cam is 222/234 .544/.568 110 LSA from LE. Motor is still a stock bottom end LT1,

https://www.youtube.com/shorts/7MVExEPhukU

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I've updated the EOIT settings in the tune, and currently adjusting the VE table in SD, injector data is still the same initially from blindsquirrel using the 12613412 injectors, spark dwell settings matched to a vehicle with the d585 coils, and a few other small things here and there.

I just wanted to get some feedback on the tune based on the log provided to see if there's anything like out of whack that you guys might see that i'm not aware of, tune is currently SD with LTFTs turned off so just tuning the VE tables off the short term trims.

The car to me drives pretty damn good in terms of part cruise and idle, smooth off the line and no boggin during gear shifts etc, only if I let the rpm drop too low during a u-turn or something then it starts to buck but seems like that would happen with any manual car. Ironically Id argue that the part throttle and cruise is better now than it was without the cam and heads

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Maybe the only thing I was expecting a bit more was the pep in the pedal, it feels like I need to really get on the pedal to feel the car really pull, maybe its just normal and I'm not used to it, or maybe it isn't.

I plan on getting to the dyno hopefully this may to get the timing dialed in, currently using a table that I had to infer of other people's setup. VE table up top is some what inferred also because getting the cell counts there is a bit difficult without breaking the law too badly lol. Also got GM genuine KRs on the way cause I'm pretty sure this other set I installed isn't working either.

If I need to log any other tables or what not let me know.

So I did a second gear pull and I couldn't break the tires loose, but I also put on fairly new 315s out back so maybe due to that.

But would like to get some feedback to understand if I'm down on power or anything.

Timestamp starts at 7:06:20.7
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I put the pedal to the floor, I let off the throttle at 7:06:24.1

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Wideband AFR is pretty close to the commanded AFR.

It takes around 3.4 seconds to go from 22mph to 53mph, well its actually 21 mph to ~50.5 mph in 3.4 seconds because I have the speedo calibration set to a 27" tall tire and I'm on a 25.7" tall tire now. And that is from 2k rpm to essentially 5k


For a full weight b-body with a camshaft and heads + full exhaust system. Is that about right? Is there something wrong? With the stock camshaft and 255 tires out back I remember it was always squirrely when I got on it, so having a hard time telling if I'm down on power or the grip with the new tires is making it feel that way. File attached below, the tune itself can be found one post above.

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I should mention I'm still in SD for tuning purposes

I feel like what you are missing to tie it all together is gearing. Even the F-cars were pretty lame off the line with a 3.42 gear and the 6spd. 4.10 was a lot better performing in those cars and they are a lot lighter than a B-car.

In your prior post you mentioned it taking a lot of pedal to get it to pull. That is how the stock throttle body feels in those. The early TPIs had a very linear 1:1 kind of pedal linkage that was very touchy response wise. GM updated that to a non-linear D shaped eccentric that allows for a lot of initial pedal travel with minimal throttle opening that really killed the throttle response.

That is good to know, I actually have 4.10s in the car but as you said it still is a big boat. (If it wasn't already mentioned this is a t56 swapped car also)
I did a 1st gear pull and spun the tires all the way through so it still got it. Think I got the VE as close to as I can get it street tuning so time to go do MAF and then tie it all together.

Well remember how I said it just felt like the pep from the pedal wasn't there.

With the recent thread talking about proportional fueling I watched the video posted in the comments.

I then took a look at my tables for (12480, 12482, 12470) and I noticed for the most part my tables were way off from what the stock values were (from the base Torqhead tune). This was from the remote tuners (who I cut ties with pretty quickly) starting file that I used as my base and I just kind of ignored these values since I didn't have any understanding of them.

So I set the values to what they were in the TH base file and the pep in the pedal is back, it's too noticeable of a difference that I don't think its just a placebo effect considering I wasn't even expecting a change at all other than fuel trim values.

Don't have enough of a understanding why but very interesting.

That being said there is still some surging below certain rpm and what not so figuring that out.

I honestly doubt that would have made a difference. but maybe

Have you tried running this in OL? I know it's not a huge cam but LT1's even with the PCM's they came with had a hard time with overlap, NBO2's getting fooled, split BLM/fuel trims etc.

I never really did it run it in open loop because my wideband and narrowbands seem to agree with each other for the most part. I've never really had split BLM issues either, the one time I did was when I swapped to the gen 3 bosch injectors to which I immediately went back to the 12613412 gen 4 ones and the issue went away

Just threw my latest MAF tune and log in here of a city drive, maybe there's something that indicates something is off but with my very limited knowledge it looks solid for the most part.

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https://www.youtube.com/watch?v=621bcy3Epzo

So I was following this guide on Tuning the IAC Effective Area but my values just seem way low. Using the idle desired / dynamic airflow * IAC formula the values I'm getting are all in the 20ish range

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Based on how it was adjusted in the video I followed the same and ended up with this, which i assume is very off, not sure how the other values would be interpolated with such a big value change.
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I also noticed that my idle desired airflow is like half of what the dynamic airflow is at idle and doesn't seem to match the table values either.
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In terms of car driveability I really don't feel anything off except maybe the slight stumble here or there coming to a stop but its never consistent enough to really bother me, that being said I would like to fix it properly lol, what am I missing

So this was interesting, I presumed my KRs just didn't work.

Did a lot of pulls at 32 degrees when I was tuning SD and didn't see any knock.

I'm in the process of tuning MAF on the upper cells and knowing that it was fairly rich I upped the WOT timing to 34 degrees just to feel if there was any difference and what do you know, there's some knock retard. I'm gonna set it back to 32 deg at WOT but I kind of just assumed LT1s ran pretty high advance at full throttle

The heads are AI TFS 215 cc with around 10.4:1 compression with 91 octane.

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I haven't logged the burst knock PID but based on when it happened that's what it seems like to be.

I've heard of burst knock not working properly in SD so maybe that's why I didn't see any.

So I can either do one of two things, or do both, go back into SD and do WOT pulls at 34 degrees to see if the car actually knocks at 34 degrees. Or put it to 32 degrees in MAF, if it pulls then I know its just burst knock happening.

Hmmm, so I finally put the car back in dynamic, with COT and DFCO turned back on.

Car drove great, nothing unusual to report.

But... I got out of the car and took a look underneath and I saw the driver side cat slightly glowing red, I don't recall if the other side was but the garage was fairly dark. From reading this indicates the car is running rich or has a misfire or something like that, but nothing in the logs show that.

Is it possible I may have cooked them during the tuning process with DFCO and COT turned off? I definitely forgot to re-enable the startup correction table under catalyst heating after i installed the cats sometime last year so that was a fail on my part. Bleh just annoyed with myself for that if I did screw up these expensive cats

Log cut short due to it freezing so i'll get a better one later, will pull some spark plugs to physically inspect if it is actually rich.

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Quote:

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Originally Posted by toonwarrior

Hmmm, so I finally put the car back in dynamic, with COT and DFCO turned back on.

Car drove great, nothing unusual to report.

But... I got out of the car and took a look underneath and I saw the driver side cat slightly glowing red, I don't recall if the other side was but the garage was fairly dark. From reading this indicates the car is running rich or has a misfire or something like that, but nothing in the logs show that.

Is it possible I may have cooked them during the tuning process with DFCO and COT turned off? I definitely forgot to re-enable the startup correction table under catalyst heating after i installed the cats sometime last year so that was a fail on my part. Bleh just annoyed with myself for that if I did screw up these expensive cats

Log cut short due to it freezing so i'll get a better one later, will pull some spark plugs to physically inspect if it is actually rich.

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Your ideas for causing a cat to overheat are correct, but incomplete. There is also the possibility for physical breakage to cause clogging, which then results in overheating. However, the likelihood of this depends on what type of core your cats use.

Was it exceptionally dark when you were looking at the cat?

If so it's pretty normal.

If it doesn't set P0420/P0430 codes (and the codes & other tests aren't turned off) they are working fine. Those DTCs are pretty strict, most of the ones I have dealt with with those codes that weren't from contamination, by all measures the cats were still working just not quite well enough to satisfy the diagnostics. In other words if it didn't have the codes nothing in the data would lead you to think there was any problem.

Yes it was pretty much night time, I guess I've never looked at my cats in the dark while the car was running before. But otherwise I wouldn't have noticed, don't feel a lack of power and no DTC's so fingers crossed.

Well its been sometime since the last post. Driving at part throttle and idle has been pretty solid for sometime, there is times were it intermittently surges but cant complain

I took the car to the impala nationals and here's where some issues started popping up. During the drag racing portion of the event, I lined up my car against my buddies stock lt1 caprice with no tune. Thinking my car would pull on him we launched, his car stayed in front of me the whole run which made no sense as I have AI 215 CC heads, an LE cam with 222/230 .544/.568 110 LSA
I trapped at around 97 mph, he trapped at 95 mph.

There was also my buddies caprice wagon with LE2 heads and the same cam as me, but 500 pounds heavier that was trapping 99mph.

Considering I'm lighter than the wagon and should have more power than the stock lt1 caprice I should definitely be quicker than what I did.

I took a few logs and I can see somethings.

My commanded AFR keeps changing, this used to not happen when I'm tuning MAF/SD separately. Is this cat overtemp kicking in? Essentially I had it setup to just run 12.5:1 at WOT, which it was when I tuned WOT in each mode separately.

Now it starts off at 12.5 then drops to 11.3.

On top of that it pulls timing sometimes, not sure why this is happening as I'm running 32 to 33 degrees at WOT which I feel is pretty conservative, maybe a byproduct of it going rich.. The guy with the wagon and LE2 heads is running 36 without any knock (obd1 computer still)

I know the heads are pretty large for a stock bottom end but for it to barely eek out a bone stock lt1 on 87 octane something isn't right.

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The tune in the car is slightly different but very similar, the laptop I had the latest tune on fried but this should be very close regardless.

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Would love to get some thoughts on this, have more logs if needed, sometimes no timing is pulled, sometimes there is. I know it isn't based on ECT or IAT since the temps look fine there, not sure if its false or not, but rather be on the safeside.

It sounds like cat over temp protection.

LT1's can be ran pretty hard. I've had many take up to 42 degrees at wide open.

They can be leaner than what people here are used to also. 13.2ish

They are super sensitive to heat and make best power around 140 F.. So if you have time try to cool it way off between runs.

In terms of adjusting COT to make it less intrusive would I be messing with the EQ ratio (table 12200) under the fuel > temperature control tab?

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I agree I think I can run more timing but i've been pretty conservative with it for now since this is still a process of dialing it in for me.

Once I sort out the COT AFR i'd need to go back to the strip and start bumping up the timing and see if the trap speed increases but also not be knocking at the sametime.


Or is messing with the COT not a good idea and i just live with the AFR its at.