Blower/Larger Cam Timing Theory with Pics

[ddnspider]

No love on ls1tech, so thought I woudl try here.

Being new to the supercharger realm, I'm still dialing in my timing on the car as time allows. I am NOT looking for a blanket statement about hypothetically how much timing the car should take, etc. This is more of a sanity check to my thought process. You can see my build thread here:

https://ls1tech.com/forums/forced-in...w-turbo-s.html

Cliff notes of the current setup:
2000 SBE
Futral F13 cam (230/230 114)
Yank 3600 stall
3.23 gears
D1SC with 4" pulley and front mount intercooler kit- makes 6-8 psi depending on rpm and belt slip
60# injectors
Here is the dyno of the car when it was NA from the previous owner


I switched to SE 1 7/8" long tubes and Y pipe and fabbed up the D1SC kit with front mount. I also added ls9 head gaskets and head studs. This is a strictly 92/93 octane 100% streetcar setup that will go to the track on rare occasions. My PE starts at 12.4 at idle and ramps down to 11.2 by 4000 rpms. Here is my spark table.



Spark Table

Keep in mind the entire tune is scaled 30% so as not to max the MAF. The car drives amazingly well and does exactly what I tell it to, so not going to argue about ditching the MAF or loss of resolution when scaling the tune.

Anyways, I was running 12 degrees of timing from ~3000 to redline. I start pulling timing at any IAT 122* or up. I just bumped it up to 14* from 5k and up, keeping it at 12* from 4-5k since the cars peak torque is around 4800. I plan to log and check the plugs again of course. My thought is that between the larger cam, which moves the RPM band up significantly from stock, and the blower which does the same thing, 14* at 6-8 psi with a centrifugal blower setup should be plenty safe and may even have the ability to increase the timing. From my logs at 12*, the car is moving around 70#/min of air so its making good power, but 12* felt like it was super safe. If it was a turbo setup I'd be more inclined to think I was closer to the edge. SO, is my thought process sane?

[joecar]

Post some log files.

On your recent post at ls1tech, I saw MAP go to 103 kPa... which MAP sensor do you have (are you also scaling MAP)...?

May we see your tune file...?

Do you think it could run more timing/TQ (incremental dyno experiment)...?

[ddnspider]

Here are some of the early logs that were OLMAF when i was dialing it in. No VE table whatsoever. I don't have any good CLMAF logs yet.
4 inch pulley CLOSED LOOP MAF ONLY_02os knock tables_30 percent scaled tune_2_idle changes_idle .ctzLog_4 inch pulley_MAF ONLY-30 percent scaled tune-4.efiLog_4 inch pulley_MAF ONLY-30 percent scaled tune-3.efi

Stock MAP sensor Yes the car doesn't "read" boost, but that is handled via the MAF cells inherently. Its a centrifugal blower, not a turbo, so no chance of an overboost condition from a failed wastegate or something. Continuing the conversation from the other thread, thats the only real downside I could think of with a tune like this, if you change pulleys/boost, you would have to retune as opposed to a pure SD tune that could accommodate multiple boost values. Also, if I get a bunch of belt slip all of a sudden and lose a couple PSI, I would likely be rich.

As far as timing, I'm looking for feedback on my theory. If the blower and the cam BOTH move the power up in the RPM range, and I don't hit peak boost until close to redline, theoretically I should be able to handle more timing in most of the RPM range. I am running a STOCK 4L60E with full torque reduction on shifts to keep the transmission alive, and am currently shifting at 6000 rpms as rpm's are a huge component to killing the transmission. I bumped the timing to 14* below 4000 rpm's and then above 5000 rpms and it was a significant SOTP improvement and the plugs I checked had no signs of detonation. Let me know what you think.

[joecar]

14 degrees should be ok with 8 psi... dyno would show you if TQ went up or not, your SOTP indicates improvement.

Do you have knock phones (they can be made cheaply) that you can listen to...?

( yes, I'm always worried about detonation/knock, I don't like even the smallest momentary incidence of it )

[ddnspider]

14 degrees should be ok with 8 psi... dyno would show you if TQ went up or not, your SOTP indicates improvement.

Do you have knock phones (they can be made cheaply) that you can listen to...?

( yes, I'm always worried about detonation/knock, I don't like even the smallest momentary incidence of it )

I've never thought about making a set of knock phones, but that's a great idea. Do you have a DIY you followed from someone online? I am super paranoid about knock myself. If you see log 3 right when the car down shifts there is a spike and then nothing. It did that NA so I think it's the mechanical noises associated with a downshift suddenly and there's no sign on the plugs. I've been paranoid enough that when I updated to the O2 OS i was sweating the differences in knock table differences. I would LOVE so feedback on if the later year OS were more aggressive with timing, aka less retard from knock tables or were they overly restrictive in the early years.

[ddnspider]

Joe what did you think of the tune, any red flags?

[joecar]

I took a very quick look at it, I'll be able to look closer at it tonite/tomorrow.

~ by phone ~

[joecar]

There's a thread on here somewhere about knock phones.

I happen to have a Chassis Ear that I use sometimes (I should use itmore often).

~ by phone ~

[ddnspider]

I took a very quick look at it, I'll be able to look closer at it tonite/tomorrow.

~ by phone ~

no prob

[joecar]

Looks good to me.

If you're using LTFT's you can set B3809 to better utilize the trim cells, i.e. try 1500, 2500, 3500.