Thread: Tuning for a 3.5" pulley upgrade

What really annoys me is when people start a thread, drum up all sorts of help, and then never post the solution. What I'm getting at is that I've come across 4 page threads the same as this.....without the OP posting the fix.

There is a sabrewings thread like this, but it appears he hasn't used the site in years.

Anyway, i'm using the DHP AFR vs time vs RPM table which richens less with time in PE than does stock.

That didn't improve anything. It's more like increasing KR with increasing boost. Thinking of trying a stupid PE AFR like 10:1 or 13:1 to find the direction of improvement.

So just to re-iterate, the biggest of my concern now is when I roll on throttle, it runs pretty good until hitting PE where I get a couple degrees KR, then with more throttle KR goes up to 8ish.

I usually let off as soon 6* KR shows up.

As far as mechanical problems, yeah, I think it's OK. No misfires. Thought maybe a vac leak at first, but then I would expect pegged fuel trims. I think.

Knock sensors should be fine, there are no CEL.

No WB.

I should have caught this earlier, but:

i see on the scans a commanded AF of 11.9... i would say lower that try 11.7 or 11.6 see if it gets better or worse.

if that doesnt work reset back to what it was and then use your IAT spark table to pull 1-2* of timing IE -2 on it. no need to change the entire table but say from 32*-122* you can start like 1/3rd the way down till the bottom so your cruse isnt effected.

if your KR is not bad until after you get into PE then your AE is fine and you need either less Timing or more fuel.

I have similar mods to you but I have a catback and 1.9 rockers which don't make much a difference in tuning. I start at 20 degrees of timing and 11.5:1 a/f at the bottom of 1st gear and richen up to 10.8:1 with 16 degrees by the top of second. Richening it up and pulling timing a couple degrees are the only way I can run knock free at the top of 2nd. It's possible my valves are still carbon'd up. Some cars can run more timing and leaner mixtures some less, you'll have to see what your car will allow.

When tuning a knock prone car I like to start at 11.0 a/f ratio and progressively add timing. This gives me an idea of what timing it will like with leaner mixtures. Try running 11.2 a/f ratio and stock timing as a starting point and see if you get knock. If you can't run at least 11.0 a/f ratio and stock timing you might need more mods.

Also, I'd like to see a better scan. Something like this: get up to 45mph, put the trans in 2nd gear and progressively go into WOT. Take about 3 seconds to go from idle to WOT. This will take ae and shifting out of the equation.

Originally Posted by SnowFlake

Any progress on this issue?

Today or later this week I will be getting another scan and re-flashing a lower base PE AFR. Right now, there is a lot of PE knock. I'm hoping to re-install the stock pulley and plugs over Christmas. If there happens to be a warm day, close to melting that is.

Also wondering what you guys use for TCC lock and unlock settings in the normal and hot tables, 3rd and 4th.

Originally Posted by SnowFlake

When you say "PE knock" do you mean KR as soon as you enter PE at partial throttle? Or do you mean just WOT?
These cars do weird things sometimes. I was tuning an N/A Gp a few weeks ago and the car had KR everywhere. He then did a full maintenance work up, added headers and 1 step colder plugs along with a new 180 t-stat. We were figuring it would handle a ton more timing... we were wrong. It still knocked badly.

Went through the whole shpeal looking for false KR and all that and came up with nothing. In the end all I could do was send him on his way with a 12.8 AFR at about 19 degrees of timing. It made no sense at all especially considering I was getting away with 30 degrees of timing on my aunts NA GT that has no mods at all.

KR as soon as I enter PE, and anytime in PE. That leads one to believe PE AFR is too rich, but I am already leaner than stock by 0.4. To sum it up, I'm seeing about one degree of KR for every PSI of boost. My car is your friends car's bastard child.

BTW, I was having a lot of sub-PE KR in the summertime, until I switched IFRs. Then, after you looked at my file, you put it back to stock. Somehow its been working very well sub-PE with the same settings that were killing me in the summer.

Machines can be wierd.

Thanks for the help.

OK, so I flashed a base PE of 12.2 and stock RPM-Time modifier table. Some improvement, but time will tell.

Oh I bet you guys will give me **** if it was just my poor patience.

His MAF table looked okay, i've asked him for scans a couple times though lol.

Originally Posted by mechguy

KR as soon as I enter PE, and anytime in PE. That leads one to believe PE AFR is too rich, but I am already leaner than stock by 0.4. To sum it up, I'm seeing about one degree of KR for every PSI of boost. My car is your friends car's bastard child.

BTW, I was having a lot of sub-PE KR in the summertime, until I switched IFRs. Then, after you looked at my file, you put it back to stock. Somehow its been working very well sub-PE with the same settings that were killing me in the summer.

Machines can be wierd.

Thanks for the help.

Your base PE was a little too high for your mods. I wouldnt run higher than 12.0 base PE on a 3.5 pulley unless it was cammed. Lol.

Yeah, if he got me those scans i could see if the airflow isn't right for his mods.