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Most timing I could get before kr with a 3.2 was 17*. I'm trying a 3.3 and at what point will more timing yield more hp than the loss from going up a pully size?

I always hear you want to up your timing before you up your boost. The faster you spin that m90 the less efficient it becomes. However, the best way would be to take it to the track and try it both ways see which nets you a better time.

1337ssei wrote:I always hear you want to up your timing before you up your boost. The faster you spin that m90 the less efficient it becomes. However, the best way would be to take it to the track and try it both ways see which nets you a better time.

I've decided to tune my timing with the 3.3, then I'll try putting a 3.2 back on.

Yeah, that totally depends on how your car runs, as well as track altitude, fuel, etc. I've always had better luck with increased timing and bigger pulleys as opposed to the other way around. FWIW I run about 19-20* timing. Stock is 16*

Heat also might come into play here. Smaller pulley yields more heat right?

Also I have never seen a stock 3800 get 16* of timing, let alone a lightly modded one with a preburned PCM. I see 14 on most common gtps with a 3.4 and other minor bolt ons.

Where do people get this number? Before I started getting into tuning I saw 12 with an intense PCM.

Allmachtige wrote:Heat also might come into play here. Smaller pulley yields more heat right?

Exactly, hence the need for an IC or Alky once you max out timing and pulleys and need to drop pulley sizes and kill KR. I've never had good luck dropping pulleys and lowering timing to compensate. Always ran slower that way. So tuning you're adding fuel to kill KR, but if you get too rich as well you will go slower as well with too much unburned fuel even if your timing is higher, right.

Oh and I forgot to say that anything over about 20-21 WOT is going backward from what I understand. Didn't see any mention of that.

By the way Kyle, saw your time slip. Nice . Whats the track and altitude?

Byron, IL

Not sure on the elevation.

I have done no tuning and only have the Intense PCM.
Timing is usually 12 running with the 3.1"
I use the alky injection and use the timing commander to bump 5 degrees with 0 kr.

On the street, I have to be careful when not using the alky. It's fine running full throttle from a stop, but if running at speed, sudden acceleration will spike the kr rediculously high! I have to let off so the kr zeros and then I can get into it.

That makes sense Paul. I could probably run a 2.8 with only 12* of timing because I can get up to 17* on a 3.2

Allmachtige wrote:Byron, IL

Not sure on the elevation.

728ft. Basically sea level. Might make about 0.1 difference is all.

I still say run the higher timing and bigger pulley. Try it out, but you will probably find that result. I think you can still squeeze out some more. Was that on pump gas? Race fuel or some Torco would probably get you down to 13.2-13.3 and allow you to still run higher timing and maybe a 3.1 or 3.0 pulley.

If I lived as close to Intense or ZZP as you do I'd let them do a dyno tune on race fuel and see where it goes.

At about the same elevation as you Paul and I both ran 13.4 on rockers and 3.2 pullies. There has to be more in there. How are those O2s doing?

Because I drive only short trips where the trani temp never goes above 150F and SC temps keep the top end less than 140F, I choose the 3.1 pulley because it has so much more noticeable torque around town. Spinning tires at any speed.

So even though the timing is not there with the 3.1, it feels better.

For the highway I pop on the 3.4

13.4 is fast enough for me with 60 coming up in 5 seconds or better.

I need this car to last a few years without trani work.

O2's are solid 930's to low 940's.

I'm still tuning timing on a 3.3, but today I got quite a bit of KR (2-3 blips through 2nd gear) with me trying to get 19*.

So I'm going back to my timing table that got me 13.5 at the track, which is about 17* of timing. Strange that going up a pulley size isn't helping me gain any timing, so I'm starting to wonder if I can drop a few sizes with the same timing that got me my personal best.

This could be heat though. It was somewhat mild last time at the track and during today's scan it was over 80F.

So what do you guys think? I suspect I'll need to run a 3.4 to keep up this much timing in the dead of summer. I'm starting to think its not the pulley sizes that hurt me, but the maybe my car just doesn't like anything over 17*. I don't get it.

I thought that Intense specs being able to go as low as a 3.0" with a cam without KR.

I think 17 is pretty darn high compared to what I'm getting.....untuned.....9-12.

2000Silverbullet wrote: I think 17 is pretty darn high compared to what I'm getting.....untuned.....9-12.

Its good but GTP drivers constantly tell me "With a cam you should be able to run a 3.0 with 19* of timing".

That's what frustrates me, so I'm trying to figure out if its better to go with stock timing and a very small pulley (like yourself) or go with as much timing possible with a large pulley.

2000Silverbullet wrote: I think 17 is pretty darn high compared to what I'm getting.....untuned.....9-12.

Have you tried running a larger pulley? 9-12 seems like it would be unfavorable but then again you somehow ran a 13.4 on that setup so it must be working for you.

Running the larger 3.4 pulley makes no difference with timing for me but the intake charge runs about 15F cooler (all things being equal), and no KR at all.

If I run the 3.1" I see more KR blips and use the alky injection in spirts to cool things down.

If I run the 2.9" the alky injection is on all the time and I can turn up the WOT timing 5 degrees.

I have not raced with the 2.9" and alky injection with my current mods, only the 3.1"

I expect with the 2.9" I could easily knock another two tenths off................at the expense of my geartrain.

Kyle, do not listen to the GTP crowd on tuning the bonnie. It just isn't the same. You are experiencing exactly what the limit is on the Bville without a big intercooler. Its just the limitations for some reason, and after three years of tuning myself I still can't get much better than that on a bonneville. So I think you are doing fine. For the summer time you are going to have to run a 3.4 or even larger most likely to not have any KR over 80*F ambient temps. I run the 3.3 and the intercooler going all the time when that happens and it still gets a bit warm and KR if I hit it. That's the problem with having a DD and going more than 30-50 miles and then wanting to get on it without KR. It just doesn't happen at that point. That's why at the track you can't hot lap it and keep the times down.

Now if you add 100 octane at the track I still think you can squeek out a little more. But I think you are still going to be limited to the 3.2 or 3.1. I never went faster with the 3.0 then I did with 3.2 and I didn't have a 3.1 to try. They where always the same.

What are your shifts set at? The recommended shifts on ZZP are something like 6400, but the bonneville is just too heavy for that I think. I've had better luck with setting them a bit lower with this cam so far, but I haven't had it dyno tuned to actually see what is the best power band yet.

Oh and by the way, Kyle probably already knows this, but the PCM won't add timing automatically just because the pulley is larger. If you are only getting 15 or so and no KR on a 3.x then going a size larger won't do anything for timing, just heat. You have to manually add more timing until you get KR with either the tuner or the happy knob.

my shift points are set to 5900 for 1-2 and 6000 for 2-3 shifts, but because it's a stock trans (minus the shift kit) the rpms get to about 6100-6300 before the next gear is fully engaged. At the track I hold 2nd to 6400rpms so it won't shift going across the finish.

And yeah I'm starting to think I'll need to put the 3.4 on for summer I keep this timing up. Timing > boost eh?

Yeah, that sounds pretty good. I would up your 1-2 to 6000 in the PCM and lower the 2-3 to 5950 and then shift into third before the finish. You have a shift kit and you won't have to worry about the lag and you should improve in time a bit. You can try it anyway and see if it helps you our hurts you. I personally wouldn't hold it to 6400 on a stock tranny especially if you have the TQ reduction set to zero.