dropping pulley size

[jnl518ssei]

So a quick question regarding dropping from a stock 3.8" pulley to a 3.6" pulley on my 2000 ssei. After contacting the only two reputable speedshops in my area, Ive gotten two different stories. One garage says I can drop with just supporting mods and not need a tune the other claims I need the supporting mods and a tune as well. Whats the deal? Is not everyone on the same page? What do I really need to do? My pulley seal is leaking now and I plan on changing it, but if im gonna pull it, I might as well drop the pulley size. Do I need a tune and what supporting mods are necessary to go to a 3.6 or a 3.4? Thanks in advance.

[nos4blood70]

To drop a pulley I would recommend an intake and headers. That should safely run a 3.6. You might be able to run a 3.4 with that, but I would get a scantool to monitor KR.

Tune should be done after you pulley down to take full advantage of the extra boost.

[jnl518ssei]

What the possibility of damages without a tune?

[00Beast]

For a 3.6, an intake, 180* thermostat and some way to measure KR is definitely necessary. I don't think headers are really necessary at that point (I ran a 3.6" for years without headers, then added a ported front manifold and downpipe). Hell, I ran a 3.4" for about a year with just an intake, but I wouldn't recommend that either. Too much KR.

The biggest thing is you want to maximize timing and boost. If you're putting in more boost, but the PCM has to pull timing to keep from pre-ignition of the fuel (knock, detonation, etc), then you're not doing much good at all. You want to be running the best premium fuel you can regularly buy (which you should be doing anyways) then go out and scan for KR before you do any mods. (WOT runs, monitoring the peak, as well as how much KR you see throughout the pull). Then you will know whether or not it's safe to pulley down at all. Then I'd add the supporting mods (180* Thermostat, Intake at the bare minimum) let the PCM learn that for a few day's drive, then go scan again. Then you will know whether or not it's safe to pulley down.

A tune maximizes your setup. Your tuner can play with timing, fuel tables and many other variables to eliminate knock, and maximize power and driveability, along with raising shift points and pressure in the transmission. One other thing I'd recommend is a shift kit, it helps maximize the longevity of the trans by making reducing slippage, which in turn helps the transmission run cooler. It also shifts quicker and firmer, which gives a great performance feel, lol.

[jnl518ssei]

Thats the answer I was looking for. Ill have to scan for kr before I start modding. Generally, your saying I could safely run a 3.6 with a 180* tstat and intake depending on kr. Since im stock right now, what should it read from the beginning at wot, or peak? Is there a baseline?

[00Beast]

Ideally it'd be 0. However, in the real world, that's not always the case. Also, it's hard in winter, because heat is one of the big killers. When the air coming in is below freezing, it's a lot easier to prevent knock than in the summer when the air coming in is body temperature. Especially if you live in the north. The whole point of Knock Retard is so that the computer can adapt to changing situations, and mitigate damage to the internals of the engine. I'd do the intake and thermostat right away, and when it warms up, check for KR. Then we can talk about dropping pulleys.

I'd say +/- 1° of KR is safe to pulley down on, but then you need to keep a close eye on it after that.

[jnl518ssei]

Thanks. Ill try tp get a read tonight

[jnl518ssei]

Took me long enough, but got it scanned on a snapon solus scanner and im running 0kr. Even at wot.

[00Beast]

Right now you are. Wait till it gets hot out, then you'll see KR...

[nos4blood70]

Even in these temperatures if you let the car heat soak you'll probably see KR rear it's ugly head.

[jnl518ssei]

Scanned it again last night. 8* kr at WOT.

[MattStrike]

Are you using premium gas?

[jnl518ssei]

91 octane

[jnl518ssei]

This was found when the car shifted. Could it be false knock?

[Jfridge92]

Our transmissions are noisy and can definitely cause false knock, mine usually spikes to about 4-5* around shifts. Try running it with 93 and see if that helps as well.

[yourgrandma]

91 octane is pretty marginal. If you drop to a 3.6, you wont want to run any less than 92-93.

I dont remember is torque management shows up as KR, but it could be some type of false knock that youre reading. 8* is pretty high. In my experience, if youre actually knocking, it doesnt really go away until you let off. If it does, I think its more possibly false.

I would say do an intake, 180* stat, new copper plugs and do some more scanning. If youre still at or near 0*KR, drop the 3.6 on there. You usually need some help on the exhaust side though. Rockers or headers are a good way to go.

[jnl518ssei]

I just did new iridium plugs and delco wires. Im planning on the t stat and intake in the very near future. Ill scan again after the changes. Why copper over iridium anyways? Iridium is the oem replacement

[yourgrandma]

Copper works better with elevated cylinder pressures. At stock boost levels, the iridium plugs are just dandy, but as pressure and temperature climb, the smaller electrode tip of the iridium plug tends to form a hot spot that can lead to pre-ignition.

Obviously the downside is that coppers dont last long. After about 6000 miles, my first set of aoutolites were completely shot to the point that my car ran like crap. Its a bit tedious, but the copper autolites are dirt cheap and fairly easy to replace. Im running NGK racing plugs now. I cant recall the part number, but theyre holding up a lot better.

[jnl518ssei]

So ordered a JMB intake. Should be here next week. 180* tstat and copper plugs are in my center console.

[buickman104]

NGK TR55 are a good copper plug to run.