To get the most power you will want an Intake and exhaust. Because you are pushing in more air you need to move more out. It will also allow the Super to suck in air easier getting more in. For more power aswell. You ususally want to upgrade the pulley after an intake and exhaust system.

Side effects: You will create more heat. Which may or may not really affect you. Water injection systems can be made fairly cheap and work exteremely well. I've seen drops of 150 degrees on the intake air after it goes through the forced induction system (this was on a turbo Eclipse). But you may or may not need to do the water injection. Depends on the size pulley change too.

You'll want to put in a AUX transmission cooler to combat some of the extra torque you make. It will cool down the fluid faster. If your fluid breaks down your transmission isn't going to be protected.

The WRX STI with the 300 hp turbo uses water injection.. stock.

The stock computer has a good management system in it. I have never heard of anybody breaking anything because of a 3.4" Pulley. If you were to go to a smaller pulley than that, you may have problems, but a 3.4" Pulley is fine, if not ideal, for a stock L67. When you run a smaller pulley on your supercharger, the supercharger will spin faster, when it spins faster it will make more boost at the disadvantage of the air getting even hotter during compression, and more boost means more air (not in certain conditions where boost stacking applies, but I will not get into that), more air means more fuel, more fuel means more power. A pulley is the cheapest high power mod available.

The problem:
Like I said above, the smaller the pulley you run the more heat it is going to make. Heat is bad, once the air is so hot it is going to cause knock, GM designed the engine with knock sensors, when the sensors detect knock they will give you less timing (the computer will retard the timing), less timing means less power, since the engine isn't working as hard the heat will reduce and no damage will be done. This is called Knock Retard. Since the computer detects the knock it doesn't hurt anything but performance. By running a 3.4 pulley most L67'* will tipically see between about 3-10kr. Anything over 10kr is pretty bad because you will be losing a lot of power (10kr is going to pull 10 degrees of timing, 1 degree of timing is ~2hp, so if you get 10 degrees of timing pulled you will lose 20hp, but if you only get 3 degrees pulled you will only lose 6hp, but the pulley itself will gain about 25-30 horsepower if it is seeing no KR. I would run a 3.4 pulley, and the car should get faster, sometimes it will be significantly faster, sometimes just a little, but if you feel that you lost power or lost top end power over stock then switch back, because you are getting so much power taken away that you would've had more power with the stock pulley, this is rarely the case. This article may be turning you away from getting a 3.4 pulley, but it was not meant that way, definately get a 3.4 pulley, but I don't know of any situations where someone actually lost power with a 3.4 pulley. Since the computer has a management system built in you cannot hurt the engine unless you try to run a pulley that is way too small because the computer can only handle so much. If you do other mods along with the 3.4 pulley it will make the engine cooler or flow better or get more air or whatever and all of those things will reduce heat, which will reduce KR, giving you more power.

If you have any questions feel free to ask, I will be happy to help you out.

If you have any questions feel free to ask

When you are running that much boost (14.5psi) on an All-Aluminum DOHC 4 cylinder you need an Intercooler and Water Injection to be able to afford your warranty costs. They are fast little cars though. But, what you don't want to know is that the Lancer Evo runs 19.5psi stock, that is some boost, and a very easy way to blow head gaskets, intake manifold gaskets, etc....

Is a new pulley and tensioner something that I can do?

Or do you need specialized tools/experience etc?

PLEASE LISTEN TO ME ON THIS. IF YOU JUST WANT TO GET INTO THE 14s, please do just these two things (you may only need the first):

1.) Airlift rear airsprings $60. You just slip them in your rear coil springs and pass the inflation lines through the lower rear license plate holes for a stealthy and convenient fit. Inflate to 35 psi at the track and 3 psi when driving on the street. You have enough trap speed to run 14s right now with enough hook. Lower tire pressures in the front experimenting between 24-30 psi and raise rears to 45 psi. I'm able to run 14.5-14.7s easy with this combo on my dad'* otherwise dead stock 1996 Bonneville SE */C with 60 foots in the 2.10 to 2.15 range.

2.) Retune your PCM for 6000 rpm upshifts to take better advantage of the available powerband. No need to remap fuel/spark.

The above two mods will not shorten the life of your trans or increase the chances of detonation like a smaller pulley would. Make sure you use high quality stock sized tires (cheap tires are heavy and you can measure a drop in trap speed).

You cannot change the pulley unless you have a pulley tool. They can be rented for about $35 from ZZperformance and other vendors like that. Personally I purchased a pulley tool for $130 and have used it many times to help people change theirs. The tensioner is just a bolt. You put a wrench on it and loosen it. Very simple.

Wow... You enjoy wasting money don't you?

For the rear springs instead of using airsprings you can go to autozone and buy a couple packages rubber spring blocks for like $5 a package, like I said in my post. This way you can put them between the springs so the rear end is jacked up as high as it can go and there will be no spring travel, and then you can take them out for the street. It is a lot cheaper and a lot less work. But once you jack up the rear end using these you create a problem, the front end is higher. So you buy another package from autozone with front spring compressors (also like $5). This allows you to pull the front springs down so you get more weight over the front tires which will give you more traction and better 60 foot times. Put rear tires at 44psi, and front tires at 22-24psi.

Why would you spend the money to get the computer reprogrammed for later shifts when you can install a pulley that with 100 octane gas will gain 20-30 hp on most cars, that is way more gain then you are going to get by raising shift points 200rpms as long as someone can use the stock computer to their full advantage. DHP which raises shiftpoints, changed fuel tables, reduces KR and all that still say they only give an 8-12 hp gain, and 1-2 tenths in the 1/4. 1 tenth of that is the 8-12hp that you aren't going to get by raising hp, the other 1 tenth is the change from 5500-6000rpms shiftpoints, and if one can use the stock rev-limiter of 5800 to their advantage by holding the gear until then they aren't going to get much gain from the other 200 rpms where most L67'* get valve float anyways. So raising shift points is going to give you a MAXIMUM of 1 tenth gain, whereas you can change a pulley and get 3-4 tenths gain.

And like I said a smaller pulley is not going to increase detonation because the computer will not let it. When it thinks it is going to detonate, because it hears the noise of pre detonation it pulls timing so it can't. A smaller pulley will not hurt the engine at all unless you go to like a 3" or smaller on the stock engine because the computer then can't handle that much detonation.

I am not making this stuff up, I know what I am talking about. Our GTP runs 12.8'* consistantly and has a best time of 12.780 @ 106.05 using these methods, and believe me it is not only the horsepower getting these times. We have only been to the track 2 times ever, with a total of 15 runs combined, and we pull 1.7 60 foots on slicks and 1.9 60 foots on stock Eagle RSA'*, that is with basically no launching experience at all. I don't know what our Bonneville runs but with the very few mods it has if I had to guess I would guess between a 13.9 and 14.2 using these methods. 60 foot times are the key to good ET'*. If you get a bad launch, you are going to have a bad launch.

Staged did you guys power brake it on launch?

I did brake torque the launch to spring off the line. However the throttle was tipped in aggressively and not slammed to the floorboard. The spring blocks are a good idea too, I thought of doing that before the airbags. I personally like the airbags since I can simply go to the back license plate, undo the schraeder valve cap, pump some air in there and be done in a minute or two without getting my cloths dirty or having to bring a blanket to lay on. To me it was worth the $50 or so premium over spring blocks.

Like I said the trap speeds "aCiD" is running can get him into the 14s with more bite and without the need for a smaller pulley (his/her question was just to get into the 14s which I also presume on pump gas?). The SSEi is a massive car so the mass + added power will no doubt make the trans loose its shift crispness more quickly than if the stock pulley was left. The 4T65-Es don't have much reserve capacity before e.t. killing shift sloppiness comes into play. There may be a shift improvement kit or calibration pkg. to complement higher boost, but again not needed to get into the 14s as aCid asked.

As quick reacting as the PCM is to preventing detonation on a new L67 with a 3.4" pulley, I can't imagine the setup being robust from detonation when the motor has many miles, the motor is carbon'd up, fuel injector spray pattern degrades (better atomization leads to better cooling effect), the ring seal isn't as great and hence the likelihood of detonation or excessive knock retard is much higher especially on varying gas quality and stock spark calibration. With many miles and a 3.4" pulley with stock calibration and pump gas I believe you'll be running some knock retard sometimes (hence giving you no appreciable gain over a stock pulley) and when you're not getting KR you're accelerating wear & tear on the transmission.

Heck, even our stock 1996 Bonneville with 140k miles has an occasional audible knock just after WOT upshifts that quickly disappears; something I didn't hear at <100k miles. Original trans shifts very crisply however!

Hence if you want, you can up your shiftpoints since the 4T65-E has wide ratio spacing; even though the L67 broad torque curve is forgiving to wide ratio spacing, I see that the powerband can be better utilized. The shiftpoint mod is admittedly a small gain but I think it'* a harmless gain vs. some other mods considering your requirement to get into the 14s (you're closer than you think aCiD, albeit high to mid 14s!!!).

Now if you're setting your sights on low 14s and faster, well there'* no way out of the need for a smaller pulley and other supporting mods.

Ok, all this info is very helpful, but now I'm bombared with contradictions and varying ideas.

You both agree that springs blocks are a good idea.

dbtk - Is raiding the rear tire pressure that high safe for the tires?

And I had the car at the place where I get all our car work done, and they said an engine mount would have to be removed in order to replace the tensioner and SC pulley. And he said if we supplied the parts it would cost about $100 CDN in labor to install them.

And I don't know if I've said it, but I should, this car has about 180,000KM highway on it. Which is about 112,000 miles. As well the current tires on the car are Michelin X Ones. The code on them is: P225/60R16.

What diameter is the stock pulley?

Thanks guys!

44psi is the max rating on the tires. Any more than that is not safe, but the tires say right on them that 44psi is max. It is probably not a good idea to leave that kind of pressure in them on the street, but it isn't going to hurt anything for a few 1/4 miles. We always pump up the rear tires on the GTP to 44psi at the track.

I have never been under the hood of a pre 2000 SSEi before but I can't imagine that an engine mount would be in the way of the tensioner or pulley. The tensioner comes off with 1 bolt removed, and as long as you can get a wrench in to remove the bolt, the tensioner will come out. The pulley is a 20 minute job if you have the correct pulley tool, there is no need to pay someone to do it for you, it is very simple.

Our 2000 SSEi has 73,000 miles and counting on it. It has had a 3.4 pulley on it since a couple months after we bought it and it runs very very good, it wasn't until 65,000 miles that we did all of the other mods listed in my signature, so a 3.4" Pulley on a stock engine is completely safe IMO. A pulley is not going to decrease engine life at all, because as I have said before the stock computer has a very good management system that doesn't allow damage to be done to the engine.

3.8 Inches

The stock computer is very sufficient at controlling knock with any amount of miles. Even if you do see some KR, I have never heard of a case where someone lost power with a 3.4 Pulley because of KR. Installing a 3.4" Pulley on an L67 that is getting 0KR is going to give you a 30hp gain. It takes quite a bit of knock retard (15+ degrees) to lose the advantage of the extra 30hp, and I don't know that I have ever heard of someone getting 15 degrees of KR with a 3.4 pulley unless they had major engine problems. Even on pump gas a 3.4 pulley is going to give a significant gain. If ported exhaust manifolds are purchased, as I said would be an option in my initial post, it would mostlikely rid of any KR that the 3.4 pulley is giving anyways. If you would put a 3.4 pulley on your car, you would know what I am talking about. Anyone who has put a smaller pulley on their L67 knows that it makes a HUGE difference even with KR, it completely transforms the car.

That audible knock is not knock, it is something else making the noise. Our SSEi has what sounds like audible knock and it gets 0 KR, and I know the knock sensors are fine. Audible knock would be well over 10kr, probably more like 15 or 20kr, and if you are getting that much KR with the stock pulley the engine has other problems. The original trans shifts really wimpy when it is stock brand new, if it shifts "crisply" as you say it has a problem, unless your view of crisply is my view of you can't even feel the shifts at all. The transmission in our 2000 SSEi performs just as it did when it was brand new 73,000 miles ago. A shift improver can be purchased for $99. It definately makes shifts MUCH better. We have one in our GTP and it shifts very firmly, it has even broke the tires loose on the 1-2 shift a few times.

It seems there are some doubting the L67'* ability to run more boost. GM chose to run a 3.8" pulley on the L67 stock, so in all appications, with all exhaust and intakes, then engine would be able to very safely run the 7psi, to keep their warranty costs as low as possible. They also included a very good system in the computer of the car in case for some reason there is an engine problem and engine is getting knock with the stock setup, and for those idiots that would run a 3" pulley on the stock engine. Since GM makes hundreds of thousands of these engines they have to be very lienient on many things. So to be safe they run the 7psi, it is the amount of boost that they chose would be best to make power and cover their warranty costs. The engines are IRON block and IRON heads. The engines can easily handle over 20psi with the right management systems installed. GM knows that most L67'* can safely run a 3.4" Pulley stock, but for the few engines that may not be able to they don't use them stock. Installing a 3.4 Pulley on a stock L67 usually makes about 10-11psi. This is the most boost you want to run a stock L67. It is very safe, especially with all of the safety nets GM builds engines with, and it will in most, if not all cases, make 20+ hp and 30-40lb.ft torque gain safely, and if you don't know how much extra power that is, it is a LOT. If you go more boost than that you start to get the restriction of the stock air intake, the stock cam, stock rockers arms, stock blower, and stock exhaust all combined, and you start having problems, a 3.4" is the perfect size for the stock engine. Since most of the performance companies that sell parts for the L67 have figured out that it is safe to run a 3.4 on a stock L67, that is the largest size pulley most sell, and is their most sold product, it is very common for them to be sold out of 3.4 pullies. Some sell 3.5 and 3.6" pullies, but they are not very popular, and usually the people that purchase the 3.5'* or 3.6'* switch them to 3.4'* pretty quickly anyways. When you start to go to 3.25 and smaller pullies you will get a problem. To safely run a 3.25 pulley most will need headers and 1.9 rockers, or an aftermarket cam. To run a 3.0 inch or smaller it will require a full exhaust (including headers) a very good air intake with cold air coming in (not engine air) a cam or 1.9 rockers, colder plugs, colder t-stat, etc... To go to smaller than a 3" pulley it usually requires and Intercooler among many other mods. But to safely run a 3.4 it takes a stock L67, that is it. On our GTP we run a 2.7" Pulley on the street making 14.4psi, and we see 0kr in 80 degree weather on pump gas (Haven't tested in warmer weather). We run a 2.6" Pulley at the track (using race gas) making 14.965psi and it sees 0kr in 75 degree weather (Again warmest weather we could test in). The engine is completely internally stock except for the 1.9 rocker arms and stronger valve springs and pushrods, the rest of the engine (cam, heads, pistons, etc...) are all completely stock. It is running the stock transmission, except it has a limited slip differential and a shift kit, but those don't make the tranny any stronger, it still has stock clutches and all that. When you can run the engine basically stock internally, with the stock transmission, with 0kr on PUMP GAS with a 2.7" Supercharger pulley and have absolutely no problems with it, you know it is a strong engine (and tranny). Some of you make a bigger deal out of running a smaller pulley than you should, if you run a pulley that is the right size for your mods, you will have absolutely no problems at all. These engines are very strong, and not only can they handle the extra boost, but they WANT the extra boost. If you haven't installed a 3.4 pulley on your car yet, do it soon, you will like what you get.