I can't imagine this hasn't been discussed, but it's not in a sticky or FAQ, and searches like "should ____ be done with ____" or "what should be done with____" are tough to really get combinations of several items. The other complexity is that there's different angles to come at... "what should be done along with ____ for more power" is a whole different conversation than "what should be done along with ____ for reliability". Of course lots of discussion on "moar powah!" but less on the latter. And heck - you can't even search for "17%", it's too short.

Disclaimer over...let me put it this way:

I picked up an R52 with 106K on the clock and I'm looking to both improve and maintain it. Some things already have become logically linked like dominoes:
I'm getting a P1688 at highest revs, so I've cleaned the MAP and TMAP, so maybe my crank damper failing... so I'm replacing/updating that, and since that's apart, might as well do the supercharger pulley and the tensioner and the belt for reliability.
And if I do that - I'm spinning the supercharger faster, so I should change the supercharger oil, and since that's apart - I should replace the water pump and gaskets - also for reliability.
You see where I'm going.

So since I've locked into the 17% pulley already for the fun factor and RPM range I'll most appreciate personally, this question now keeps going through my adult brain:
Another way to put it: I'm installing a 17% pulley because now's the time I'm taking the pulley side apart, I don't want to risk detonation, and I would like to keep my factory redline if possible.

Thinking of this as a car guy does - we're increasing air, so we want to increase fuel to avoid getting lean - but it's feasible that the car's ECU can keep up. That the injectors and pump might have headroom to keep up too.
On the spark side - most of the threads seem to agree on using slightly colder plugs, and I've seen lots that's said "don't bother" with a coil pack upgrade. Fine.

So-
Do the factory injectors keep up? Should a 380cc set of injectors be swapped in? Bigger?
Is a tune needed if you do swap injectors in? Or maybe - if you do a tune, you won't need to swap injectors?
I've read where some people say 380cc injectors plus a 17% pulley seem to be "fine", without running rich, or lean - apparently 15% pulley plus the same injectors can run rich - which at least isn't lean - but wouldn't make me think 17% would be magically ideal.

In my case, it's mostly going to be a fun car that's a cruiser, but want it to be quick, and will probably autocross 5 times a year as well.
I can see other dominoes falling going in this direction, but I'm willing to knock them down if I can avoid risk.

Thoughts on If I'm installing a 17% pulley as my power-adder, what other mods should correspond to ensure base-level reliability?

 

So funny enough... Just the act of posting this thread makes the "related topics" box appear, and there's some intriguing threads there, particularly the 19% pulley threads, which I hadn't even thought to look for:


I think it's safe to say - if people are running 19% pulleys on stock injectors and ECU maps, I can feel ok about running a 17% pulley at least for this summer.
For future readers, three of those links:

• https://www.northamericanmotoring.co...-inectors.html
• https://www.northamericanmotoring.co...uirements.html
• I don't necessarily trust a thread this old - but the others back it up: https://www.northamericanmotoring.co...ouldn-t-i.html

The other two threads aren't even really good threads for what I'm searching for, so maybe this isn't a common question like I expected.

But at least here's my takeaways from the threads I've found:

• You can run a 17% (and even 19%) pulley safely, without upgraded injectors or even an ECU tune.
• I didn't even see any high-rpm or wide-open-throttle risks of running too lean mentioned.
• If you run a smaller pulley, you'll realize more performance benefits by running larger injectors and a tune. Seems "a tune" is also a complicated topic worth researching in "current year" threads.
• The larger the pulley, the more heat of the intake air - and it seems "intercooler upgrade" is a complicated topic - even saw a thread that claimed upgrading in the stock location was pointless.

At least those are my takeaways I'm going to run with at the moment, from the threads I've read here.

 

I’ve always read the car would run on a stock tune with 380’s, but 400’s and larger are a no go, even for a short distance like installing the injectors at home, then driving to the shop to get a dyno tune.

Being on the East Coast it’s probably not an issue for you, but I would factor in if 93 octane is available in your area.

Also, not sure how much an extra 1 or 2 percent will make regarding power or issues, but if you’re going with an ATI crank pulley, the “stock” size is actually about .8% larger than stock. Too further complicate your decision, you could also consider a 16% pulley with either ATI.

If 93 is available, I would probably go with a 16% or 17%, a “stock” ATI, at least 380’s, colder plugs, and an Adriancl tune.

 

This is a very good topic and I agree. With as long as the R53's have been around, it seems there would be an accepted (and stickied) what mods to do and what mods complement each other.

I don't have 93 available and I'm running 17% with colder plugs. Everything else is stock and I've been running this for about a year with no problems and my car runs great. I daily drive it (spiritedly) but am ashamed to say I haven't had much time to take on the local "fun roads" to drive it in its element and show my daughter what this car is about.

I have 380 injectors, DDM intake and a boost gauge (for fun!) ready to install and waiting on one last piece of computer hardware so I can get the Adrianci tune. Engine mods I still want would be Milltek header and exhaust. I really like the idea of a bigger intercooler but some say the larger Ebay intercoolers don't flow that well and the only intercooler that is larger and flows well is crazy expensive.

 

Thanks, I've seen similar statements - good to hear another, that gives me some assurance that I don't need to worry with "holy crap" urgency, once I do replace my pulley.

But I do think there's a little falling-dominoes effect, so here's my current thoughts (a little restatement in easier to read form):

• I should replace my crank damper pulley, especially since I'm getting a P1688 occasionally, despite my cleaning and even replacing my MAP and TMAP sensors.
• Since I'm doing that... It's a perfect time to upgrade to a reduced pulley - for my driving style (and the occasional autocross), a 17% sounds right.
• Since I'm doing that... a new belt... the shorter belt makes sense to do.
• Since I'm doing that... a new tensioner just makes sense.
• But since I'm doing THAT... which will spin the supercharger enough to raise boost from 10psi to 15psi... I should change the oil in the supercharger because it's probably never been done.
• And since I'm doing that... replacing all the gaskets on the supercharger is smart to do.
• And since I'm going to do all that... the water pump of course.
• And since I will have all that apart...
• ...maybe a new thermostat? Maybe the WMW aluminum thermostat housing?
• I already recently replaced the wheel hubs and CV shafts...

It can definitely spiral, I just don't know how far makes real sense.

 

And since you got the supercharger off might as well put in the BVH and the upgraded cam, and on and on and on.......😀😀😀 They literally are more expensive than the boat I used to have! And that's saying a lot since boats are just holes in the water you throw money into! Have Fun😃

 

This question often come up as I'm often asked this about 17%, and the other pulley sizes as well. Been working on these cars for 20yrs now and I can say the only thing you need to do with ANY pulley change is go with the correct size belt, and colder heat range plugs.
https://www.waymotorworks.com/wmw-pulley-package.html
The vendors and people telling you that you have to get this that and the other stuff are selling you parts. This also happens all the time with sway bars and end links. I love to sell parts, but not going to tell you to buy something that isn't necessary.

Often people get on the need an intercooler or bigger injector train to keep from ruining the engine. Well facts are I personally have installed well over 600 pulleys, and sold more than I can count over the years. Over 90% of the people that have bought a 17% from me I know have not gotten injectors, or intercoolers and their cars are still running and driving fine going all the way back to 2004. Also if it was true about the 17% just killing engines you would see many threads here titled installed 17% pulley and now engine dead. The Forum has been around for over 16yrs so the post of the issues would exist if it happened. So clearly they don't cause the engine to just die, don't be afraid of the pulley.

 

​​​​​That needs to be on a shirt!!! 😃

 

I'd buy one.

 

Thanks, WayMotorWorks!

I see you replied before I went offline for my wedding and honeymoon, and actually the last three evenings after work and dinner I've spent wrenching on the car, replacing:

• Crank damper (ATI) pulley
• 17% SC pulley and shorter belt
• New tensioner while it was apart
• NGK plugs one degree cooler
• CV axles on both sides
• Hub assemblies on both sides

It was late so I didn't test drive the car until this morning, but so far all seems fine in a general sense...
I only did a quick drive around the [residential] block, so I haven't brought the revs up to see if the P1688 exists, but I've proactively bought a new T-MAP sensor as well in part because my stock crank damper pulley looked perfectly fine. Maybe instead of split pulley slippage there was belt slippage - who knows, but in case the P1688 T-MAP sensor code actually IS the T-MAP sensor - I'll have it handy.

I mainly wanted to get this done in advance of this weekend, there's a "MINIs At The Glen" event at Watkins Glen this weekend which is about a 3 hour drive from me, plus a pace-car led drive around the track - so I wanted to at least get that much done to feel confident that my crank pulley wouldn't let loose 2 hours into the drive, or on the track, or something along those lines.

I did purchase the WMW "ultimate supercharger oil change kit" with the water pump, and a valve cover gasket (mine has a minor leak), so I do have some more wrenching ahead of me in the weeks to come.

I also previously saved some Audi injectors (Bosch 06A906031BC ...380cc I think) on a wishlist on FCP Euro. Yesterday I saw an Email that they went on sale from $38 to $32, so figure that was worth ordering as well, as another 100,000 mile maintenance item if nothing else. But I appreciate that they aren't necessarily needed, so I won't be too worried about driving it around as-is! Thanks.