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Question Thread - Boxster S - Bolt-on power mods

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Old 10-25-2023 | 01:53 AM
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Default Question Thread - Boxster S - Bolt-on power mods

Hello! I've been kicking around questions and reading so many threads and have reached a point where I'd love some answers to questions regarding unlocking power in my 3.2L boxster motor. I'm not expecting the world, and if I never did anything to my car and just drove it I'm sure I'd remain a happy camper. With that said, I enjoy doing my own maintenance and repair on the car and have no problem replacing parts over time if it unlocks performance or drives efficiency in my existing motor. I may someday do an engine out, send the heads to hoffman, and perhaps do a nickies build to 3.4/3.6. If I choose to do that, it will be a while. I'm unlikely to go the FSI route - my wife will want a new kitchen/bathroom/whatever first. Forever.

In any case - based on my reading, the boxster is intake and exhaust limited. Based on Jake's comments here: https://rennlist.com/forums/996-foru...l#post15565150 and also here: https://rennlist.com/forums/boxster-...l#post15774611

I have a plenum and throttle body from a 996 C4S on hand. Can I simply pickup a 996 intake manifold and runners on ebay like this one? Will this bolt up directly?

Also, the airbox is also frequently called out as a restrictive component. Can I simply fit in this 987 airbox?

Based on the Jake post above, I'll have opened up the intake from the airbox to the head. Other reading and threads state that I'm still limited by the factory boxster tune, that said, I've also read that I could have the car flashed with a ROW 996 tune to cause it to pursue the carrera fuel/air mapping table. Am I on the right track here? Another option I've read is that I can flash my car with the Special Edition tune to make it perform on par with a 2005 987 S.

These items so far don't seem to break the bank or put me in "spending 911 money on a 986" - I welcome a reality check if I'm missed something.

On to the exhaust side of the engine. I have a 2004 boxster S which has two sets of cats. I'm sure I can lose one and still pass Texas emissions and all that. I'm under the impression there are imported knock off headers that may be less restrictive. I'd love to see some suggestions or examples. I honestly prefer the current understated exhaust note, but my muffler is 20 years old. It will need to be replaced at some point and something lighter and more free-flowing is a reasonable replacement.

These are my current questions so far. I've dived into the rabbit hole of purchasing a 996 or 997 motor and going from there, but I'd like to work with what I have if there's upside available. I KNOW that the best investment in my car is seat time and brakes from a general "be a faster/better driver" so I'm not looking to cover over those things in the slightest. I'm just perfectly happy to invest my time and marginal dollars into making my car more efficiently make more power.

Lastly, if you have a thread book marked and don't feel like typing up a reply that's answered already, I'm all ears. Any input and direct experience is appreciated.

Last edited by fazm; 10-25-2023 at 02:14 AM.
Old 10-25-2023 | 08:43 AM
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There’s nothing worthwhile for the 3.2L motor IMO. A quality full exhaust will help the engine breathe and so pull harder/faster under load. Head and cam mods cost a fortune and return little in terms of bang-per-buck. Anything else, other than a capacity increase, is just placebo. These cars are meant to handle the twisty bits at pace. Your money is better spent updating/modifying the chassis and maybe the brakes to create an even quicker car point-to-point
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Old 10-25-2023 | 11:48 AM
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Default Bolt On Power

Check out Pedro's Garage. He truly answers the question you're asking.
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Old 10-25-2023 | 01:00 PM
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You can check this out...
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Old 10-26-2023 | 09:40 PM
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It isn’t as active anymore but most of the info you seek is over on 986forum.

http://986forum.com/forums/performan...-2s-motor.html

Jake’s advice is spot on. I considered all of this until I sold my 986 S too.
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Old 10-27-2023 | 12:24 AM
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Thanks man. I read that thread a few months ago with the guy lowering his motor, etc. At one point he simply posts "I don't think I'd recommend all this as I'm not sure it's worth it."

I guess where I'm at is like, I'd be happy to do any and all of the stuff that you'd do to support a nickies build when going to 3.4 or 3.6 and open up the 3.2. Jake says that the engine is crippled from the factory, but it's left as an exercise for the reader to divine what uncrippling entails!
Old 10-27-2023 | 02:28 AM
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With no sarcasm whatsoever, I can honestly say that I simply plan to LS3 swap my Boxster S as a proven way to increase its power. Sure, this is not for everyone...but I literally bought my Boxster S for its gearbox as I knew I'd be doing an LS swap in the future. That is my idea to bolting on more power to this platform, as searching for 5-25 hp just isn't going to make a noticeable difference. Even worse, some of these quality engine builds will ultimately get close to the cost of an LS swap, if not exceed it.

Before anyone gets agitated, my Boxster S is a very sad example that was probably otherwise going to find its way to a parts yard...not a cream puff! I want to give it a true second chance to become a more serious mid-engined Porsche.
Old 10-27-2023 | 08:32 PM
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So look at the motors he sells and a while ago there were lists available of at least the internal parts that were going to be improved. It was almost everything but you aren't going to be spending nearly the cost of one of his motors I'd guess nor getting anywhere near the results from bolt on stuff.

There is no substitute for displacement. And flow and tuning to match it. And other parts to make the engine more reliable.

There were at one time 28 known failure modes for a M96 engine to fail that Jake knew of. In one of his complete builds, he addresses all the ones he could. And he should for triple the cost of the car.

So say you decide to do bolt-ons and put several k into them. And then there is a catastrophic failure. How are you going to feel?

I put my money into reliability improvements. The common failure points. Likewise a couple of k$ but I got 5 years of trouble free use from the car before my lifestyle changed and I sold it. It ran perfectly when I did. And was running perfectly several years and two owners later.

I've been reading these forums for 20 years and never have I ever heard of a magic bolt-on that would transform the driving experience.

Further thoughts https://sites.google.com/site/mikefo...isntfastenough written probably 15 years ago but still true.
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Old 10-28-2023 | 12:34 PM
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Originally Posted by mikefocke
So look at the motors he sells and a while ago there were lists available of at least the internal parts that were going to be improved. It was almost everything but you aren't going to be spending nearly the cost of one of his motors I'd guess nor getting anywhere near the results from bolt on stuff.

There is no substitute for displacement. And flow and tuning to match it. And other parts to make the engine more reliable.

There were at one time 28 known failure modes for a M96 engine to fail that Jake knew of. In one of his complete builds, he addresses all the ones he could. And he should for triple the cost of the car.

So say you decide to do bolt-ons and put several k into them. And then there is a catastrophic failure. How are you going to feel?

I put my money into reliability improvements. The common failure points. Likewise a couple of k$ but I got 5 years of trouble free use from the car before my lifestyle changed and I sold it. It ran perfectly when I did. And was running perfectly several years and two owners later.

I've been reading these forums for 20 years and never have I ever heard of a magic bolt-on that would transform the driving experience.

Further thoughts https://sites.google.com/site/mikefo...isntfastenough written probably 15 years ago but still true.
Thanks Mike. Between your write up and Art's youtube channel I think I've got the lay of the land.

I had a chance to drive a new track yesterday (G2 Motorpark - great track!) and I need to update my courage + confidence in the car long before I need to really worry about power. I'll be investing in seat time and instruction for a while, I believe. I'm headed to Eagle's Canyon for a full day next Sunday and look forward to pushing myself (the car is barely stretching its legs, I bet) some more.

In the meantime, I'll work on the same things Art does in his videos while I'm doing maintenance/etc and work with my local shop on tuning as needed.
Old 10-30-2023 | 11:47 AM
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Originally Posted by fazm
Hello! I've been kicking around questions and reading so many threads and have reached a point where I'd love some answers to questions regarding unlocking power in my 3.2L boxster motor. I'm not expecting the world, and if I never did anything to my car and just drove it I'm sure I'd remain a happy camper. With that said, I enjoy doing my own maintenance and repair on the car and have no problem replacing parts over time if it unlocks performance or drives efficiency in my existing motor. I may someday do an engine out, send the heads to hoffman, and perhaps do a nickies build to 3.4/3.6. If I choose to do that, it will be a while. I'm unlikely to go the FSI route - my wife will want a new kitchen/bathroom/whatever first. Forever.

In any case - based on my reading, the boxster is intake and exhaust limited. Based on Jake's comments here: https://rennlist.com/forums/996-foru...l#post15565150 and also here: https://rennlist.com/forums/boxster-...l#post15774611

I have a plenum and throttle body from a 996 C4S on hand. Can I simply pickup a 996 intake manifold and runners on ebay like this one? Will this bolt up directly?

Also, the airbox is also frequently called out as a restrictive component. Can I simply fit in this 987 airbox?

Based on the Jake post above, I'll have opened up the intake from the airbox to the head. Other reading and threads state that I'm still limited by the factory boxster tune, that said, I've also read that I could have the car flashed with a ROW 996 tune to cause it to pursue the carrera fuel/air mapping table. Am I on the right track here? Another option I've read is that I can flash my car with the Special Edition tune to make it perform on par with a 2005 987 S.

These items so far don't seem to break the bank or put me in "spending 911 money on a 986" - I welcome a reality check if I'm missed something.

On to the exhaust side of the engine. I have a 2004 boxster S which has two sets of cats. I'm sure I can lose one and still pass Texas emissions and all that. I'm under the impression there are imported knock off headers that may be less restrictive. I'd love to see some suggestions or examples. I honestly prefer the current understated exhaust note, but my muffler is 20 years old. It will need to be replaced at some point and something lighter and more free-flowing is a reasonable replacement.

These are my current questions so far. I've dived into the rabbit hole of purchasing a 996 or 997 motor and going from there, but I'd like to work with what I have if there's upside available. I KNOW that the best investment in my car is seat time and brakes from a general "be a faster/better driver" so I'm not looking to cover over those things in the slightest. I'm just perfectly happy to invest my time and marginal dollars into making my car more efficiently make more power.

Lastly, if you have a thread book marked and don't feel like typing up a reply that's answered already, I'm all ears. Any input and direct experience is appreciated.
There really isn't anything that is bolt on that is going to give you any real noticeable gains with a stock engine other than an underdrive pulley:

https://lnengineering.com/products/p...ft-pulley.html

If you rebuild the engine, punching it to 3.8 makes the most sense and having the heads ported. Alternatively you could use a set of 3.4 heads and have those ported.

If you put a 3.4 996 intake on the engine, you will have to make a set of spacers to drop the drivetrain as it doesn't fit under the engine cover. I did this years ago with my own 99 Boxster.

The 987 airbox is a must when installing the larger engine - we had to pull mine out to do this swap. Added 40 horsepower on the dyno with the 3.8!

It's hard to beat the stock exhaust when it comes to horsepower. I would keep the stock system or if you are ok with something that is louder, maybe consider a Soul system with sport cats, if available.

I had the 3.4 RoW tune put in my 99 by my local dealer, but again I was taking a 2.5 to 3.4, so that was a must. The stock 3.2 DME will adjust to the increased displacement as long as all the sensors are working properly.
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Old 10-30-2023 | 10:09 PM
  #11  
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Thanks Charles. You actually shipped me an order from LN this morning! I'll get the underdrive pulley next quarter.

I thought the 3.2 and 3.4 had the same heads on them?
Old 10-31-2023 | 11:02 AM
  #12  
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Originally Posted by fazm
Thanks Charles. You actually shipped me an order from LN this morning! I'll get the underdrive pulley next quarter.

I thought the 3.2 and 3.4 had the same heads on them?
You are most welcome.

The 3.2 heads are indeed different from the 3.4 heads but can be made to work with the increased displacement. If it was me, I'd keep the stock 3.2 heads and intake, put the 987 airbox, and add a IPD competition plenum and larger throttle body. It's not worth going down the 3.4 intake route and everything required to make that work. Plus, that will save you a bunch of money too that can be spent elsewhere.



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