Ask me Anything - I run a 3.2 engine in a 996 cabriolet

Hi All This topic has come up a few times and people seem to talk about it with hushed understanding - you get why someone would cut their losses and spring for 92% of the stock engine but you don�t really want to admit it. Well I�m here to tell you about how I did it and I�m pretty happy. I got my 2001 Carrera 4 Cabriolet for next to nothing with a blown engine on a sign of goodwill from someone who wanted to see it driven and not stripped for parts; it had just over 125,000. At the time I was working in public service and this was literally the closest I ever imagined myself to living the 911 life. I Even at one point debated between a 2.7 and 3.2 but ultimately a 3.2 with a recent IMS replacement popped up on EBay and I took the plunge for about $3,000 shipped to my door. The engine cost was covered almost exactly by selling the 944 I was driving at the time. At the time I was pretty set on saving up for a 3.4 after getting whatever engine I got. After I got the engine i originally ran it with the Boxster intake, fuel lines, and non stock exhaust because I was nervous about having the bosses drilled on the 3.2 head to accept the 3.4 intake and fuel lines. This was a big mistake- I ended up having to alter a lot of stuff to accommodate the Boxster accessories and placement but it was one of those situations where once I realized how much easier(even if a little terrifying) drilling the holes would be it was too late. I got the car running about 4 months after receiving it working on it really occasionally. I had to fix a few things over the last three years but more or less, everything worked without too much drama. I never tuned the ECU because it ran pretty consistently without triggering any CELs. I averaged around 16.5-17mpg which seemed a little low. But I also mostly drive in the city. The car was really peaky and revved fast up high. Another side effect of not drilling the head is that my exhaust was not fantastic(Boxster headers and first cats to an x pipe style muffler and then exit) it droned super bad around 2,500rpm. I put about 7,500 pretty happy miles on the car in that setup. More recently I decided to drop the engine and drill the bosses in the head for the intake and exhaust hangers spurred in part by oil leaking from the AOS(pretty sure it was the line that connects now that I pulled it out). I actually just got back from my maiden voyage after doing this work(I also converted to RWD) and took it very easy because I had so much pulled apart and want to take it easy for a bit to listen and feel for loose bolts and such. I will give it a drive or two or three to figure out if it actually feels faster but the math says it should be with the larger intake and exhaust from the 3.4. I long ago sold the original mid pipes/cats from the car because they were coolant and oil soaked when the engine kaboomed for the original owner to a cat recycler. So my car is pretty much everything stock but with the DesignTek 200 cell cats. So that�s the story of a guy who was too poor(at the time) for even the cheapest 911, making it work with a donor car and a 3.2. Now a days I�ve moved into more lucrative work but still not sure if I�ll end up with another 911. Most likely I will keep an on Caymans(yes, a blaspheme like me would even consider a 4 cylinder) so I have a coupe and a drop top. But first I�m putting my money to other good uses. One thing is almost certain, I am no longer considering the move to a 3.4 - I would consider doing a full on rebuild of an M96 with nikkies and larger pistons but there is no way I�d replace what I have with a stock 3.4; just not enough difference and anecdotally the 3.2 has less chance of failure. If you have any questions, let me know. I�m sure the car is better with the 3.4 but I also know that it sucks how many people part their cars because they don�t have the money for a Rebuild and the cost/risk of a used 3.4 is high so they don�t know what else to do. So I wanted to tell my story so people consider the option of a 3.2. It�s not for everyone but it certainly works.

I reached out to you a little while ago. Thanks for the help. I'm about to pull a 3.2 out of a donor Boxster soon I'm fact!

Did you drill the head yourself or take it to someone else to do it? If you did it yourself, any tips?

I wonder if the 3.4 heads would fit on the 3.2 or wether the valves would be too big and hit the tops of the cylinders, then you could use a 3.2 short motor and everything else would just fit, also another idea I had was as the 2.7 and 3.4 have the same crank etc, I was thinking of leaving my 3.4 in my car for now and build a big bore 3.8 short block from a boxster to then swap over , and still end up with a good 3.4 short motor for spare or to sell on as would be work a lot more as a short motor than a boxster and could re coup some of your build money if you get what I mean. Watch this now boxster short blocks to go through the roof!

My compliments "neilll", an eminently reasonable alternative to replacing a roached 3.4 with a used motor of unknown pedigree. Bravo!

Prelude guy- I remember our messages - glad you found an engine and good luck getting your car on the road. Tex Squirrel - I did the drilling myself. I used a small drill guide to ensure I was drilling straight. I used a punch to mark locations with the intake runner, then checked locations again, and then started the holes with a dremel to be accurate. I used cutting fluid, checked depth often, and prayed. The tapping was actually pretty easy but again, cutting fluid and go slowly. Noz - I believe that the heads will fit. But don�t hold me to it. Thanks Weazer- I thought it a good solution too.

Pretty cool you did this....got you in on a good 911 at low cost. Plus, it looks like you learned a ton. A couple of years ago I was thinking of putting in a 2.7 in a 911 for my son when he was 16. My thinking was it would get him to experience rear engine car without the power😁 Once again nice job and thanks for sharing.

I researched this swap a few years ago. That's when I ran across Neilll's post. If I remember correctly, the 3.2L engine is essentially the same as the 3.4L. The heads, block, crank, cams. That's why you only need to drill out some bosses to make it work in a 911. The only difference is the cylinder bore size. Porsche detuned the 3.2L so it didn't come too close to the 911'a power. With the 996 throttle body and intake related parts, the 3.2L puts out around 270-275 hp. I'm hoping to test this idea one day. Dyno a properly fitted 3.2L in a 996.

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If you install the 996 intake manifold you will lose some low RPM torque which is the worst thing about most Porsche engines especially if it is a manual trans.

Byprodriver- Just seat of the pants after a couple of drives; I suspect you may be right about low down torque but the dip that the 3.2 has from 3,500-4,500 doesn�t feel as pronounced as it did before; the car pulls more smoothly and consistently from 1,000-5,000 than it did before. So I think in the long run some low down torque loss for possibly a higher peak hp, a little better layout for some things in the engine bay, and some improved drivability is a fair trade off. Lowpue- thanks, glad you enjoyed!

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You also lose low RPM torque with the smaller engine displacement. Might increase clutch wear.

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How will clutch wear increase?

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You have to rev engine higher to engage clutch when you lose off idle torque, better chance of stalling too.

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No, not at all. You shouldn't have to rev cars much more than 1k RPM if driven correctly. Besides, the tq differences is neglible at that low of an RPM. By that theory, my 240SX would eat through clutches much faster than 996s because it only had a 2.4L.

Having driven a bunch of manual cars; the amount of lost torque from the 3.2 in any configuration is not sufficient to need clutch abuse to get going. It�s very within the noise types of numbers in differences. I�ve found this car to be very easy to get going under all circumstances. I know people get sensitive about parts being designed for a certain car and motor. But the 3.2 doesn�t have a specifically designed intake and exhaust for its engine- it was literally lifted off of the 2.7. So although generally speaking free flowing intake and exhausts lead to less torque- the 3.4 could very well just be a better better match and not have lost torque. Until someone like me or Preludeguy takes it to a dyno - it�s just conjecture. There are 3.2 boxsters making numbers on the dyno(including torque) close to 3.4s stock from intake, exhaust, and a tune - obviously comparing dyno runs is a bit suspect but you can get a sense of the gains people make.

I get really sh*tty mileage about of my 2000 C4 Cab which runs well and doesn't smoke or make any unusual noises but I only get about 14-15 miles/gallon, which is as bad as the FJ Cruiser that I use to own, and I don't really push the car that hard. Of course, when I see the topic discussed, everyone seems to say they get 20+ mpg in their 996's. I'm willing to live w/it, since I don't plan any long distance drives in my 996 and since "if you can afford it, you shouldn't have to ask the price" but if anyone has any suggestions to improve the MPG, I'm all ears. BTW, I get 20+ mpg in my BMW 335i, 25+ in my MR2 Spyder and about 18-20 in my MB ML350 SUV. The only other vehicle of mine that gets such sh*tty mileage is my F250 Diesel, which also runs about 14-15 mpg. Go figure! LOL!

Interesting read. Glad you got to enjoy a 911 on a shoestring budget. I've long wondered if used 3.4L engines will ever be "affordable" Ie not 7k on eBay with 100k miles and zero service history. I wonder if salvage yards just leave them on the shelf to rot instead of selling at a reasonable price.

I get 17.5 mpg. Thats pre-COVID commute numbers. (Lots of stop and go traffic) Lately I haven’t been dealing with stop and go traffic, so my normally 2.5-3 hour commute is now 1 hour. I need to check my new mpg.

The MPGs don�t bother me much but I did think it was good to note. I am curious to see if the change to rwd and the stock air box and exhaust changes things. My COVID driving has been minimal so it may be a while until that gets clearer. Garrett I agree wholeheartedly about the 3.4s with 100k miles- spending $7-8k on one of those doesn�t make sense to me. I gambled a bit on my 3.2 but there were some assurances and the gamble was half the cost. But everyone has a different risk tolerance and purpose with their car. I have to imagine the target market for those motors are people who want to replace a busted engine and walk away. Easier to sell a running 996 for $15,000 than a roller for $5,000 I would guess.

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I'm in a rare position where I could drop 7k on a new engine and still be into my C2 coupe for well under 20k but I don't think my situation is common

I also had the predicament of going for a 3.4 or used three boxster 3.2 but luckily I managed to get a 3.4 engine for �3k, it had 80k miles on it ! I stripped it down and probably spent �1500 on parts , I didn't go mad on upgrades I just upgraded the ims and did new chain guides and bearings etc so my engine was like a new factory engine or as close to as possible with an upgraded ims , but it depends what's wrong with your engine? You could source a 2.7 or 3.2 say if you need the crank then sell off the other bits, I was surprised at how much money I made back from my old engine , about �1800!! I sold the heads, half of the block, a few pistons etc!

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hello, I am having the same problem that you have encountered when you decided to swap the 3.2 into your 996. Mine is a 996 from 1999. And I would like to put in the 3.2 engine Boxster. Is there anyway that I can tap into your knowledge? thank you very much Marco

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It's been two years since he posted. What you wanna bet he's sold his car and moved on?

I didn�t sell it, I got hit by another car and it sat in a shop for 6 months and they couldn�t source the parts and the damage was right under 50% of value. I�m driving a new integra and waiting for the right time to get back into a 996(or Porsche). I was actually eyeing up another car with a blown engine 2 weeks ago. But yes, without a Porsche I haven�t come around very often. Marco, I accepted your friend request and am happy to help you navigate as best as I can remember. Realistically, if you�re willing to drill/thread those bosses(which I did at home with just a standard drill and tap with a basic drill guide) then it�s plug and play. One difference for your car I suppose is that you are potentially running a cable throttle and a different air meter- but as long as you carry over the hardware original to the car(not the new engine) you�re good.

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Ouch... sorry to hear that man! That sucks. But glad to hear you're safe and on the road again. I assume the car was deemed a total loss by the other driver's insurance? Did you come out ok true market value? If so, I guess I'm a little right in that in theory you sold it to the the at fault insurance agency.

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thank you very much. I�m very new to this application. I�m not quite sure how to do the whole quote and stuff so excuse me if I am responding to the whole message. Lol i�ll try to send you a message and whatever you remember, it�s fantastic and I will gladly listen

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yeah, they bought it and I gave a pretty detailed email of what I did and why they should know my engine wasn�t original and they more or less shrugged their shoulders and cut a check at around full value. I felt bad knowing that the knowledge of the swap would get lost in the chain of sales between me, the insurer, the salvage auction(or wherever); but I kind of accepted I didn�t have control over how they handle it. I miss the car so much.

Very cool thread but sorry to hear about the accident. Glad to hear you're ok & hope to see you in another car soon enough.

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LoL you beat to the punch....Glad to know others with good running engines get **** MPGs as well. When I got my Targa it showed 16.9 and now at 15.7 and seems to be going down....Oh well I know its not a Toyota and not meant to save on gas

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I had a drop in mileage from the mid 20’s to the high teens. Changed out the pre cat 02 sensors and that fixed the problem. Took 20 minutes. I also changed the air filter since I took out the box to get at the sensor connection

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Can�t we roughly achieve the same thing (with less effort) by changing the throttle body to a Boxster�s? I�m also interested in the idea of detuning cars for inexperienced drivers.

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I had a drop in mileage from the mid 20�s to the high teens. Changed out the pre cat 02 sensors and that fixed the problem. Took 20 minutes and I needed to change the air filter anyway.

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Sorry hard to believe these engines get mid 20s unless that's highway driving...I would never expect that....I was happy 16.9. At almost 73k miles I know some things need to be changed out...Thanks for the tip

another necro-bump - wondering if you had to use a 996 flywheel?