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Old 09-17-2022, 11:07 AM   #1
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Installing a 2.7l engine in a Boxster S of the same year...

If all goes well I will be buying a 2000 Boxster S with an engine problem. I have a spare 2.7 engine, also from a 2000, that I plan on installing, as long as there are no major complications. I see the 2.7 engine as a temporary solution, I want to test the 2.7 engine anyway. Once the 3.2 is out I can have a look at it to see if it can be repaired. Supposedly it has a failed IMS bearing, based on the fact that there is metal in the oil filter. If the 3.2 engine can be repaired it will go back into the car. If not I will sell off any useful parts and put them towards buying a used 3.2.
According to the article in the 101 projects book and on the Pelican site the 2.7 should be compatible, but a re-map of the DME would be needed. I assume that the transmission would bolt right on. Would the clutch be a problem? I will have both the 2.7 and 3.2 clutches available.
Also, what exactly is involved in remapping the DME?
Any help appreciated, thanks in advance.

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Arctic Silver 2000 Boxster S - bought with a broken engine, back on the road with the engine replaced
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Old 09-19-2022, 05:19 PM   #2
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You actually will not need to remap the dme, so long as you keep the maf housing the same. The dme cares not the displacement, it just needs accurate measurements of air coming in, so that it can deliver the proper amt of fuel and then have it check out on the exhaust size. If you change your maf housing, however, you will need a new map. PIWIS II is what you'll need - I wrote up a diy on flashing procedure a few years ago.

I don't think that the 6 speed bolts to the 2.7. Someone check me on that, but I'm pretty sure the patterns are different.

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Old 09-20-2022, 02:42 AM   #3
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Quote:
Originally Posted by ike84 View Post
You actually will not need to remap the dme, so long as you keep the maf housing the same. The dme cares not the displacement, it just needs accurate measurements of air coming in, so that it can deliver the proper amt of fuel and then have it check out on the exhaust size. If you change your maf housing, however, you will need a new map. PIWIS II is what you'll need - I wrote up a diy on flashing procedure a few years ago.

I don't think that the 6 speed bolts to the 2.7. Someone check me on that, but I'm pretty sure the patterns are different.

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Thanks, good to know that the remap is not necessary. I did some searching and can't find any suggestions that the bolt patterns differ.
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1987 924S 5-speed (Sold) - Blue 2000 Boxster 5 spd (Sold)
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Old 09-20-2022, 04:03 PM   #4
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One of the cars I bought was a 2000 S with a 2.5L (1997) installed with the 6-speed transmission. No issues with bolt pattern.
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Old 09-22-2022, 07:27 PM   #5
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I seem to remember that from a 6 speed conversion thread. I could definitely be wrong though.

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Old 09-23-2022, 04:30 AM   #6
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Originally Posted by ike84 View Post
You actually will not need to remap the dme, so long as you keep the maf housing the same. The dme cares not the displacement, it just needs accurate measurements of air coming in, so that it can deliver the proper amt of fuel and then have it check out on the exhaust size. If you change your maf housing, however, you will need a new map. PIWIS II is what you'll need - I wrote up a diy on flashing procedure a few years ago.

I don't think that the 6 speed bolts to the 2.7. Someone check me on that, but I'm pretty sure the patterns are different.

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Not necessarily true. The dme can adjust only so much to remove fuel to get the smaller motor to a reasonable a/f, so you may hit correction limits
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Old 09-28-2022, 09:22 PM   #7
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Not necessarily true. The dme can adjust only so much to remove fuel to get the smaller motor to a reasonable a/f, so you may hit correction limits
I have read the same thing about the correction limits, and I've seen both 20% and 25%.

My 2.7 runs on a 3.4L tune at-17% long term fuel trim without issue and afr is spot on.

I would assume that if all other components are left stock (intake and exhaust), a 2.7 would run around -15% on a 3.2 tune.

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Old 10-04-2022, 04:34 AM   #8
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It's only going to be spot on when cruising though in closed loop fueling. Once it enters open loop fueling it will ignore the oxygen sensor for the most part and run programmed values. The primary oxygen sensor is not a wideband sensor and is not used for full time close loop control as I understand it in this car.
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Old 10-04-2022, 05:47 AM   #9
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Thanks for the remarks... even though I don't really understand what all that means. What I take away from this is that the car will run well enough to test out the car and the engine, but will not be at its most efficient.
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Old 10-11-2022, 04:15 AM   #10
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The 3.2 engine and 6 speed transmission are now out of the car. When installing the 2.7 I am assuming that I can use the original 2,7 flywheel with the 3.2 clutch disk and pressure plate. Any other parts that must be switched?
The other difference I see is the backup light switch wiring. If I remember correctly on my base boxster the connector is different and I don't see the wire on my 2.7 engine so I suspect that it goes to the cars wiring harness not the engine's.
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Arctic Silver 2000 Boxster S - bought with a broken engine, back on the road with the engine replaced
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Old 10-14-2022, 07:40 PM   #11
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Originally Posted by subieworx View Post
It's only going to be spot on when cruising though in closed loop fueling. Once it enters open loop fueling it will ignore the oxygen sensor for the most part and run programmed values. The primary oxygen sensor is not a wideband sensor and is not used for full time close loop control as I understand it in this car.
This is not correct. This is the entire point of ltft adaptations. My afr at wot is 10.5-12 depending on load and slope.

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Last edited by ike84; 10-14-2022 at 07:43 PM.
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Old 10-17-2022, 06:56 AM   #12
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This is not correct. This is the entire point of ltft adaptations. My afr at wot is 10.5-12 depending on load and slope.

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thats insanely rich. You'd want to see closer to 12.8. 10.5 is like pig rich. Power would be down a lot.
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Old 10-17-2022, 09:21 AM   #13
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This is not correct. This is the entire point of ltft adaptations. My afr at wot is 10.5-12 depending on load and slope.

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How your you arriving at your "AFR" figures?
AFR gauges?.... Dyno runs?
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Old 10-22-2022, 06:07 PM   #14
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The 2.7l engine is ready to go into the car. Engine 2.7l, 6 speed gearbox and flywheel, clutch and pressure plate from a 3.2l. As others suggested there is no problem with the bolt pattern.

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Arctic Silver 2000 Boxster S - bought with a broken engine, back on the road with the engine replaced
Green 2000 Boxster 5-speed and 1978 928 auto
1987 924S 5-speed (Sold) - Blue 2000 Boxster 5 spd (Sold)
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Old 10-30-2022, 11:11 AM   #15
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Originally Posted by elgyqc View Post
The 2.7l engine is ready to go into the car. Engine 2.7l, 6 speed gearbox and flywheel, clutch and pressure plate from a 3.2l. As others suggested there is no problem with the bolt pattern.



Nice work!

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Old 10-30-2022, 11:12 AM   #16
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How your you arriving at your "AFR" figures?

AFR gauges?.... Dyno runs?
Yes, i have an afr guage installed.

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Old 11-03-2022, 09:10 AM   #17
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The engine is in the car and it runs, although it is a bit rough. I am assuming that it will take awhile for the ECU to come to grips with the engine change. The more I drive it the better it runs.
So the answer to my original question is: yes the 2.7l engine can be installed without major problems. If the ECU is able to adapt to the engine the only other (minor) incompatibility is the backup light connection.
I will continue to update my experience on the thread for the car at:
Bought a 2000 Boxster S project.
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Arctic Silver 2000 Boxster S - bought with a broken engine, back on the road with the engine replaced
Green 2000 Boxster 5-speed and 1978 928 auto
1987 924S 5-speed (Sold) - Blue 2000 Boxster 5 spd (Sold)
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Old 11-04-2022, 05:31 PM   #18
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Some tips at this point...

Let it even out the idle before you drive. It will take 60 seconds or so to adapt. This is important though because it tunes the base of your ltfts.

When driving, go easy so that it stays in closed loop operations. This will fine tune your ltfts over about 50 miles of driving so that the dme can adjust to new maps. Don't push it into open loop until after your ltfts have settled out (somewhere around -15%).

You really shouldn't have any rough running as you're gonna be rich if anything. If you haven't already, clean your MAF sensor really well.

Btw, job well done

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