1998 Boxster 2.5 To 2001 2.7 Engine Swap Upgrade

[78F350]

Originally Posted by Erlinrys

I'd appreciate as much feedback from experts in the process and the steps required...

I'm far from an expert, so I can't offer much help, but your post made me curious. Why are you doing this particular swap?

The shop will begin the engine swap process Tuesday.

I'm sorry... did you say Tuesday? as in this week, tomorrow? ..and you are asking these sorts of basic questions now? ...I mean, "NOW?"

I can drop in the 2.7 motor into the 98 Boxster and to utilize the 2.7 motor mount(s).

Yes, physically they fit and mount the same.

Wiring Harness (Can I utilize my 2.5 engine harness in the 2.7 motor?)

Here's another issue for you to consider: The Tiptronic transmission harness is bundled into the engine harness. If you don't use the 2.5's harness, you will need to tear it apart and rebuild it or find a 2.7L Tiptronic harness.

Throttle Body Intake Manifold (swap the 2.5 to 2.7 engine? ... just as simple as running a 12v wire and another wire to Pin 59 into DME ... and smooth operating Boxster, I can probably consider it.

Know what you are going to do before the shop tries to put the replacement engine in. (Are they experienced and do they have any suggestions about these issues?)
Throttle body: 1998 is actuated by a cable and gives position (load demand) info to the DME.
With the 2001, the gas pedal has a position sensor that gives load demand to the DME, which activates a servo on the throttle body, then a position sensor on the throttle sends feedback to the DME.
My guess is that the 5.2.2 DME will only work with the cable throttle and the 7.2 DME will only work with the eGas throttle. Programming and wiring will not fix that.
Either DME and throttle set-up will need custom programming to function well.
The 12v wire and DME pin 59 is specifically for controlling the flapper valve on the 2.7 intake's second cross-tube with the 5.2.2 DME. I don't think that pin 59 on your 1998 986 DME is going to be active without reprogramming. The engine will run without the flapper. It will have trouble meeting the correct fuel/air mix and have some flat spots in the power curve.
Unless you are ready to pay en experienced, skilled pro to get it all configured, swapping various parts will just be a poor compromise and give less performance than a proper 2.5L engine.

Transmission (Shall my Automatic tranny bolt into the 2.7)

Yes. TC and tranny bolt up, no issues.

... Alternator (for Automatic), Starter, Engine Air/Oil Separator, Water Coolant, thermostat, Air Filter, Engine Oil Filter, Fuel Filter, Spark Plugs, Crank Seals, Oil Cooler O Ring Gaskets, Lower Upper and Idler Pulleys, Serpentine Belt, Three Gallons of Porsche Antifreeze.

That's good planning. Other thoughts: IMS bearing and seal. Cam tensioner/adjuster pads.

My related experience is swapping a 2.7L manual engine into a 2.7L Tip and owning a 2000 S that had a 2.5L (1997) swapped into it before I bought it.

My advice.... Read Woody's (itsnotanova) post about a dozen more times and let it sink in. Don't take any action until after the holidays.

[Erlinrys]

Thanks for the feedback. See my input below.

Originally Posted by 78F350

I'm far from an expert, so I can't offer much help, but your post made me curious. Why are you doing this particular swap?


Had to replace Engine. i over heated the 2.5

I'm sorry... did you say Tuesday? as in this week, tomorrow? ..and you are asking these sorts of basic questions now? ...I mean, "NOW?"

Yes, it was Towed today at 8:15am. I did my research first. The idea sparked up from a guy name Roger from Auto therapy who works on Porsche‘s and then I began this unpractical process and based on my references it should work. Roger supposedly has compeleted these swaps and he informed me the DME actually reprograms itself without reflashing it.


Yes, physically they fit and mount the same.

Sweet!!

Here's another issue for you to consider: The Tiptronic transmission harness is bundled into the engine harness. If you don't use the 2.5's harness, you will need to tear it apart and rebuild it or find a 2.7L Tiptronic harness.

I did also order a 2001 automatic tip Tronic harness. Should arrive in the next couple days.

Know what you are going to do before the shop tries to put the replacement engine in. (Are they experienced and do they have any suggestions about these issues?)
Throttle body: 1998 is actuated by a cable and gives position (load demand) info to the DME.

They are not Porsche specialist. He operates Kash customs exhaust center and interlock services. He did not make any suggestions. I kind of went over this plan with him and we will see what happens.

Utilizing the 2.5 manifold and throttle body on the 2.7 engine and remapping my 5.2.2 dme hopefully solves this system. ( I am still also planning on running the 12 V wire and the other wire to pin 59 and try To place the 2.7 Throttlebody and manifold) 2

With the 2001, the gas pedal has a position sensor that gives load demand to the DME, which activates a servo on the throttle body, then a position sensor on the throttle sends feedback to the DME.

Yep. The 7.2 system. Using my 2.5 throttlebody hopefully resolves this problem


My guess is that the 5.2.2 DME will only work with the cable throttle and the 7.2 DME will only work with the eGas throttle. Programming and wiring will not fix that.
Either DME and throttle set-up will need custom programming to function well.

Yes, I’m planning to re flash the 5.2.2 dme to control the new engine.

The 12v wire and DME pin 59 is specifically for controlling the flapper valve on the 2.7 intake's second cross-tube with the 5.2.2 DME. I don't think that pin 59 on your 1998 986 DME is going to be active without reprogramming. The engine will run without the flapper. It will have trouble meeting the correct fuel/air mix and have some flat spots in the power curve.

If the 2.5 throttlebody and intake manifold do not respond appropriately I might have to encounter this problem or system with the 2.7 Throttle body and intake manifolD.

Unless you are ready to pay en experienced, skilled pro to get it all configured, swapping various parts will just be a poor compromise and give less performance than a proper 2.5L engine.

There’s only a 10 hp power gain difference. Will see.

Yes. TC and tranny bolt up, no issues.

Sweet!

That's good planning. Other thoughts: IMS bearing and seal. Cam tensioner/adjuster pads.

The engine that I purchased currenty has a serial no., On the IMS bearing, since there is a serial number on that ims bearing maybe the previous owners replaced it. Because I believe the stock I am as bearings do not bring serial number (see image)

My related experience is swapping a 2.7L manual engine into a 2.7L Tip and owning a 2000 S that had a 2.5L (1997) swapped into it before I bought it.

Oh wow. Yeah, it clearly referenced in 101 Porsche Projects that “Very early 1997 cars had non-programmable DME’s. If you have one of these cars you may need to purchase a new DME and matching immobilizer to go along with it. Immobilizer codes for these early cars are not stored in the Porsche Dealer information system, so there’s no way of linking the existing immobilizer to have a new DME. Don’t buy a 1997 if you are definitely planning on doing an upgrade as you might get stuck with one of these non-programmable th very early 1997 cars had non-programmable the Emmys. If you have one of these cars you may need to purchase a new DME and matching immobilizer to go along with it. Immobilizer codes for these early cars are not stored in the Porsche Dealer information system, so there’s no way of linking the existing immobilizer to have a new DME. Don’t buy a 1997 if you are definitely planning on doing an upgrade as you might get stuck with one of these non-programmable DMES”.

My boxster is 98.

My advice.... Read Woody's (itsnotanova) post about a dozen more times and let it sink in. Don't take any action until after the holidays.

I really hope it all works out. If not, does anyone want to buy a 01 2.7 Boxter Engine with 79k?

[Erlinrys]

Wow, that is interesting. Wish I had an S. And Wish I had 2.5L instead of the 2.7. Will see what happens.

Originally Posted by 78F350

I'm far from an expert, so I can't offer much help, but your post made me curious. Why are you doing this particular swap?

I'm sorry... did you say Tuesday? as in this week, tomorrow? ..and you are asking these sorts of basic questions now? ...I mean, "NOW?"

Yes, physically they fit and mount the same.

Here's another issue for you to consider: The Tiptronic transmission harness is bundled into the engine harness. If you don't use the 2.5's harness, you will need to tear it apart and rebuild it or find a 2.7L Tiptronic harness.

Know what you are going to do before the shop tries to put the replacement engine in. (Are they experienced and do they have any suggestions about these issues?)
Throttle body: 1998 is actuated by a cable and gives position (load demand) info to the DME.
With the 2001, the gas pedal has a position sensor that gives load demand to the DME, which activates a servo on the throttle body, then a position sensor on the throttle sends feedback to the DME.
My guess is that the 5.2.2 DME will only work with the cable throttle and the 7.2 DME will only work with the eGas throttle. Programming and wiring will not fix that.
Either DME and throttle set-up will need custom programming to function well.
The 12v wire and DME pin 59 is specifically for controlling the flapper valve on the 2.7 intake's second cross-tube with the 5.2.2 DME. I don't think that pin 59 on your 1998 986 DME is going to be active without reprogramming. The engine will run without the flapper. It will have trouble meeting the correct fuel/air mix and have some flat spots in the power curve.
Unless you are ready to pay en experienced, skilled pro to get it all configured, swapping various parts will just be a poor compromise and give less performance than a proper 2.5L engine.

Yes. TC and tranny bolt up, no issues.

That's good planning. Other thoughts: IMS bearing and seal. Cam tensioner/adjuster pads.

My related experience is swapping a 2.7L manual engine into a 2.7L Tip and owning a 2000 S that had a 2.5L (1997) swapped into it before I bought it.

My advice.... Read Woody's (itsnotanova) post about a dozen more times and let it sink in. Don't take any action until after the holidays.