2.5 to 3.4 conversion

[WillieB]

I should have my 3.4L Conversion back as well by Wednesday. It has been approx. 3-4 weeks. But went to look at her on Sat. and she is looking great. Fired up on the first crack. Remaining parts to be added cats, exhaust, etc. I have a 99 Boxster pre-egas. Can't wait! Props to Todd Holyoak and Trent Carter for their assistance on this. The information they have provided on this has been awesome!!!

[z12358]

Are there any limitations that prohibit dropping a 3.8L engine into a pre-2000 Boxster? Is the 3.4L the largest engine that fits? How about in a post-2000 Box? In other words, is a 3.8L mid-engine track car possible for around $30k ($15k for old Box + $15k for mods)?

Z.

[RandallNeighbour]

All you 3.4 conversion guys need to post observations, impressions, pix, movies, etc. for all of us 2.5 Boxster owners wanting to do this one day but being too broke today to do it!

[pecivil]

based on what I found out, it isn't the physical size of the engines, its the electronics that control them.

If you have a pre 00 boxster you do not have Egas. So the easy swap (easy meaning that the ECU and wiring stuff all is pretty much P&P) is a 3.4 carrera engine that did not have egas.

If you have a 00 or 01 boxster (I am not sure about 03) then you want a 00 or 01 carrera 3.4. This engine has egas, and has variocam, exactly like the boxster 2.7 does.

If you have a 00 Boxster S, then you go with a carrera 3.6. This engine has variocamPlus, which the boxster S has. Plus it has the 6 speed tranny, that is the same as the 996.

If you have a 03 or later boxster, I think you go with the 3.6 carrera engine.
If you have a 03 or later BoxS, then I think you can do the 3.8. Not positive on this.

If you have a 987, then you definitely go with the 3.8.

So its not that you can't do the 3.6 or 3.8 in the earlier boxsters, but you need lots!! of electronic wizardry to make the electronics work right. I think it has been done, but it makes the swap much more difficult, time consuming.

I would have loved to done a 3.6, but my 2.7 doesnt have variocamplus, only variocam, so I needed a 3.4 to be plug & play with my stock harness & ecu.

Make sense?

[WillieB]

Mine is a 99 Pre-Egas Boxster. So like Pecivil said, it has to be a 99 Pre-Egas 996 3.4L Engine. As for impressions from my first drive? Words cannot describe it. I rolled out of my mechanics shop today to give it a test run. The new clutch engages much faster. Guess I needed a new one anyway. Just took it easy until I got on the freeway as at low speed drives the same. The car sounds great. Hit 175 KPH or 110 MPH with little effort and got there very fast. I was blown away. I was then rolling in first gear and then put the pedal down and the rear wheels started to spin. I eased off the gas and went whoa!! Better give her some respect or she will own me. Kicks in at 3500 RPM and then around 5800 RPM another kick (VarioCam) right through to 7200 RPM redline. I wanted to keep driving all night long because it was so much fun, but figure there is always tomorrow. Was it worth it? Hell ya IMHO!!

Here is a pic of my ride and my mods to date are as follows:

1999 Boxster
3.4L 996 Pre-Egas engine (99) - 5 Speed
Evo High Flow Intake
Schnell Boxster S Headers
Dansk Sport Cats Boxster S
GHL Exhaust Boxster S
Sach's Heavy Duty Sport Clutch
FVD ECU Re-Map
H&R Lowering Springs
18" TechArt Formula Rims w/ Pirelli's
B&M Short Shift Kit

[Adam]

Originally Posted by pecivil

based on what I found out, it isn't the physical size of the engines, its the electronics that control them.

If you have a pre 00 boxster you do not have Egas. So the easy swap (easy meaning that the ECU and wiring stuff all is pretty much P&P) is a 3.4 carrera engine that did not have egas.

If you have a 00 or 01 boxster (I am not sure about 03) then you want a 00 or 01 carrera 3.4. This engine has egas, and has variocam, exactly like the boxster 2.7 does.

If you have a 00 Boxster S, then you go with a carrera 3.6. This engine has variocamPlus, which the boxster S has. Plus it has the 6 speed tranny, that is the same as the 996.

If you have a 03 or later boxster, I think you go with the 3.6 carrera engine.
If you have a 03 or later BoxS, then I think you can do the 3.8. Not positive on this.

If you have a 987, then you definitely go with the 3.8.

So its not that you can't do the 3.6 or 3.8 in the earlier boxsters, but you need lots!! of electronic wizardry to make the electronics work right. I think it has been done, but it makes the swap much more difficult, time consuming.

I would have loved to done a 3.6, but my 2.7 doesnt have variocamplus, only variocam, so I needed a 3.4 to be plug & play with my stock harness & ecu.

Make sense?

To give a quick rundown on computers and add some info, the ECM's on pre-2000 boxsters had Bosch motronic 5.2.2.... 2000-2002 cars had Motronic 7.2 and all 2003-4 cars have Motronic 7.8. I think 2005+ boxsters have 7.8 motronic too, but I'm not positive. Boxster owners would want to make sure their ECM is compatible with the correct 996 engine.

[z12358]

pecivil, Adam, -- thx for the information. I recall reading elsewhere and also concluding that it's the Box model's electronic nervous system that limits the choices of engines. Otherwise it gets too complicated and expensive.

WillieB, pecivil, and others who are doing this -- Congrats on your "new" cars and good luck! Can you pls give rough numbers on the total cost of the engine upgrades? Also broken down by items would be nice.

Thx,
Z.