2.5 to 3.4 conversion

[yfz/700R]

i was thinking about an exhaust and maybe a new clutch for my 99 boxter w/ 56,000miles but i think i might put that money aside for the 3.4 conversion. i been searching old threads for about a week but i couldnt find any answers for the questions i have.
is there a particular year/car 3.4 motor i should look for? what would be considered low mileage for a 3.4? is there anything else i should look for?
thanks
willy

[insite]

you need a '99 motor w/o egas. look for one with ~45,000 miles or less. there's tons of info on this site regarding these conversions. search around and you'll find what you need.

yeah.save up you money and go with the 3.4 motor

[blinkwatt]

Originally Posted by yfz/700R

what would be considered low mileage for a 3.4? is there anything else i should look for?

Low mileage would be anything under 60k,those engines can last a long time if properly carred for. I saw a 3.4L on a 996 that had 140k on the original engine.

You should also consider changing your clutch to a Sachs Performance/Sport Clutch Kit to make up for the increase in power.

[yfz/700R]

Originally Posted by insite

you need a '99 motor w/o egas. look for one with ~45,000 miles or less. there's tons of info on this site regarding these conversions. search around and you'll find what you need.

thanks, i have been searching for about a week, and the few threads i did find didnt indicate what year or car they got there motor from

[yfz/700R]

Originally Posted by blinkwatt

Low mileage would be anything under 60k,those engines can last a long time if properly carred for. I saw a 3.4L on a 996 that had 140k on the original engine.

You should also consider changing your clutch to a Sachs Performance/Sport Clutch Kit to make up for the increase in power.

thanks for the reply, so i guess i'm looking for a 1999 996 3.4 motor

[racer_troy]

...this is most likely the ideal upgrade in my mind...smooth reliable power increase with relatively little stress on the engine...the clutch upgrade is a good idea...but i've been told it's not an absolute must unless you are some sort of hot shoe and are notoriously hard on clutches...at the minimum...you will have a 3.4 interface to contend with and a converted 3.4 std clutch would likely be all that is required...I also know patrickmotosports.com is making a bolt in clutch for the specific conversion you are looking for...they also have a good and solid reputation for track prep cars and porsches...

if you are comfortable with a used motor...this guy at instant-g may be able to help you out...he generally can locate a motor for you and will go through it to make sure it's ready for the transplant...again, i think he echoes the comments of blink in regards to under 60k....it's all about what you are looking for....

http://www.instant-g.com/Projects/Boxster34/

the 3.4 conversion page is just pictures…you’ll want to surf around to get a real feel for what the guy is doing…the page is a little down home, but for me, I think that's the appeal, some guy with a phd just loves to build and race porsches...built a racecar for his wife (btw racecar spelled backwards is racecar)...and seems to be a straight shooter, which i always appreciate...I asked him to quote me a conversion and it was in the $8-9K range and he ships me the motor, wiring harness, mounts, brackets, exhaust, et. al....if you want him to do the install, it's going to run around $12-13K and 2 months, one for install and one for shake down...

also, if you want to source your own motor, you may want to give http://www.oklahomaforeign.com/ a shout...his been lisking a 6o somthing K motor on ebay off an on for the last 6 months...I believe the motor is still available and the price jumps around from $5000 - $5500 depending on his mood...

Anyway, you should be OK with the 5spd tranny with just the 3.4 conversion...other shops may tell you otherwise (RUF, Gemballa), however, Instant-G and FVD.us believe the 5spd is fine for up to 300bhp...

....good luck and have fun with this conversion...it is the way this car should have been delivered from the factory...

cheers,

--troy

[pecivil]

I am supposed to get my 00 box back from the shop tomorrow from its 3.4 conversion. :dance:

I can speak for Steve Timmons at Instant G. I bought the entire instant g header/cats/muffler set up for the conversion. The quality of his product is outstanding. It takes a awhile to get it, as he makes them when he gets an order. It is not cheap, but the stock boxster header/cat/muffler strangles the 3.4. Of course you can't use the 3.4 stock exhaust stuff cause it dont fit.

You can probably sell your 2.5 for something. I bought a used 2001 3.4 with 31k miles taken from a front end wreck. Subtracting out the price I got for my 2.7l (with 56k miles) the 3.4 cost $4500. My mechanic was able to throughly go over it before I paid.

On the clutch, you cannot use 996 components with the boxster 5 speed tranny. The splines dont match. Plan on buying completely new clutch stuff. My clutch was shot at 56k, and I also needed a new flywheel, as it was too messed up to resurface. I went with the AASCO lt wt flywheel. At least, you pay no extra for labor, since the tranny is already out.

The 996 carrera came with the center radiator, like the Boxster S. You need to think about wheather or not to add it. There are a couple of places that sell a add on kit for it, or your mech can just buy the stock porsche parts. I decided to add it to be safe, but my mech told me that you are probably ok without it for the street. Of course, if you do add it, you will need a boxster S or 996 or GT-3 front bumper cover with the opening for it.

Have you mech replace the RMS on the 3.4 as a precaution. Use the new, revised seal.

You will need a 3.4 throttle body. The boxster one does not work. You will also need some "revised" intake tubing, as again the stock boxster one does not make it distance wise to the filter.

Another easy thing to add is a oil temp & pressure gauges. You use the 3.4 oil pressure sender already on the engine. Add a temp sender on the opposite port (to the oil pressure sender) on the block, and run the wires in to the cabin. I am going to mount then in one of the cubbies below the radio.

You can also do a ECU remap for the 3.4 from GIAC or FVD. They take into account the exhaust mods if you get them. I am going with GIAC.

FVD also has "sport cats" for this engine, which they add to their conversions, I believe. I will see how it feels without the cams. I may add them later. Supposedly they make a big "feel" difference in the motor.

Hope this helps

Monte

[yfz/700R]

Originally Posted by pecivil

I am supposed to get my 00 box back from the shop tomorrow from its 3.4 conversion. :dance:

I can speak for Steve Timmons at Instant G. I bought the entire instant g header/cats/muffler set up for the conversion. The quality of his product is outstanding. It takes a awhile to get it, as he makes them when he gets an order. It is not cheap, but the stock boxster header/cat/muffler strangles the 3.4. Of course you can't use the 3.4 stock exhaust stuff cause it dont fit.

You can probably sell your 2.5 for something. I bought a used 2001 3.4 with 31k miles taken from a front end wreck. Subtracting out the price I got for my 2.7l (with 56k miles) the 3.4 cost $4500. My mechanic was able to throughly go over it before I paid.

On the clutch, you cannot use 996 components with the boxster 5 speed tranny. The splines dont match. Plan on buying completely new clutch stuff. My clutch was shot at 56k, and I also needed a new flywheel, as it was too messed up to resurface. I went with the AASCO lt wt flywheel. At least, you pay no extra for labor, since the tranny is already out.

The 996 carrera came with the center radiator, like the Boxster S. You need to think about wheather or not to add it. There are a couple of places that sell a add on kit for it, or your mech can just buy the stock porsche parts. I decided to add it to be safe, but my mech told me that you are probably ok without it for the street. Of course, if you do add it, you will need a boxster S or 996 or GT-3 front bumper cover with the opening for it.

Have you mech replace the RMS on the 3.4 as a precaution. Use the new, revised seal.

You will need a 3.4 throttle body. The boxster one does not work. You will also need some "revised" intake tubing, as again the stock boxster one does not make it distance wise to the filter.

Another easy thing to add is a oil temp & pressure gauges. You use the 3.4 oil pressure sender already on the engine. Add a temp sender on the opposite port (to the oil pressure sender) on the block, and run the wires in to the cabin. I am going to mount then in one of the cubbies below the radio.

You can also do a ECU remap for the 3.4 from GIAC or FVD. They take into account the exhaust mods if you get them. I am going with GIAC.

FVD also has "sport cats" for this engine, which they add to their conversions, I believe. I will see how it feels without the cams. I may add them later. Supposedly they make a big "feel" difference in the motor.

Hope this helps

Monte

good info, thanks
i live in sandiego, did you buy your motor locally? it sounds like you got a good deal
thanks
willy

[pecivil]

I bought the motor from a wreck up in LA.

[yfz/700R]

Originally Posted by pecivil

I am supposed to get my 00 box back from the shop tomorrow from its 3.4 conversion. :dance:

I can speak for Steve Timmons at Instant G. I bought the entire instant g header/cats/muffler set up for the conversion. The quality of his product is outstanding. It takes a awhile to get it, as he makes them when he gets an order. It is not cheap, but the stock boxster header/cat/muffler strangles the 3.4. Of course you can't use the 3.4 stock exhaust stuff cause it dont fit.

You can probably sell your 2.5 for something. I bought a used 2001 3.4 with 31k miles taken from a front end wreck. Subtracting out the price I got for my 2.7l (with 56k miles) the 3.4 cost $4500. My mechanic was able to throughly go over it before I paid.

On the clutch, you cannot use 996 components with the boxster 5 speed tranny. The splines dont match. Plan on buying completely new clutch stuff. My clutch was shot at 56k, and I also needed a new flywheel, as it was too messed up to resurface. I went with the AASCO lt wt flywheel. At least, you pay no extra for labor, since the tranny is already out.

The 996 carrera came with the center radiator, like the Boxster S. You need to think about wheather or not to add it. There are a couple of places that sell a add on kit for it, or your mech can just buy the stock porsche parts. I decided to add it to be safe, but my mech told me that you are probably ok without it for the street. Of course, if you do add it, you will need a boxster S or 996 or GT-3 front bumper cover with the opening for it.

Have you mech replace the RMS on the 3.4 as a precaution. Use the new, revised seal.

You will need a 3.4 throttle body. The boxster one does not work. You will also need some "revised" intake tubing, as again the stock boxster one does not make it distance wise to the filter.

Another easy thing to add is a oil temp & pressure gauges. You use the 3.4 oil pressure sender already on the engine. Add a temp sender on the opposite port (to the oil pressure sender) on the block, and run the wires in to the cabin. I am going to mount then in one of the cubbies below the radio.

You can also do a ECU remap for the 3.4 from GIAC or FVD. They take into account the exhaust mods if you get them. I am going with GIAC.

FVD also has "sport cats" for this engine, which they add to their conversions, I believe. I will see how it feels without the cams. I may add them later. Supposedly they make a big "feel" difference in the motor.

Hope this helps

Monte

so how does it run? did they do a good job on the install?

[Rail26]

pecivil...thanks for the great write up. I am not interested in doing the conversion, but always wondered what was involved. I would love to know how the conversion stands up to the new '07 box.

[pecivil]

still waiting to get her back..... the shop doing it is a very good shop, but it is only a 2 man shop and they are taking forever!! They work on several racecars, so every Friday, they tend to only work on racecars going out that weekend, and on Monday, they tend to only work on broken race cars coming back from the weekend. So all the "street" cars they work on get squeezed into Tues, Wed, Thurs.

Friday was the 2nd "it'll be done" that didnt happen. But the bottom line is they are doing an excellent job, which is what really matters.

So....I should get it this week. As soon as I get it, I will do a write up on how it feels.

[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.