3.4L Engine Conversion
 

I was replying to a question regarding information on the 3.4L conversion when the forum magically reset to an earlier time.

A good thread on an engine conversion can be found here:

http://www.renntech.org/forums/index.php?showtopic=4798&hl=

The quote I got last year for the conversion on a 98 Boxster goes as such:

"Price is usually about $6K for a decent motor, $1500 for reprogramming, $2000-2975 in exhaust and $1500 for installation and conversion parts."

Sadly, I have heard that a 97 Boxster requires a new DMU. For some reason, it can't be programmed for the conversion.


P.S. I was re-reading the renntech thread. My favorite part is when somebody brings up the idea a supercharger with the 3.4L conversion. More power, more power! :D

I'd take a 3.8L swap over a S/C 3.4L any day of the week. Swapping in a 3.4L and then supercharging it is just a more expensive and less reliable way to go just as fast.

How feasible is swapping the 3.8 into the Box? I have a 2000 S with only 27k miles but am considering doing a swap to a 3.4. If the 3.8 would fit with little modification then that is the way to go. Any comments?

RUF in Texas does the 3.8 swap for [are you sitting down]...$36,900!!

www.rufautocentre.com

It takes about 2-3 weeks for the 987. I don't know the price for the 986.

I guess almost anything carwise is feasible if you throw enough money at it. As bmussatti pointed out, the RUF site is a good place to check out. Here's how RUF divides out their conversions:

http://www.rufautocentre.com/conversions/Boxster.asp

One thing I notice is all of the conversions mentioned by RUF is for e-gas. MNBoxster has pointed out that it's no small task to go non e-gas to e-gas. So for pre-2000 Boxsters, it makes "sense" to go with a cable throttle body 3.4L.

I spoken with RUF in the past and they are quite helpful. They could probably point out why they put the 3.4, 3.6 and 3.8 in the model year Boxster that they do. You could search this site also. I know that engine conversions have been discussed.

I was involved in a project that entailed a BoxsterS with a 997S 3.8L engine. The main problem on the market today is figuring out how to control the VarioCam PLUS which came on the 3.8S. After long hours, I was able to tune the car and control the VarioCam..
A Boxster with a 3.8L is awesome.. I'm a 911 guy, however after driving the 3.8, I'm looking for a Boxster to convert myself.

The conversion itself is VERY simple, you will be surprised! The electronics, well they are simple now :)

If it were me, I would go with a SC Boxster S.

Seems simpler and cheaper, no?

Cheaper yes, simpler maybe not. I have had many supercharged vehicles including a C5 vette and 2 350Z's. Tuning is key with a blown application and this is where things can get crazy on a high compression motor as I found out TWICE on EACH 350Z...2 blown head gaskets. Just my thoughts...and btw, the cars were tuned by professionals and only running 6lbs of boost.

FVD is now doing 3.8L swaps for $24K total including labor. They are also doing it for all model years, despite the differences in electronics/wiring in pre-'02 cars. :confused: I wonder if post-'01 cars get a little discount.

FVD-USA

These 3.8L swaps seem to be in the back of everyone's mind, and I'm dying to see a forum member go through with it and do a good write-up for everyone. :D

Sheesh guys if you want more power take the 20-30k add it to your 30k boxster S and buy a 996 turbo.

or keep your boxster and buy a used z06 haha 2 cars then.

"keep your boxster and buy a used z06 haha 2 cars then."

Not a bad idea!

Here is where I'm slightly confused. Egas is drive by wire as it's commonly called. Basically a motor that controlls the throttle vs. a cable like the 97-99 cars have.

I swap 1.8T motors into older VW's often and they have drive by wire throttle bodies. The older VW's run a regular throttle cable. So we pull off the drive by wire throttle body and put the original throttle body that was on the old motor on to the new motor and hook the wire back up with a custom mounting bracket to hold the cable. Big deal. Hell I used an Integra GSR throttle body on a 1.8T motor into a Rabbit to make it work (and it does quite well, low 12's in the 1/4) with a small adaptor plate.

Why would we convert the car to drive by wire instead of just swapping out the throttle body to a normal style that will hook upto the cable we already have? Will the 2.5 and 2.7 TB not fit on a 3.4L motor? Why not just machine an adaptor plate then that will make it fit? An hour on a mill can whip that up sort of like hub adaptors to use wheels that have a different bolt pattern on your car (say 5x100 to 5x112 conversion) type of thing?

OOOH you are right there. A high compression engine with aftermarket FI needs to be rebuilt - at least with lower compression piston and a different cam, then the best seals you can find - OEM won't cut it unless it was spec'd out for FI.

Where can you get a decent 996 turbo for $50-$60k???

$63,900


$58,995

There are tons of them less than 70k on autotrader right now....... these are just two of them. I like the silver one!

Sorry dude, gotta call BS on you here. 6psi will not pop the HG on a VQ35 no way. The tuning is negligable on the motor espically with a superchager that makes less power on the top end than a turbo does by far. CFM of even a centrifugal charger will be way less than a full frame T04 by far.

http://www.turboneticsinc.com/ts_applications.htm

Turbonetics kit runs a full frame T40S which is a fairly large turbo and runs 8psi of boost. They lay 385hp all day without failure. The VQ35 has entured 15psi on pump gas on quite a few cars making almost 450whp and not suffered from HG failure.

I would love to know what kit you were running and see some pics of the install. Also what professionals tuned the setup and what were they using for tuning? Were you running full standalone or emanage or what?

I do what your talking about for a living and 6psi on a VQ35 espically from a supercharger wouldn't blow up the motor, they simply just don't make enough power.

http://www.turbomagazine.com/features/0307tur_350z/

This car was in turbo mag a while back. Runs twin 18G mitsu turbo's. At 5.6 psi it layed 334whp and thats a bolt on greddy kit with a pre-programmed emanage that is not tuned to once specific car, its a generic bolt on kit. Those kits run all day long with no problems.

6psi from a charger poped the HG? Unelss you were not adding fuel and had some serious detonation issues it's not gonna happen.

Apparently, the work lies in getting the wiring and DME (DMU) working right with the 3.6L and pre-2002 Boxsters.

http://www.renntech.org/forums/index.php?showtopic=6162&hl=

That's more in the $60k-$70k range still but they have come down quite a bit. I may have to save up for when you can get one for $40k-$50k with decent mileage... I can dream.

It's called the 'sleeper effect".... and mid-engine handling.

Good call on FVD whoever mentioned them. They seem to be alot more reasonable than RUF and at the same level as far as professionalism and expertise.

Everyone in the forum seems to be on HP race. Where on Earth are we going to unleash the full potential of the car, witout losing your license car etc?
In NY don't even bother because you are going to get nailed eventually. Boxster handles like no other car in the market and is super quick. Top speed over 160 miles and hour. Only the newer 911 can top that and again not by much. The 986-987 will outhandle everything thats out there. I my assesment spending over 20K for an engine conversion is rediculous and insane. I have a 2003 S. Its fast, looks great and handles superbly what else do we need? Yes I know more power! :D

http://www.gordon.u-net.com/pages/timal1.jpg

Exactly.

I understand what you're saying, but where on public streets can you really exploit the boxster's handling without being reckless? I'm talking pushing it close to the limit...not a "spirited" ride at 8/10th's on some twisty backroad which is still dangerous IMO.. HP is not all about top speed. It's about acceleration more than anything. People want to accelerate quickly because they find it enjoyable and fun. They want to go from 50-70 quicker! ....not 0-170mph.

The great thing about America is that you can spend your money on pretty much anything you want!

Let the good times roll!

986jim

His head gasket prolly didn't blow. My guess is valves...

Keepup did you lengthen the valve overlap at all? If not you would have peak compression WAY higher in the chamber than your set boost was supposed to provide.

More overlap would reduce pressure in the combustion chamber as boost would be blown out the intake or exhaust valves depending on how you overlap the engine and where your dwell time is.

If you put a larger performance cam on a stock engine and you do a compression test before and after you will notice a drop in compression because of the larger overlap. On a VQ35 we tested from 230psi or so in each cyl to about 195-205 give or take with a set of larger cams.

The only way it's gonna pop is really bad tuning Ie NO fuel added for the charger with 6 psi of boost. Honestly thats childs play. I run 30psi on 117octane gas on my talon and lay over 500whp. I tune it on the fly at the track with a laptop and wideband now... I'm no professional tuner either (well I don't pay myself if thats what you wanna call it) and this is on a 4 cyl making 125whp per cylinder so tuning is fairly critical and it doesn't pop a HG ever.

[QUOTE=986Jim]More overlap would reduce pressure in the combustion chamber as boost would be blown out the intake or exhaust valves depending on how you overlap the engine and where your dwell time is.

Yup. That's what I'm talking about...When we have seen VQ35 blown by sensible FI, most of the time the problem is valve timing...if you don't want cams, it can be tuned in, and should be to the limit of scavenging.
I mean surely the kit came with correct feul maps...

Damn straight... I was considering an engine swap for my boxster last summer, but skipped my slot this winter. I was actually lined up with Rooke for a 3.8 swap, not FVD, as Georgia was easier access for me from DC. Im now taking that cash and at the end of this summer (06), am going to look for a 2 year old low mileage turbo cab. I want the power and the awd, but I am going to miss the mid engine.


Finances aside, the other reason I made this decision was Rooke kept telling me they were having problems with broken drivetrains on the 3.8. I drive my cars for all their worth, and I dont want to worry. Next summer I guess my dogs can sit in the back as we cross the century mark on 95 :)