987 3.8 conversion

[Ray_s]

I'm almost done with converting my 3.8 engine to fit into the boxster, finished engine wire harness last night.

Only things missing are new connections for the air/oil separator, waiting for hoses and small parts shipped to me next weekend.

I noticed some differences to the 3.6 conversion described by Wayne, will try to summarize once I'm done. Generally, it's less differences in my 987/997 conversion.

Small vacuum hoses - less, just one resonance flapper valve instead of two

I'm not entirely satisfied with the power steering return line solution...

The air/oil separator is in the way, it is located in a different location, exactly where the power steering return line sits, there is a sensor in that place on the 987 engine instead on top of the case.

Anyone came across that issue as well yet? My current solution is to cut the line and extend it a little bit with a hose so the line runs between seperator and oil cooler..

[Wayne 962]

Can you post some pics, and then maybe I can offer some suggestions?

-Wayne

[Ray_s]

Wayne,

attached is a picture showing how I worked around the issue.

The red line shows the normal position of the line using the Boxster line as the 997 line would require a cut and connection of the Boxster line in another position. as you can see - it would go directly through the air/oil separator... which cannot be put elsewhere, nor could I use the Boxster separator which sits in an entirely different spot ( left front corner of the 987 engine) as the 997 does not have the connection below the separator where the oil flows back into the engine beneath.
The 987 engine has an electrical sensor (no sure for what ) sitting at exactly the place where the 997 has the separator - lucky I found the same sensor at the 997 engine not too far away, further on the left side on top of the engine case, so I was able to plug the cable in after loosening the harness less then an inch for that cable...

BTW - this was really the only connection where I had to loosen the harness a little bit, all other connections seem to be in perfectly the same place...

(of course I fit the additional VarioCam connectors on either side plus the Oil Pressure sensor in additionally)



The yellow lines show the piece of hose where I cut the line and fit a piece of hose in on both sides.... no better idea how to handle it.

My assumption is it should hold as the return line hopefully has very low pressure on it, the oil is just pumped back into the reservoir?

[Wayne 962]

The sensor you're talking about is probably either the knock sensor or the oil temp / oil level combo sensor - both are located in this area.

As for patching the PS lines, that might work okay. I would double-hose clamp them for extra security, as the metal lines that you cut don't have barbs on them.

-Wayne

[tholyoak]

That is the PS supply line, I wouldn't use hose clamps on it. On the 3.8 conversions I've done I've rerouted the line through careful bending of the aluminum pipe.

-Todd

[tholyoak]

I personally would not cut and use hose clamps on that line. It is the pressurized supply line for the PS rack. On the 3.8 swaps I've done we were able to reroute the aluminum line by reforming it carefully to take a usable path without cutting it.

-Todd

[Wayne 962]

Originally Posted by tholyoak

I personally would not cut and use hose clamps on that line. It is the pressurized supply line for the PS rack. On the 3.8 swaps I've done we were able to reroute the aluminum line by reforming it carefully to take a usable path without cutting it.

-Todd

Bending and reforming the line is indeed a much better solution. I'm not sure what the pressure in this line is, but it is the return line for the pump, not the high pressure line that comes out the side. The return line is still under pressure, but presumably less pressure than the primary supply/pressure line. See attached PET diagram.

If you can figure out how to use the line without cutting it, then yes, that's the much preferred solution. However, the line does convert into a rubber line later on after this metal line. But, the rubber hose that it uses is much bigger and thicker than the one you're using, and it's also swaged on there by the factory.

I would see if you can do what Todd is suggesting before you button it up.

-Wayne

[Ray_s]

I will try the hose thing and keep it as is - it might go wrong, in that case I'll have to re-do it later which will be a pain of course while in the car, would require to remove the left intake and some hoses.

It is the return line, pressure can't be very high I think. Will of course be a risk but none that'll blow the engine worst case.

BTW - engine and transmission are in the car now, not perfectly fitted in height yet on the front bearing (hanging about 2 cm too low on longer bolts still) but quite a milestone.

The sensor described seems indeed to be the Oil Temp/ Oil Level sensor.

[Wayne 962]

Double-hose clamp it then, if you still have access to it...

-Wayne

[Ray_s]

I get a P0300 and a P302 error code, meaning I get misfire at cylinder 2.

Well, not sure where to look at - which one is cylinder 2?

Front left?

[tonythetarga]

left side middle.

left side back of car is #1 middle #2 and closest to cabin is #3
right side back (bumper end) is #4 middle is #5 and right front corner (cabin side) is #6

[tholyoak]

You have it backwards, on a cayman/boxster cyl#2 is right side middle

Front
4 1
5 2
6 3
Back

Back

[tonythetarga]

Originally Posted by tholyoak

You have it backwards, on a cayman/boxster cyl#2 is right side middle

Front
4 1
5 2
6 3
Back

Back

HAH! Clearly I have my head up my 911
Thanks for correcting.

[Ray_s]

Thanks, right side middle is where I pulled the spark plug, it seems ok, no oil, no gas on it

Coil looks ok as well but I'll try another one.

[Ray_s]

I seem to have a massive oil leak into the exhaust, however it's not cyclinder 2 which is the only indicated trouble code I have.

Is there an oil channel beneath the gasket of the headers where oil could get into the headers? If yes easy fix, if not.. well, no idea where this would come from...

***

Update:

Ok, well, got a problem with the air/oil separator which made a lot of oil come through the intake. Will fix that next week.

Also, one of the gaskets was wrong, header/head, which made the oil coming through the engine partially leak through there, will fix that all next weekend.


Got a PSM error code - hope it goes away once the wheels hit the ground again, refers to steering angle sensor not active etc..

[Ray_s]

Now, a little bit further down the road, the car is running, test drove it last night and will now have to fix the flaws...

After an initially frightening long list of faults I get no more error codes (although the DME is not re-flashed yet, thus still running stock 987 mapping).

Feels like I have less than half the power with the 987 stock DME, of course valve lift is not active yet etc..

Great step! Wow.. happy..

[Ray_s]

Wow, car is now running, got dynoed with 345 HP at the shop who flashed my the DME, will pick it up tomorrow.
That's more than I expected at that stage.

This is with the stock 987 exhaust, stock MAF and airfilter housing, plus a simple to-be-improved connection between throttle and MAF.

Thus around 10 HP missing because of a interim-hose connection to the MAF, around 10-15 HP more could be made with an improved exhaust (which is underway).

Anyone got an idea if there is a proper throttle to MAF/arifilter connector available?

I stepped across the IPD Plenum for 3.4 engines, and this seems to be the hose I'm looking for - I might consider the plenum as well but not sure it is appropriate for a 3.8 engine and it's connectors..

Is there any such hose like on this picture available (in ONE piece, no more connectors) which would fit my 3.8 conversion? Inside diameters are 80mm at the throttle side, 89mm at the MAF side.



I don't like my current solution consisting of 3 connected pieces (80 degress angle, 80-89mm connector etc)