xschop's 928 LS1 build...repost from frenemylist

hey 'Chop- top secret, no pics. (out here in Ca. they kinda frown on that kind o stuff...)
plus nobody likes carbs and mech. fuel pumps any more... i'm a simple fellow.
the rest of my junk is vintage fords- 65 mustang conv. and 69 boss 302- team shelby road race clone.

rest of my junk is vintage fords- 65 mustang conv. and 69 boss 302- team shelby road race clone.

Some pictures would be nice!

sorry to hijack the thread- i will work on the pic gallery,my buddy took a few good ones at a local show,and i might find a 928 shot...
lastly, thanks to 'chop, i bought a vertical mill last year(small Clausing 8520-built@1966ish)
it's ALL your fault! (my wife calls it an oversized etch-a-sketch)

back to topic!

I actually wish I had one in the garage...I'll be getting a CNC lathe soon at the shop. I have two Clausing manuals that I wouldn't trade for nada.

Hey Rob, please tell this CA dude your name.

CA Dude, Rob (xschop) is the (Guru as in expert), we all respect him for the advice and parts that he has brought to us all in the 948 community.

Mike, there are many Gurus here that even I have learned from, that's what makes this board worth visiting in my book. I started the build thread over on renny to get various info on the 928 suspension, electrical, etc and there are some helpful people there, just not so many that can think outside the box when it comes to swapping drivetrain components. The 928 engine block is made from the same brittle alloy that the 944/951 is (reynolds A390) and they are cracking at the same rate as the 944/951 blocks. Just look at the various threads on renny. Having machined it on various projects over the years, IMO it has a very short shelf life compared to other alloys as it's Silicon content is higher than 14% (hypereutectic) and therefore heat-cycles to a brittle-ness that is scary for a rotating assembly. That said, my 928 is getting the LS treatment too.

Where is the best place/website to see the bare harness connectors from a factory harness and what to get rid of for a standalone/swap application?

Have you looked at Brendan Patten's website?


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I'm going with a standalone that will have the T56 reverse lockout added in for the future 6-speed

Alright, everything's done minus exhaust. I went with the PSI Harness and it was plug n play, I just had to lengthen the IAT lead, no biggie. The engine mounts and TT swap parts I designed worked out very nicely as the cable TB sets way back so a DBW will clear a large tower brace. The Cable TB and intake clear by 1.125". The factory 928 one is Fugly and needs to be stronger.....

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I Went with the Odyssey PC925 as the LS folks say it does a good job of cold cranking. I'll post the dims of the custom bracket when it's done.

I won't be building extra adapters for the G35 mirrors, just one-offs, but these can be made fairly easily with flat-stock and bolt right up to the flag bases with a 1/2" cap-head. I Haven't decided how far from the body I want to tuck these in or if I'll hook up the heated elements, Probably just cut the cord and gut it, but it's already lightweight. I think they look great on my OB and aerodynamic too. Piss on the flag mirrors.

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4340 axles for the OB...
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bumper shock delete done....

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The garage finally thawed out. I installed the new brackets and bumper then stood on it...it passes the xschop design modulus....

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Forgot I need to update the thread. The 928 LS1 has about 250 mi. on it since completion. It's super quick as there is no interior, no AC stuff, no front bumper shocks, no fog Lights, lightweight race seats, lightweight battery. I haven't removed the 15-20 Lb battery box yet as I'm still on the fence weather I want to rid the 2" duals and install the 3" single magnaflow (No Cats). I still have to cut springs 1.5", but other than that she's a daily driver. The 928 gear ratios solve the problem that the 951 trans had (1st gear still too short). Take of is much better, 1st gear does not run out too quickly and 3rd gear feels like a mule on roids when getting on hiway. 

Fixed hood alignment issue (same as 944)...

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Working on front bumper cover....
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Got rid of another 8lbs from the fog lamps.....[You must be registered and logged in to see this image.][/URL]

I hooked up aftermarket oil pressure sender to blue\black and blue/white and it works.
Found the temp wires at 14 pin. Not sure about later models, but the '78 14-pin's black\yellow wire has a resistor or diode that does not allow +12v from ign. Switch. I traced back and you must connect GM PCM ign/switched red wire to the    empty 928 ign transistor terminal with the 2 black wires.

Also fixed the ign switch after cleaning inner contacts, the housing came apart at the factory indents (yellow marks). I just taped and reset with punch. Good as new. However I ordered a new one.
Last thing to do is cut the springs. Will get details from Dinsdale. I will probably have to cut 2 to 2.5" off them as it is super light up front now with LS and no AC, bumper shocks, fog lights.
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Going to clean up wiring on pass side and and take it on a long spin to use the old gas, which wasn't to bad. I added 2.5 gal 100% petro and 6oz acetone. Not even a miss. No telling how long that gas was in there....
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The Lexus calipers on the Boxster S rotors are insane with factory 928 Booster and MC. Even with factory rear brakes this thing tosses your cookies. I may not even add 4pots to the rears.

Not going to draft out these as they are simple to make.
3/4" dia alum. rod
4.625" total length
tapped 1/4-20 on each end....

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I used this ebay bracket and it fits perfect on the PC925...

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I've installed my brand new ign. switch and discovered the tumbler mech inside the wheel lock column is worn not allowing good contact on starter position. After driving around a few days with a screwdriver for a tumbler switch, I fixed the tumbler by grinding the detent on the housing allowing a few more degrees rotation. Good for another 100K mi.

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Before I forget, the GM PCM tach wire needs to have a 5K Ohm 1/4 watt resistor added to it and connected to the GREEN wire terminal at the empty Porsche ECM connector located on the passenger side engine bay/fender.

Rob, Does this apply to the 944 Tach also? I have had one factory Tach expire on me. Thanks, Mike

Not 100% sure, as I got the info from Dinsdale and it works pretty good (idle is a little low) on the 928 tack with LS1 signal. IIRC the LS1 puts out a 4 cyl signal.

I replaced the 5k resistor with a 4.7K 1/4watt and the tach at idle is now 1000 rpm, where it was reading 750 or so with the 5K ohm resistor. The battery has not moved a bit with a good curve thrashing this weekend, although I did add a few washers between the bracket and standoffs. I would probably make the standoffs 4.75" length on a future swap. The factory cables do not need any modding either....

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Last big item was the front springs, I cut exactly 1.5 turns off the bottom portion xschop style lol....
I'll drive around a week or so and let them settle in. Free increase in springrate to boot...

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Was that "Offroad" stance based on lighter LS engine? So the nose came up so much?
Its odd that Porsche guys say that you ruin the handling by putting in a lighter engine...and same time they drive around with 911`s which have engine in the back...

Propably fittling with the suspension you can get the corner weights ok so you should not see any difference in handling...exept the car is lighter in total weight?

1300 front and 1500 rear according to Dinsdale. All I know is it turns on a dime for a 928 now.  

"factory" 928 front springs/suspensions are KNOWN to ride high for quite a while when lifted/unloaded.
as a result, the car is to be driven and brakes hit fairly hard to "settle the front suspension"...

after that, it's adjust to taste time...

  

This LS 5-speed is up for sale. Gotta make room for my next project with Dins. PM with offers.

I'm going to try and find a scale station and weight it. I'm hesitant to put the new windshield in just yet as we are still in hail season. The dash has the infamous crack just like the 944 and will need a cover/repair and as soon as I get a chance I'll make a matching billet gauge face. At this point in the build, it either needs paint/carpet or a roll-cage so the sale price is $9,000 firm Here's the duals I went with, no cats...
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Seats weigh 22lbs each. It been fun driving around with the passenger seat delete (still new in box) My dog will ride with me but my wife won't lol.
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It seems that the paint did not stick on the bellhousing.
But it is aluminum so it does not matter.

Are those seats bottom mounted?

I have buckets going in but those are side mounted and to my liking those leave the seat too high, so I propably need to cut of the original seat mountings and build new ones...which I would not like to do.

I should have pre-bled clutch before installing Throwout bearing when I installed torque tube adapter. Hydro fluid has no mercy on any coating lol.
These seats are bottom mounted with 1\2" thick billet rail adapters.I posted adapter dimensions.

Attes, I'll have your conversion kit sent today. Make sure to send me shipping info.