My Porsche LS1 build

I just made my harness for my car... It's not that hard; just follow the manual. The connectors for the ECU even have each wire numbered when you open it up which makes it very easy to follow. It's a very messy job!! lol my hands where black when I was done ripping all the tape and sheathing off.

I modifed my own harness, I have a GTO engine which also came with a body control module that I had to eliminate. I also had to add a few pins for the A/C request, and one of the fan relays. It's not hard, just a little tedious, and invest in a lot of electrical tape!

I got a couple of things done last weekend, maybe enough to keep me on track for getting this thing done by the 21st of August. Only being able to work on it for two evenings a week is really slowing me down, especially with a 3 hr drive at each end of it. Luckily I’ve got a whole week in the middle of August that I can dedicate 24-7 to the car, hopefully I can use it to tie up all the loose ends and finish the exhaust plus paint all my custom parts.

A couple of parts came in while I was gone:

SPEC “Stage 2” clutch, full Kevlar friction disk
SPEC 12lb Aluminum flywheel
GM throwout bearing
New throttle cable

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Some things I’ve ordered:

Clutch fittings and hoses
Braided SS brake lines
Brake master cylinder
19mm rebuildable ball joints and spindle machining service from Rennbay
3.5” inlet/outlet muffler
12’ of 3.5” exhaust pipe
3” inlets to 3.5” outlet y-pipe
Porsche pilot bearing

Some things I can’t find and would like some suggestions:

What have people used for a 3.5” inlet/outlet flex pipe?
A 12mm x 1.0 banjo bolt, I can’t find any banjo bolt with a 12mm x 1.0 thread???
Good Oil cooler, what do people recommend as a budget minded solution?

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or

http://www.summitracing.com/parts/PRM-401/

possibly?

I’ve kept a really detailed budget with every expense, part and receipt, I was thinking about uploading it when this project is done. This might offer a more detailed idea of how much this cost for people that are interested in a price. That seems like a pretty common question on this board.

I got the engine sitting pretty on its engine mounts at 1:30AM Saturday morning. I just ground off the tack welds on the uprights and adjusted the jig a little bit, everything is hunky dory now. I also had to make a small modification to the drivers side of the oil pan, next weekend I’ll re-weld all the pieces back onto it and make sure it’s oil tight. I think I’m just going to buy some aluminum paint for protection. Right now I have about .75” clearance between the firewall and valve cover.

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My dad surprised me with a comfortable creeper; I was just using a piece of plywood with four dollies. I almost fell asleep on this guy.

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Another step forward was my radiator fitment. I cut the flanges out of the radiator area and then got rid of the front latch crossmember all together. I was playing with the idea of making the latch member removable, but it doesn’t seem to be structural because of how it’s mounted. The nose panel also attaches to it, but seems plenty rigid without it. I decided to make my own top radiator mount anyway. The way I have things now the bottom of the radiator isn’t any lower than the stock unit was. This also opens of the interesting possibility of having the air intake right where the intercooler was before. I also cut the fan shroud enough to get it to fit onto the radiator as well. The top radiator mount also functions to mount the fans. I can modify the existing bottom radiator mount to work. That way I can remount the belly pan and such. Is that even something you can do once the V8 is in?

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Where can I find a good schematic to help me plumb the heater core, overflow tank, etc into the cooling system? I’ve never had to run the hoses in a custom setting like this so I’m not sure what to do. Any advice on this would be helpful. Do you put a solid cap on the radiator and a pressure cap on the Porsche overflow tank?

Cheers,
Luke

Wow, it's been a long time since I've posted in this thread.  This is sort of a jump, I've been driving the converted car for a while now.  I've put on the ZR1 11in rear wheels and 9.5in fronts with 295's and 265's, plus a bunch of other stuff; including new bushings and struts all around.

Most recently I put together a new intake I thought I'd throw up a picture of, thanks to pormgb for giving me the info on the intake.  I used a K&N 63-3073 FIPK and a heat gun to slightly warp the ducting to fit under the hood an nose panel.  It GREATLY improved my highly restrictive 90+ deg elbow, gave me nice cold air instead of hot stuff straight off the headers, and increased my filter area.

old:
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new:
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Here's a little update, new manual 924 rack and new tires.  Remember to right click and open each picture in a new tab if you want to see the rhs of the photo.

Front Wheels/Tires:
-255/40R17 Nitto NT555
-ZR1 17”x9.5”, 56mm offset
-5x120.65 bolt pattern
-Final Offset with adapters/spacers: 35mm
-.827” 21mm spacers from Motorsport Tech with a 5x130mm to 5x120.65mm bolt pattern conversion
-Minor fender rolling, setup might work without any at all

Rear Wheels/Tires:
-315/35R17 Nitto NT555
-ZR1 17”x11”, 50mm offset, 5x120.65 bolt pattern
-Final Offset with adapters/spacers: 35mm
-.591”, 15mm spacers from Motorsport Tech with a 5x130mm to 5x120.65mm bolt pattern conversion
-Fender lip rolled

I can't say enough good things about Motorsport Tech, their spacers are really good quality and fit snugly.

Here is a photo of the new tires:
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Here is a photo of the car with old tires (Khumo 295's), but same wheels:
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The old tires were discontinued, so I had to fit 315's instead of 295's. It turned out well though, the Nitto's were cheaper, better in the rain, and had a 300 instead of 180 tread wear which meant I can keep them on the car longer than a summer.

The de-powered rack was too heavy and come to find out you can't just disconnect the hydraulic lines... There is a slender shaft between the intermediate shaft engagement and the pinion.
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Instead of making the 944 power rack rigid I decided to go with a 924 manual rack.  This would lighten the effort need to steer and best of all, remove the extremely loose feeling front end cause by the twisting of the shaft on the 944 power rack.  I went with a 924 rack because I couldn't find a 944 manual rack in left hand steering.

To get the 924 rack to fit I had to do some modifications.  I thought at first I might be able to just use the 944 power rack in the 924 housing, but the rake on the teeth is different, even if the pitch is the same.  The power rack is on top.
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The overall length difference between racks was .375 in (944 power rack was longer).  However, I had more than enough adjustment left in my outer tie rod ends for .1875 in on both ends.
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You can see here the relative size of the pinions.  The ratio for the 924 rack is 119mm for 3.5 turns, the old 944 power rack was 133mm for 3.5 turns. (source: [You must be registered and logged in to see this link.]
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The mounting between the 924 rack and the 944 rack is different.  The mounts on the 924 unit are solid, whereas there are the rubber bushings on the 944.  The 924 mounting points are closer together as well.  Below is what I used for a bolt pattern conversion.
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Also, to keep the centerline of the 924 rack the same in the forward/rear direction even after I added an adapter plate I had to cut the protrusions off the crossmember and shave 1/8" off the 924 rack.  Even with the nubs cut off the crossmember, there was still close to 1/2" of aluminum to tap into.
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Essentially I made two 1/4" steel adapter plates that I bolted to the crossmember with grade 8 10mm flat head machine screws (the same ones used to hold the engine mount adapter plates to the engine).  The 924 rack then bolted to these plates with the same bolts that were used on the old 944 power rack.  The underside of the car is filthy in this picture from grinding.  That wire in the second picture is also not normally hanging.
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The other issue is that the manual racks were made for female inner tie rod joints and the power racks all had male inner tie rod joints.  I essentially drilled and tapped the ends of the manual rack.  It took a 14mmx1.5 tap (an oddball).
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To keep the new male inner tie rod joints from backing out, and also to act as stops on the end of the rack I cut up the old female inner tie rod ends.
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In order to get the same travel as the 944 power rack I cut the stopper nuts such that the length of the large diameter was .350 in.

Lastly, I lengthened the intermediate shaft that came with the 924 manual rack by .675 in.
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All greased up, painted, and with new boots ready for installation
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All in all I couldn't be happier with the steering feel.  The car is very responsive, parking is less painful, and the dog doesn't walk the person around truck ruts anymore.

I also braced the firewall and increased the pedal ratio on my manual brake master cylinder.  I now actually really like the brake feel and can lock up the big 315's.  I was thinking about going to an ABS power brake setup until now.
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Wow.

Andy

acorad wrote:Wow.

Andy

Thanks! The 924 rack was one of the more rewarding bits of fab I've had to do on this conversion. I'm sure it's been done a whole lot, but I didn't find a writeup.

Cheers,

Luke

340 to the rear wheels. I don't know if that's any good for a stock LS1 or not.

Cheers

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340 to the wheels is very good for a stock LS1.  That'd put it around 410 crank.  From a stock LS1 I'd guess most would see something like 300 or 310.

I've heard that mustang dyno's are usually generous with they're numbers though.

chadfjones wrote:
I've heard that mustang dyno's are usually generous with they're numbers though.

Just the opposite, they are typically lower than a Dynojet.

Great numbers for a stocker.

The RWHP is about right for a GTO motor. My car with a 2004 GTO motor made 327 at the wheels with a 90deg bend intake. Using a straight intake and a better exhaust than I have should make more power.
Do you have pictures of the firewall brace installed? What size F/R MC and what ratio are you using for your brake pedal. Awesome skills, BTW.

Hello,

I noticed that photobucket has messed all the pictures up, which is a shame, but seems to be happening all over the web. I have since made a Facebook page with lots of info on my build. I put the page together while I'm in the process of selling the car, but I hope to keep to online indefinitely as a resource. In the photos section of the page there are a few images of the ledger with all the costs and part numbers.

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Thanks guys for all the support over the years, I wouldn't have been able to do it without you!

Best,

Luke

P.S.

Arthropraxis wrote:Do you have pictures of the firewall brace installed? What size F/R MC and what ratio are you using for your brake pedal. Awesome skills, BTW.

There are photos on the FB page, the MC is a Wilwood 260-7563 1” Bore, 1.1” Stroke, the clutch MC is aTilton 75-875U .875” bore, 1.1” stroke. I'm not sure what the exact pedal ratio ended up being

So how can I get my hands on one of the conversion Manuel