Here's the start of a retrospective build thread of my LS1 conversion. It took a few years to get it done mostly due to not wanting to be a slave to the project, and work on it for the enjoyment; and of course when family obligations allowed......teen daughter and high maintenance wife

What I started with was a local orignal owner '75 2.0 with 139K miles. The original owner "drove the heck out of it" until something died in the electrical system and he parked it in the garage for 14 years, as evidenced by the renewal tags. Only body damage was when he submarined the rear of a Mustang and creased the hood and flattened the left signal light pod. Otherwise, it was a good condition rust free (SoCal) car.

Brief specs are: '01 LS1 Z28 motor, Audi 01E 6 speed tranaxle, 911 front suspension, custom made rear trailing arms, Koni shocks, 993 wheels, and AC.

Below, are photos of what I started with, and what I ended-up with. I'll do my best to re-trace the build process, so if you have any questions along the way, please ask.

BTW, how does one place text between photos in the same post?

Andys

In Full Edit mode - just add space lines with your enter/return key & type in there.

IMHO the pix look better with a line space between them anyway, especially when large.

I decided quite quickly, that I wanted to go with a modern V8 motor with all the EFI controls, so I went with an all aluminum LS1. Before acquiring the motor, I went through the somewhat difficult process of selecting the kind of transaxle that would be rugged enough, reasonable in cost, decent gearing, all in a modern package. I really liked what the Audi 01E transaxle offered, but there were two problems. 1.) The FWD version was never available in the US, and 2.) no one made an adapter plate (at the time) to mate to a LS1. Being the engineering type with a background in managing prototype machining, I could make the adapter plate myself. So now I'm relegated to find said 01E. My search took me to Europe, and after a number of inquiries, I found a low mileage (12K kilometer) 01E from an '02 Passat TDI, which has the more desireable gearing of the 01E series. After a few phone calls and arranging a freight forwarder, it arrives at my door in exactly one week! Price? $1100 landed, though this was some years ago when the exchange rate was way more favorable than it is today. Needless to say, I got a killer deal that's likely to never be duplicated again.

Andys

Tom,

What do you mean "in full edit mode?" Is this done while I'm in the New Post/Add Reply window? Where would I find that button/tab/selection?

Thanks,

Andys

Andys,
It doesn't matter, keep the photos coming! I love the story so far.

I wanted to avoid having a motor shipped, so I started searching for local yards that may have a LS1 with reasonably low mileage. What I found, was a salvage yard that specializes only in late model Camaro's/Firebird's, but motors go fast so I had to stay on top of them with frequent phone calls. They get two cars in, so I run down there right away. There's a '02 Firebird with 30 some K miles, and had the late and more desirable LS6 heads, but I found a mount for a nitrous bottle in the truck, so I passed. The other car was a "01 Z28 with 49K miles. Looked well kept and was hit in the rear. Started immediately, so I closed the deal. I had to come back the next day so they could pull the motor. Turned out that when I got there, they hadn't even started, so I waited another 1 1/2 hrs before they were ready to load it into my truck. Motor came complete with all the systems (harness, PCM, manifolds, cats, flex plate, starter, even the Camaro air intake box).


Andys

I wanted to start by adapting the motor to the transaxle, which would allow me to do all my trial fitting of the assembly into the chassis. So, adapter plate, flywheel here we come!

I layed-out the transaxle bolt pattern using a surface plate and height gage with indicator. Did 'x', then rotated the transaxle 90 degrees, and did 'y' coordinants both about the center of the input shaft. The LS1 side was simple, since it has the same bolt pattern as a Gen I SBC, minus one of the holes. There are two bolt positions on the oil pan that some people don't use, but I chose to use since the oil pan is deemed a structural component. From this information, I made a master plate of 1/4" aluminum cast tooling plate (for its stability) to check the alignment.

Making the adapter plate is only part of the story, as you need to resolve the starter, flywheel, clutch disc, pressure plate, and TO bearing interfaces. Again, no one at the time made anything for the LS1, so I started from ground zero. After much research, I finally hooked up with QuarterMaster as they were so willing to field all my questions, and of course being race guys, they understood what I needed to get everything to fit up. Let me take a moment to gush at how great they were to deal with, typical Mid-Western stock car race guys that were very accomodating to all my needs; second to none in my book!

So after all the planning and designing, I started in on the fab work. I started with a 3/4" thick hot rolled steel plate and had the profile water jet cut, which I then sent out to get blanchard ground on both sides down to 1/2". I then drilled and tapped the necessary hole pattern on my mill. Final yellow zinc plating. To get the correct axial spacing, an additional 1" of thickness was required to clear the flex plate and accommodate the starter. I water jet cut a piece of 1" cast aluminum tooling plate as a spacer. I also made alignment dowel extenders to span that distance.

For the flwheel/clutch, I went with the QuarterMaster 8 1/4" button flywheel and bronze/ceramic clutch disc. The pressure plate diaphram spring that was recommended make this combo good for 450 ft-lbs. QuarterMaster does make a button flywheel with the LS1 crank bolt pattern, so no adapters were necessary. I did have to make a 1.1" thick spacer plate to move the whole clutch assembly to locate properly on the transaxle input shaft. I used a QuarterMaster spherical faced TO bearing which I adapter to the existing TO bearing carrier on the transaxle. This way, I could retain the stock TO fork and hydraulic slave cylinder.

That was long-winded....here are some photos:

Tell us about that jack!

Bruce,
I spend 6 years on the car, and you ask about the jack..........

Made trom an ATV jack, it colllapses down to 4". That allows me to get the motor under the car without having to raise it up so high. Handles the LS1 and trans just fine.

Lovin this story and the work you did.
Looking forward to hearing the rest of it..

ask about the jack!

Well yeah... the cars freak'n gorgeous and the trans setup is sweet. But that jack, that's a great piece of work.

Well done! On all accounts.
Did you make the hood vent, or is that from something else?

Keep going! We need more!

I know you did custom axle flange work but I will through out that Boxster output flanges (100mm) snap right in. I was going to go your route but the factory Porsche (Audi) part fits so well.

Bruce,

Yeah, I used the heck out of the jack; glad I took the time to fab it up.

The hood vent is a creation that was designed by an Art Center College of Design student, since I have zero artistic/creative skill. Modeled it out of foam, then covered in f'glass.

Andys

With the motor and transaxle coupled together, I now set about the task of fitting it to the car.

Initial fittng revealed that the motor damned near fits with the water pump in place, which means it still doesn't fit. After some measuring, I determined that if I use the LS2 water pump with the short pulley, I'll reduce the length by about 2" (from memory, which is not that great anymore). Found a brand new LS2 water pump on Ebay along with a LS6 Vette crank pulley (which is also shorted than the LS1 by some 3/4") to line up with the water pump. Fitting again revealed that I would only need to move the firewall hump into the cabin 1 1/8" to get everything to clear......well almost. The water pump outlet points straight forward into the firewall, so I needed to re-think that. Some of you may think why should I goof with the stock water pump, when a remote mechanical or electric water pump (Meziere) might offer an easier solution? Well, frankly I like stock components over aftermarket as they are properly engineered and designed for dependability. Another issue that led to my decision, was the need for a properly configured thermostat, and heater hose and valving. To resolve the water pump outlet, I capped the original outlet, drilled a hole pointing toward the passenger side, machined a new neck with barb for a 1 1/4" hose, and TIG welded it in place. I did a similar thing with the inlet side; I machined a neck with barb, and TIG welded it to the stock thermostat housing in a more favorable position.

Great work, keep the pics coming!

Great work! keep the pictures coming. I keep coming back to the site every 10 mins.


Bob

While not exactly in the correct sequence of the build, I will probably group things so as to keep some sense to the project. While waiting for one thing, I would switch over to say the flare installation or chassis stiffening in between, but anyone that's done this kind of thing before, knows what I'm talking about.

Let's proceed to the accessoy drive on the front of the motor. The water pump pulley and the crank pulley are in alignment, but the AC part of the crank pulley is now about 1" closer to the block than the LS1 AC compressor pulley, so I had to fab a plate that moves it back,,,,,but not so fast. The compressor now interfers with the header (stock cast iron LS6 header), so I remake the plate to also moving the compressor down by 3/4"....but now the compressor interfers with the cool looking Vette aluminum motor mounts I got from Ebay. After some thought, I decide to fab my own motor mounts. Ok, back to the accessory drive. The alternator (in it's stock position) needs to move closer to the block as well, so I found it easier to fab my own alternator mount; done deal. Now, the serpentine drive needs to be configured. What I came up with was to mount the tensioner high and somewhat centered, which coincidentally turns out to be the same solution that Factory Five uses on their GTM cars (their bracket is steel, mine is aluminum). I measured the necessary belt length with a string, then searched the Goodyear site and found what I needed.

Not as many photos as I'd like to display, but that's all I have. The zinc plated part is the alternator front mount (there's also a rear mount).

Amazing. Inspiring. I wanna drive it!

I am in awe. Amazing skills and work. Keep 'em coming.

Cool conversion, way out of my league

Holy smokes, you're a handy guy to have around the shop. Makes my work look shameful.

I mentioned earlier the need to move the firewall hump by 1 1/8" to get the water pump and accessory drive to clear. I wasn't sure how I'd deal with the intrusion into the cabin, but it seemed to be something I could tackle later in the build....I actually don't like proceeding without figuring everything out in advance (typical engineer!), but I though it was low risk.

The firewall hump only needed to be moved forward at the top. The crank pulley and alternator clearance at the bottom was adequate as is. What I did, was to cut the outline of what I needed, but not cut the bottom. I simply cut and inverted 'U', (attached at the bottom) and bent the it forward at the top. I made filler sections, and welded them in. Also, as all us 914 types do, an access panel was fabricated. Notice too, I had to make a sort of pie cut portion on the drivers side of the hump to clear the accessory drive serpentine belt.

One additional area that required clearance, was the thermostat housing. The firewall needed a small hump there too, so I decided to make a removable hump thingy. I don't have a photo of the removable hump, so I'll describe it briefly. I only needed about 3/4" worth of hump, so I took a sheet metal pan I found at McMaster-Carr that was about 4" x 8" x 2" deep and cut it to 3/4" and welded a flange around its perifery. Not as easy as it sounds, since if you notice in the photos, there are stiffening ribs in the firewall which required the flange to change planes, so it was a bit involved. As with the access panel, I made this hump thing removable as well. To get the motor out of the car, the thermostat housing needs to be removed beforehand....things are that tight!

Photos are out of order, and some show the result in its final painted form, but you get the idea.

have you left the tranny in the original location or have you moved it back a bit as in most v8 conversions? [half shafts canted back wards toward the tranny flanges]

I'll get to that in the next post or two.....stay tuned!

Andys

10/4 just wondering why all the effort on the front side and firewall and if it was necessary.... i know stupid question....

Determining where the engine/transaxle assembly would best be located was driven by a couple of things. The motor has to fit in the hole (engine bay), and the transaxle drive flanges need to line up both front to back, and height wise to the wheel hubs at ride height. I was fortunate in that the 01E transaxle is shorter by 1" from the drive flange axis to the bellhousing than the 901. After adding in the adapter plate thickness stackup, I basically ended up with the drive flange axis very close to the original front to back location, and about 3/4" lower (the axles are angled slightly upward to meet the wheel hubs). I couldn't get the motor/transaxle any higher in the chassis, as the bellhousing would run into the trunk floor at a point where I prefered not to cut it due to structural concerns. The amount of axle angularity was acceptable to me.

With that info at hand, I set about designing the mounting scheme. What I decided on, was a cradle arrangement that would allow me to R&R the engine transaxle as a unit. You'll notice in the photo where the engine/transaxle is on the jack, that I fabricated a temporary engine mount bar so that I could experiment with the exact location. First, I had to fab a set of motor mount pedestals, since those neat aluminum Vette motor ones interfered with the AC compressor, as mentioned earlier. I decided on using the stock Vette hydro-elastic mounts. Being close to the header flanges, I decided to make some heat shields to guard against damage. I found some stainless cannisters at WalMart, cut them down, drilled holes, and welded in some re-inforcement; turned out kinda blingy. For the rear transaxle mounts, I fabbed up some trans mounts, and I used some Chevy Caprice transmission mounts.

Where the rear cradle bolts to the 914 chassis, I did a little re-inforcement around the chassis mounts just in case....they looked a bit whimpy to me. So the whole cradle stays bolted to the motor/transaxle assembly and mounts to the 914 chassis in the stock locations (6 bolts).

I like your work! Weight wise you better off with that mass forward. This car will scoot when your done.

The 01E transaxle flanges are a tripoid design which requires adapters to couple to the 911 axles/CV's I intended to use. However, Audi does make an output flange that is the same pattern as the 911 CV; not sure what car/application uses those, but they are available. So why didn't I simply use those instead? Well, it's kind of a convoluted path I took, but perhaps you'll follow my logic(?). Let's see if you can follow this: The 01E output flanges are not symmetrical about the centerline of the transaxle.The centerline offset is 3/4", so one adapter would have to be 1 1/2" thicker than the other. For the axle length to work out properly, the short side adapeter just wouldn't work out (it would if I used the aforementioned compatible output flanges, but there's more). I liked the idea of using the larger 911 wheel bearing, but that won't fit the stock 914 trailing arm......and I wanted to use the 911 rear brakes too, so I decided to make a custom set of trailing arms which would allow me to place the bearing where it wouls accomodate the 911 axle length. More on the trailing arms later.

Anyway, this post is about the transaxle flange adapters and how I resolved that issue. So, to keep axle lengths equal, and hub bearing locations in a favorable location, I decided to offset the motor/transaxle assembly by 3/4" toward the passenger side. So I set about machining adapters that are equal in thickness, and would accept the 911 CV. They would receive a final zinc plating.

Andys

great work. I also like the jack. I missed the part about the input shaft bearing. Is it the same size as the chevy? Or does the new flywheel have the appropriate bearing?

I think you're asking about the pilot bearing. I had to machine and adapter that press fit into the Chevy crank, and I press fit an Audi pilot needle bearing into that. The adapter had to move the pilot bearing towards the transaxle in order to engage the input shaft. What I have seen with the designs since then, is where they mount the pilot bearing in an extension that's part of a custom flywheel.

Andys

So we've got the motor/transaxle mounted, and the CV adapters made, how about we move on to making some custom trailing arms. The idea here, is to accomodate the larger 911 hub bearing (and 911 5 lug hub), and since the 911 axles combined with the 01E transaxle place the hub bearing farther outboard by 1.1", I can configure the trailing arm accoringly.

I first started by designing and fabricating a fixture that places everything at the proper relationships to each other. The fixture can make trailing arm geometry with zero, 1 1/2 and 3 degrees of camber relative to the pivot shaft. The stock angle in 1 1/2 degrees. Additionally, I can change the height of the (lower) shock mount to accomodate a lowered car. I chose to stay with the 1 1/2 degrees of camber, and the stock shock mount position (though in retrospect, I should have chosen a lower position). Oh, one other variable the fixture can accomodate, is the bearing carrier position. It can move inboard or outboard....as mentioned, I needed to move it outboard by 1.1" for my setup.

First on the list, was to machine the bearing carrier. That was a lot of work mostly due to all the hogging of steel when starting with a solid piece of round bar, but it got done! Then on to machining the other various components including the 911 caliper mount, the handbrake caliper mount, and so on. The pivot shaft housing (tube) is designed to accept Delrin bushings.

Once all the pieces were fabricated and placed in the fixture, I started TIG welding. Dang, that was a lot of work!

Hopefully, the photos will go a long way towards explaining haow it all got done, cause I don't type so fast!

wow........ that is impressive

You, my friend, are insane! Incredible work!

Holy mother of God! I thought the Jack was a piece of artwork.

Thanks for all the nice words!

A couple more comments on the trailing arms. Welded structures are subject to movement due mostly to shrinkage from heat. As such, I did get some movement here and there, but the most significant area was the pivot shaft tube. Basically it was no longer straight, so I had to subsequently heat and bend it until it was straight. Also, the bearing bore diameter, to my surprise, shrunk a small amount which I didn't expect since the weld was what I thought was an adequate distance. Now we're talking about tenth's of a thousanth of an inch, but this is a press fit and needs to stay within a suitable range. In the end, the correct final step after welding, would have been to normalize or stress relieve the structure, but that would have added cost, time, and required an alignment fixture....too much added hassle so I didn't do it.

The overall weight of this custom piece is about the same as a stock trailing arm with reinforcement kit, so I think that worked out well. I had considered, and even started machining parts to make an aluminum trailing arm, but the risk just wasn't worth it.......A welded aluminum structure requires a multi step treatment cycle to relieve stresses, normalize, anneal, and heat treat. And in the end, it's still suseptable to sudden fatigue failure. I added a photo of the aluminum bearing carriers that I didn't use.

The parking brake is a Wilwood mechanical spot caliper, and I configured the linkage such that the stock 914 parking brake cable and clevis setup could be used without modification. The Wilwood caliper is a floating type which means it sits loosely in it's mount. The result is that it rattles when driving the car; very annoying! What I may do, is design some type of slide cofiguration (pins and bushings) to eliminate the rattle.

So the big unanswered question surely on everyone's mind, is why blue? Had a can of Ford engine enamel.......and now that they're on the car, the color looks kinda cool actually.

I threw in a photo of the stock trailing arm in the weld fixture.

What color is that jack, fire engine red?
j/k



BTW, this looks like an ad for viagra.

I re-enforced the inner suspension ears with a sort of scab plate and boxed combo along with the traditional link to the firewall. I made cardboard templates for the scab plates, cut out some sheet metal, and TIG welded those into place. As with most inner ears, the hole for the pivot shaft usually gets worn out-of-round, so I made sure to add some weld bead and ream the holes true.

I added some double shear pickup points to mount some removable re-enforcement links. What I decided on, was to make a compound link that has two legs; one goes straight forward to the firewall, and the other angles upward and anchors to just above the motor mount structure. Some heims and threaeded clevis', and it's done......oh, and zinc plated. I don't have any real clear shots of the final installation, but I threw in a few where hopefully you casn pick out the re-enforcement scheme.

You really should have just made 2 of everything

Then sold your leftovers to me cheap . Your way ahead of me on your conversion. Not to mention your attention to detail is way beyond mine

Let's install the Engman chassis stiffening kit. In preparation, I pre-fitted the plates and maked through the holes in order to grind away the paint to expose fresh metal for welding. While trial fitting, I discovered a few problem areas that required some attention.

I first noticed that the plates are not in intimate contact with the longs due to the longs not being flat; some areas are slightly bowed out (convex), while other areas are slightly bowed in (concave). So, the areas that were bowed out, I took a rubber hammer and gently hammered these areas flat. This helped reduce the gap at the bowed in areas to a somewhat reasonable amount. As any welder knows, a gap between plates like this will result in excessive shrinkage, and of course reduces the structural advantage.

I noticed too, that the seat belt anchors did not line up with the pre-cut holes, so some work was needed there. Also, the plate that goes across the rear required clearance notches be added for the ribs in the floor pan. Other areas requiring detailing were additional clearance around the cross brace where it meets the long, re-positioned holes so as to line up with the lower backpad screw holes, and the speaker grill screw holes needed the same attention. Once prepped, the work could start.

The chassis was placed on jackstands (at the donuts) and shimmed level. I first measured the door gaps in three places on each side. Then before welding, I placed a jack under the chassis centered in the middle of the long to where it just started to remove the weight from the the donuts. This was done to as an alternative to removing the doors and installing door braces.

I don't own a MIG welder, so TIG was my only best option, but I did quickly learn that TIG is not the right tool for this operation. Torch in one hand, rod in the other, operate pedal with knee, and contort body in ways never before experienced is just not the way to go. I was careful with my weld sequence to best manage heat build-up. Since I had no door braces, I worked slowly, and stopping often to check the door gaps. I would switch back and forth from the drivers side long to the passenger side long to again, manage the heat. I did this over a span of three days to insure that the door gap shrinkage was minimized. I did tack the rear cross re-enforcement in a couple of spots to hold it in place until the longs were done, then I finished welding that in place. When done with all the welding, I of course ground the welds flush.

I forgot to mention, that I put a few Tek screws on the long and rear re-enforcement plates to better hold them flush against the chassis prior to welding. They were of course removed, and those holes welded as well.

Andys

You need a thumb control Andy. They are perfect for stuff that doesn't require real precision when you don't want to use a knee or elbow on the pedal.

Nice job, the car looks great!

You know Jim, I got pretty good at the knee/back of knee/leg/etc pedal actuation so that was never the biggest problem. It's the need to get both hands into a confined area (filler rod in one hand, torch in the other) that is the killer. For example, welding the long re-enforcement in the footwell area....My body hurts just thinking about it! A MIG is so much easier for that kind of stuff.

Andy

I installed fiberglass flares, and here's why. At the time, the AA steel repro flares were not available, and the only one's that were, were $$$ and not easy to find. Additionally, the fiberglass flares were just a tick wider than the steel, and would accomodate my rear 993 wheels and 255-40-17 tires. As for the wheels, I found a local Ebay seller, so that worked out well. The flares I got from a shop that purchased all the old Mitcom molds, so I bought the flares, rockers, and 916 rear bumper (which I didn't use).

The first thing I did, was to prep the flares by making sure the right to left side periferies were the same. After some minor trimming, they were good. The next bit of prepping, was to grind the high spots on the inside where the flare would be in contact with the body of the car. The result was that the flares were much more flush than before, so it was a worthwhile step. Since I knew the rear tire was a tight fit, I trimmed the inside lip of the rear flares to about 5/8".

I then marked the axle centers (used an aluminum bar across the car with plumb bob's), and taped the flares (centered) into position and marked the body with a Sharpie. I did make sure the flare fit the rockets as well. Removing the flares, I next marked a scribe line 1" to the inside of the first line for some overlap. I then took my sabre saw and cut to the inside line. I taped the flare back into position, then drilled and installed Tek screws every 3" or so. Removed again the flares, and ground away the painted area between the cut and the 1" scribe line.

After some research, I decided on a two-part epoxy product called PC-7. It's mixed viscosity is about that of Bondo, but has a lower shrinkage rate and it's a structural adhesive. Oh, it also has a favorable pot life of 1 hour, and a service cure of 24 hours (7 day full cure). I got mine from The Do-It Center, but it's available at a number of retailers.

So, I'd trowel on a bead adhesive onto the 1" paint free area of the body (sorry, only photo of this is with wife clowning around), and also "butter" the inside of the flare, then position the flare and drive the Tek screws into place. This operation went really fast. The adhesive that oozed out was simply wiped off, both outside, and underside. Bam! A flared car! Ok, well not quite, as there is a whole lot of filling and sanding necessary to finish the job. If I were to do it again, I'd go with the steel flares just because the fiberglass one's take so much effort to get right. I spent countless hours on the shaping, then spray on some primer in order to spot any imperfections, then do it over and over till it was right.

I discovered a big problem further along in the build when I got the car on the ground for the first go kart test drive (no doors, no glass, etc). The tire would rub against thefront edges of the front flares when turning the wheels even a little bit. A shout out to 914World got me some measurements of the wheel openings of the steel flares......and sure enough, the fiberglass flares were less by about 1 1/2". What I figured was the fiberglass shrunk and the opening closed-up. Needless to say I was PO'd, though I guess I wasn't surprised, since fiberglass parts in general don't hold their shape well when un-supported. The fix was many more hours of pie-cutting, re-glassing, and filling to get both the opening and shape right

As the cooling system is a crucial part of a V8 conversion, I wanted to be sure to apply good practices for both performance and reliability. I first set out to configure the layout. As such, I decided on thru hood venting rather than the traditional thru fender venting. What I don't care much for with the thru fender venting, is that it creates a big under hood hot box. The thru hood venting, with appropriate ducting, allows the heat to rise naturally thru the opening which is especially important when sitting still in traffic. Down side of thru hood venting is of course it's affect on the car's styling. Enough pontification; lets build a cooling system!

I started with an aluminum radiator from AFCO; P/N 80133N which is an ASA racing radiator, dual pass, cap delete, 27 1/2 x 16 x 3. I see now that Summit sells them, though it's about $100.00 more than I paid a few years ago when I bought directly from AFCO. I'm going to gush a bit about how great these guys at AFCO are to deal with. Again, your typical Mid-Western stock car supplier/manufacturer that is a joy to work with...great attitude, etc. Anyway, the radiator size works out well in the 914; all that was needed was to tip it slightly forward, and it fit.

First I cut an opening in the front bulkhead, and re-enforced the center rib with a formed piece of channel to help stiffen the structure. I then determined the most suitable position for the radiator and went about designing a mounting scheme. I did what I've done on race cars, which is to build a U shaped channel lined with foam into which the radiator gets inserted into. This avoids any hard mounting, and completely shock mounts and isolates the radiator. I always cringe when I see folks hard mount radiators. There are of course other ways to shock mount, but this is how I like to do it. I made the U shaped channel out of aluminum with tabs in strategic locations for mounting. For the mounting points, I also shock mounted this structure to the chassis with two rubber isolators on the bottom, and two rubbber grommet mounts on the top. I used two Zirgo 10" puller fans and mounted them to a shroud. I also made some silicone rubber flaps to pass additional air at higher speeds thru the shroud as well. The shroud bolts to the structure.

For the ducting, I made some sheet aluminum ducts both front and back that mount to the radiator U structure, but do not fasten to the bulkhead, but stop short with foam gasketing to make the final seal. For the exit side, I made a duct that turns upwards. A foam gasket seals the gap between it and the hood.

The hood vent piece (diffuser) was designed with the help of an Art Center College of Design student, as I have no styling talent what so ever. I made a foam model which I covered with fiberglass and filled and sanded smooth. The size of the opening in the hood is 1.7 times the inlet side to help create the requisite pressure differential to draw the air out (with the help of the vent/diffuser). This diffuser sandwiches a rubber gasket to protect the paint, and is fastened to the hood by stailness button head screws from the underside (I bonded threaded inserts into the diffuser). With all this however, like very much what byndbad914 did with the louvered diffuser on his track car. Looks racey and subtle; if I would have known at the time, I would have simply gone that route instead.

I'll get to the piping in the next post.

WOW... Nice work!!

Has anyone tried a "cowl induction" style hood?" Think 69 Camaro style. That's what I think I'm going to try when I get to this point....

A cowl induction hood takes advantage of the high pressure zone at the base of the windshield. this would be very detrimental to potential airflow over the radiator. it's intent is to force air from this zone into the intake via ducting built under the hood.

under car, through the wheel wells or ,as the op has done, through the hood are pretty much your only viable choices.

As promised, here's what I did with the radiator water management and piping. I wanted to design a system with the correct elements necessary to ensure good performance. My main focus was on a system that would separate air from the water, and to reduce or remove the possibility of trapping air pockets. To start with, the LS1 motor has 4 steam vents in the heads; the early LS1/LS6 plumbed all four into the top of the radiator, and the later ones use only the front 2 steam vents. The traditional front engined layout tips the motor slightly back so 2 steam vents would be ok, but the 914 layout has the motor sitting level, thus I chose to use all 4 steam vents. Wegner Automotive sells a nice steam vent adapter that has a 1/8 NPT f'male thread complete with o-ring and stainless screw for cheap. I installed those, and used 90 degree compression fittings for 1/8" tubing. I decided to try some 1/8" nylon hard line as it is small and easy to route. You'll see how I ran those to my header/air separator tank.

I fabricated an aluminum flow-thru header/air separator tank, and mounted it on the drivers side of the engine compartment. I also fabricated a small purge tank. With this location, I needed to run a line from the right side water pump outlet under the motor to the left side. I made a stainless crossover pipe; I got some stainless 90 degree elbows from McMaster-Carr and welded them in, then mounted it to the motor mount bar with Adel clamps.

I decided to make under car hard lines. I first made a pattern using EMT and EMT bender so that the pipes run in the two depressions in the floor pan. This helped me a lot when making bends in a heavier walled steel tube. I went with mild steel here because it's easy to bend, where stainless thin wall is nearly impossible. After bending, I coated the inside of the steel tubes with POR-15. I did weld thin wall stainless tube ends with hose beads on each end. I attached photos of a beading tool I made and the resultant bead.

I cut a hole in the lower trunk area for the piping to pass through. What I did find was that the 911 aluminum suspension cross member was too bulky, so I used the tubular stock 914 cross member instead.....it was a tight fit. I've got some photos of the under car piping, but can't seem to find them at the moment; maybe later? Anyway, I hope the photos show enough to make sense of it all.

I found a couple of more photos (with the exit ducting removed) of how the piping routed in the front trunk and insulated.