Center mounted oil cooler project, part 2

[Chuck Moreland]

I've made a lot of progress on this project since originally posting Part 1

Project is far from finished, but most of the rough work is done.

The biggest part of the project was fabbing up the airbox:



It's aluminum and weighs about 3-4 lbs. Not much heavier than the steel section I cut out of the front of the tub.

I first fabbed the airbox in cardboard, but still ended up remaking / revising every panel at least once. A sheet metal bar folder was indespensible.

All the seams are welded. As my first experience welding aluminum, this was a real learning curve. I really didn't get good welds until close to the end of the project. I then re-visited all the critical points to ensure strength.



The box tappers from the 22 inch bumper opening down to the 19.5 inch hood vent width. It has lips that are turned up and down to seal across cooler.

The cross-section of the airbox is never less than 3" x 19", so it should provide plenty of airflow capacity.

The airbox climbs pretty fast, the better to clear any future fuel cell that might find a home in my trunk.

Top of the airbox seals to the hood underside, then opens backwards. Top of the box was carefully contoured to match the gentle curve of the hood. Weatherstrip will be applied to make the seal.

Eventually, I'll use a seam sealer where the duct passes through the bulkhead. For now, I've just got it bolted in. The goal is to make this as water tight as possible.



The cooler mounts flush against the duct. I'll be putting weatherstrip in between to seal the gap.

I welded new brackets on the sides of the cooler and attached it to the tub using rubber isolation mounts.



With the cooler and duct roughed in, it was time to attack the hood.

I like the stock hood and want to minimize the visual impact. So I moved the opening up fairly high on the hood. I also beleive the center of the hood is the lowest pressure zone, so putting the vent there should help suck massive air through the cooler.



I layed out the planned cuts with tape.

The tape helped me get a visual perspective, and also a guide to cut. Then.... pause..... decide you really want this..... and start cutting.



I peeled down the front and held it open with a block of wood, cut to size. Then made some sides with polycarbonate to form a mold for the 'glass. The 2x4 was used to smooth the bend.



Glass it up, let it cure and ....



Voila..... hood vent is roughed in.

[Chuck Moreland]

Obviously it still needs finish work and paint. And I need to bridge between the hood vent and the air duct.

But I couldn't help slapping the bumper on for a sneak preview.



After prep-work, the hood will be repainted blue. This will make the vent less visible. It's present off-color sides make it stand out.

[randywebb]

nice

Now make 2 grill2 for it (intake & exhaust) that match the intake gril for the cabin air...

[89turbocabmike]

That's coming out very nicely Chuck. I'm sure that first cut into the hood was nerve racking. All painted up it will be a very subtle look with a great cool factor when someone realizes the vent is there

[87coupe]

Nice work! Is this a track only car, or should I keep my eye out for a blue and orange blurr zipping around town

[Chuck Moreland]

I drive it on the street too, so yes watch for the blurr

[dean]

Beautiful job there. How many hrs do you figure you have spent on it?

Dean

[widebody911]

Very clean!

Now you need a thru the hood fuel filler...

[Chuck Moreland]

Dean, I don't know the total hours. I've been working on this off and on for weeks.

But I have a lot of time in it. Every single part was either custom fabbed, or modified. There were plenty of mistakes and rework done along the way. Lots of time spent planning, especially the airbox. Fabbing the airbox itself took extra long since I needed to learn to weld aluminum.

I made it extra difficult by choosing a cooler that had fittings on each end. I had to make custom hose ends (not pictured) so it would fit cleanly behind my bumper without interfering with the 1/4 turn fasteners that secure the bumper.

It would be easy to slap it together, but I wanted it to fit really well, seal really well, allow easy bumper R&R, and look good too. I realize I haven't achieved the "look good" part yet, but give me some time to do the finish work.

[FrayAdjacent911]

Wow Chuck! That turned out really nice! You do great work! Thanks for sharing with us.

[DW SD]

Looks very nice! Great work! What did you learn about welding AL? (I know it is off topic). What are you welding with?

Doug

[dean]

Originally posted by Chuck Moreland


I made it extra difficult by choosing a cooler that had fittings on each end. I had to make custom hose ends (not pictured) so it would fit cleanly behind my bumper without interfering with the 1/4 turn fasteners that secure the bumper.

Damn, now that you can weld Alu. you could have modifyed the oil cooler to have the fittings on one end

Again very nice job.

Dean

[Chuck Moreland]

Coolers that have fittings on the same end are readily available, I have a bunch sitting in my shop and they work very well.

But when the fittings are both on the same end, oil wants to flow close to the fittings following the path of least resistance - the opposite end of the cooler sees a reduced flow.

Fittings on opposite ends creates a "diagonal flow". With a diagonal flow, the oil moves through the cooler in a uniform manner, the manufacture claims this yields a 10% improvement in cooler efficiency for a given size.

The downside is a more difficult installation. I thought I'd give it a try myself to see just how difficult. Having now done it, I would only recommend the diagonal flow for those capable in custom fabrication, or willing to cut holes for hose routing.

[adomakin]

great stuff Chuck. was the mod purely for better cooling or were you looking to take advantage of the increased downforce as well?


Andy

nice work as usuall Chuck. Shes come a long way baby!

[mjshira]

that is PHAT. nice work Chuck! very cool!

[rsa]

Fab job looks great!! You mentioned the seal to the hood. Does the entire aluminum box seal tight against the hood?

[cary]

It looks great. I saw Jeff Gamroth build kind of the same thing on a 3.8RS 914 he was building for a customer.
With all if us always looking for more cooling. It is a thing of beauty. But no room for golf clubs. LOL.

[RickM]

Very nice fab work. I see an Argon tank in one pic. MIG or TIG?

(PS: I was at a fleemarket a few weeks ago and a guy was selling spools of aluminum MIG wire for 2 bucks a pop. I picked one up to experiment with. Too bad he ran out of stainless wire.)

[widebody911]

Originally posted by Chuck Moreland

Fittings on opposite ends creates a "diagonal flow". ...

The downside is a more difficult installation.

It's not that bad...