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505 Tech: Front Mount Intercooler Fabrication
This is the most involved and probably the most interesting modification done to my 505 as of now. The front mount is something that i couldn't wait to do since i got the car. I didn't like the idea of an interCOOLER on top of the exhaust manifold... Interheater would be more appropriate. Besides, what a nice day to start some intercooler fabrication...
The Parts:
The intercooler system was fabricated with 2.25" aluminized mandrel bends that were purchased from www.jcwhitney.com. The intercooler is from a chrysler conquest aka mitsubishi starion. There are two different front mount intercoolers that came on these cars, a 16-row and a 14-row version. I have heard that the 14-row intercoolers flow better, so i assume the rows in the 14-row intercooler are just larger. The one that i have on the 505 is a 14-row. It was purchased from ebay for $200. You can find them cheaper but they are usually a bit banged up after almost 20 years on the road. I ordered some silicone couplings to piece things together. Unfortunately they were out of black so i recieved blue. I ordered the couplings from www.roadraceengineering.com. Roadraceengineering.com is a DSM place in southern california. I got a transition coupler (3" to 2.25") for the throttle body to intercooler piping connection, and enough straight 2.25" coupler to do the rest of the system. The clamps are 'constant torque clamps' purchased from www.partssystems.com. They are pretty cool i suppose, but i'm not convinced that they are any better than normal T-bolt clamps. The t-bolt clamps are cheaper too, and if i had to do it all over again i'd probably get those. Although i must add that i've had only ONE coupling blow off in the whole time the system's been in tact, and it's seen allot of boost. The blow-off was probably my fault in not tightening the clamp right anyway. The constant torque clamps seem to do a great job of holding things together regardless of whether they are any better than T-bolt or not...
Intercooler fitting:
The A/C was removed to make room for the intercooler. You can see where my priorities are. :-) The intercooler sits right where the a/c condensor used to be, about an inch or two in front of the radiator. It's mounted with some L-brackets that i bent out of thin steel. They are pretty flimsy but the brackets in conjunction with the charge pipes hold the intercooler very firmly in place. I will probably make some better brackets when i get more important projects out of the way.
To route the charge pipes, a few things had to be moved out of the way. On the turbo side, the little intake air filter 'bathtub' (505turbo owners know what i'm talking about) had to be cut up and shifted toward the side of the car. Since i use a K&N cone filter anyway, it doesn't really matter. I eventually replaced the whole tub with a little 'bridge' that i made out of steel. It mounts just like the tub did. I'm going to weld a 3" pipe onto it so i can get rid of that nasty plastic adapter that the filter attaches to. You can see a bunch of compression fittings and aluminum hard lines in the bridge picture. That's one of my attempts at reliable boost control. It was similar to the autospeed DIY article on boost control for an audi, but it didn't work too well.. overboost and 10 psi were within about a half turn of each other on that regulator (10psi regulator, verified by testing). It spiked like crazy just like every other method. Oh well, boost control is a different story...
On the driver's side of the car, the battery needed to be repositioned. Originally i was preparing to move it to the trunk, although i was dreading that task. I eventually found that i could fit the charge pipes if the battery was angled and shifted slightly toward the drivers side of the car. I had to take the windshield washer fluid reservoir out to do it, but it worked beautifully. I welded 2 square, hollow steel pieces onto the stock battery mount location. This gave me the elevation i needed, which i believe was about a half inch higher than the stock battery. Then a new tray was bolted down to the rods with the correct angle and positioning that allows the charge pipe through with an acceptable amount of clearance. The battery is now mounted with some cheesy little wingnut/threaded rod/hold down thing from kragen. It isn't all that pretty but it works perfectly.
After this stuff was out of the way, we started fitting the pipes. We had to grind away a little bit of the vertical support that is next to each side of the radiator. This provided enough room for the pipes to clear. From there it was just a matter of getting the bend angles correct. It took allot of guess'n'check work. Another problem spot was the elbow that clears the distributor. It's VERY close. Even now the charge pipe gently rests against one of the spark plug wire boots. We ended up having to track down a 2.25" bend with a really tight radius. I can't remember what the radius was, but it was very small, and just enough to barely clear the area. The bend we ended up with was not aluminized, it was plain mild steel.
All the pipes were carefully fitted... which took a LONG time. We used duct tape to hold them together while we fitted them, and then welded a few joints with the flux-core welder. This was my first ever welding experience. It turned out 'ok' considering it was my first time. There was allot of grinding afterwards. After i ground it all down i used some jb weld to make it a little prettier... it was pretty uneven because of my poor welding skills. JCwhitney sent me one stainless bend by mistake. So i used that one to make the pipe that comes off of the turbo compressor itself. I figured i'd use that at the hottest spot (right next to the manifold). You may have noticed the orange coupling by now. That was something i found in the junkyard. It's a GM part but i can't make out the number. It's a hump hose and allows for a little flex. I really really liked the construction. it looked about 10x better quality than the silicone stuff i got from roadrace. If i knew the part number and was so inclined, i may go over to a GM dealer and get another one for the drivers side joint. It's probably from some huge turbo diesel.
I ditched the oem intake hose. It was an 'accordian' style hose with a big huge brass fitting in it for the PCV hose. It wasn't to my liking so i replaced it with a 2.5" mandrel bend, and got a pair of couplings from the junk yard. One is an accordian style rubber boot which i believe was from a saab 9000 turbo. The other is just a simple 2.5" coupling that i got from a volvo turbo compressor. The piece fits in there perfectly and allows for lots of flex. The intake turned out nicely.
The bypass valve is from a volvo. There are a few types that came on the volvos. I've tried two of them, one has a closed head (silver), and the other has vents on the head (gold). They both work beautifully. At only a few bucks from the junkyard, there's really no better deal for this part. They are all constructed entirely out of metal, no plastic junk like you find on most factory systems. They are also adjustable. In my setup, the bypass valve is very audible when i want it to be, but i can also drive around and keep it from popping as long as i'm light on the throttle and don't produce boost. (i think that's a big plus :-) )
When i was doing the final assembly of the system, my buddies decided to mess with me a bit because i used a 12" extension to tighten the clamps. They didn't seem to think my long extension was necessary. So I went inside and when i returned to the garage i found every single extension in the garage piggybacked on my ratchet, ready for me to tighten down the bolts. I dug it :^).
The system is DONE
After a while, the non aluminized stuff started to rust a little. It also rusted where the aluminized coating had been groud off of scratched off of the aluminized parts. So i got out the sandpaper and cleaned the pipes up and painted them with some high temp "cast aluminum" colored paint.
We drove the beast around for a while with the grill off... We thought the charge pipes looked rather wicked, kind of like an upside down evolution VIII. The intercooler was still novelty at that time :-). Here are some pictures of the finished system.
Compare to the original 505 turbo engine bay..
Bumper modification
You might be able to tell that the bottom of the 5mph bumper is hacksawed... Yes, it pretty much blocked the entire intercooler from the incoming air stream. So we checked our priorities again, and got out the jigsaw. We cut a bit off of it to expose about 3 intercooler rows or so from straight ahead. Just recently, about 7 months later, I finished the job and cut another couple inches off the bumper. I figured i might as well since i had planned to put a few coats of black bumper paint on them. Oh and those oil puddles on the floor in the picture.. those aren't from my 505, those are from my parents brand new Honda... really, i swear! *-8}
Grill modification
When i had some spare time a few months after the intercooler was completed, i decided that i'd change up the grill to flow a little more air down onto the top area of the intercooler. The grill rows curved upward, shooting the air up over the intercooler, which isn't where i wanted it. I basically cut them with a dremel and flipped them upside down.
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