Miata Turbo Forum - Boost cars, acquire cats. - Build Thread: An Exercise in Heat Mangement

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Build Thread: An Exercise in Heat Mangement

I've been researching and collecting parts ever since I got my first miata two years ago and I've finally gotten to a point I'm ready to commence the turbo build. I'm on day two of what will probably be a full winter of a build. To date I've started with a 95' NA built it up into a regionally competitive STR auto-x car, then swapped over to a NB when a good deal came along and have turned the focus more towards a track build that can still auto-x for fun. I'm not aiming for a particular class which I know means I'm pretty much screwing myself for being competitive. I love wrenching and fiddling with cars and this is just an outlet for my interest, I'm aiming to make the car versitile enough to auto-x, HPDE, time trial and eventually hill climb in whatever class it'll fit in hopefully embarrassing it's share of camaro's, mustangs and corvettes along the way. I've been able to pick on these type's of cars in an auto-x setting, going to have to do something if I want to do the same on any track with a strait away. It'll get driven to the events and I don't want any heat issues no matter how crazy I get with it in the future.

https://cimg6.ibsrv.net/gimg/www.mia...36108c5d73.jpg

With an eye towards a tight budget the car (oo' SE) is setup with:

chassis
Ebay Bilstein setup with 800/450 lb/in springs
Stock Sways
Blank rotors / carbotech XP10's f/r / Adj. prop valve
Roll bar / harness / Sparco sprints
Weight removed and cut out wherever I can find it
9" 6UL's 225 Rival S, soon to go to a 245 Maxxis or a 225 RS3 to get some life on track
Fully adjustable control arms
Delrin bushings where articulation isn't needed

Drivetrain
low mile JDM BP4W, 190 psi across all cylinders cold
MS2e
6 Speed
3.90 Torsen
Full 2.5" exhaust (fabricated by me)

Now onto the build, I've bought most of the parts already so feel free to make suggestions.....but I'll probably ignore them.

Turbo build
BEGI cast manifold / Inconel studs
GT2560
3" stainless downpipe
2.5" exhaust, no cat, strait through muffler (this will get upgraded to the requisite 3" later)
MS3x, WB, traction control (selling MS2)
RX8 yellow injectors
walbro 190
Skunk Honda intake and TB
Ebay intercooler
Massive aluminum radiator
Massive oil cooler
Spec stg. 3 sprung 6 puck ceramic / 12lb flywheel

First stage of this build is to maximize the stock bottom end with a flat 210-220 ft/lb of torque from 4k to a reduced redline of 7k, the idea of these conservative numbers is to try to get this thing to live on track. I have another block that will eventually get forged internals and then I can crank the knob until the 6 speed implodes or the garrett just makes heat instead of boost.

Day 1 included a saws all:
https://cimg6.ibsrv.net/gimg/www.mia...d6959d2879.jpg

And a pile of parts:
https://cimg8.ibsrv.net/gimg/www.mia...505b0b8335.jpg
Just a wee bit bigger radiator:
https://cimg8.ibsrv.net/gimg/www.mia...8674819114.jpg
(Trying to get a slab of steel to finish this welding table.....plywood is a horrible ground)

After a few hours of cutting I was able to mock up a couple of options for the 160$ summit racing radiator (mopar application has the outlets generally in the right location). I had two options in mind as far as mounting, conventional:

https://cimg2.ibsrv.net/gimg/www.mia...5eb736b1f6.jpg

Then I tried out what I really had in mind:

https://cimg5.ibsrv.net/gimg/www.mia...bbc783c8f4.jpg

Before you ask:
https://cimg8.ibsrv.net/gimg/www.mia...d5d54fca83.jpg

The idea behind laying the radiator down this much is to allow for a V-mount setup with the intercooler mounted low. I always hated the compromise of stacking the intercooler in front of the radiator. If you don't seal it to the radiator the air flows around it and you get high IAT's, seal it to the radiator and you just relegated 1/3rd of the radiator to greatly reduced flow trying to pass air through nearly 5" of heat exchanger. Neither of those options allows for enough flow through the intercooler. The key to making something like this work is ducting.....and I'm going to have a LOT of it. It's getting vented out the hood. I'm going to try like hell to vent the intercooler out the hood as well, but this massive radiator is going to make this tough. Using the rule of 1/3rd vent area to the size of the heat exchanger (I've seen 1/4 to 1/3 thrown around as a rule of thumb) i would only need a 2" vent path (27" by 6" intercooler) for the intercooler air stream. As a last resort I'll vent the intercooler under the car. The reduction in lift by getting the radiator flow out through the hood will easily cover any intercooler air being vented under the car. I'm also not afraid to shorten the radiator, this puppy is 19" tall where the stocker is ~16" to make room for ducting.

I want to keep the car street "legal" and that term is very loosely enforced in WV. If the inspection station even bothers to look for a cat they are doing good. In keeping it streetable I need cruise control, easy enough, and I would really like to keep the A/C...... with a balls out build like this it seems silly to screw up the airflow by leaving it in but man is it nice to kick on the cool air for the 2-4hr drive home from an event (no truck and trailer here). Packaging is already looking tough, so it may end up on the shelf yet.

Day two I turned my focus to the Honduh skunk intake.....not even sure what version this is or if it's a knock off. Considering I picked it up for 100$ with a 65mm throttle body I'll make it work. It was actually already modified for a BP4W by welding additional tabs onto the honda flange and redrilling for the proper bolt pattern. Haven't seen it done this way before but I got it so cheap because the lower flange ears were all snapped off. After test fitting I can see why, it was jammed into the shock tower to the point that any engine movement would have it touching which is what probably caused the cracking.

https://cimg9.ibsrv.net/gimg/www.mia...ac3eda040d.jpg

Luckily I had a spare VICS manifold laying around so out came the band saw:
https://cimg3.ibsrv.net/gimg/www.mia...b0e525bd05.jpg

Some time on the belt sander and:
https://cimg7.ibsrv.net/gimg/www.mia...595206b1e6.jpg

Ugly but functional:https://cimg9.ibsrv.net/gimg/www.mia...b2a952e5ec.jpg

I ended up having to cut down the miata runners a little closer to the flange to get it to fit right but it's tacked up and ready for final welding and porting:
https://cimg0.ibsrv.net/gimg/www.mia...b4a0441d7c.jpg

I've got an A/C line that needs tweeked (already looking like it's on the chopping block) but it's got plenty of room to the shock tower, runners ended up a little shorter than I wanted but space dictated what I got. Factory fuel line routing will not work, add that to the to-do list.

Now you're caught up on my progress so far, I'm taking the whole week off and planning on spending every hour I can find in the garage so I'll probably make some good headway this week but won't get it wrapped up till x-mas...... not like I can use 250 whp in the snow anyway.

I'm seriously open to any suggestions or idea's, yes I've bought quite a bit of parts so far but if you think I'm overlooking something or wasting my time on something let me know, This site is a wealth of information and I based my build plans around the research I've done here over the past two years. Hopefully I help repay some of that knowledge with some of my idea's, whether they be success' or massive failures. Probably going to be the latter.

With the front mouth taken up, where is the oil cooler going?

Great question, it's going in the passenger side bumper corner, it'll get a dedicated inlet via the fog lamp bezel which will probably have to get enlarged. Air will get dumped into the fenderwell or ducted to the edge of the bumper. Initial mockup shows I was smoking crack to get something that big (10.5" x10.5") in the corner but I haven't given up yet. Worse case scenario is I order a smaller one. This is actually a Derale trans cooler which is built identically to their oil coolers. NPT fittings in / out, stacked plate design 78$.
http://derale.com/products/fluid-coo...9000-plate-fin

https://cimg8.ibsrv.net/gimg/www.mia...7f7890d5e9.jpg

Fog inlet on drivers side will go to an airbox to feed the turbo inlet.

Ok, so the front mouth and fog inlets are taken up. What are you doing for brake cooling?

Brakes in general need upgraded, I don't expect my current setup to do much other than maybe a shake down track day at half boost. I like making rather than buying and I've built my own brake setups on other cars using larger OEM based calipers on cars that they never came on. So far I haven't found a setup that can beat the trackspeed kit, all OEM 4-piston options use pads that quickly pass up the costs of the willwoods or just cost more than them outright with more expensive pads. The individual kit component costs shake out to where the brackets cost less than 100$ and for that kind of coin I'll spend my time elsewhere. On top of that I don't have a milling machine yet so I'm not exactly equipped to make 3D brackets that are needed for the miata spindles. I'll match the fronts with sport rears. I also want to look into a dual master setup eventually but with the adj. prop valve I have now I should be able to keep it balanced as long as I can aim for a bias and hit it within a +- 25% range.

Said all that to say, currently plan to get the air for the vents from the sides of the radiator ducting. Hate to bleed off pressure that could be used to force air through the radiator but as opposed to punching another hole in the nose this looks to be my best option.

Day Three:

Got a full day in and made some progress. I started with finishing up the intake. Have you ever tried to weld chinese aluminum to Japanese aluminum? It was a trip, I beveled the runners quite a bit trying to get full penetration but I still ended up needing to back weld the joint. I had to put a lot of heat into the weld to get the impurities to float out of the weld bead so the flange did end up warping a bit. The belt sander was able to straiten it up nicely.

https://cimg1.ibsrv.net/gimg/www.mia...766e92a1c8.jpg

https://cimg6.ibsrv.net/gimg/www.mia...00545b79ed.jpg
After an hour or so of porting
https://cimg1.ibsrv.net/gimg/www.mia...b9458bd1f1.jpg

https://cimg3.ibsrv.net/gimg/www.mia...c570a6d2b2.jpg

Finished product:
https://cimg7.ibsrv.net/gimg/www.mia...34e4dcbd76.jpg

I give it a 50/50 chance of cracking into a million pieces. Just no way not to have weld contamination with two pieces of used aluminum. I'll be bracing this in an attempt to get it to last longer than 5 min.

I then turned my attention to the sandwich adapter. This is a 20$ ebay special that I tapped about a million holes in. I wanted to route oil to the cooler but didn't want the complication or point of failure of a thermostat so I'll just have to take it easy until the oil warms up. Of course to know if it's warmed up I'll need a temp sensor, and then an actual pressure sensor, both of which will go into the megasquirt an activate a warning light and be displayed on the tablet I have mounted in the center stack.

https://cimg6.ibsrv.net/gimg/www.mia...9ef6743db3.jpg

https://cimg0.ibsrv.net/gimg/www.mia...b11796db4b.jpg

I finally got started on the downpipe, man you would think just squishing a 3" pipe into an oval would be easy, but cut the ell an 1" shorter than the true centerline of the bend and give it a 20 deg. twist and shit gets real. In the end I was happy with the result.
https://cimg2.ibsrv.net/gimg/www.mia...b6aaad217c.jpg
https://cimg8.ibsrv.net/gimg/www.mia...ad3e6cd561.jpg
https://cimg0.ibsrv.net/gimg/www.mia...791efdf07d.jpg

It doesn't look like it from this angle but I have 1/2" of clearance to the firewall. You'll also notice I had to put a bend in the heater hose connection to make room as well.
https://cimg1.ibsrv.net/gimg/www.mia...dd04f37604.jpg
https://cimg8.ibsrv.net/gimg/www.mia...a89b1192fc.jpg

Making progress

Im pretty sure that's a genuine honda manifold. I've done a half dozen knockoff manifold conversions and something about your manifold looks different, that and the knockoff weld really well. Good job on getting a weld in the runners, thats a tight spot.

Day 4:

Got about a half a day in the garage today. I focused on the downpipe and was able to get it finished.
https://cimg8.ibsrv.net/gimg/www.mia...35b076edf6.jpg

You'll notice the downpipe terminates in a lovely 3 to 2.5" reducer, this will get cut off when I get around to fabbing up the rest of the 3" exhaust.
https://cimg6.ibsrv.net/gimg/www.mia...96956df1b8.jpg

First time welding stainless, made pretty puddles but it's no roll of quarters...... more like a pocket full of change.
https://cimg7.ibsrv.net/gimg/www.mia...48606e30bd.jpg

So I warped the flange....should have had it bolted to something. Belt sander got it close but I can still see light through the flange connection with a flashlight shining on the inside. I know you don't use a gasket between the manifold and turbo, can I get away with a steel shim gasket here? I didn't run a feeler gauge in it but it's ~.005" looking at it. May just keep at it on the belt sander and see what I can do.

UPS guy dropped off the last of major components today as well.
https://cimg5.ibsrv.net/gimg/www.mia...1f55ddd71b.jpg

That's a rev9 intercooler, looks like one of the good ones. I'll get some up close photos of the inside to be sure.

I would just spend more time with the sander. As annoying as it can be.

I had the same issue with my downpipe flange...
Its amazingly hard to hold that flange flat on the sander with that big chunk of pipe working against you. If only we were smarter and welded the flange and flattened it before welding the whole downpipe on hahaha.
I finished mine by hand with some sand paper glued to a flat handheld block.
At 0.005" I would probably call it good enough. I'm using a metal gasket on that surface and its been fine for the past 5 track days and 5kmiles of street driving. I don't foresee any issues coming up.

Well 3 hours later and I was able to improve it from a measured .006" to .002" it ain't getting any better. At this point I'll run the stainless shim gasket and of i have issues I'll pull it all off and find a machine shop that can mill it.

At .002 would give it a try without the gasket. Have you cranked it on yet and warmed it up?

No, I had thought about that...... Not sure I can get any appreciable heat in the flange with a propane torch, oxy/ accetaline setup isn't online yet

That was my last best idea.

Stuffed full of turkey....... so no progress today. I did get a little bit of time to start mounting the radiator yesterday after blowing 3 hrs on the belt sander with the downpipe flange. Now that I have it tacked up I started to second guess my mounting solution.
https://cimg9.ibsrv.net/gimg/www.mia...29e28345b6.jpg

Right now it's mounted solidly at the front with the bracket above, and the rear is supported with a longer piece of plate aluminum that is also rigidly mounted but allows plenty of of movement via flex. My worry is that with this solid mount any chassis movement will work to crack off these brackets most likely resulting in lots of spewing coolant. Think I'm going to go back and sandwich this bracket with a thick piece of rubber top and bottom to allow some movement.
https://cimg4.ibsrv.net/gimg/www.mia...025839220b.jpg

The intercooler mounting position is shaping up nicely. Looks like I'll have room to route the exit path around the sway bar and vent it through the hood with the radiator air. To do this cleanly the A/C just has to go. Way too many compromises and extra work to implement it. If I do get really cranky and want air I'll probably have to come up with some custom lines that works around my ductwork. Man I'm getting old.
https://cimg4.ibsrv.net/gimg/www.mia...39604743a2.jpg
https://cimg6.ibsrv.net/gimg/www.mia...300fa10255.jpg
( The intercooler does not sit below the crossmember so I can run a splitter in the future that will help protect everything.)

Originally I had planned to duct the intercooler inlet separately from the radiator so that i could dictate the balance of the air to each, but after seeing how well they lay out as they sit I might just try it first. If the IAC's are too high I may add the ducting from the intercooler to the nose that way I can bias the amount of flow, if I find that I'm running out of enough air to keep the IAC and the ECT cool enough then it's time to start cutting up the bumper to allow more air in. Really don't think this will be a problem with the optimized exit path ducting, the way I have it planned I've got my source at the highest pressure point and the outlet at the lowest point on the front half of the car.

Spent a ton of time getting the mounts for the radiator finalized and the intercooler brackets added on top. Against my better judgement I went ahead and hung the intercooler off of the radiator. Wasn't a whole lot of options with the radiator hanging over it like it is. In the end I'm happy with how it's shaping up, very solid. I got started on the relocated filler neck since the one that came on the radiator was pointing towards the ceiling.
https://cimg8.ibsrv.net/gimg/www.mia...7c6f3c1ccb.jpg

https://cimg3.ibsrv.net/gimg/www.mia...b1d8015ef2.jpg

Tha'll get braced once it's welded to the radiator.

I would be really worried about solid mounting a radiator...

Why not get some rubber legs to isolate it a bit?

I agree, the mounting ears you see are getting sandwiched between two police's of 1/4" rubber and the through holes drilled oversize to allow movement. I envision the frame ears moving up and down more than anything so I need to allow for that and just general vibration.

Got the massive 10.5" by 10.1" 17 row oil cooler mounted this morning. Extremely tight squeeze, I was really close to sending this back and going with something smaller. The reason I went with such a large cooler wasn't because I think I need the cooling capacity it's that I wanted to reduce restriction to flow to keep the pressure loss minimal. I'll actually be under ducting air flow to this cooler to start and enlarge as needed based on oil temps. In case you were wondering the exit ducting will protect it from debris coming off the tires.

First I had to build a funky little bracket that got welded below the head light.
https://cimg1.ibsrv.net/gimg/www.mia...44c08e0a78.jpg
https://cimg2.ibsrv.net/gimg/www.mia...f81ad40dc8.jpg

It still needs the lower mounts, which will be 1" steel straps that will attach to the bottom of the headlight bucket.
https://cimg5.ibsrv.net/gimg/www.mia...48c7ef19e6.jpg

And here's the money shot.......that's a lot of heat exchangers.
https://cimg8.ibsrv.net/gimg/www.mia...2997fb9f09.jpg