jdm65's JDM-inspired Gen3 Coupe Build

[cgundermann]

Really, really looking forward to following along on this build. Like your taste!

Chris

[jdm65]

Really, really looking forward to following along on this build. Like your taste!

Chris

Thank you!!

Probably no updates for a while as work is back in full swing, but I hope to wrap up the brake/steering soon, couple neat things there I'm looking forward to

Excited to see progress on your build thread too! Hope to see lots of carbon haha!

[gtrclark]

Hey there, just checking to see if you have any new pics of this build! Would love to see some more angles of those wheels on the car!

[jdm65]

Hey hey I have a LOT of updates!!

Sorry for being quiet for the past few months life got pretty busy with the whole world opening up again but I finally got a chance to work on the car again.

I'll write up a big big post later in chunks but here's a sneak preview for now!

spoiler alert I redesigned my entire ITB setup, it now uses BMW M3 ITBs which are larger and have a straight intake chamber instead of the angled M5 ones

[q4stix]

Awesome! Glad to hear of the progress. I'll be looking forward to reading the writeup about it all!

[jdm65]

Ok guys, here it is

I spent probably well over a hundred hours into this project over the past few months but we're nearly finished!

Here are my fully custom BMW ITBs for my Coyote!

Originally I was going to use an adapter from my friend Blaine at Carmena Performance but I decided to remake it myself using M3 ITBs instead of M5 ITBs.

This new design does away with the angled adapter and the angled M5 ITBs for a direct 15 degree angle (matching the angle of the ports on the Coyote head)

Really quick as a note before I go into this I'm absolutely not an engineer of any kind, and this was actually my first CAD project, but I did get a lot of input from a lot of my close friends who are engineers of all shapes and sizes!

But here it is! This is a 3D render I did of all the assembled components.

ITB manifolds will require some kind of vacuum collector, and that's the two black boxes directly underneath the filter plates.

The velocity stacks are my design, but for the actual car I'm just going to use Toyota 4AGE ones because I made an adapter to make them fit (they are approximately the same inner diameter as the 52mm BMW ITBs)



Here's a close look at the throttle mechanism, which reuses a factory Ford electronic throttle body! The center brace that holds all the pieces together is going to be made out of 1/4" thick 304 stainless, cut and bent from Sendcutsend. The rod ends in this iteration of the design are just 12mm rod ends from McMaster-Carr but I'm working on a redesigned version that uses 3D printed housings with needle bearings instead which will work better and also cost significantly less. The anodized blue linkage components are my design, but I've since also resigned those to be 3D printed instead, so the new ones are uglier, and not cool and blue haha

I guess this is basically the expensive pretty design, whereas the one on the car will be the utilitarian cheap 3D printed design LOL



And here's the real important part - here it is on the engine, on the car, showing that both throttle rods move at the same rate. All the components in this photo except the throttle body and BMW ITBs were 3D printed out of PLA, but the final version, where there are printed parts, will be printed in carbon fiber infused nylon. The materials called PA12-CF and it's very strong, very heat resistant, and fuel resistant!



Here's a cool photo of the adapter printing! This one's a prototype, so it's mostly hollow. I still have to make some final tweaks before I get this thing produced.



But more or less, that's basically it for the ITBs!

I'm going to split my updates into posts as I've been really bad about updating this build thread - the car has gotten a ton of progress and I haven't posted about it LOL

[jdm65]

Ok here's the next project LOL

Here is my custom floor mounted Tilton pedalbox setup!

I chose this for a multitude of reasons but one of the reasons was that I've always wanted a car with floor mounted pedals, and I am still missing my Wilwood pedal box from my POL haha

First I just loosely mocked up the box in the drivers side footwell where I wanted it and clamped it down with a 2x4 underneath it.

I'm fairly tall and I also have long legs, so this actually gives me a little bit extra legroom, and also frees up the space behind the dash for a future, completely hidden EPAS setup!

I chose the standard Tilton 600-series floor mounted pedalbox over the underfoot one due to cost and simplicity, but if I were to do it again, I'd probably go underfoot as the clearance between my header and brake lines is probably gonna be tight enough to warrant a very serious heat shield.



Once I had it perfect, I went to go design a brace to go under the pedalbox to be welded to the floor of the chassis. Since the floor pan is the lowest part of my car, I don't want the pedalbox to be bolted in as I might just scrape the bolts off, so I want to keep the floor of the car completely flat.

I designed this as a sheet metal part, so if needed I can go back and make it thicker, but after welding it to the chassis, it's not going anywhere so I'm probably done with it haha.



A few days later and Sendcutsend sends me this:



And here it is welded in with the pedalbox mounted properly. The back bolts on the box go into that bit of chassis at the back of the pedalbox, and the front (closer to you) are secured using two nuts that are spot welded to the pedalbox mount.

I'm also going to make an adjustable heelplate later, but with the shoes I usually wear and my big feet it's pretty much perfect so I'll just leave it for now. The holes below the pedals are for mounting stuff in the future and that bend is there to give the bracket rigidity.



I also ran and secured all of my brake lines. This loop is just to make it easier for me to get the nut in

I'm contemplating being super extra and also making a hardline for the clutch, but I honestly cbf so I'll just leave it for now haha



That's basically it for the pedalbox for now - I'm still going to have to cut the aluminum panel since the master cylinders mount sandwiched to the panel now, and I'm definitely going to have to make a very serious heatshield. I did check the header clearance and everything clears with a couple inches of space, but if need be I'll modify the headers to clear. I won't need that side header next year anyways ��

[jdm65]

Here's a dog photo just before we get into the next part of this update



Anyways brakes!! The car does need to stop so I do need to do this hahaha

For brakes, like I said at this point years ago, I wanted to use Cadillac ATS brembos. I know a couple other builders have used this now but I figured I might as well document my experience. My adapter kit is from S&S engineering and consists of 4 offset mounting nuts that have to be pressed in, and two thin spacers to space the rotor out to match the caliper.

To do this swap you need to first knock out the pressed in mounting nuts in the calipers as sent. I'm sure there is an elegant way but I chose to stick it in my vise, thread a bolt in, and whack it really hard with a hammer. I didn't use enough microfibers when clamping the caliper down so I unfortunately scratched the finish quite a bit, but that's no big deal as I'm planning to paint these calipers anyways!

Here's the nuts knocked out of the caliper, and the new nuts installed! I used a cheap Harbor Freight (Princess Auto, my Canadian homies!!) hydraulic press to press the new nuts in!





Pretty sick!!! Basically the bolt spacing on the SN95 spindle is just a little wider than the ATS so all these nuts do is offset the bolt holes in the caliper. That's it. The spacer is just to space the rotor out.

I can't remember which rotor, but I'm pretty sure this is a SN95 Cobra rotor. 13" or something? Also, since I wasn't sure if this setup would fit the Factory Five spindles, I bought the absolute cheapest rotor in the case they did not. They fit, so I'll be buying slotted an drilled ones!

Looks sick!!



Oh also, here's that spacer.



I also drilled out my steering arms for my bumpsteer kit. There's kits out there that have the correct balljoint taper, but mine requires you to just drill the taper out to straight so I just did that and finished the setup.



Whew! That was a good bit of work! Really happy with the results though.

[jdm65]

Headers are in and MAN... that is CLOSE

I will have to build a very good heat shield...





I can slip a hand in, so I'll make a heat shield, worst case scenario I'll probably have to modify that header

Also, I was finding it really hard to mount my Bride seats to the flat steel floor provided on the chassis by Factory Five, so I boxed the whole floor in instead

[jdm65]

Tiny updates

Rad is on, and I also redesigned part of my ITB setup to be 3D printed

This used to be a 12mm heim joint but now it's a 3D printed adjustable rod holder that uses a really easy to get needle bearing



It replaces this, which I used originally to hold the center throttle shaft



I also mocked up all the aluminum paneling for the radiator and mounted the rad using a 6mm rivnut instead of the specified self-tapper



Seems to be normal that the rad is shifted over to the drivers side, but I actually might be able to center it since I'll be cutting the barb fittings off for -16AN fittings instead, so I can straighten out the inlet and outlet pipes. More on that soon

[jdm65]

Oh and, I figured I might as well share some 3D rendered eyecandy of the ITB setup. The prototype one on the car is gonna be pretty ugly with a lot of 3D printed pieces and haphazard hardware, but I'll replace everything once I get it running right with nice billet pieces and polished rods and whatnot



The linkage setup looks so good

It looks a little confusing but basically how it works is that the two banks have to rotate their throttle shafts mirrored to each other. Meaning from the front of the engine, one will turn counter clockwise and the other will turn clockwise. The throttle shafts connecting the outer rods to the center one are different bank to bank, one bank's throttle shaft rotation is matched to the other, and the other bank is mirrored, so when the bank's throttle shaft rotates one way, the center shaft rotates the other. Basically once everything's all adjusted (I ran into some issues getting the throttles to open exactly the same but sorted it out) rotating the center shaft will rotate both outer shafts equally.

BMW saved the effort and just used two throttle actuators, one for each bank, lol. Shoulda done that. I'm not the first to use a setup like this but it's also uncommon enough that I can't just copy someone's homework and base the design on someone else's so unfortunately this is entirely my own (completely untested) design lmao



Also here's an incomplete idea of what I kinda want with this setup

I'm gonna have the airbox seal to the hood of the car with some thick foam or weatherstripping and have twin intakes that go to the airbox. That way everything is nice and filtered (and cold!) as it enters the engine, but when you open the hood you can still see the stacks. I have this as an aluminum airbox right now (designed to be made out of bent sheet aluminum) but I think I'm gonna make a carbon one instead using a 3D printed form, seems a little easier

I also designed some really simple couplers that can go into the airbox so I can use pretty much any 4" pipe. Not sure on filters yet, maybe I'll throw in some more JDM and do some HKS mushroom filters? hahahah



Anyways to anyone that's reading this and wants to do ITBs - just buy the innov8 setup, this wasn't worth it to save a few grand LOL