Twin Charged FD - Fraternal Twins

[RX SE7EN]

Hey Everyone,

The purpose of the build is to twin charge my FD. Yes, I said twin charge. I’ve been researching for about a year now, this type of thing isn’t very well documented anywhere (well from what I’ve seen anyways). So I’ve been slowly designing the system and collecting parts. My goal is to have it working by deals gap, not sure if it’ll be done, but that’s the goal. Before I get started, I’ll just say that I know that these kinds of threads come along and then nothing ever happens, and that could very well end up being the case here, but I’m going to give it a shot and see what happens. I welcome all constructive ideas, but please refrain from posting negative criticism (I’ve made up my mind to try this, no turning back now)

I’ve currently got the Greddy T78 kit. When I had it tuned, it made 454whp at 18psi. Which is a little low, and the previous owner blew an engine on the car so I think it has seen better days. I’ll be sending it off for a rebuild in sometime this month, so even if this project doesn't work, I'll at least gain a fresh turbo.

I bought a remanufactured Eaton M62 supercharger in September. It’s got a clutched pulley and I plan to have it disengage after its done doing its work down low (1k – 6k rpm), then the turbo will take over entirely. I’m aiming for around 500whp somewhere around 20psi (with meth injection). But with torque down low, and no lag. If this actually works, I’ll upgrade to a larger turbo to make more top end power with no lag.

I’ve been debating going 20b, and would if the car wasn’t already single turbo and using the TEC GT ecu. Going 20b would require changing out the ecu, buying a 20b, buying a mounting kit, and paying someone to make new piping for me. Those are the big costs that I would incur; I know there are many other small items that would add to it. So the next best thing is attempting to grow my hp level, but decrease lag and increase torque down low. That’s where the twin charged setup comes in. And if it works, I can then transfer it to a 20b application a few years from now, which would be the ultimate setup.

I've come across a bunch of videos on youtube during my research:
Coolest silvia I’ve ever seen:
http://www.youtube.com/watch?v=4SjNgVH_HN0

And my true inspiration: go to 1:60, it’s instant boost (I know there is no load on the engine, but still cool)
http://www.youtube.com/watch?v=wLB2P1ziXYA


I’ve found numerous threads on twin charging, on many different forums, but never really anything that shows start to finish, with a DIY. And definitely nothing on this forum. A lot of the info I found was geared more towards big V8's with short rpm ranges with a supercharger on top of the engine and turbochargers compounding through the supercharger, with both systems on all the time, so those don't really help me that much (wouldn't be great on the FD). But I was able to find a picture of what could possibly be the best FD setup ever: (couldn’t find pictures at completion or information on how it was controlled)

[RX SE7EN]

Also, TitaniumTT has been absolutely essential to the build so far. Thanks Man!!!

He's been doing all of the welding (which you'll see pics of later on) and also letting me use his tools to make the pieces I need. And he's also a great source of knowledge, having someone to bounce ideas off of is great.


Here is a quick recap of where the project is and where it needs to go.

My current setup:
94 R2 FD
Brilliant Black
Street ported engine with oil and coolant passage mods
HKS Hypermax coilovers (courtesy of RX7 Boutique / PureRX7)
Racing Beat Sway bar (front)
PFS Large Race SMIC w/ duct
Meth injection (2 x 625 ml/min nozzles w/braided lines to shurflo pump, Snow Performance progressive controller)
TEC GT ems with upgraded coils (coils located by brake vacuum booster & master cylinder)
Battery relocated to passenger bin
Greddy T78 turbo kit
Greddy Elbow
3” exhaust from turbo back (Borla resonator, HKS catback)
1680 secondary injectors
720 primary injectors
SARD FPR
Aeromotive Tsunami fuel pump (in tank)
HKS SSQV BOV
HKS EVC IV boost controller
Short Shifter (came with car, not sure of brand)
PLX DM100 gauges x2 – modules for boost, wideband AFR, oil pressure, fuel pressure, water temp, oil temp, AIT
Taylor 8mm spark plug wires (made them myself, actually turned out really nice)
Eliminated AST
Koyo Radiator w/ stock fans

New setup requires the following changes:
Power Steering delete – the supercharger is going to be placed where the power steering pump used to be, so I found a good used Maval manual rack (thanks Allrotor)
Oil Filler neck – this needs to be modified and routed to the rear of the UIM, as the rear of the supercharger takes up all the room in the neck’s stock location.
Most likely a rebuild too

[RX SE7EN]

Stock power steering and A/C bracket:




Cut, Cleaned, and Squared:




Aluminum mounting plate, there are two of these, this one is fixed to the bracket. The other is larger and is what the supercharger will bolt to. This bracket is only tacked together, now that I know it fits, we're going to weld it up and also add some gussets to strengthen it.






Test fit:




The larger plate (for bolting the supercharger down):


Supercharger: close to its final place, I need to trim part of the throttle mechanism bracket on the throttle body, but things are lining up nicely:

Not much room but it looks like it'll work!

[RX SE7EN]

Here is the modified bracket, it now has 4 gussets to make it strong:
Check out these welds, I owe a HUUUUUGGGEEEE thanks to TitaniumTT, although he mostly lives on the "other" forum. I need to duplicate this over there.


I cleaned and cleaned, and baked and baked, but I think because this piece sits under the power steering pump, and I've had leaks before, the cast aluminum just soaks up so much oil and grime, making it a little tougher to weld, but it came out really nice regardless.


And I got a big package, with 6 little packages inside
Piping!!!!! - 2.75" diameter, 2x18" straight pieces, 2x45 degree bends, 2x90 degree bends:




I've also modified my throttle body throttle linkage to give me a little more room. I took off the cruise control linkage, and moved the normal throttle linkage into its spot. The little bushing that holds everything in place came apart really nicely (it's just pressed together). Then I swapped the outer throttle cable holder to the inside where the cruise control cable linkage was. Now I just need to cut off about an inch from the small bar that the spring butts up against, this will give me room to slide the supercharger back just a hair.

Throttle Body (you'll notice it's there is only one piece to hold a thottle cable, which now sits where the cruise control cable hookup used to be):


Close up & removed cruise control cable hookup:


Piece I need to cut about 1" off of, which will give me just enough room for the inlet to the supercharger. This is what the spring that springs back the thottle valves loads against.


sorry for the poor Iphone pics

[RX SE7EN]

Check this out!!!

Finally got the baseplate welded to the bracket. Absolutely amazing looking (well I think so anyways).

Again, a huge thanks to TitaniumTT for the great welds.

Now all I've got to do is mount it, line up the pulleys, and then drill 4 holes in the plate for the supercharger to secure the supercharger through its stock mounting holes.













After its bolted down and secure we can start fabbing up the piping

[TitaniumTT]

Sweet! Finally you made it over, awesome! Glad to help people that appreciate it, ya know? So yeah, welcome to RCC, you won't have any negative critismn over here, we don't roll that way.... but check out post number #4 though... copy/paste got ya I don't mostly live on the other forum, they perma banned me again because I am of no value to the community apparently

You said send it out for a rebuild... I thought you were talking about the engine at first! Got me worried you found something out before we did the obligatory comp test.... which as someone pointed out to me last weekend is just like an AIDS test, you want to know, but do you really wanna know?

[RotorDad]

I saw this on the other forum & I'm glad you decided to share the build over here. I remember I had mentioned the idea of twin charging over there & all I received were negative comments. Very interested in seeing how the build progresses goes for you.

[djmtsu]

Looks like good stuff! Brian, help him get this to DGRR, as long as it doesn't make your FC suffer!

I am fond of all the liquor in the background of nearly every pic. Win.

[vex]

wait... I'm confused... Are you compound charging it using a twin system, or are you going to be doing some crazy valve work and using the turbo's separately from the super?

(In other words are you going to be running the super charger pressure into the turbo's or the turbo's pressure into the super, or are you going to be running them at the same time and which ever one is running the higher pressure you'll be using)

[RX SE7EN]

The flow will be:
Clean Air -> Turbo -> Supercharger -> Throttle Body -> UIM

I was originally going to have some valving, allowing the turbo to bypass the supercharger at high RPM, but have since decided to keep them in series (compounding) all of the time. Once I have it working, then I'll do some R&D to see if I can come up with a bypass system. I've got a good design for it, but time constraints and cost will keep me from exploring it for a little while.

Your confusion may have been caused because I copy/pasted my old build thread from the other forum, and skipped a lot of the discussion around which routing combination to use. My research concludes that compounding the turbo into the supercharger is absolutely better than vice-versa. I do like the idea of a bypass system (would really come in handy if I decide to use a smaller than stock supercharger pulley, so i can almost over-rev the supercharger by 6k rpm engine speed for even more boost down low and then let the turbo take over). But that can wait until I have a basic system that works.

And I swear I'm not an alcoholic. My kitchen table triples as a liquor cabinet and car part picture taking stand haha.

[My5ABaby]

I'm really interested to see where this goes. I'm pretty sure if it's finished for DGRR I've got dibs on a ride. Maybe the same deal I've got with B...

[vex]

So how are you going to cool down the compound charge? It would seem to me that the increased pressure would cause a slightly warmer intake temperature (PV=RT and all).

[RX SE7EN]

A few different ways:
1. the wastegate on the turbo will be opening earlier due to the compounding multiplier effect that the supercharger will have on the turbocharged air. Meaning the turbo will actually have to do less work in order for the engine to see any desired PSI. And since the supercharger alone will never produce more than 10-15psi (due to pulley sizes), the turbo wastegate will regulate all boost above those levels by reducing turbo CFM (allowing more exhaust air to bypass the turbine).

2. Intercooler. My above post is flawed, sorry about that. the true flow is this:
Fresh Air -> Turbo -> Supercharger -> Intercooler -> Pipe to throttle body (methanol added) -> throttle body -> UIM.

3. The methanol mentioned above will also reduce heat

[prrex4ever]

Looking forward to seeing the final results, looking good.

[vex]

Don't let Peter see that...