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Different Take on a V8 Swap - Duder's 4.6L Twin Turbo 245

The most offset I would be comfortable running with the rears would be 25mm, 13mm might be okay. Any less and you will need a considerable amount of pulling (this is basically to get the same amount of fender clearance as myself, assuming you move the axle forward 3/4" for extra clearance like I did.
 
The most offset I would be comfortable running with the rears would be 25mm, 13mm might be okay. Any less and you will need a considerable amount of pulling (this is basically to get the same amount of fender clearance as myself, assuming you move the axle forward 3/4" for extra clearance like I did.

Cool, yeah. I have talked to both Towery and Homer about this very situation, and I think something like a 5mm - 7mm spacer with these wheels, giving ET6 - ET8 might work, with shortened trailing arms and some fender rolling. Of course the hubs will need to be redrilled to 5x120 to make this work (sub-10mm adapter thickness technology is not yet mature).

Towery: "I ran 9.5" ET38 with 35mm adapters on the rear, so ET3 effectively."
"On the inside of the rear wheel wells, it seems to narrow towards the front. I had some rubbing along the inside, mainly forward of the shock. I also had rubbing on the trailing arm."

Homer: 245/40R17, 17x9 ET6, "If the axle were perfectly centered I'd have ~17-19mm of clearance between the widest part of the tire and the inner fender. I've heard it rub a handful of times only on nasty articulation."

With these 17x9.5s and 255s I might have to pull the rear quarters out, and of course trim or roll the lip a bit. But I feel like there is a solution.

I used an online calculator to visualize Homer's setup (left) vs. what I'm looking at (right). It says I'll have 7-8mm less clearance on the inside, and 3-4mm less on the outside.

 
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This is my go-to calculator as well. It should fit OK. Redrilling the hub is most likely the way to go. That mentioned, I would personally go with studs that use smaller shanks than stock. They will get awful close to the hub's outer edge.
 
Maybe some scope creep here, but this sounds like the time to Ford 8.8 that bad Jackson if it wasn’t already mentioned.

This has quickly become one of my favorite builds on the forum. I can’t wait to hear the lump fire up, ima Chevy guy if I had to pick, but those Ferds sure do sound good!
 
Maybe some scope creep here, but this sounds like the time to Ford 8.8 that bad Jackson if it wasn?t already mentioned.

This has quickly become one of my favorite builds on the forum. I can?t wait to hear the lump fire up, ima Chevy guy if I had to pick, but those Ferds sure do sound good!

Heh, thanks. Not really scope creep; I'm not expecting the Volvo rear to survive at 500whp, but maybe this will be a later phase of the project.

8.8 and 9" are on the consideration list. And then part of me wants to investigate an IRS swap to E39 or something similar.
 
Heh, thanks. Not really scope creep; I'm not expecting the Volvo rear to survive at 500whp, but maybe this will be a later phase of the project.

8.8 and 9" are on the consideration list. And then part of me wants to investigate an IRS swap to E39 or something similar.

YES.
 
Heh, thanks. Not really scope creep; I'm not expecting the Volvo rear to survive at 500whp, but maybe this will be a later phase of the project.

8.8 and 9" are on the consideration list. And then part of me wants to investigate an IRS swap to E39 or something similar.

:wtf: Toyota IRS? Fawk.
 
I hope no one's expecting insane rates of progress on this. You will be sorely disappointed if so. But I did manage to find some time to work on it over the past few days. Got the foam crap off of the upper firewall and cleaned it thoroughly, followed by more inner fender degreasing. Then today I pulled the Disco Potatoes (Patatas?) off of the Mustang cast manifolds and did a quick mock up in the 245.



This is more or less the turbo positioning that I'm thinking. Battery will go back in one of the buttcheeks, and I'll cut the OE tray out, so the driver's side turbo should sit a bit lower. Housing clocking angles are not at all defined yet. This is very rough. The angle is to promote free-flowing downpipe design straight out of the turbines, so they don't have to make a sharp bend directly after the turbine outlet (that's bad...mmmkay). Manifolds will be fairly straightforward. Logs facing forward, more or less in plane with the exhaust ports. Then some short up-pipe adapters between manifolds and turbine housings. The downpipes will be the most difficult part of this whole swap I think. There's plenty of room on the passenger's side, but not much at all on the driver's side due to the steering column. I'm thinking that the driver's side downpipe will have to run across the engine bay down low and then tee into the passenger's side. Either that, or maybe each side can sneak under the manifold...maybe.







On the compressor side the outlets will likely feed two separate intercooler cores. I think that's the simplest way to set this up. I might put twin airboxes and filters under the inner fenders, then run tubing up between inner & outer fenders and into the compressor inlets. What could be simpler!?!?





Another confounding factor is that this car will have AC. For sure. It's non-optional. The '05 Mustang has the AC compressor down low on the passenger side, which is fine in & of itself, but will restrict my available downpipe real estate for sure. Here's my planned serpentine belt routing below. I discovered the idler pulleys weren't on correctly for the past 10 years (remember this was a dumb show engine).



Still haven't done a hood test fit yet, but clearance is gonna be close or nonexistant to the rectangular throttle body mounting flange. I still may space the crossmember a bit under the framerails which will lower the engine and give me more hood clearance, not to mention space for manifolds and downpipes.



Next up is test fitting the trans to the engine, then determining fore/aft position and starting on motor mount design.
 
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I'm not a ford engine guy at all but the design that went into those manifold is very impressive and it's very cool that you designed it.

Should be a very cool build. Can't wait.
 
I'm not a ford engine guy at all but the design that went into those manifold is very impressive and it's very cool that you designed it.

Should be a very cool build. Can't wait.

Thanks! It seems like a lifetime ago that I designed those. I learned a lot about 3D surfacing in Catia through this project, that's for sure. Tried to emulate the OE manifolds in terms of runner size and routing, as much as possible. We 3D scanned the manifolds using a GOM "white light" scanner to get the port geometry and pierce points. The passenger's side downpipe was the biggest challenge - turbo position left us with super tight clearance to the firewall, hence the cobra head shape.
 
Got a bit more done yesterday. I mated the trans to the engine for the first time and was glad to see everything should work out. The trans is a T45 5-speed from a 1999 SVT Mustang Cobra, so it originally lived behind a 4-valve 4.6. I wasn't 100% sure that everything would play nice with the 3-valve, but looks good so far. I need to decide on a flywheel, clutch kit, and hydraulic TOB, but the main goal this weekend was purely test fitting engine+trans in the car for the first time, to start converging on a final engine position.

XzLOtixh.jpg


There were two bosses on the top of the bellhousing that I cut off due to interference with the tunnel. Otherwise it looks to fit quite nicely, indeed. Shifter location is just about perfect.

This T45 is kind of a forgotten trans, which is appropriate I think. From research I found that it is more or less a 5-speed version of the T56 internally. Externally it looks vaguely similar to a T5 but I'm told that it should be much stouter. Not sure how long it will live behind the megatorks from the twin turbo V8 but if needed I could build it up with upgrade parts. Or swap to something else entirely later on. I'm curious to give it a try though.
 
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I found this description of the T45. I've seen varying claims about torque capacity. I'm certain this thing will be underrated for the engine, just not sure by how much.

Borg Warner/Tremec T45
With the introduction of the mod motor 4.6L in 1996 came the introduction of the T-45 5-speed manual transmission. All Mustangs equipped with this transmission use an 10.5" clutch. The T45 shares many attributes with the T56, so it is a strong transmission. Its weak link is the 10-spline input shaft which limits power handling. 1996-98 Mustang GT T45 transmissions had an 8-tooth speedometer sensor drive gear and a forward located transmission mount. 1996-1998 Mustang Cobra transmissions had a 7-tooth speedometer sensor drive gear and a rearward located transmission mount. 1999-2001 Mustang GT and Cobra transmissions used an electronic pickup "hall-effect" sensor for the speedometer signal and all had the rearward located transmission mount. 1996-01 T45 transmissions use the exact same shifter as the T5. The 1-2 shift fork is shared between all 96-01 T45s. The 3-4 shift fork was updated in 1998 thru 2001 and is a common upgrade for 1996-97. The reverse fork was also updated in 1998 and there are three different versions available. Speaking of reverse, the T45 was the first Mustang transmission to feature a fully synchronized reverse gear. All T45 varieties use a ribbed aluminum case with integral bell housing.

Gear ratios for the T45 are:
1st: 3.37
2nd: 1.99
3rd: 1.33
4th: 1.00
5th: 0.67
Rev: 3.22

The T45 can be found behind:
1996-1998 Mustang GT 4.6L 2V V8
1996-1998 Mustang Cobra 4.6L 4V V8
1999-early 2001 Mustang GT 4.6L 2V V8 with transmission code 6
1999/early 2001 Mustang Cobra 4.6L 2V V8 with transmission code 6
early 2001 Mustang Bullitt 4.6L 2V V8 with transmission code 6

from: https://lmr.com/products/Mustang-Transmissions-What-Transmission-V8-Mustang
 

Thanks for the link. I've seen various numbers quoted between 330 - 400 lb-ft as the torque capacity but I suppose I'd have to talk with a Tremec engineer to get the straight story. From what I've read the 10-spline input shaft is the main weak point, and there's a higher spline count shaft available somewhere. This car will be more of a highway cruiser than anything; it won't be a drag car so I think I can get it to live for an acceptable period of time if I limit hard launches. Or just make sure I'm always on old, hardened rear tires.
 
I dug up one of our old dyno plots from my file archives, which I forgot I had.

It actually made less torque than I remembered. 487 lb-ft at ~4500rpm. This run was on a Dynojet so these are rear wheel numbers, but still, I'm feeling a little better about the T45's chances of survival.

8ziBUXc.jpg


You can see what a dog the 3-valve 4.6 was originally and how less than 10psi of boost really woke it the F up.
 
300 lb-ft was the rated capacity for the V8 Stang T5’s; 330 lb-ft for the aftermarket T5z. Suspect the way you want to use it, 3rd gear might be the weak point - it’s the furthest away from a support bearing. I’m 2 years/4000 miles into a 40k mile T5z in perfect condition behind a new crate LS3. No super sticky tires, no hard launches. Working just fine so far. Suspect the biggest unknown, assuming it’s unknown, is what kind of shape the t45 is in. Keep in mind, all these rated capacities were also linked to a manufacturer’s warranty. The trannys may well hold up to higher numbers, but not with a warranty backing them.
 
Love what you are building with this project. My brother and I have a project 67 MGB GT with a 289 swap in it. They used spacers on the crossmember to get that bit of extra clearance for things. Give yourself more room with spacers.
 
300 lb-ft was the rated capacity for the V8 Stang T5’s; 330 lb-ft for the aftermarket T5z. Suspect the way you want to use it, 3rd gear might be the weak point - it’s the furthest away from a support bearing. I’m 2 years/4000 miles into a 40k mile T5z in perfect condition behind a new crate LS3. No super sticky tires, no hard launches. Working just fine so far. Suspect the biggest unknown, assuming it’s unknown, is what kind of shape the t45 is in. Keep in mind, all these rated capacities were also linked to a manufacturer’s warranty. The trannys may well hold up to higher numbers, but not with a warranty backing them.

Good to hear this feedback from someone who's in the same ballpark, and point well taken about the official ratings re: warranty. I'm pretty easy on transmissions. Haven't managed to break one yet, even the silly old Super T-10 behind the LM7 in the Lemons car. My teammates broke that one :-P

Man that power curve is flat

Yeah I'll take 400-500 lb-ft from 3200 to 6200...should be sufficient for merging onto the 405.

Love what you are building with this project. My brother and I have a project 67 MGB GT with a 289 swap in it. They used spacers on the crossmember to get that bit of extra clearance for things. Give yourself more room with spacers.

That is in the plan now for sure. It will give me more clearance for manifolds & downpipes, hopefully will allow the hood to close, makes a bit more room in the tunnel and might even make the oil pan mods less severe, if I end up gaining any clearance between engine & crossmember. Right now I'm weighing pros & cons of mounting the engine to the crossmember or directly to the top side of the frame rails, incorporating the upper crossmember bolts.
 
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