2023 GT Premium - My Twin Turbo Build

[NGOT8R]

@AcceptableNebula I‘m going to compile a list of questions this week. I’ll PM you, so as to keep your thread uncluttered with my questions. If you would, please BOLO for it. Thanks

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[AcceptableNebula]

The front GT350 conversion was a bit more involved than I had planned. The aluminum knuckle was the draw all along, and the other pieces were just necessary to have it. Radial mount front calipers ended being great since the rear Dark Horse calipers are also radial mount. Two years ago when I bought the front parts, converting the rear to DH wasn’t even a thought (nor did it exist).

Unfortunately, a lot of parts listings are incorrect for the GT350. All the numbers I had come up with actually didn’t fit the aluminum knuckle. I had to work with Quirk Parts in Boston for the numbers, and even their Ford system did not have part numbers available for the tension links. I had to look through part numbers and guess at the correct part based on description. Fortunately my guess was correct. Tie rod ends are specific as well even though a lot of listings show the MEF314 as correct but it’s not.

Since the front lower control arm for the GT350 has a bearing instead of a rubber bushing, the ginormous tension link bushing would be the only rubber bushing in the car. So I elected to ditch it for a Cortex spherical bearing. I won’t didn’t have time to make these front bearing spacers over in titanium but it’s hot on my list after I rebuild the transmission and get the car aligned.

The 15.5” rotors definitely fill the 20s a lot better than the GT 14” setup. I am not a fan of the one time use bolts, so I ordered a set of stainless caliper studs from OPMustang.com. Hopefully I can find a correct stud for the rear ones.

For those wondering why there is a steel rotor in the picture, this thing needs a serious alignment. I am going to leave the steel on until all the work is done. I don’t need an “oops my wrench slipped, and broke your rotor” story.

 

[AcceptableNebula]

Well it’s back together and somehow it actually drives down the road straight. I may shim the front up a touch as I think it’s a bit low. Overall I am pretty happy with the stance as a straight line car. Now it’s time to take it back apart and do the transmission.

 

[AcceptableNebula]

Before taking the transmission apart I bought another CDF drum and P3 planetary so I could open up the fluid holes. The lube circuit pressure has slowly been bumped up by Ford over the years, but the holes never have. I’m fairly certain the 23 got the latest pressure update, however, getting more fluid thru is a good thing. I decided to slot the holes so I wasn’t limited to a drill size of the engagement area. These slots in the CDF drum are now 75% larger than the originals. The P3 got the drill bit. Not for any scientific reason, I just got sick of picking up the holes and slotting them. The drum holes were 6 degrees apart but a random number of seconds after the 6, so I couldn’t just plot the next location. X axis measurements were spot on but rotary didn’t pan out for me. So by the end of that I was done with slotting. The P3 went from 0.110” to 0.149”.

The E and F clutches definitely were taking it to the face. The steels are lighting fluid on fire from the launch. Since 502 miles were stock, and it has 844 miles now, one can only conclude it’s from the drag strip. My guess is it’s from the fluid pulling away from the stock filter and it’s starving. Could also be some slippage from not being able to hold the power.

I decided to put the Ratiotek PRX shift kit in the valve body. I spoke with Steve Younger on the phone, and after just a couple seconds I could tell he has been doing automatic transmission work longer than I’ve been out of diapers. He had a lot of good suggestions and others on here have spoke highly of his kit. My friend got his PRX kit installed a couple weeks before we took mine apart, and is very impressed with it. TCC engagement is very firm but overall it’s solid. Also threw in the Sonnax clip supports. The Ratiotek kit also adds a shim to bump up the pressure of the main pump.

Since the GPZ clutches need almost double the clearance of the stock clutches, you’d think in the Stage 2 kit you’d get the correct snap rings. That isn’t the case so I need to get the smallest snap rings for the C D and F clutches. I’m 0.020” off from the minumum GPZ clearance on the D clutch. I have to hunt them down tomorrow.

Since I had some time, I put in the MMR rear main holder, Suncoast SFI flex plate, and the OPM caliper studs on the GT350 calipers. Threading bolts in and out on aluminum knuckles is not good so hopefully these last for a while.

 

[AcceptableNebula]

Included a couple pics of the rear suspension completed.

 

[NGOT8R]

Included a couple pics of the rear suspension completed.

Looks like you’re gonna be ready for some 1.3 short times real soon. That’s the first set of rear springs that I’ve seen with isolators every other coil. Did those come like that or did you just decide to add them?

 

[AcceptableNebula]

Looks like you’re gonna be ready for some 1.3 short times real soon. That’s the first set of rear springs that I’ve seen with isolators every other coil. Did those come like that or did you just decide to add them?

They came that way from Eibach, as drag springs. They stagger and protect all 4 shorter coils. The 1st 4 coils are tight and are nearly touching when the car is on the ground for road driving. The bigger 4 coils absorb the squat nicely when launching. Granted I was launching at 1800 rpm with the stock converter like a N/A Mustang with no IMRC. The new Suncoast Pro-Loc is stalled at 3400. If I don’t like it, I can change the stator myself as it’s bolt together.

I bought the Eibach springs as they are literally just a spring company, so I assume they know their stuff and more importantly they were grey. Couldn’t have a regular red on a rapid red car.

 

[HKusp]

When you get bored with this build, I'm going to buy it from you, for pennies on the dollar....

 

[AcceptableNebula]

Had a little time today to tinker. I took the output flange off the transmission as it looks like a herpes sore. It’s amazing how much get painted on a car but others just get left raw to rust.
A quick sandblasting and some Cerakote fixed that.

Since I had some left in the gun, I coated the first brake hose bracket replacement. There are 2 permanently attached steel brackets to the brake hose after this one, so I can’t see any scenario where this bracket needs to be steel.

 

[AcceptableNebula]

I took a cruise over to Lamoureau Ford in East Brookfield. Fortunately, the guys there have done parts for a long time. It took him about 15 minutes to cross the engineering numbers over to actual replacement part numbers. More importantly, when they arrived on Wednesday, all 3 were correct. I have attached the part numbers for the thinnest snap rings for the CDF drum in case anyone needs them.

After checking the clearances with the new snap rings in the CDF clutches, the rest of the transmission could be reassembled. Lining up the squares helps keep the assembly in balance. Suncoast sent me one of their new design filters that should help keep the inlet of the filter in the fluid on launch. Not much needed to be changed as everything still looked unused inside. The original shell was not anodized, so I’m glad I bought one. My assumption was a 23 would have it already.

I decided to put on the PPE transmission pan on for now until I come up with something better. The thing weighs 12 lbs and doesn’t offer much of an advantage. I emailed PPE asked if I could mill down the insanely huge heat fins off the bottom. They claim it is part of the structural design of the pan and can’t be reduced or removed. Without knowing the loads the pan sees, I just left it alone. I did like the idea of something massive and strong bridging the massive opening in the case. I’ve also seen a couple of the plastic pans begin to warp and distort. The LS/LT platforms use the oil pan as part of the structural design. The GT500 also has a cast aluminum oil pan instead of a plastic one.

I was able to foot brake the converter to about 2400 with the wheels off the ground and just the rear brakes holding. I may need to run a 2-step to push it any further. After I adjust the tune for the the valve body kit and higher stall, and more importantly get a very thorough alignment, I’ll do some street testing on the transmission.

Now that the car is together in basically the form it will be in all year, I threw it back on the scales. The steel rotors on the car are about 5lbs heavier than the GT stock rotors. So 20 lbs there, about 8 lbs from the boat anchor transmission pan, and some weight from the ebrake calipers. The net was about 45 lbs heavier than this time last year. I did also install the roll bar but the spare tire was in the trunk last spring so that’s a basic wash. The Suncoast Pro-Loc converter is considerably heavier than the stock unit. The carbon rotors will take more than the 45 lbs off the car in the best place possible. Posted weights without and with me in it. The numbers are off a touch as there was 13lbs in stuff in car I forgot to take out.

 

[Epiphany]

Very nice.

 

[Whitedevil95]

What a fun build to follow! Looking forward to some updated drag strip times!

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