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Seven Years in the Making.

9K views 51 replies 12 participants last post by  Funktacular 
#1 · (Edited)
DISCLAIMER: I'm brand new to this stuff. If I'm dead wrong on any of this, I am more than glad to be told so. Don't pull any punches, and feel free to tell it like it is. I'm looking for a productive conversation, I'm not looking for a bunch of people to agree with my plan and tell me I'm awesome. If you disagree with any of my poorly-built theories, please tell me, and tell me why! I'm excited to do this, but I'm more interested in doing it right than anything else.


I've been waffling from option to option in terms of what I wanted to do with my Focus once I had the funds to get serious with it. I knew I wanted a high-quality and aggressive suspension set-up, which I now have; but I've been unclear on what I want out of the drivetrain. I know don't want extreme power, and I do know I want to keep it FWD. I've considered a high-compression 3.0 Duratec with individual throttle bodies, I've considered a high-compression 4-cylinder with ITBs, I've ever considered putting a built 2.0 in the car because I like the way they rev. For years, though, I've been certain that turbocharging was not the path for this car.

I guess at this point, I'm sick of waiting around to make up my mind, and I just want to get the car where I'd like it. Plus, I've now got TWO other cars I can chase my natural aspirations with (HA! GET IT?). So, I've made a deal which will be pointing my Focus in the direction of forced induction by way of a FocusSport (yes, it's old) turbo system. I found a low-mileage setup with a 28R and water-cooled conversion for dirt cheap, and have decided to pull the trigger. The system has right around 30,000 miles on it, and the seller is confident that everything is in perfect working order. Considering who fabricated and assembled the system, I have a hard time doubting him. Now for the current specs...

2006 ZX4 ST, 2.3L Duratec MTX-75
FSWerks Stage 2
Garrett GT28R (for sale once I have it)
Moving to a Garrett GT28RS (Disco Potato) before install
Bosch 42lb injectors
Water/oil cooled
Standard wastegate
Standard 2.5" downpipe
My own 2.5" mandrel-bent exhaust with only perforated-core resonators, no baffles
Bailey Motorsports diverter valve
GReddy Profec-B electronic boost control
AEM wideband o2 sensor
Torsen LSD
Exedy Stage 1 clutch and lightweight flywheel
SCT XCal 3
205/40-16 Falken Azenis RT-615Ks which are in big trouble once the car is running

The car:



The uses:
Occasional street cruiser: The car is no longer a daily driver and will be driven only in nice weather.
Autocross: Track days/nights are seldom and expensive. I will be filling in the time between them with autocross.
Open Track: The car will mostly see Lime Rock Park and Thompson Speedway in CT.

My Preferences/Taste:
Autocross dictates that I have absolutely as little lag as possible. I occasionally co-drive a car that uses and upgraded turbo with an inlet restrictor (class rules), and lag is an issue. As much as I adore the car, it is downright infuriating in tighter courses. Open road courses and street use do not make lag as dramatic as autocross does, but I'd still like it to be virtually undetectable in these situations.

The Long-Term: I will be installing everything as-is with the GT2871R so that I change the fewest variables as possible before I get the car running with boost. This will make tuning as simple as possible for Raffi, and allow me to enjoy the car and get used to the power. Next winter, I will begin preparing the car for over 300whp, which brings us to the main reason for this thread...

I know that combining high compression and boost has been discussed at no short length on this forum, and would like especially to thank Bryce for his posts on this subject. My understanding of the concept has been greatly improved from what it once was (none at all) already, but I'd like to know more before I pursue this with my own car. I'd really like the static compression ratio of the car to be around 10.5:1 when I build it, and am looking to make somewhere in the neighborhood of 15psi with the GT28RS. My best hazard at a guess for power/torque with this is somewhere around 340whp and 310-330wtq with stock cams and intake manifold. Iv'e got a few questions, though...

1. Can we get into a discussion about how the Cosworth intake manifold affects the torque curve of a forced induction car? I understand how it works with natural aspiration, but I'm not familiar with how compressed induction changes this. My current plans, in the interest of building torque as early as possible, are to keep the stock IM. I'd be more than happy to be talked out of this.

2. High compression. I've briefly looked into this, and I think it is an interesting path to take in the name of preventing lag. When I spoke with FSWerks earlier this week, I was assured that their lowered-compression (9.0:1) builds have proven to be reliable and fun to drive time and time again. I agree, but I'm looking for something that is as responsive and torquey as possible. I was informed that with a bump in compression, a compromise in timing would be their preventative course of action, leading to a possible nullification in peak power gains seen by a bump in compression. I am okay with conservative timing lowering peak power, but will it also negate my proposed gains in responsiveness? Please excuse my ignorance on this subject.

3. My current plan is to use either Cosworth or Carrillo Super A-Beam rods simply for the sake of using the best equipment possible. The Eagle rods offered by C-F-M do bring up a very interesting question, though. Are the others, which are 3x the price of the Eagles, truly worth the added cost in my application, or are the Eagle rods already excessively strong for a 330-370wtq application (I'd liek to give myself some room for growth if I decide to up the ante)?

4. I am confident that I will be able to make the Exedy Stage 1 clutch last at least through next season, as I drive in a pretty conservative manner. I don't power shift, I seldom drop the clutch, and I know how to rev match properly. If I decide to change the clutch in the future, is the Exedy Hyper Single pleasant to use on the street? The car will be seeing a lot of track use, but I still want it to have some damn manners on the street,

5. Ricer Question: Above all, I want this car to be fun; a overall visceral experience. If I can safely tune the car to make fire as much as possible, I'd like to do so. This isn't a show queen, but I will admit that a vehicle shooting fire on overrun will legitimately make me cackle. Ray's tow vehicle shoots 2 and 3-foot fireballs out of the side exit routinely, and there's pretty much nothing on this planet more enjoyable. It is to my understanding that if the car is tuned to be a bit lean on overrun and a bit rich on tip-in, fire will be encouraged. Is this true?


Proposed engine build: Here is what I'm thinking will net solid results and an enjoyable drivetrain. If you see any issues with this, please let me know what you would do differently. I'm open to any input!

-GT28RS
-3" turbo-back with wastegate exiting into downpipe
-Carrillo Super A-Beam or Cosworth connecting rods (will the Carrillo rods come with bearings?)
-Ranger crankshaft
-Cosworth main bearings
-FSWerks 10.3:1 forged pistons
-Head skimmed .030"
-Siemens 60lb injectors
-Stock camshafts
-Stock valves
-If applicable, upgraded valve springs
-ARP fasteners throughout
-Either stock or Cosworth intake manifold
 
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#41 ·
Stock is a TTY, like 30ft lbs then 90 degrees or something. Works out to be fairly low. At least that's my exp with the SVT and Zetec blocks. Dura's might be different. Going with ARP studs you change the torque requirement anyway since it's a different material and the 'spring action' of the head bolts requires more clamping force.

To be honest tho, i'd just go with what jared said, he's got loads more experience than i do on this. FWIW my XR's torqued to 85ftlbs on the head studs.
 
#42 ·
http://arpinstructions.com/instructions/151-4204.pdf

ARP recommends 60ftlbs, we have been going to 80 which seems to push up the threshold about 50ftlbs of torque or so before the head starts to lift. Like I said probably not a concern on the stock motor since the bottom end should let go long before you lift the head.
 
#46 · (Edited)
The Coupe had a GT28RS installed when I bought it from FSWerks back in 2010, I believe, and man did I love that turbo. Virtually no lag, low end torque, just a fun powerband to have on a car with a stock engine. The car only made about 220whp but man was it fun!

Once I got a hold of a tranmisson with a Quiafe LSD it turned into a different monster. Handling was excellent and tire spin decreased dramatically. I never installed the Cosworth intake manifold I bought for it but I wish did.

I agree though, you should get a Cosworth manifold.
 
#47 ·
I'm just catching up on this thread...

Remember that a smaller turbine wheel doesn't always mean faster spool. A bigger turbine wheel with better geometry and efficiency can out-spool a smaller wheel that's more restrictive. The GTX2867R .82a/r and GTX3067R .63a/r will have little difference in spool time. If one is faster, it's the 30r. Yet, the GTX3067R will have much more potential in mid-high rpm due to the less restrictive hot side.

I also disagree with the bashing of the other brands. I recently witnessed a brand new GTX55R Garrett compressor wheel come apart on the 3rd pass on an Outlaw 10.5 drag car. I also know of another Outlaw 10.5 car running twin Precision turbos for 5 years now with no issues, including 2 class championships. Now I'm not saying that Garrett is bad, just saying that every brand has lemons. These other manufacturers have had issues when they first began due to the learning curve. They've learned and come a long way since those days. Nevertheless, you're gonna find brand loyalty anywhere you go.

Put a Cometic head gasket on it with ARP studs and tighten it to 75-80lbs. Done.

If you want to improve low rpm response with whichever turbo you choose, grab a set of adjustable cam gears and adjust your stock cams down to a 108 or even 106 LSA with a 104 to 102 ICL. This will increase dynamic pressure and response down low. Just be mindful that it will also decrease piston-to-valve clearance, increase overlap (though not enough to cause harm with the stock cams), and increase the liklihood of detonation.
 
#48 ·
Currently in the air between a Stack wideband gauge and the AEM UEGO. I like the Stack's aesthetic better, and I really like th eidea of having a high-quality part that isn't seen in every car on the planet; but the UEGO's ubiquitous use in the states combined with strong reputation are a very good argument in its favor.

Does anyone have an opinion on the two in comparison to each other?
 
#51 ·
-Charge pipes are in
-Turbo is mocked up (waiting on gaskets)
-Tune file is on the way
-A/C is removed

This week:
Start the car on test file
If it starts and idles, we will then take it up and down the road once or twice, then do the transmission/clutch.
Once the trans is done, we tune it for WOT at 12 and 15psi

After the tune is done:
I get it home and start building the splitter, rear seat delete, and hopefully have enough time/money left over for the front seats and trunk spoiler

Should be an interesting push to FR, but I think I'm in good shape. We'll see!
 
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