TT 351W Engine Pictures
I am adding this page as a reference to those who may be interested in duplicating our efforts on the Twin Turbo Capri. It is not a difficult system to build but slightly time consuming and requires some patience (but then again what doesn't). The pictures here are from the capri after assembly and I will try to hit the most important parts of the build-up. If you have any questions or feel I have missed any pictures that you may be interested in feel free to EMAIL me.
The latest engine shot that I have from when the motor was still in the T-Bird, doesn't look like much, but don't let that fool you. The remaining pictures are all from the motor in it's new home - The Capri, more affectionately known as the Crappie.
Current Capri Parts List
1972 351W short block,
bored .030" over, crank cut .010/.010"
Federal Mogul / TRW Power Forged 27 cc dish pistons.
Resized 1972 351W Truck Rods, stock "football" head rod bolts.
Oil pan and pickup from a 351W Crown Vic.
Trick Flow Twisted Wedge Cylinder heads 2.02 int / 1.60 exh. FLOW TEST
Crane 1.6 ratio roller rockers (optional)
2 - Garret TO3s from 85-86 5-speed Tbird TCs .63 A/R, if using 302 short block use turbos from automatic TCs, .48 A/R.
Crane camshaft (216/228 @ .050" duration .484/.512" lift)
Stock 83-85 mustang holly 600 modified for mechanical secondaries, any double pumper w/solid floats is fine.
K/N carb bonnet/plenum. (most expensive part on engine, $99)
Performer intake manifold, or whatever is free or cheap.
BBK 5.0L unequal length shorty headers, flipped upside-down and elongate bolt holes to align header with exhaust port.
1970 C-4 transmission, 10" 3000 RPM converter, TransGo shift kit #60-2.
Home-made solid motor mounts.
Carter street/strip 100+ gph, 9psi, mechanical fuel pump, modified for boost reference.
A pile of PVC pipe for intake piping.
Barb connection fuel injector for additional fuel under boost, and adjustable pressure switch.
High pressure in-line ford truck pump, and pressure regulator.
Just recently a friend of mine opened the hood of the capri to show it to a few bystanders - one of the comments I noted was "this cobbled together piece of crap would be lucky to run 13's...". Well that statement is about 50% correct, it is a cobbled together piece of crap, but a 10 second one. Looks are not everything as you are about to see, but if you spend the time to do some research and have a good plan it is quite surprising just how fast you can go for just a little money. A good place to start is with a book called turbochargers by Hugh McInnes and published by HP Books. You can find this book at many automotive/aftermarket stores and it is full of slightly dated, yet good turbo system design information. Read it from cover to cover - twice - then start building.
Amount of money currently invested is less than $2800, parts/machine work only of course! This including purchasing the motor / trans and all related parts to make this capri run in the high 10s. Hopefully we will be able to get an 8.8" rear and our intercooler installed for less than $200, could this become a 9 sec, $3000 car? (highly illegal though, safety stuff is expensive and we are only legal to 10 flat) We already have enough power/MPH to run low 10s with a little more traction, next spring we will see!!!
Please excuse the dirt on the vehicle, this car is driven regularly and not trailered - mainly because we have neither a truck or a trailer. We do try to wash it regularly though.
The first shot is just a view of the entire engine, notice the distortion of the PVC supply piping. 14.5 psi is just a little too high a temp for the plastic pipe as well as a little tough on the connections (notice the last minute zip ties to keep it connected to the bonnet), steel will replace all supply tubing this winter. Just a little note here - with 14.5 psi that 4" connection to the bonnet sees a 182 lbs of force at full boost.
These two pictures contain a view of the passengers side of the motor. The exhaust supply to the turbo consists of the BBK header and a connecting pipe. The connecting pipe is just plain steel 2.25" exhaust pipe. Stainless steel would be the preferred choice but this tubing has held up well over the last 4 years.
Here is the drivers side exhaust supply system. The flanges that connect the pipe to the turbo were produced by me but can now be purchased for a reasonable price from Turbo City. Notice the water lines for the cooled turbos. I don't feel cooling is necessary in this application with the turbos out in the front of the motor, and if I was to do it again I would not plumb the turbos for cooling water, would make for a much cleaner installation.
This is the switch we use to turn on the additional injector under boost, currently set at 4 psi. When this switch activates the injector just runs at 100% duty cycle, with no pulsing. The injector is necessary to be used at higher boost levels where the carburetor is not capable of supplying the necessary fuel. While this system may sound quite crude, it works quite well with a blow thru turbo system. Turbos have the handy ability of a quick transition from no boost to full boost in a very short period of time. It is only during this transition time that the fuel curve on this car is less than very good (notice I did not say perfect, it is still a carb). Once full boost has been achieved, charge density remains mostly constant across the RPM range. Simply put, the injector adds the fuel necessary for the increased air density (boost) in the manifold, the carb handles the chores of supplying the fuel across the RPM range. Boost does not change the volumetric efficiency of the engine (remember I said engine, not system), it will still ingest the same CFM naturally aspirated or turbo charged, but the turbocharged motor will have more mass per unit volume (density) than it's counterpart. Once full boost is reached and is more or less constant, the injector supplies just the necessary constant fuel for the increased density. the A/F ratio of the Capri remains at 12.8 to 13.0 from 2500 - 5000 RPM.
In these two shots you can see the
modifications necessary to the mechanical fuel pump. Basically a fitting is
threaded or epoxied in this case to the atmospheric vent on the side of the
pump. I added two in this case to ensure adequate pump operation at high RPM.
The other end of the hose is connected to the bonnet, BEFORE THE CARB, this
is required. With this modification fuel pressure to the carb is increased
1 psi for each psi of boost to maintain fuel flow into the carb under boost.
This can also be done with a high pressure electric fuel pump and a boost
referenced regulator. Also seen here are the turbo oil supplys from the oil
sending unit location in the engine block.
The shot on the left shows the compressor on the passengers side from looking at it from the drivers side. This is the location that I chose to install it, you can be quite creative and install it just about any way you want to as long as it remains horizontal and you "clock" (rotate the housings) as necessary to keep the oil inlet on the top and the drain on the bottom. The oil return on turbos is gravity fed so it is necessary for the turbo oil outlet to be above the oil level in the oil pan, otherwise you will have to add a scavenge oil pump to pull the oil out of the turbo and pump it into the oil pan. The photo on the right shows the path of the pressure supply tubing across the front of the vehicle, into the Y where it meets the other turbo's outlet and travels to the bonnet.
In these two photos you can see where I installed the turbo oil returns, this is the drivers side return and the other return is located in the exact same spot on the other side. Most important things to remember about the oil returns is to install above the oil level in the pan , which is at the top of the section of the pan which passes over the steering rack on the double hump pans. Be sure to maintain a downward slope across the oil return line fron the turbo to the pan.
Here are two shots of the bonnet we are using, it is made by K&N, and costs about $100. This was the lowest profile unit that I could find so the system would fit under the hood of the bird. The choke horn has been milled off or the Ford/Holley 600 CFM carb to allow for additional clearance in the bonnet, and just recently the bolt holding the bonnet to the carb was drilled and tapped to accept a 5/16 stud. The stud sees about a 345 lb load under 14.5 psi boost so the smaller stock 1/4" stud should have been adequate (safety factor of 2.6), but it did pull out, it is highly possible that we may have overtorqued it a time ot two though.......
Here is the injector we are using. It is mounted in a brass compression fitting which is threaded and epoxied into the plastic supply. It is about a 30 lb unit with a barb hose connector on the end. When adding injectors to supply piping the correct position is perpendicular to the airflow, basically aimed at the other side of the pipe. As for location in the pipe, it is necessary that the injector is located after the intercooler, if so equipped, but as far from the bonnet or throttle body as possible, granted that there is no place in the system after the injector that the fuel can puddle, creating a potential bomb. The further the injector is located from the intake manifold, the more advantage you have of cooling the charge by extracting the latent heat of vaporization from the fuel.
Shot on the left is the drivers side compressor as seen from thru the fender well. Located just behind the compressor is the radiator coolant catch can. The picture on the right is showing the location of the high pressure fuel pump regulator in the drivers side strut tower, this adds a nice firewall between the fuel system components and the hot turbine housings and associated plumbing. I cut the regulator mounting pad and associated regulator plumbing from a stock turbo coupe fuel pressure regulator then added fittings as necessary. Any high pressure in line fuel regulator would be adequate for this application, but the price was right on this one. We are currently using the capri's stock fuel line as the regulator return to the fuel cell, all fuel supply lines to the engine are 1/2" aluminum lines.
Just a view down the passengers side exhaust system.
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