S4Gunn's Split-port DIY & Lessons Learned
Q: Why do a splitport upgrade? For starters, a 99-04 Mustang is rated for 193HP/225lb-ft while the same 3.8L block in the 89-97 Mustang only made 140HP/215lb-ft of torque. Given that V6 Mustangs are plentiful, the parts are cheap so this is one of the best bangs for the buck you find find.
In my case, I needed a cheap yet reliable way to boost the HP of my 24 Hours of Lemons track car (they give you a residual after every race so I made my intentions clear to the judges). Plus, I also didn’t want to upset the weight & balance of my track car by dropping in a 302 engine because after 2 races, the suspension and brakes are quite well suited for my existing block.
The following post will document the lessons I learned in my upgrade of my 1995 Ford Thunderbird 3.8L from a single port to a Split-port manifold/heads for the 24 Hours of Lemons. This might not line up 100% with what you need to do but I’ve tried to compile ALL the information I’ve collected over the 9 months of this project so you should have a good idea of what you want to do for this upgrade.. Please also note that I use the term ECU and PCM interchangeably here.
Q: How much time will this take?
A: Since this is my track car and I didn’t have any future races committed, I took my time here. According to my records, this project took approximately 90 hours of my time on evenings/weekends for all the on-vehicle work and including several times when I repeated a step to correct an error and/or solve the problem in a more effective manner. All of this is documented below so a more talented mechanic should be able to bang out this project in a weekend or two with sufficient preparation (i.e.: finishing up all the fuel rail and intake manifold modifications in advance). The upgrade and extra fabrication for the Windstar intake and the tuning/analysis to figure out why the engine didn't rev beyond 4K RPM tool up another ~58 hours. Seriously.
: Project Complete. I finally tracked down my rev issue -- my ignition timing was screwed up. I'm now working on the cars "theme". Next upgrade: 4.2L (if I can find one) or 302 V8 (which introduces all sorts of new and exciting problems to solve).
LESSON LEARNED IN MARCH 2013
: This engine lasted 19 laps before blowing up. Before you dump a pile of effort into a splitport upgrade, consider what base block you are working with and how many miles are on it. My engine, a reman block with ~60K miles on it, did NOT like being rev'd to 5K RPMs repeatedly on the track and blew up in spectacular fashion. For your own piece of mind, consider refreshing the bottom end (i.e.: check tolerances, new bearings, new rings and re-bore if necessary). Had we refreshed our V6 block before tackling this splitport upgrade, our V6 would probably still be running and we wouldn't be trying to not blow up a V8 today.
BEFORE YOU BEGIN
Read up on the following threads. This will help you figure out what parts you should be looking for with your specific project. As you can see, there is a bunch of data online about splitport swaps but there are still improvements that can be made (SixPackStang's thread is probably the most comprehensive but still doesn't outline most of the "gotchas" for folks (like me) who have never tackled a project like this before.
4.2l Swap Article
-- for 4.2L swap but many of the principles are the same with a 3.8L Split-port swap.
I also collected the factory shop manuals for the related head gasket replacement procedures for both engine blocks.
- My instructions for the 1995 Thunderbird 3.8L came from my Ford Shop Manual. At the time of this DIY creation, you could find these manuals (often with the EVTM) for ~$15 on eBay.
- My instructions for the 2001 Mustang 3.8L came from the local library. With my library card, the Palo Alto library system gives you online access to EBSCO’s Auto Repair Reference Center (ARRC). It’s kind of like the Mitchell system independent auto shops use. Other libraries limit access to their physical libraries only so YMMV here.
- 2001 Mustang Split-port Heads: since these are aluminum heads going on an iron block, do yourself a favor and take them to a machine shop to have the bottoms honed flat before installation.
- 2001 Mustang Split-port upper intake manifold. Modifications suggested (see seperate section below).
- OPTIONAL: Over the course of my research, I also found out that the Windstar upper intake provides an improvement in heat soak (it’s plastic vs. aluminum) and airflow for an overall gain of ~7-15HP. See below for the Addendum.
- 2001 Mustang Split-port Lower intake manifold. Modifications required (see modifications section)
- ALTERNATIVE: 4.2L upgrade
- Advantage: While your HP won’t increase much, you will allegedly reach “near V8 levels” of torque without the weight penalty of a 5.0L engine (the V8 that will readily mate with my existing M5R2 transmission).
- From my research, I found that the 4.2L engine uses the same block but different crank, pistons, and connecting rods.
- Problem 1: you will need to muck with the block. I have a perfectly working 3.8L engine before the splitport upgrade. If I was going to muck with the block, at that point, it will probably be more cost effective in terms of time for me to buy an entire 4.2L engine and swap the engine over – leaving my original splitport engine as a “spare”.
- Problem 2: you need to find the parts and/or engine. I never found a good deal here.
- ¼” diameter solid Aluminum Rod to block off butterfly valves. I needed approximately 13” per side and I purchased this from Orchard Supply Hardware for ~$13.50
- 2001 Mustang Split-port Engine Wiring Harness:
- I needed the IACV and Throttle Position Sensor (TPS) connectors
- You may also need the fuel injector plugs if your harness plugs are different from your chosen fuel injectors.
- 2001 Mustang Split-port Fuel Injectors + Adapters
- There are two different styles of fuel injectors EV1 and EV6 – one’s fat and one’s skinny.
- You don’t care about the size as both are compatible with the Split-port intake manifold but the connectors might NOT be compatible as there are two standards: JETRONIC and USCAR.
- Using the 19# injectors over the stock 14# injectors was recommended to me because they have a spray pattern that matches the Split-port manifold; from my calculations it also looks like the 14# injectors are close to being maxed out in the original non-Split-port application.
- There are 2 adapters on the market -- hard plastic adapters or more homemade looking ones with exposed wires between the connectors. If you have the budget for buying adapters vs making your own, you might as well go with the hard plastic adapters. After all, you can always make your own adapters by splicing the fuel injector plugs from the Split-port harness to the car’s existing harness if you are encountering budget limitations.
- I bought the following (8pack) set of Jetronic to USCAR adapters (Ford Racing Part# M-14464-A8) from buyfordracing.com.
- Make sure you confirm that the adapters work for your chosen style of injector and harness (you don’t want to get adapters for the exact opposite of your application).
- Finally, In order to run 19# injectors in a car that originally shipped with 14# injectors, you will need to do an ECU reflash. I explained what I needed and Don @ Lasota racing was willing to burn me an SCT chip to match my needs and maximize the value for this Split-port upgrade.
- NOTE: This project will work with the stock ECU and stock 14# injectors from your old intake – you just won’t get the full advantage of the Split-port swap. In case you decide to stick with the 14# injectors though , here's a word of warning about the SK "injector rebuild" kit model SK57 -- the included pintle caps have the wrong sized opening. From what I can tell, they work with the 30# injectors that come with early SuperCoupes. I rebuilt my 14# injectors to use with my spare engine block and in doing so I needed to reuse my old pintle caps.
- 2001 Mustang Throttle Body, TPS, and IACV
- The Split-port throttle body is a different shape
- The Split-port TPS is mounted in a different orientation and has a different sensor. You need a TPS sensor that opens from 0-5V in a clockwise fashion (Windstar is CCW. You may also find yourself building an adapter place if the mounting holes are 90degrees offset (I did).
- The Split-port IACV mounts to the throttle body and not the intake manifold and has a different connector
- Split-port compatible Return Style Fuel Rail
- Original Tbird Fuel Rail: donates the Fuel Pressure Regulator (FPR) assembly
- 1 or 2 Splitport Fuel Rails. Going with two costs slightly more but saves you potential points of failure (see details below)
- Fuel Rail Buying Tip: when purchasing the fuel rail second hand from the internet, make sure to confirm if the seller will send you the fuel pressure sensor (FPS). Even if you won’t be using the FPS to regulate the fuel pressure in the system, you need the FPS to plug the hole in the fuel rail. Since I wanted to minimize the DIY points of failure in my fuel rail system, I had to go searching onto the internet for a replacement FPS for the one that the supplier of my second rail didn’t send to me.
- SpringLock to Barb Adapters: There are multiple ways to solve this Problem. I actually tackled it twice. In my final iteration (after I realized that outside of injectors and the ECU the fueling system is a budget exempt category in Lemons), I purchased the following:
- Ron Morris Performance Female Supply Springlock to Barb Adapter RM9141
- Ron Morris Performance Female Return Springlock to Barb Adapter RM9142
- (2) splitport compatible returnless fuel rails
- You will need good quality, SS hose clamps. I found that #4 SS clamps are available for ~$2 in “10pc contractor packs” from Lowes.
- Fuel Hose:
- You also need J30R9 fuel injection hose (vailable in bulk from Autozone). J30R7 hose is significantly cheaper and more readily available but is NOT rated for the pressures found in FI systems.
- Alternative: the “proper” hose recommended in other DIYs is to use Aeroquip FC332 socketless hose and fittings. That stuff is spendy so to keep with the spirit of the “24 Hours of Lemons”, I went with the J30R9 hose.
- Cost Saving DIY Alternative #1: Build your own Springlock to Barb Adapters
- Supply Line Springlock
- Female Springlock Connector from original fuel rail
- Steel Tube Nut model BLF-15C-5 from Autozone (sold in 5 pack): 3/8” Tube size, 5/8”-18 inverted thread size
- Female 3/8” Flare to 3/8” male Barb coupling (Orchard Supply Hardware)
- Return Springlock to Barb Adapter
- Female Springlock Connector from original fuel rail
- Steel Tube Nut model BLF-14C-5 from Autozone (sold in 5 pack): 5/16" Tube Size, 1/2-20 inverted thread size
- Female 3/8” Flare to 3/8” male Barb coupling (Orchard Supply Hardware)
- Cost Saving DIY Alternative #2: acquire one from a First Gen Ford Ranger
- A friend and fellow TCCOAer (jco1385) who followed my splitport build reported that you can find the very same return springlock to barb fitting I purchased from Ron Morris on a First Gen (89-92) aka "square body" 4cyl Ford Ranger
- You can easily cut this fitting off with some heavy duty snips and you can find it on the driver's side underneath the intake pipe towards the rear
- A 2nd gen Ford Ranger or one of the V6 first gens might have a similar fitting but I don't have confirmation of this so please go to the junkyard and if you find one, let me know and I'll update this DIY.
- Triple 3/8” male Barb Tee (ACE Hardware)
- See Fuel System Modifications Section for more details
- 2001 Mustang V6 throttle cable / accelerator cable
- This one threw me for a loop as I didn’t see it mentioned in other Split-port threads/DIYs.
- The end connector (how the accelerator cable physically attaches to the throttle body) is different) between my tbird and the mustang’s throttle body.
- The V6 mustang’s cable is also 36” and the tbird’s was 40”. A new one is only ~$30 if you look but please note that for my 2001 intake manifold and throttle body, I needed a cable specifically for a 2001-2004 V6 mustang.
- The mounting bracket is also different. I also had to purchase one for a 01 Mustang (came with my second fuel rail).
- 2001 Mustang Upper and Lower Intake Manifold Gaskets
- 2001 Mustang Thermostat Housing, 2001 Mustang upper radiator hose, and 2001 Mustang thermostat gasket.
- I was originally hoping to re-use the 95 tbird’s original upper radiator hose and thermostat housing because I had modified the upper radiator hose to allow for additional coolant injection under pressure (a lemony way to keep your car on the track with minimal pitstops if it starts consuming coolant). However, the original thermostat housing hits the coolant pipe that wraps around the intake manifold and the original molded cable won’t reach the 2001 Mustang’s thermostat housing.
- There are TWO upper radiator hoses at Autozone that will work for this application (Dayco #E72077 and Dayco #D71909). You want to go with the Dayco #D71909 hose as it places the radiator hose just a tad farther away from the tensioner pulley. After a few hours of driving, i found a groove in my E72077 hose that would have cause more serious problems on the track.
- Your old thermostat is reusable here but I found the thermostat gaskets to be a slightly different shape.
- O-rings for coolant hard pipes: I found two cooling pipe related o-rings that merit replacing:
- One was for the hard pipe that goes into the top of the waterpump. My waterpump actually came with the necessary o-ring.
- The second one is for the smaller hard coolant pipe that attaches to the back of the lower intake manifold. I found a compatible o-ring at Lowes in the plumbing section as the only ones Autozone carried with the necessary inner diameter were too thick. 1/2" ID, 5/8" OD, Size #28, comes in a 2-pack: http://www.lowes.com/pd_174733-72906...3137361&rpp=16
- Optional: Bypass the heater core with a 180 degree U-shaped tube to connect them. NOTE: one of the coolant tube openings is slightly larger than the other one. Dayco Part# B87629
- 1995 Thunderbird Intake Tube - modified
- More details below in the Re-Assembly Section
- 2001 Mustang Head Gasket Set
- Fel-Pro multi layer steel gaskets were recommended.
- Copper gaskets are apparently available but I didn’t explore this further as they are a) way outside the 24 Hours of Lemons budget and b) require decking of the engine block.
- 1995 Ford Thunderbird Head Bolts
- Buy the head studs/bolts that match your engine block – not the Split-port heads
- After 96, there was a change that was made that make the long studs just a little too short. I confirmed this by testing the length that the old head bolts protruded both the Split-port heads and the old heads while on my workbench. They were the same so therefore any change that merits a difference in headbolt length would need to be in the block.
- Alternative: Head studs
- Head Studs are available from ARP directly that work for 95 and older blocks.
- 153-4203 (12pt nuts)
- 153-4001 (6pt nuts)
- For 95 and older blocks, you can also buy the head studs for a "Chevy 2.8L V6" and save some money. They are identical and cheaper.
- 233-4303 (12pt nuts -- Chevy 2.8L V6 application)
- 233-4003 (6pt nuts -- Chevy 2.8L V6 application)
- For 96 and newer 3.8L engines, Tom @ maronav6racing.com commissioned ARP to make the right studs but they are pricey ($230+ when I last looked)
- My thread on this subject: http://3.7mustang.com/vb/f5/q-about-...-heads-266472/
- My Decision: Given the price, I just went with FelPro Head Bolts: FEL-PRO Part # ES72131 (for 94-95 mustang and 89-95 tbird)
(continued in next post)