following info from:
Apten Performance
Suggested Modifications
We have put hundreds of hours into the development of Thunderbird SC products and finding out which combinations work best. After significant time at the dyno, we have come up with this list of suggested modifications. We realize there may be other aftermarket parts you can add, but these are the ones we have found to be most effective.
First stage: Basic Bolt-ons
Following these will get your SC up in the 210-220RWHP Range. They are listed in the order we suggest
1. Cat-Back Exhaust System
2. Magnum Powers Intake kit
3. 5% Overdrive Pulley
4. Computer Chip
Second Stage: Extensive Bolt-ons
Putting all of these together with the first stage will get your car safely past 250RWHP
1. Magnum Powers MPII Supercharger
2. Magnum Powers Supercharger Plenum
3. Magnum Powers 85MM Throttle Body
4. Pro-M 76MM or 87MM MAF, and 42lb injectors (with chip reburn)
5. 255lph aftermarket fuel pump
6. Magnum Powers Raised Top
7. Magnum Powers FMIC Intercooler Kit
Third Stage: Pure Power
This is the final step to making power with available parts. Once you have done everything in these three lists, you should have a 12 second capable 300RWHP car. At these power levels, you will have to be sure that your transmission capable of handling the power. In some cases, a stronger engine with forged pistons and rods may be necessary. We have seen stock super coupe pistons and rods make over 400BHP, but the car needs to be tuned or atleast dyno tested for that power to last.
1. Stiegemeier complete cylinder heads
2. Stiegemeier Camshaft
3. Ported Exhaust Manifolds
4. Chip reburn with dyno pulls
Notes on Other Modifications
Here is a list of other modifications, and our notes on them.
Headers
While headers may be a benefit on some motors, they are not one of the first modifications I would do on a super coupe. We have found that porting the stock manifolds is adequate for cars running 300RWHP and even slightly beyond. If you aren't looking for the MAX power available from your super coupe, we would suggest saving the cost of headers and putting that money into something of the other modifications we listed above. When you are all done with the things we listed, you can always add that if your car doesn't meet the goals or if you want to make even more power.
MAF Meters
We recommend two brands for replacement MAFS. The only two companies we recommend are Ford and Pro-M (Also known as Granitelli). Upgrading your MAF will be necessary when you have added most of the parts in our second stage of modifications. The factory air meter is restrictive, and will not flow enough air in the usable voltage range to be effective on high HP SC's. Three common Air meters are the ProM 76MM, ProM 87mm, and Ford 90MM Lightning MAF. All of them will work well on cars up to 400RWHP. We recommend having the chip reburned when you change air meters and injectors. Never, EVER modify your stock MAF by cutting out the center post. Doing so will change the flow characteristics, and cause the electronics to send false signals to the computer. We support cars with C&L meters, but we recommend the Pro-M meters above them because we feel the Pro-m meters are more accurate..
Fuel Injectors
1989-1993 Super Coupes come with 30lb injectors, while 1994-1995 Super coupes come with 36lb injectors. When you get into the second stage of modifications, you should have at least 36lb injectors. Depending on your power levels, it may be necessary to have 42lb injectors.
Supercharger Overdrive pulleys
On lightly modified Super Coupes, we only recommend a 5% overdrive pulley. Using a smaller pulley could result in premature head gasket failure. If you have high flowing exhaust and a ported supercharger, you can step up to a 10% overdrive pulley. We have observed that overdriving the supercharger more than 10% may decrease HP. Spinning the Eaton M90 too fast will cause excessive heat, which will result in a power loss.
Intercoolers
By far, the most efficient intercooler available in kit form is the Magnum Powers Front Mount Intercooler. It not only cools better, but it also has less pressure drop than the stock intercooler and tubing. If the Front Mount Intercooler is out of your budget, you can commonly find homemade double intercoolers online for around $600. At the dyno we saw nearly a 20HP gain by swapping a Front Mount intercooler in place of a double intercooler.
Radiators
For most cases, you won't need an upgraded radiator until you get well into the third stage of modifications. It really depends on your climate and driving habits. The chip will help cool the car significantly by itself because it lowers the fan turn-on temperatures.
Cylinder Heads and Camshafts
Depending on what your goals are, good flowing cylinder heads may be critical. The difference between the heads we sell and your basic ported heads with valves is in the flow. You want heads that flow good on the exhaust port, and also at low valve lifts. If you want to run a 12 second Super Coupe or faster, you should consider investing in a set of these heads. It is also important to have a custom camshaft made based on the flow characteristics of the heads. Aggressive camshafts that lift past .600 will also require some special springs that will not bind at high lifts.
Underdrive pulleys
While gains can be made with Underdrive pulleys, we left them off the list of important modifications. We did this because we feel that the gains from those pulleys are somewhat small compared to the cost. If you figured out the dollar cost per HP, it would be higher with underdrive pulleys than most of the other things we suggested. If you have done everything else we suggested and still cannot reach your goals, that might be the time to look to underdrive pulleys for additional gains.
Cold Air Intake Kits
There are several aftermarket cold air kits to choose from. There are two important things to look at when making a purchase decision on these. First, you want to be sure there are no bends in front of the MAF meter. Some intake kits available have a large bend in the tubing in front of the MAF meter. That bend will cause turbulence in the air, which will give your MAF inaccurate readings. This can cause a drivability problem, as well as a lean condition. The second considerations is that your intake kit pull cold air. Some intakes have conical filters inside the engine bay with no cold air divider. This will cause the filter to suck in warm engine air while you are driving. The warmer air entering the intake will result in a loss of power. Super Coupe performace makes a good air intake kit that works well.
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Cars and Dyno Results
Below is a list of Super Coupes that we have recently tuned, along with information on the car and the dyno data.
Chris Wise - 1990 Thunderbird SC Auto
391RWHP / 481RWTQ 11.91 @ 114MPH
4.2L Forged V6. 50lb injectors, 90MM Lighting MAF,
ported and welded heads, Camshaft, custom liquid I/C,
Custom I/C tubing, MP Plenum, 85mm TB, Ported M90,
Complete Exhaust, custom fuel system, Apten Chip, and more
Dave Neibert - 1991 Thunderbird SC Auto
374RWHP / 461RWTQ 12.5 @ 109MPH
3.8L Forged V6. 50lb injectors, Pro-M 87mm MAF,
ported and welded heads, Camshaft, MP FMIC, Apten Chip,
MP Plenum, MP Supercharger, 85mm TB, Complete Exhaust,
and more
Bill McNeil - 1993 Thunderbird SC 5-speed
360RWHP / 413RWTQ
3.8L Forged V6. 42lb injectors, 90mm Lightning MAF,
Morana Ported heads, Camshaft, Double Intercooler, Apten Tuner file,
MP Plenum, MP Supercharger, 85mm TB, Complete Exhaust,
and more
Anthony Rongo - 1992 Thunderbird SC Auto
348RWHP / 365RWTQ
Factory 3.8L short block. 42lb injectors, 90MM lightning MAF,
stiegemeier heads and Camshaft, MP FMIC, Apten Chip,
MP Plenum, MP Supercharger, 85mm TB, Complete Exhaust,
and more
Gary Kuhn - 1991 Thunderbird SC 5-speed
340RWHP / 391RWTQ
3.8L Forged V6. 42lb injectors, 90mm Lightning MAF,
Stiegemeier heads and Camshaft, custom FMIC, Apten Chip,
MP Plenum, ESM Supercharger, 85mm TB, Complete Exhaust,
and more
Tony Serno - 1994 Thunderbird SC Auto
332RWHP / 380RWTQ
Factory 3.8L shortblock. 42lb injectors, 90mm Lightning MAF,
Stiegemeier heads and Camshaft, MP FMIC, Apten Chip,
MP Plenum, MP Supercharger, 85mm TB, Complete Exhaust,
and more
Chris Mendola - 1995 Thunderbird SC Auto
316RWHP / 404RWTQ
3.8L Forged V6. 42lb injectors, 90MM Lightning MAF,
Stiegemeier Heads, Camshaft, complete exhaust, Apten Chip,
2.2L Autorotor supercharger with custom built intake,
laminova liquid intercooler, and water cooling system
Kurt Kriesz - 1990 Thunderbird SC Auto
316RWHP / 378RWTQ
Coy Miller Stage II heads, forged short block. 42lb injectors, Pro-M 87mm MAF,
Spearco Intercooler, Apten Chip, S-model supercharger,
MP Plenum,70mm TB, Complete Exhaust,
and more
Chris Spanel - 1994 Thunderbird SC Standard
303RWHP / 378RWTQ 13.7 @ 104MPH
42lb injectors, 90MM Lightning MAF, Stiegemeier Heads,
Camshaft, complete exhaust, Underdrive pulleys, Apten Chip,
ported exhaust manifold, raised SC top
Rodney Bushong - 1992 Thunderbird SC Standard
291RWHP / 378RWTQ 13.7 @ 104MPH
42lb injectors, 76mm ProM MAF, ported heads, Camshaft,
complete exhaust, Magnum Powers FMIC, MP supercharger, Apten Tune,
Magnum powers plenum, Magnum powers Intake tube
Todd Jelle - 1990 Thunderbird SC Auto
291RWHP / 378RWTQ 13.0 @ 106MPH
42lb injectors, 76mm C&L MAF, CMRE Stage II Engine,
S-Model supercharger, Spearaco Intercooler, MP plenum
Apten Tune, and more...