Although there are substantial differences between a stock Turbo TA chip and a stock Grand National chip, the ECMs are identical. Thus, any Grand National performance chip can be used in a Turbo TA with generally similar results.
Aftermarket chip suppliers offer TTA-specific calibrations that eliminate the factory "stumble" and can safely increase boost and timing for more power.
Synthetic oil is recommended for turbocharged vehicles. Synthetics resist "hot soak" and "coking" of the turbocharger bearings, and at extreme temperatures have superior flow characteristics to conventional oils.
It is critical to use the correct oil filter for the TTA. The horizontally-mounted filter must have an anti-drainback valve to prevent oil starvation at engine startup.
| Filter | Notes |
|---|---|
| A/C PF-1218 | GM recommended. Widely available, improved anti-drainback valve. |
| Fram HP-4 | Originally specified by PAS. Also a good choice. |
| NAPA 1086 | Smaller alternative for those concerned with clearance between oil filter and idler arm. |
Normal boost for a stock TTA is 16.5 PSI at wide-open throttle. High turbo boost most often occurs due to a problem with the wastegate control hose assembly — a group of three rubber tubes leading from the turbo compressor outlet, wastegate actuator, and wastegate solenoid to a plastic "Y" fitting under the turbo.
These tubes are exposed to heat and will eventually crack and leak. Once this happens, there won't be enough pressure to open the wastegate, and overboost occurs. Severe or prolonged overboost can lead to blown head gaskets and melted pistons.
If your TTA has low boost, the culprit is likely the plastic "Y" fitting, especially if the wastegate control hose assembly was recently changed.
The "Y" contains a metal restrictor which regulates boost pressure applied to the wastegate actuator. The original factory orifice was 0.040" in diameter. Newer replacement "Y" fittings have a larger 0.050" opening, which causes the wastegate to open sooner and results in low boost.
Solution: Re-use the original "Y" with new hoses. Also verify the "Y" is not connected backwards.
The restrictor should face the line coming from the turbo compressor outlet. One arm goes to the solenoid, the other to the wastegate actuator.
Check the serpentine belt tensioner pulley — it is likely making contact with the air conditioner pulley. The original TTA serpentine belt was slightly longer than optimal.
Fix: GM replacement belt p/n 12399983 is 16mm shorter than the original, yielding a full inch of clearance between the tensioner and A/C pulleys.
The turbo inlet tube (p/n 12399984) is made of thin plastic. Overtightening the hose clamp will cause it to buckle, making an airtight seal nearly impossible.
Fix: Cut a short (<1") length of 3" exhaust pipe and insert it into the end of the inlet tube. It's a perfect fit and allows much tighter clamping.
Oil accumulation inside your intercooler significantly degrades its efficiency, causing hesitation, rough idling, and poor performance. Regular cleaning is recommended — the procedure involves flushing with a suitable solvent and compressed air.
Installing a new fuel pump in a TTA is an involved task, as the fuel tank is located above the rear axle and exhaust. The tank must be carefully lowered to access the fuel pump assembly.
After building the first ~350 TTAs, PAS ran out of "Turbo" fender emblems. All subsequent cars were delivered without them. Emblems were later shipped to dealers for installation with a placement template, but some dealers attached them incorrectly — and some never attached them at all.
| Part | Number |
|---|---|
| Serpentine Belt (improved) | 12399983 |
| Turbo Inlet Tube | 12399984 |
| Oil Filter (GM) | A/C PF-1218 |
| Oil Filter (Fram) | HP-4 |
| Oil Filter (NAPA) | 1086 |
| Hood Struts (front) | 14019157 |
| Rear Hatch Struts | 16604426 |
| Touch-Up Paint | 1#1052906 — White, Code 40, WA8554 |
| T-Top Sun Shades | Kit 10071496 — Color: Beechwood |
| Service Manual | S-8910-F (Firebird) + S-8910-FAE (TTA supplement) |
If your steering wheel radio controls stop working, the issue is usually oxidized electrical connectors. The button assembly has three cables: power, data, horn, and panel light circuits. The data line is optically coupled via an LED/phototransistor pair. Check all connections at the turn signal cam commutator rings before suspecting a faulty radio.
When your hood or rear window hatch begins to droop, replace with: front struts p/n 14019157, rear struts p/n 16604426. You'll need a T-50 Torx bit and a helper for the rears.
A broken power antenna is a common problem on all late third-generation F-bodies, and the TTA is no exception. The motor assembly typically fails due to the nylon cable stripping inside the mast.
Proper Idle Air Control Motor adjustment is essential for smooth idle and proper operation. This should be performed any time the throttle body is cleaned or the IAC valve is replaced.
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