Mods That You Don't Need

Thanks to Zommer from ZZP for this information.

Transmission coolers
The idea of a tranny cooler is a good one. Keep the transmission running cooler and it will last longer. Fluid stays cleaner and parts last longer. Those are theories. The problem is that Grand Prix don't have a problem with transmission temperatures. A tranny cooler might be a great idea on some cars but the Grand Prix is not one of them. Little known to most is that the GP PCM monitors transmission temps and if the tranny temps get too high the PCM will set a check engine light and possibly take precautions to limit abuse.

Here is a quote from INTENSE racing (they build performance transmissions for GPs) "Should I run a tranny cooler?

Only if you're planning to pull a trailer through the mountains. Otherwise, we recommend against it on vehicles with the 3800 FWD/4T65E drivetrain.

We have dissected more of these trannies than anyone else in the performance after-market, and we have yet to see a single heat-related failure. Hard parts break in these trannies, and these failures will not be prevented by a tranny cooler."

We have also done dozens of transmissions here at ZZP and we know from opening them up that a tranny cooler is not helping things. We've seen tranny's break with 50 miles on them and others with 125k on them. Problems have NEVER been related to fluid temperatures or fluid break down.

At the point where we can't convince our customers to take off their trans coolers or not to buy one we often hear the response "well, it can't hurt" or "I'll just play it safe" Wrong! Transmission coolers have many down sides. Going back to the opening of this article we broke down all the reasons not to buy unneeded mods but the tranny cooler is especially dangerous and here's why:

We have had to rebuilt more than one tranny due to a failure of a tranny cooler. When your cooler leaks it can cause very serious problems. Below is a pic from a car in Grand Rapids where a severed line left this owner in the cold.

http://www.zzperformance.com/images/info/tranny_cooler_failure.jpg


Here is a quote from a member of the RegalGS forum:

"I installed the GM cooler 10 plus thousand miles ago along with the Thrasher shift kit. (second setting) I'm a bit "old school" when it comes to these things. I figured if the cooler is on the Police Impalas, it would work with the GS trans nicely. Further, I do have a hitch on the car and haul a small trailer on occasion. For me, I feel more comfortable in using a cooler.

However, during the installation, I double clamped the lines and triple-checked for leaks. There were no leaks and the installation worked great for a while...until...on a WOT jaunt up a back road on my way to an appointment, I noticed a bunch of smoke behind the car. I stopped and looked under the car and noticed fluid pouring out of the front of the car. I thought it was antifreeze and traveled another two blocks to the appointment where I finally opened the hood. FIRE! I carry a fire extinguisher in the trunk and the fire was put out quickly. There was no damage from it too, thank god!

It turns out, one of the "double clamped" lines blew of the steel line and sprayed trans fluid all over the exhaust manifold. Fortunately, I was two blocks from the dealer. Still, I had it towed, I didn't want to risk more fire and a bad trans. The dealer replaced the lines and flared the ends so the re-clamped rubber lines wouldn't come off again. Just a little story of my experience."

With nothing to gain and a lot to lose, you can see why we are so strongly opposed to tranny coolers. Even if the cooler doesn't fail you are adding weight to the car, costing yourself money and blocking some of the airflow to the main radiator which in turn makes the car run hotter costing your HP.

Aftermarket coil packs
The stock ignition on a Grand Prix is very good. So good that we run stock coil packs on all of our cars at ZZP. Failure rate of stock coil packs is almost zero and the spark output is extremely high. We have A/B dyno tested aftermarket coil packs and seen no difference in HP. We have seen many aftermarket units fail and when customers have a problem it's very hard to diagnose with 'extra' mods on the car.

Aftermarket Plug wires
Unless you have a problem with your stock wires, don't buy aftermarket ones. In our experience of working on GPs the failure rate of aftermarket wires is over 10 times that of stock wires. GM puts everything they have into making cars get the best mileage they can with the least amount of problems. A poor ignition system would increase emissions, which GM couldn't afford. This means plug wires from the factory are designed for high spark, low radio noise and excellent performance. All of the ZZP cars run stock wires.

Air temp modules
An air temp module is simply a fancy packaged resistor made for people who don't know any better. Companies like SLP offer this for ~$25 and many are lured into purchase by it's low price and ease of install. It tricks your PCM into thinking it's cold outside and therefore "optimizes timing". In reality it does little to nothing and cannot change commanded timing by more than 1 degree (and that's on a hot day where you probably can't use the extra 1 degree of timing anyway). Save your money and don't buy it. If your curiosity gets the best of you, buy an 8k resistor from Radio shack and save $24.50

Adjustable Fuel Pressure Regulator
On many boosted cars fuel pressure needs to be raised as boost is added to compensate for extra air. The Grand Prix uses 2 methods to control fueling which render an AFPR worthless. The MAF sensor on the car reads the airflow and tells the PCM how much air is coming in and therefore how much fuel to deliver. As you mod and increase flow the MAF reads more and increases fuel. The stock FPR changes fuel pressure with boost. As your boost increases so does your fuel pressure. By changing this function by replacing the factory regulator you make your car impossible to tune. Adding fuel pressure doesn't change the maximum pressure because your stock pump is limited to low 60's in psi. So even though you might add 5 pounds at idle and cruising you're not adding that much at WOT. This makes tuning the car a nightmare. All the ZZP cars run stock regulators. If you have an aftermarket unit on your car, sell it and go back to stock. Thank us later...

TPS Enhancer
If you want to increase throttle response, upgrade your PCM or buy other mods. The TPSE is an electronic gimic not worth the money.

Walbro fuel pump
If you have an M90 on your car then your stock pump is capable of flowing enough fuel. Our 97 GTP put down 410WHP using a stock pump, our 2000 Monte Carlo (L36 200HP stock engine) put down 387WHP with the stock pump. Changing your fuel pump greatly increases the chance of pump failure or problems due to hoses coming off. If your stock pump is still working keep it! Another down side to the in tank Walbro is the fact that it won't suck your tank dry. Your factory 17 gallon tank will be reduced to a 15 gallon capacity.

AutoTrans Interceptor
The trans interceptor is an electronic device that plugs in line with your transmission. It is supposed to improve transmission performance. Your better off doing the job properly with a reprogrammed PCM.

Tornado
With promises of increased gas mileage and HP the Tornado is a total scam. It does nearly nothing and we have dyno tested it on a Dyno jet chassis dyno and it displayed a .5 HP loss.


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interesting
thx

Well done sir...
Thank you from all of us "newbs" to tuning for saving us a lot of easily wasted money!
Great post BIG-L