Tech Tips

Why doesn't INTENSE™ pre-gap spark plugs before shipment?

We don't pre-gap spark plugs for three reasons:

  1. The gaps can easily change during shipping
  2. Plug gaps should ALWAYS be checked before installation
  3. Gapping tools only cost $2 at most auto parts stores.

What's the best way to do burnouts with an INTENSE™ LSD?

Over the last two years and several hundred passes down the quarter mile, we have learned a few things about launching our FWD cars.

  1. A good 60' time is essential to achieve to lowest possible quarter mile ET.
  2. Launch technique and equal tire temperatures are essential to achieve the lowest possible quarter mile ET.
  3. Proper burnout technique is essential to equalize tire temperatures.

Front wheel drive cars have an inherent disadvantage in the burnout box. When doing a burnout, front suspension geometry forces the front tires into the ground. The weight of the engine and transaxle sitting over the front tires exacerbates this problem. Even with a top quality differential, these disadvantages make it possible to do a 'Johnny one-wheel' with improper burnout technique.

Burnout Tips:

The key to overcoming this disadvantage is to do a burnout at a fairly high engine speed. This creates higher tire rotating speed, which helps to 'lift' weight off the front tires. We do all our burnouts with the gear selector in manual '2' and the parking brake set.

Stab the throttle to 'shock' the tires loose and bring them up to speed very quickly. The transaxle will shift into second gear right away. Ideally, a burnout RPM of approximately 4,000 RPM in second gear will heat the tires quickly and keep them spinning fast enough so they can't dig back into the pavement and cause a one-wheeled burnout to occur.

A burnout performed in first gear around 2,000 RPM will almost always cause a one-wheeled burnout because this scenario exposes the disadvantages listed previously.

Burnouts at high speed will add life to your new INTENSE™ Second Gen LSD by eliminating one-wheeled burnouts.

Piston Ring End-Gap Specifications:

Top ring: .020"

2nd ring: .022-024" unless gapless ring is used

Wiper ring: .015" minimum

Should I purchase a Throttle Position Sensor Enhancer?

If you want to increase throttle response, upgrade your PCM or buy other mods. The TPSE is an electronic gimmick not worth the money in our view.

Should I purchase an IAT Spoof Module?

The Intake Air Temperature module is simply a resistor packaged impressively and marketed to customers who don't know any better. These can sell for as much as $25 and many are lured into purchase by its low price and easy installation. 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 one to two degree (and that's on a hot day where you probably can't use the extra degree or two of timing advance anyway). Save your money and don't buy it. If your curiosity gets the best of you, buy an 8k-Ohm resistor from Radio shack and save $24.50.

Do I need platinum or gold or iridium coated spark plugs?

We've done extensive testing on every type of spark plug we can fit into our cylinder heads. Boiled down, two main findings stand out. First, colder spark plugs do seem to help control Knock Retard. And second, cut back ground electrodes do produce a few more horsepower. All the platinum, gold, iridium and other expensive metals make no measurable difference on the dyno or at the race track.

Do I need an adjustable fuel pressure regulator (AFPR)?

On many boosted cars fuel pressure needs to be raised as boost is added to compensate for extra air. The 3800 FWD supercharged engines use several methods to control fueling, which render an AFPR worthless in many cases. The MAF sensor reads the airflow and tells the PCM how much air is coming in and therefore how much fuel to deliver. The MAP sensor monitors manifold pressure (vacuum or boost) and fueling is adjusted by the PCM. The ECT sensor monitors engine coolant temperature and also has some effect on fueling. And then the front oxygen sensor (B1S1) monitors overall air/fuel performance and tells the PCM how well the actual air/fuel matches the desired air/fuel.

As you begin to mod and increase the overall airflow of your engine, the MAF and MAP sensors detect the increased airflow and/or boost, and the PCM automatically lengthens your fuel injector pulsewidths to compensate. The stock fuel pressure regulator (FPR) changes fuel pressure with vacuum or boost. As your boost increases so does your fuel pressure. By changing this function by replacing the factory regulator you run the risk of making your car more difficult to tune. Using an AFPR to increase static fuel pressure may not change the maximum pressure available because the stock L67/L32 fuel pump usually can't reach 70 psi on most vehicles. So even if you might add five psi of fuel pressure at idle and cruising, you may only be adding a pound or two at WOT. And this loss of linearity can make tuning the car a nightmare.

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 aftermarket, 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.

Tranny coolers add unnecessary weight and opportunities for fittings to leak. A leaking fitting can let your tranny run dry in minutes and ruin it far faster than a little heat ever could.

Our trannies are cooled by the same radiator used to cool the engine. So running a colder engine thermostat will make both your engine and your tranny run cooler.

Should I get rockers or a cam?

Generally speaking, aftermarket rockers give gains in the 20 to 30 horsepower range, while a properly selected cam will give gains in the 20 to 50 horsepower range. Cams can provide more horsepower per dollar spent, but are MUCH more labor intensive to install. In addition, some of the more radical cams can trip S.E.S. lights, but rockers have no such side effects. So, it all boils down to how much you want to spend, how skilled you are at parts installation and how much sacrifice you want to make.

Should I run water injection?

Not in our opinion. None of the ten quickest 3800 FWD cars runs water injection, although we know at least three of them ran it at one time in the past. And we believe there's a good reason for this evolution.

How will steeper gear ratios affect my car?

Generally speaking, steeper gear ratios will improve your acceleration and E.T., while reducing your fuel economy and trap speeds. In round numbers, each gear step (from 2.93:1 to 3.29:1 for example) will reduce your quarter mile E.T. by about a tenth of a second and your trap speed by about 1.0 MPH. Your engine speed (RPM) will increase by about 13% at any given vehicle speed and your gas mileage will be reduced by about 7%. Changing from 2.93:1 to 3.69:1 gears will approximately double all the effects listed in this paragraph.

What's the deal with older L67 cylinder heads?

Apparently, there was an issue with early L67 cylinder heads being prone to cracking. It appears that the casting was actually changed DURING the 1998 model year. Old castings are G.M. #24503436 and have .855" valve spring seat pilots. New castings are G.M. #24507848 and have .810" valve spring seat pilots.

You can remove your heads, and have them checked for cracks by a machine shop. Or, you can remove one valvespring and measure the diameter of the valve spring pilot seat. Those are the only ways we know for sure to discern whether or not you have the 'problem' cylinder heads.

How can I convert an eighth mile time to a quarter mile time?

For a VERY good estimate of your quarter mile time, just multiply your eighth mile time by 1.553. For an estimate 'range', try 1.54 (weaker launching cars) to 1.57 (perfect launching cars). You'll be dead on the money with this formula. In fact, all ten of the fastest L67-powered FWD cars fall between 1.541 and 1.565.

Will you guys build parts for my 3100 or 3400 engine or 4T45E or 4T60E transaxle?

Sorry, but we can't. Instead, we're spending all of our time and money in an attempt to be the VERY BEST resource for 3800 engines and 4T65E-HD transaxles.