The starting line at the drag strip is the last place you want your 5th Gen Camaro to get caught taking a nap, but yet that is often just what automatic transmission equipped Camaros are doing when it comes time to rev up for a hard launch. Thanks to a stock torque converter that will only allow you to spin the engine so high, Camaro SS’s equipped with the L99 and 6L80E transmission are only able to sleepily rev up to just only about twice the idle speed, while their manual transmission equipped counterparts can rev their engines to their hearts content before launching.
Luckily not all hope is lost for racing enthusiasts who drive auto trans Camaros. All you really need to do to wake up your auto trans car is install a performance torque converter with a higher stall speed. In fact your car can launch just as hard, if not harder than a manual transmission car with a simple torque converter swap, and retain a dead solid consistency that manual transmission cars will always struggle to reproduce.
Talking With TCI
Few folks know the ins and outs of automatic transmissions and performance torque converters like the guys at TCI Automotive. TCI has been producing top quality components for auto trans cars for over 40 years, but they don’t just know old-school TH-400’s. They are constantly developing new technology to provide better performance parts for today’s technologically advanced modern muscle cars, including the 5th Gen Camaro SS.
The idea behind installing a high performance torque converter is to get your stall speed up higher, so that you are into your engine’s powerband much quicker off the line.
We spoke with Scott Miller, Product Manager with TCIabout the science behind how a torque converter works, and how one of their high stall performance torque converters can really wake up your 5th Gen. Miller tells us, “A torque converter allows a car with an automatic transmission to basically still be able to idle with the transmission in gear because it ‘slips’. At a very low RPM, like idle, the torque converter isn’t ‘fluid coupled’ and is allowing the engine to keep turning without transmitting power to through the transmission.”
Ultimately, the function of a torque converter depends on the speed of the fluid moving through it. When you give the engine some throttle, and you speed up the engine, and the fluid in the converter will start to move faster. The converter will gradually start to couple with the transmission side of the converter, and the car will start moving. “The idea behind installing a high performance torque converter is to get your stall speed up higher, so that you are into your engine’s powerband much quicker off the line.” says Miller.
“To get the stall speed up in a performance converter you change the angle of the internal fins and also by changing the amount of blades and their angle on the stator. When you change the angle of the impellor blades, you are redirecting the fluid and changing the speed of the fluid. You’re essentially creating a disturbance in the normal fluid flow, and by speeding it up and changing the flow pattern of the fluid you are effectively increasing your stall RPM.”
Snoozing at the Starting Line
For the first phase of our torque converter test, we needed to run a few quarter-mile passes in our 6L80E equipped Camaro to get a baseline before installing the TCI unit. Our test Camaro isn’t a bone stocker, but rather features several upgrades that you would likely find done to just about any 5th Gen out there belonging to the average gearhead who might like to spend a little time at the track. It has a ported intake, a JBA axle-back exhaust system, American Racing headers, a custom tune by CMS to maximize the upgrades, and a set of Eibach 1”drop springs to help a bit with the stance. To take traction out of the equation, we bolted on a set of grippy Mickey Thompson drag radials.
When we took the Camaro out to the 1/8th mile track at Irwindale Speedway, in Irwindale California to get our baseline numbers, it became apparent that the stock torque converter left a lot to be desired on the drag strip. With one foot on the brake and the other on the gas, the Camaro was only able to squeak out 1,500 RPM worth of stall at the starting line thanks to the stock torque converter, forcing it to leave the line well below its peak powerband. The result was a decent 1.99 second 60-foot time on the way to an elapsed time of 8.07 at 90.69 miles per hour.
1/8 Mile Results Before Installing Streetfighter Torque Converter:
- 60 Foot: 1.99
- 1/8 Mile ET: 8.07
- MPH: 90.69
Tim Sears, owner/driver of our test Camaro tells us, “With the stock converter, out of the hole I’m waiting for the RPM’s to get up to the powerband. And hopefully with the new TCI torque converter, I’ll be able to reach that power band quicker and get off the line faster.”
…Enter the Streetfighter
It’s pretty clear that we’ve got a lazy stock torque converter that’s robbing us of valuable launch RPM’s, but never fear, because the TCI Streetfighter torque converter is here to take back all of that stolen potential. The TCI Streetfighter torque converter for the 5th Gen Camaro is a perfect match for our mildly modified test car. It’s designed to bring the launch RPM up higher and more in line with the modifications that have been done, and should give the car a stall of between 3,000 and 3,200 RPM depending on just how much torque the car is making.
Using the TCI Streetfighter Torque Converter for 6L80E in a Street Car
“Ideally, you want your torque converter to stall at the same RPM that your engine is making peak torque.” Miller tells us. “But in a street application, you want to keep your stall below 4,000 RPM, since most street cars make their peak torque below that. You don’t want much more than a 4,000 stall in a street car since it will build up a lot of heat from slipping that much.”From the dyno tests we’ve ran in the past on 6L80E equipped 5th Gens, we’ve observed their peak torque to be between 3,500 and 4,000 RPM, meaning that the street fighter is a near perfect out of the box match. Miller says, “A street car with lower than a 3,500 stall converter shouldn’t notice any negative effects at all on the street. It should pull away from a stop just like it was stock, by just giving the engine a little bit of gas.”Like all of TCI’s torque converters, the Streetfighter is a heavy duty unit designed to take some serious abuse. Miller tells us, “We furnace braze the internal fins of the converter to make them stronger and more solid. If the fins are flexing at all, that can cause a variety of problems. It can cause inconsistent stall RPM for one; it might stall one run at 3,000, and the next only 2,500. We furnace braise all of our torque converters mainly for strength, which will result in consistency.”The Streetfighter torque converteralso features TCI’s special HDT coating to help it get rid of excess heat. As you know, heat is the biggest enemy of an automatic transmission in a performance car. The cooler you can keep the transmission and the fluid, the better all-around performance and longevity you will see. Miller says, “HDT stands for stands for ‘Heat Dissipating Technology’, and believe it or not the color of the coating has a lot to do with how well it releases heat from the converter. We have an in-house R&D dyno that we can put a converter on without a transmission, and stall it at whatever RPM we want and make it build a lot of heat. We tested all different shades of colors and all different types of coatings until we found the best one for getting the heat out of the converter.”
The torque converter ultimately what builds up the majority of the heat in an automatic transmission, and if the HDT Coating helps remove a lot of that heat out from the converter, then your transmission cooler doesn’t have to work as hard. Per Miller, “We use the HDT coating on all of our torque converters; whether it’s a street rodder 1,500 RPM stall converter for a stock type application, to a converter for our Pro-X Powerglide.”
Additionally, if you need something with more or less stall than the Streetfighter’s 3,200 RPM, TCI can hook you up with a custom built converter just for your specific application. Miller says, “We also can build a custom converter for whatever stall speed you need. If you have dyno sheets, we can pinpoint the RPM where the motor is making the best torque, and build a converter with that stall speed. Even if a customer doesn’t have a dyno sheet, we can build them a custom converter if we know the basics of the motor, the tires they will be running, the weight of the car, and the rear gears that they will be using.”
Putting the Streetfighter in its Place
To install the TCI Streetfighter, we took our test 5th Gen to our friends at Cunningham Motorsports in Murrieta, California. Mike Gallo, the Shop Manager at CMS, told us that a torque converter swap on a 5th Gen is actually pretty simple. “There really isn’t much to the install. It’s actually fairly easy in the Gen 5. You first have to remove your exhaust and driveshaft, and anything else that might be in the way. Unbolt the converter by spinning the flex plate around so you can get at all three bolts, unbolt the trans and drop it down with a jack. You’ll need to prime the new converter with about two quarts of ATF, and slide it on the trans output shaft. Watch out because it’s going to barf ATF all over the place.” Once you have the new converter mated to the trans, jack the trans back into place and bolt the bell housing back to the block. Then bolt the new torque converter to the flexplate.
Gallo also offered these tips: “If you have aftermarket engine mounts like Pfadt, then the K-member must be slightly dropped to gain access to the top bolt of the bellhousing because the stiffer engine mounts don’t allow the engine and trans combo to rock back at an angle far enough. Also, a 3-4 foot extension is a must-have tool for this job so you can get at all the bolts.”
While having a handy dandy lift like the one at Cunningham sure does make a job like this easier, it’s still completely possible to do a torque converter install yourself in your garage or driveway. Of course you’re going to still need a good transmission jack, because bench-pressing the mammoth 6L80E in and out of place wouldn’t be much fun even if you are actually strong enough to do it.
The Streetfighter Goes to Battle
With the TCI Streetfighter now forming the link between the L99 and the 6L80E, we headed back to Irwindale Speedway to see how much we could improve on the lackluster stock times by just swapping torque converters. At the starting line, the Streetfighter’s higher stall speed was immediately evident, as the L99 was now able to rev up to 3,000 RPM and steadily hold the engine there; doubling the stock converter’s stall RPM, and landing us much closer to the peak in the Camaro’s power band.
I had power right off the line. I was at the power band immediately.
The higher stall RPM with the Streetfighter meant that the Camaro was able to launch much, much harder. When the light dropped to green, the Streetfighter equipped Camaro laid down a 1.72 60 foot time, knocking off 0.27 off of its short time with the stock torque converter. It’s a rule of thumb that for every tenth of a second you can cut from your 60 foot time will translate to 1.5 tenths off of your elapsed time. That rule held true in this case with an ET of 7.76 at 89.9 miles per hour, a full 3 tenths of a second quicker than the car ran with the stock torque converter. That kind of an 1/8 mile time would translate into around 12 seconds flat on a quarter mile track. After taking the Camaro down the drag strip for the first time with the new TCIStreetfighter, Sears told us, “I had power right off the line. I was at the power band immediately.”
1/8 Mile Results After TCI Streetfighter Torque Converter Install:
- 60 Foot: 1.72
- 1/8 Mile ET: 7.76
- MPH: 89.97
- Improvement of over 3-tenths
The Streetfighter torque converter made a huge difference in our Camaro at the drag strip, and will only help out even more as we continue to modify the car and make it even faster. But, best of all, the Camaro is still perfectly streetable thanks to the internal lock up that works just like the factory converter. This means that we can have the best of both worlds with our 6L80E Camaro – high revving drag strip fun and smooth operation on the street. If you’re serious about performance in your L99/6L80E 5th Gen SS, a torque converter like the TCI Streetfighter should be at the top of your “future mods” list.