From the builder of my converter.
First and foremost let me advise that my responses’ are not intended to solicit any business from this forum or to negate any vendor or participants reputation. I have read the Policy Notice on Turbo Buick and must say that you gentleman operate an outstanding information forum for the Buick Turbo Enthusiast.
I am a friend of Rob’s and yes I built his converter and will be better equipped to respond to the majority of the questions fielded. To qualify myself, although I will remain silent as a personality, I am a Torque Converter Builder that is the sole owner of a shop that has been in business since 1971. My resume would include working for three of the top race converter builders and then coming up in the ranks of the remanufacturing business. I helped clients set up converter shops on four occasions and managed a high volume re manufacturing shop that supplies the transmission industry in a three state area with a comeback ratio of less than 2%. Currently, my own shop runs at a ½ percent return ratio. There are very few of us left that are hands on from A to Z. Additionally, I consult for auto manufactures and part suppliers on an as needed contract basis.
That said, let’s move on to the first question that seemed to cause a variety of input and opinion that never seemed to help the member with his question. Members, please take note that the more information that you provide with your question the easier it is for others advise, enthusiasts like Rob and Professionals like Dusty to respond with intelligent concrete advice, hopefully with the driving motivation to be of some help.
1. If I change to a non-lock converter, how is the driveability compared to a lock up? I'm guessing it will not be as drastic of a change compared to 200r4 to th350 trans swap. Is it true going to a non-lock is more reliable and lowers the chances of having problems? For example, list rpm (cruising) at 75 mph with non-lock vs. same speed with lock up converter. What about rebuild prices? Is one cheaper to rebuild than the other? Thanks, Tim
Well Tim, Rob was correct in stating that it depends on your intended purpose for this car. A converter builder should always inquire as to the intended purpose, (street, street/strip, bracket racing, etc.) and the time spent in each category. Ultimately, we want to proved a piece or product that meets your needs as close as possible. The driveability concern can only be answered by the quality of the product. For instance, you can buy a non lock up converter that uses a lock up eliminator kit and your performance would be drastically lower than that of a quality non lock up converter that runs in a busing and on three bearings. The same factors apply to a lock up converter which I will cover later. For the most part “QUIP 6” was correct with his RPM response of 500 RPM. Take any lock up converter to a cruising speed of 65 MPH (Not that anyone in here would violate the law otherwise) and while maintaining a constant speed step on the brake with your other foot and you will see the rpm drop 300-500 depending on the quality of the converter. This takes the converter out of the intended 1:1 ratio with the motor and allows the converters original efficiency rating to prevail.
A. If you are primarily on the street such as a daily driver and fuel mileage comes to play then a good performance lock up unit such as a street/strip kit would be the best choice. These units can be a lot of fun for the consumer, allow the converter builder to get more aggressive with the build, and still provide the dependability of lock up for a long trip by taking the converter out of play.
B. If your street/strip it would depend upon how much time at the strip and whether you are utilizing a trans brake. I build a lot of the fore mentioned kits for street/strip guys on a budget which is another factor to be considered. If every weekend is spent at the strip for points and the car is driven daily otherwise I would recommend a quality non lock up unit (no clutch eliminator kits) due to the fact that the vehicle will experience more launches. However, that is not to say that a Full Billet Lock Up Converter will not run just as well and still provide dependability, generate lower heat, and provide higher gas mileage when needed. To date, the all bearing non lock up converter will always slightly outperform the lock-up with e.t and mph. I speaking of the same two converters here (same core and stall). The reason is that a non lock up can achieve efficiency ratings of 98 percent if properly built. A good Full Billet Converter will run two percent off that pace. However, at 75 mph and a 2 percent slip ratio you will still be generating some form of heat compared to a lock up converter.
C. Strip Only would benefit from the non lock up units that are built with three bearings running in a bushing. Especially, those cars using a transbrake. Speaking to that issue, a good sprag-less converter is the way to go. Remember Billet Covers are a better choice if your budget allows it. The billet cover will be a one piece cnc unit perfectly balance and stronger that any factory housing with an anti balloon plate. If you can not go this route then look for a piece that distribute torque evenly such as the balloon plate with built in bolt pattern or the cnc ring converter with the pilot properly set to serve as a anti balloon stop. Both pieces work well, however my preference is the latter due to weight concerns.
However, when someone develops the Billet Lock Up Converter that rides on three bearings and the transmission builders revisit lock up under peak spool like the Dodge Diesel Boys are doing then we are talking a whole different game.
Hope this helps Tim, now it is time to explore which core is best suited to serve your needs. Then again, many factors come into play. It really gets tricky at this point. Now we have to look at tire size, weight of vehicle, gear ratio, torque production and your turbo set up. Additionally, the same factors for driving habits and intended used come to play.
Rob and I explored every option before agreeing on a Full Billet 245 MM 9 ½ Inch Converter. Full Billet means that the damper is one piece cnc construction specifically designed without damper springs, a larger spline surface area and enlarged clutch surface area for dependability and longer performance. In the kit I use the clutch measure 1 ½ inched wide which provides the same lock up surface ratio as a five disc clutch and more than a triple clutch with less moving pieces. Using this clutch system is what allows builders (if they are good) too raise the efficiency percentage to that of most manufactures 96 percent on the non lock up units.
Remember Tim, you’re the consumer and now that your somewhat educated it is still ultimately your responsibility to explore manufactures‘, their recommendations, and how there converter is built. I’m sure Dusty and the other guys on here can attest to the fact that there are a lot of hacks out there with a couple hundred thousand dollars worth of equipment trying to be performance torque converter builders. Reputation, integrity and quality are everything, not to mention the actual performance which is what we are all after.
As far as rebuilds, it depends on the company. You will find that everyone is pretty close on this with prices ranging from 125-225 for a refresh, plus parts for any extras or alterations (stall changes and efficiency enhancements). Again, don’t let some hack screw up a unit you spend good money for. I’ll charge you double if you send one of my units to someone else and I have to correct it.