- Joined
- May 26, 2001
Since I installed my first aftermarket converter in my new turbo car in 1987 with 6k miles with the stock turbo and have done many since then on street cars and race cars into the 8's, I just want to add some comments here.
Choosing a converter is not a calculated or scientific number since there are so many variables with the car build, how it will be used and "feel" to the owner.
A good answer comes from experience and knowledge gained by doing LOTS of converters for various builds and situations.
Even the most expert "converter" guru can only provide a guess, as most suppliers offer at least one free re-stall if the customer is not happy with the results.
In the early days it was not unusual to do 5 or 6 converter changes to obtain the best overall performance. If we do not get it right the first time now, usually one, maybe 2 changes will get it spot-on in a competition situation.
Most times now with a street build we can get the stall right the first time, as many of our builds we have already done before.
The biggest "flaw" we find is that customer will ask for a stall which too tight a stall for their situation.
Like most life lessons, I was one of those customers as when my race car was going faster especially with a larger turbo, and I needed a converter for a race and could only borrowed a 5500 stall 8" to replace my 10" 4000 stall.
My car never performed better and I still use it to this day. I did take it to a 5000 stall when I had it freshened after a couple seasons when I slowed down the car for a specific bracket class.
Personally I could give a damn less about how much slippage I have at the top end, as the race is decided by my reaction time and ET, so it is extremely important how it works off the starting line!
The point here is the typical owner which has no converter experience needs to consult an experienced person with experience similar to your build to help you make the right choice.
Even at best, we still call that an "educated guess", not an absolute number!
Choosing a converter is not a calculated or scientific number since there are so many variables with the car build, how it will be used and "feel" to the owner.
A good answer comes from experience and knowledge gained by doing LOTS of converters for various builds and situations.
Even the most expert "converter" guru can only provide a guess, as most suppliers offer at least one free re-stall if the customer is not happy with the results.
In the early days it was not unusual to do 5 or 6 converter changes to obtain the best overall performance. If we do not get it right the first time now, usually one, maybe 2 changes will get it spot-on in a competition situation.
Most times now with a street build we can get the stall right the first time, as many of our builds we have already done before.
The biggest "flaw" we find is that customer will ask for a stall which too tight a stall for their situation.
Like most life lessons, I was one of those customers as when my race car was going faster especially with a larger turbo, and I needed a converter for a race and could only borrowed a 5500 stall 8" to replace my 10" 4000 stall.
My car never performed better and I still use it to this day. I did take it to a 5000 stall when I had it freshened after a couple seasons when I slowed down the car for a specific bracket class.
Personally I could give a damn less about how much slippage I have at the top end, as the race is decided by my reaction time and ET, so it is extremely important how it works off the starting line!
The point here is the typical owner which has no converter experience needs to consult an experienced person with experience similar to your build to help you make the right choice.
Even at best, we still call that an "educated guess", not an absolute number!
