Tripower secondary diaphragm spring swap

[James H.]

Has anyone changed out the stock diaphragm springs for the weakest type (Holley kit #20-13) thus allowing the secondaries to kick in sooner. I read this trick on a different forum. Kind of makes sense though. If it does work is it as easy as removing the covers and replacing the springs? Sounds too easy to be true.
Right now when I accelerate hard (67 and 68 400hp)I don't seem to feel that push in back of the seat sensation.
I've read of ways to put grease or a paper clip on the actuators to see if they're opening but haven't tried that. Cars are put away for winter but started to think about getting them out soon.
Thanks all,
Jim

[Timothy B.]

Re: Tripower secondary diaphragm spring swap

James,

IMO, check with grease/paper clip to see if the secondary's are opening completely.

If you have a stock motor and change to a different tension secondary opening spring you will probably slow the motor because a bog and that seat of the pants secondary operation (feel) takes time for the engine to recover from. The best operation is not to feel the opening of the secondarys and the motor has smooth operation.

You will know if the secondary's don't open because the rpm will only go so far and the engine will run out of power (no gas).

[Michael J.]

Re: Tripower secondary diaphragm spring swap

Don't know about all, but since they are vacuum operated, not sure it will make it better. My stock L71 doesn't push you back in your seat under full throttle until it gets over 4500 rpm, but then it is like a turbo kicking in and you have to hold on all the way to 6000 rpm for the shift. The L68 is not as strong, but you still need to get the rpms up before it can use all those CFMs.

[James H.]

Re: Tripower secondary diaphragm spring swap

Thanks Tim and Mike,
Sounds like first thing I do is grease up the shaft and see if they're kicking in. With the weather being so mild here in Ohio I should have kept it ready to go.I bet they are working because at 5000rpm there was no cutting out. Little leary about going much higher than that on my NM motor. I do wish one of my cars was an L71 to feel that solid lifter power.

[Clem Z.]

Re: Tripower secondary diaphragm spring swap

make sure the cork seals are in place between the secondary vacuum diaphragms bodies and the carb body. the vacuum created there pulls the secondary carbs all the way open