Tripower setup question
Thread Starter
Pro
Joined: Nov 2008
Posts: 543
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From: Riverside CA
Tripower setup question
Many years (25+) ago I had a tripower on my first Corvette, a 1970 LS-5, and could not get the secondaries to open...again that years and beers ago.
So now, I'm going to install a setup on my '69 L-36. The carbs were in very good condition and required only minor cleaning and rebuild. I'm not going the full show route, so wasn't too concerned about new coatings.
I used complete Holley rebuild kits and replaced both vacuum diaphrams and installed plain springs to start with as a baseline. I have tested the secondaries using a vacuum pump and they seem to open fine and don't bleed down. I called Holley tech yesterday for some advise on opening rates and was advised they (secondaries) under WOT never open 100% as Chevy designed them that. Is this true?
Also, are there tricks to do (other then swapping springs) to bring the secondaries in and open 100%?
Eric
So now, I'm going to install a setup on my '69 L-36. The carbs were in very good condition and required only minor cleaning and rebuild. I'm not going the full show route, so wasn't too concerned about new coatings.
I used complete Holley rebuild kits and replaced both vacuum diaphrams and installed plain springs to start with as a baseline. I have tested the secondaries using a vacuum pump and they seem to open fine and don't bleed down. I called Holley tech yesterday for some advise on opening rates and was advised they (secondaries) under WOT never open 100% as Chevy designed them that. Is this true?
Also, are there tricks to do (other then swapping springs) to bring the secondaries in and open 100%?
Eric
Race Director
Joined: May 2006
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Place a paper clip on the rod coming out of diaphram housing. Drive the car including WOT, if the clip moves all the way, the secondaries are opening all the way. The spring stiffnes is all that controls the secondaries.
Le Mans Master
Joined: Apr 2007
Posts: 7,353
Likes: 72
From: Graceland in a Not Correctly Restored Stingray
The "trick" is to use the weakest secondary diaphragm springs you can get away with without causing bog at WOT under load, and NOT to try and re-invent the linkage. Just get the primary carb dialed in with the linkage removed, and only hook it back up afterwards so that it just closes the secondaries with the primary throttle plates at idle. Then, let the vacuum secondaries do their thing. IMOE, with a properly setup 3x2 in good working order, demand will take care of how far they need to open just fine without one messing around with them (BTDT). If not, something other than the design is wrong.
edit - Secondary spring kit is Holley #20-13, 2 required.
edit - Secondary spring kit is Holley #20-13, 2 required.
Last edited by TheSkunkWorks; Aug 10, 2011 at 04:20 PM.
Le Mans Master
Joined: Oct 2000
Posts: 6,209
Likes: 33
From: Texas-out west
skunkworks has it right, and I also have been there done that on org 67 435 in 70 and a 70 ls5 with tri added in 73, good luck, love the tri-power
sold my last one in74 for $125 and also sold a 66 olds tripower for same price
not selling them...wish in one hand and spit in other and see which fills up first
sold my last one in74 for $125 and also sold a 66 olds tripower for same pricenot selling them...wish in one hand and spit in other and see which fills up first
