Holley vac secondary springs

[kayjayd]

I had my car tuned on a rolling road the other day and one of the things that became apparent was that the secondaries weren't opening till about 4000rpm.

I've got myself a set of secondary springs from Real Steel to have a bit of play to see if I can get the secondaries opening earlier in the rev range. The Holley manual says the default factory fitted spring is the stiffest (black). Any tips on which one I should try first out of the other six in the kit?

The tuning guy the other day said go for a lighter spring, but if you feel a hesitation when the secondaries kick in go one spring stiffer. Does this make sense?

Quite enjoying this engine tinkering lark as I've had garage withdrawal symptoms since finishing the car

[dingocooke]

yes he is right, the holley bods usually say the lighter the car the lighter spring, being a bit analytical I would work my way down from what Ive got one spring at a time.

[Marty V6]

Kev,

Where was the rolling road that you used? I could do with setting mine up as its currently spitting out foot long flames on the over run - looks brilliant at night !!! Then again, I might just leave it as it is......

[kayjayd]

Hi marty, it was bogg brothers just outside of malton. A bit of a treck for you but they know their stuff, Warren has had his car sorted there too, well recommended.

[Warren]

Hi Marty

There is a link from one of Kev's previous posts, it's at East Lutton. You can do the back roads or toddle straight down the A64 toward Scarborough and follow the turn for West Lutton. You will pick up signs for East Lutton as you go.

Regards
Warren

[Warren]

Hi Kev, I think the sticky at the top has various links to spring colours and what not. There's also a quick change kit available so you can play around.

Cheers
Warren

[kayjayd]

I've just had a couple of hours trying out different secondary springs and got it working perfectly. I settled on the second weakest spring in the end as the weakest gave a slight hessitation at about 2500rpm. The power delivery is very smooth and a big improvement.

What with the rolling road session on Thursday and the secondary fettling this morning I'm very pleased with it. I wanted it fast enough to properly scare me and it does

[gd02 cob]

Kev,

A good way of establishing if the secondaries are opening fully is to place a paper clip, appropriately reshaped, around the actuating rod connected to the diaphragm. If the clip is positioned before your run at the top of the rod, you will be able see afterwards how far it has moved down the rod therefore showing the amount of movement.

Nick