98Z28CobraKiller

iTrader: (17)

I have been under the impression that you can only go slightly more than double the spring PSI on the gate. I was discussing this with a buddy of mine that owns a speed shop and he disagreed. He said that in their old turbo race car, they could build 30+ psi on a 7 psi spring and control the entire range without CO2.

Does this sound correct? It made sense that the more boost you make the harder you are pushing on the back of the wastegate which should keep it closed. I've been thinking about it all night and the only thing that I can come up with is that the boost ref port on the side of the WG has to be being messed with or not used at all.

What do you guys think?

Phil99vette

iTrader: (11)

4 psi spring here, we run as low as 3.8psi with co2 in the 40# of boost range.

98Z28CobraKiller

iTrader: (17)

I know that it can be done with CO2. What I am asking is, is there a way to do it without CO2?

veee8

iTrader: (40)

I had .5 bar spring a TiAL 60mm gate with no CO2 and hit as much as 21 psi pretty easy with no signs of creep. I m sure it could have went higher if needed.

Johnv

I think it depends on your setup, if you have excessive exhaust back pressure before or after the turbo it will greatly effect your wastegates efficency.

98Z28CobraKiller

iTrader: (17)

So the CO2 is just to increase the level of control on the boost controller? Faster ramp and such?

98Z28CobraKiller

iTrader: (17)

What controller? How did you have the ports hooked up on the gate?

toretto

iTrader: (12)

As long as you have both ports hooked up, you can go at least 3x whatever spring you have in there on a decent brand waste gate.

Top port would go to the boost control solenoid, bottom port goes to the charge pipe.

< Done 35psi on 9lb spring on Tial 44mm.

Johnv

I've seen seen a 4" outlet turbo, with a restrictive 3" exhaust (flowmaster) have 17psi of spring in a 50mm gate and would only make 7.5 psi boost.

Exhaust was replaced with a 3 1/2 " and freer flowing muffler and boost shot straight to 17 psi and spooled twice as fast.
in fact it went from not being able to make enough boost , too having trouble controlling to much boost lol !!