noob wastegate question

[chrisb33]

ive always used an internal wg for simplicities sake but now with a bigger turbo, i decided to use a hotside for an external wg set up. my questions are:

1. what's the difference between a v-band and a two bolt?
2. for the spring rates, what are they for? minimum hold or maximum hold? i want to be able to boost upto 30 psi. what spring rate should i get

this is what im looking at to buy:

click

btw, ive been searching all over here and the tuners but didnt get much answer on question #1.

TIA

chris b

 

[turbowop]

The wastegate in your link uses a two-bolt flange, hence "two bolt". V-bands are a clamp that go around a flange on items you're trying to connect together. Same way the turbine housing is held on to the center section of a Mitsubishi turbo like the 16g.
For some reason those wastegates in your link associate "v-band" with the way the top hat that covers the spring is held on, compared to the bolts that hold the others on. If I were you, I'd look into something better quality like Tial.

Spring rates are rated for minimum boost. If you have a 15psi spring, that is the least you can run. Add a boost controller for more boost. I use a 15psi spring in my Tial 44mm wastegate and have no problems holding 30psi.

 

[chrisb33]

thanks. it makes it a bit clearer now. my buddy at the tuners recommended this brand and swears by it.

so please correct me if im wrong, if i want an external wastegate to fit into this and then have an 02 dump set up...and want to boost upto 30 psi, i get a 15psi spring and a 38mm wg? i read in some article that if you have a big turbo and you want to boost high, get a smaller wg. if you have a big turbo and want to boost low, get a bigger wg. is that correct?

also, is it true that if i get a lower spring rate, then i can only up the boost by 1.5x? or does it depend on your boost controller? let's say i get a 8psi spring can i turn up the boost via mbc to 30 psi? or would that spring just give me a spike at 30 psi and then not hold thus tapers down the boost lower and lower?

 

[1qkfwd]

To anwser your first question, the v-band will clamp down evenly around the base of the wastegate. The two bolt will clamp down on the outer edges thus leaving a chance of blowing out the gasket in the center. It doesn't happen all the time but there is that chance. I'm sure if you run a bigger turbo with a smaller wastegate, it would seem there's a chance of boost spiking. You can almost compare that to say a 16g with 3" exhaust and a stock size flapper valve. The normal fix here is to run a bigger flapper. On the spring choice, don't quote me on this but I believe that you need a spring that's half of the max boost you choose to run. Running to small of a spring could lead to all that exhaust pressure blowing the spring open to early and not being able to hit a higher boost level.