Yah, it's not so warm out there right now. So I went and pulled my wastegate off, pulled the top off, and it looks like I do only have the .8 bar (11psi) springs. I wonder if that's what is causing it. I'll have to see if Rally Sport has springs for this wastegate on Monday.

 

what color were they? if i feel better i will tear mine down and see what i have

 

Mine are grey and maroon, but I think the ones in the MV-R like I have are different than the ones in the F-38.

If you have the F-38 this is your spring rate color chart:

http://www.tialmedia.com/documents/w3_tial_38_sp.pdf

 

how do you determine what springs to run? i was looking at the chart, but it just says to combine springs. so how does a wastegate exactly work? does the waste gate open based on the spring or springs that you have?

 

Yah the wastegate opens based on the springs that are in it. Boost control affects how much boost the wastegate sees, but an 11psi spring starts to open as soon as it sees 11psi.

I believe you should get springs that are close to the boost you plan to run, but not exactly there. Whatever pressure rate your springs add up to is the pressure your wastegate will start opening at, so for instance going off that chart if you had a big red spring in your wastegate, your wastegate would be set to start opening at .8 bar (11.6psi). So say you wanted to raise your spring pressure a bit, you could add a small spring to your wastegate with the large red spring you already have. You could add a small red spring to the wastegate for a total of 17.4 psi spring pressure.

Just remember spring pressure doesn't exactly translate to boost pressure, it's just basically the MINIMUM pressure you could ever have. For example even though my spring pressure was only 11psi, when I had 0 boost control going (so it should be running only spring pressure) my turbo would still build 18-19 psi.

Does that make sense?

 

with a bigger turbo and higher boost you need to run a bigger spring, running a 11lbs spring on a big turbo that is gonna run 20+ lbs its probably gonna creep

 

So if I wanna run 29-30lbs on race day but a conservative 23-24 as my DD, what springs should I get? I don't wanna have to keep switching springs back and forth to run lower or higher boost.

 

This sounds like you had a boost leak which made your turbo pump 18-19psi. If you have a 11 psi spring on your wastegate and you connect the vacum line of the wastegate straight from your boost source, you should only boost 11 psi all the time. something else was going on in your car IMO. or the wastegate is mechanically malfuctioning. But theoretically, spring rate of your actuator should dictate minimum boost pressure since the actuator is ultimately what controls your boost and there for the spring regulates that. Unless the diagphram is busted or the 11psi rated spring is actually different once installed.

Edit: i guess there is always the possibility that you where measuring your boost right after the compressor and therefore without taking into consideration the pressure drop of the system, you saw higher boost. but I've never heard of pressure drop in a system of 6-7 psi though, therefore the boost leak should have been after wherever you're reading boost from.

 

your boost controller should be able to adjust boost levels accordingly. what i have always done in the past is get the wastegate spring to whatever my minimum boost levels are (say 18psi for example). then the boost controller can add your additional pressure to keep the wastegate closed until the desired boost level (say 25psi for example). that's the whole point of the boost controller, you can do a manual or electronic.

 

I'm not sure if there's a boost leak, there's at least not a readily-noticeable one as I've gone over everything before. I think it's possible it could just be boost creep from the turbo. The combination of the equal-length tubular manifold, ball-bearing turbo, etc may mean the turbo just creeps that high even with the wastegate fully open.

It wasn't hitting that much boost until way high in the rev range, and when the tuning was changed so there was more timing it actually dropped the boost it was hitting about two pounds. So that's why I'm thinking it may have been more of a boost creep situation.

Boost was/is measured off the manifold by a map sensor.

 

I'd go with 21 lbs, that's what I'm probably going to try.

Exactly what I've heard/thought. I hope to try 1.5bar springs, I just think the .8 bar has to fluctuate too much trying to maintain the 26lbs I'm running right now.

Love your signature btw!

 

agreed, that's a boost controller. however, it is possible to tune to the desired psi WITH a boost leak present and not know it. obviously if wgdc allow.

maybe i don't get what you're saying but i don't see how increasing nothing but timing would lower your boost. Are you runing internal wastegate or external? have you ever ran on pure spring rate? meaning, connected your vacumm source of the wastegate to the boost source of your turbo? that would give you an idea of how much pressure drop there truly is in your system.

i'm not sure why people would rate springs in "bars" since barometric pressure changes with elevation. 1 bar in sea level = 14.7 psi. 1 bar at 4500 ft = 12.36psi (ish). so if you ran a "1 sea level bar" spring here you would actually be at 1.15 bars here.... but yet 1 psi at sea level is the same as 1 psi here. i know i know, not with the same number of oxygen moles and density of air but that's not what i'm referring to here.

 

Criptballer, so your saying that if I hook up my wastegate straight to the turbo nipple on the compressor housing it would only boost max depending on whatever spring I have? So say I have a 11psi spring it would only boost 11psi correct?

 

exactly correct. and i bet you'll boost less than that because of the pressure drop in your system due to intercooler piping intercooler and so forth.

edit: by boost less i mean, the actual boost that reaches your intake manifold where you are reading from.

 

sounds to me like there are a couple things going on, not just one problem. i agree with criptballer, i'd get a boost leak test. that's simple and will rule out a lot of variables once you know the outcome of that. then go on to messing with the wastegate springs. the bcs should be able to change your boost level by a lot that you shouldn't really need to change springs. i could run 25psi on an 8psi spring just by adjusting wgdc. i'm sure you'll get it all squared away though, it's not really that complicated when you break it all down.