Just got in My Forge MBC,

Overall thuis is an awesome looking piece of equipment, i installed it with the soft spring and got 18lbs

I swapped out to the stiffer spring and on the lowest setting i'm getting 25lbs, i did notice that the spring is sitting in front of the base and not on it like the softer spring was, should i just try and force it on to the base to eliminate the initial preload?

FYI the boost guage is not the problem.

 

when fitting the heavier spring, you need to be sure that it is properly seated on the nipple inside. I got a fiver saying you don't have it seated all the way. there have been seveal of these threads already, I'm just too lazy to look to one to cross reference.

 

yeah, Juiced, you should be able to get lower boost than that on the stiff spring. The soft one maxes out at 22 or so (10psi over base wastegate pressure).

What I will be doing is installing the Forge WGA with red spring (19-24psi), and have the tension set to 20psi, so that I can never run lower than 20 even above 7k rpm, but I will then use the soft spring for adjustment in the 21-25psi range for both pump and race gas. This should be a great combo along with the adjustable Forge RS BOV - suits my daily driving and race modes perfectly.

 

100% on point.

 

Yes, should be seated all the way down regardless of which spring is in the Forge MBC. I remember this being covered in a previous thread.

 

I searched and went all the way back to Aug of 05 reading every thread With Forge/MBC/ or Eunos in the title. I just couldn't find a definative answer or even approx boost pressure with each spring (and yes i know each is car will vary)
Anywyas thanks for the help i'll be pullin the Controller out at lunch and trying to adjust the spring.

I would go with the actuator too but i'm having a custom manifold made for my turbo upgrade in the spring.

Warrtalon, i had the soft spring to max pressure and only got 18lbs but it didn't taper at all, held 18 all the way to 7500 rpm

 

Then, I would think your boost gauge is off, or the soft spring wasn't properly seated either. It provides +10psi at max stiffness, which would be 21-22psi with our stock wastegate.

 

i've tested the guage and it's all ways been right on,

when i swaped out controllers i moved the source over to the FPR instead of the BOV line.

It still pulls 15 in/mg at idle except now while driving it's between 5-0 in/mg. instead of the usual 10 it use to before. when i totally let of the throttle is drops down to 20 in/mg like it did before.

anyways thank for the help.

 

Warrtalon, do you have a problem with the Forge RS DV fluttering at partial throttle no matter how its adjusted? In 5th gear, I can't even hit 10 psi without the car jerking and the DV making this funky sound.

 

I gave a full review in this forum, but no, at the softest setting, it's not a problem. There's always going to be SOME surge in top gear with part-throttle, low-boost throttle lift. My MR DV does it just the same, but the RS on the softest setting barely does it. When I went to 10 rotations, it did it a lot and was uncomfortable. I'm now at 6-7 rotations and it will happen if I screw up in 5th or 6th gear, but it's well within my acceptance level. I have never heard any fluttering sounds, but I do get the compressor surge. It's the trade-off from having a stiff BOV that holds all your boost. Luckily, in this case, I can stiffen it at the track for maximum boost retention, and loosen it for daily driving to make highway cruising less annoying.

 

At the softest setting as in with the dial turned all the way counter clockwise? I thought that with the dial turned all the way counter clockwise, it will only hold up to 7 psi. Maybe I'm just confused between flutter and compressor surge. As it is right now on my car, its not suited for daily driving.

 

Yes, all the way counter-clockwise on the BOV. 7 psi?? No way. Our car is not even capable of running less than 11psi with the stock wastegate actuator. The RS BOV holds boost just as good as my MR DV even on the softest setting. I put it all the way to the softest setting, installed it, then went out and ran 22->20psi like it was going out of style. I tightened it up to 10 rotations and started seeing a higher boost spike with less taper, but at this stiffness, it would surge in gears 4-6. Surge is when you go part throttle with only low boost built, then let off the gas. This causes the boost pressure to go back to the turbo and try to spin it backwards, because there's not enough pressure to open the valve (too stiff). When this happens, the car bucks and is very uncomfortable. I don't know about flutter...people always use that term and I'm not sure if they know if that's the right term or not. Maybe they have intakes and hear what sounds like a fluttering noise when compressor surge occurs? I have the stock airbox, so most of my sounds are muted.

Anyway, when I turned it back down to 6-7 rotations above the softest setting, it still holds all the boost I can run on pump gas without appearing to taper much, and it only surges in top gear with poor driving (e.g. starting to accelerate then quickly letting off just as boost begins to build).

 

Thanks for clearing this up for me. It was in this post #78 that Mike@Forge mentioned about it holding 7 psi with no tension on the spring.

 

yeah, I'm not sure exactly what Mike meant, but I don't believe that means it will only hold 7psi of boost without leaking. Maybe 7psi in addition to the regular 11psi provided by the wastegate? I'm not sure what that meant, but I know I held 20psi to redline in 2nd gear on the softest setting according to my boost gauge.

Here is a quote from HKFeet that mimics what I've been saying:

"Well lately I had the tension set real tight, almost max to see what kind of boost my car can make with my xede maps, and it does flutter at partial trottle lift. I havent experienced any fluter with the way I had it set before at a loose tension.

But honestly, every valve, stock, jdm mr, old forge, fluttered on me. I changed my driving style and just lift off completely instead of slowly when Im on the highway."

Exactly what I've been saying...even down to the "driving style" comment. Letting off slowly from part throttle in high gear causes the worst surge, but just letting off completely allows the valve to purge more easily.