Boost Control Solenoid restrictor
Evolving Member
Joined: Dec 2002
Posts: 447
Likes: 1
Hi Timzcat,
You state that the restrictor is one inch from the hose that goes to the controller. Do you mean the actuator? This has me curious, because I know on the Evo VI there are two restrictors, one near the solenoid and one near the wastegate actuator. Enlarge or remove the one near the solenoid equals more boost. Reduce the hole size in the one near the actuator equals more boost. Do we have more than one restrictor in the US Evo? Help us all to understand exactly how the US car is plumbed.
Cheers,
You state that the restrictor is one inch from the hose that goes to the controller. Do you mean the actuator? This has me curious, because I know on the Evo VI there are two restrictors, one near the solenoid and one near the wastegate actuator. Enlarge or remove the one near the solenoid equals more boost. Reduce the hole size in the one near the actuator equals more boost. Do we have more than one restrictor in the US Evo? Help us all to understand exactly how the US car is plumbed.
Cheers,
Originally posted by timzcat
CT9A, I can feel the difference, too but it's not huge. Although I had a nice 4 wheel drift going tonight in the rain around a corner.
I am enlarging it because with it removed it is peaking at 22PSI which is kind of high. I don't want the ECU to start pulling timing, not to mention it is summer time. I already did the enlargement tonight to 5/32 which is the only choice unless you can get a 9/64 drill bit (smaller). I will put it in tomorrow and see what happens.
I am hoping it will knock it back to like 20-21 peak and maybe hold 17 or 17.5 up to 7K.
CT9A, I can feel the difference, too but it's not huge. Although I had a nice 4 wheel drift going tonight in the rain around a corner.
I am enlarging it because with it removed it is peaking at 22PSI which is kind of high. I don't want the ECU to start pulling timing, not to mention it is summer time. I already did the enlargement tonight to 5/32 which is the only choice unless you can get a 9/64 drill bit (smaller). I will put it in tomorrow and see what happens.
I am hoping it will knock it back to like 20-21 peak and maybe hold 17 or 17.5 up to 7K.
I am at work, I will try it tonight when I get home.I laughed because it wasn't due to the rain, I had to get a drill bit.
Like any mechanic, all the small bits are always broken so I didn't have one.
Originally posted by wtz
Hi Timzcat,
You state that the restrictor is one inch from the hose that goes to the controller. Do you mean the actuator? This has me curious, because I know on the Evo VI there are two restrictors, one near the solenoid and one near the wastegate actuator. Enlarge or remove the one near the solenoid equals more boost. Reduce the hole size in the one near the actuator equals more boost. Do we have more than one restrictor in the US Evo? Help us all to understand exactly how the US car is plumbed.
Cheers,
Hi Timzcat,
You state that the restrictor is one inch from the hose that goes to the controller. Do you mean the actuator? This has me curious, because I know on the Evo VI there are two restrictors, one near the solenoid and one near the wastegate actuator. Enlarge or remove the one near the solenoid equals more boost. Reduce the hole size in the one near the actuator equals more boost. Do we have more than one restrictor in the US Evo? Help us all to understand exactly how the US car is plumbed.
Cheers,
Well at 5/32 it looks like I am getting 20.5 to 21.0 for the surge and then it drops down to 18.5. Remember I have a 3"DP too so that has some affect. I deally I'd like to see what a 9/64 hole would do but that is not a very common drill bit and I can't drill smaller now.
As far as I can tell that is the only restrictor in the lines.
If anyone decides to attempt this mod, be sure and be careful with the restrictor when drilling it out. I basically used a pair of pliers to hold it. Wasn't easy but I didn't over squeeze it and collapse it so it was worth the hassle. Once drilled you could definitely collapse it, but I am not talking fragile.
I drove it a bit and have a really good idea where it's at. The peak is the hardest to see cause I still have to watch the road. If I find any variation in these numbers while driving tomorrow, I will update the post.
As far as I can tell that is the only restrictor in the lines.
If anyone decides to attempt this mod, be sure and be careful with the restrictor when drilling it out. I basically used a pair of pliers to hold it. Wasn't easy but I didn't over squeeze it and collapse it so it was worth the hassle. Once drilled you could definitely collapse it, but I am not talking fragile.
I drove it a bit and have a really good idea where it's at. The peak is the hardest to see cause I still have to watch the road.
If I find any variation in these numbers while driving tomorrow, I will update the post.
Yeah but the restrictor is inside the hose and unless they take it out (which is a *****) they would never know. But of course if you have a boost guage they will see it, if they are smart enough.
Originally posted by timzcat
But of course if you have a boost guage they will see it, if they are smart enough.
But of course if you have a boost guage they will see it, if they are smart enough.
Now I confused myself completely :0
We have to get together again sometime in August.
The guy doc_evo should be there this time, I am working on his car tomorrow.
If I can get some material, I can make the pills with different diameters. Hmm...
Not to be a captian obvious, but why not try using a MBC? Spiking will be reduced and boost control will be where ever you set it expecially if you tap the boost source from the BOV.