Silvia Club of NSW

Hi guys, recently removed the boost restrictor on my S14a and found an increase of 4 -5 psi, is this around the normal gain from this mod....cheers.

Ohh i did that on my s15. i took a risk and did it with no boost guage hehe oops

just curious how is this done.

i am not quiet sure on the Powergain from the Free Boost Upgrade but i pressume that is a pretty good upgrade just make sure you don't go over the maxium limit which is 16psi? not sure but 12 psi is pretty safe!



This information is found at www.200sx.org

3.18 What's this about a free boost upgrade?
It's true. You can get a 1-2 psi upgrade by removing the boost restrictor on the top of solenoid valve. It is identified by a white band on the hose which goes from inlet pipe to the solenoid valve. This pipe is at the top of the boost control solenoid. If you don't want to cut the hose, just get a piece of 1/4" fuel hose the same length, and replace the original hose with this new piece.

Remember to reconnect all hoses. There is nothing left off or disconnected after this modification. Let me stress this again, There is nothing left off or disconnected after this modification. Take the car for a drive and watch your boost gauge. Make sure there is no major increase or decrease in boost level. If there is, stop and recheck your work!

One or two PSI might not sound much, but remember that the export-spec cars run around 10psi (0.7 bar), this is up to twenty percent, or somewhere about 8-10 kilowatts at the rear wheels. On an S15, we saw 20KW at the wheels. Not bad for nothing!

So, the obvious questions are, why does it work, and will it cause any damage? It works because removing the restrictor changes the pressure signal to the wastegate actuator. From the factory, it is designed to open slowly, and make the transition nice and gentle, by allowing the wastegate to "creep" open a little before we reach the preset boost limit. The restrictor is what causes this creep, by restricting the flow from the solenoid valve. Without it, the wastegate stays shut (or as close as mechanically possible) till the preset level is reached. The opening is now a "snap" operation.

Will it hurt anything? We know of cars which have run this modification for 2-3 years without problems. If you fit an aftermarket boost controller, you generally take the restrictor hoses out anyway. Your mileage and durability may vary.



All credit to www.200sx.org

_________________
Why Drive?... When you can Drift!...

Zei20l is offically SilviaNSW's Post Whore!

damn i wanted to post that picture!

beat me to it u bastard lol

how would this work on a CA18DET

and would there be more power give to my car or nah

_________________
CATCH ME IF YOU CAN!!!

haha zei... Cable wins again!

JET23QU i would pressume so? anyone with a CA18DET done this Free boost upgrade and it worked???

_________________
Why Drive?... When you can Drift!...

Zei20l is offically SilviaNSW's Post Whore!

This thread has been spoken about previoulsy, check in the Silvai forum bit thingo.

_________________
Whoaa!

Der maybe I meant old threads, scroll down.. further.

_________________
Whoaa!

AccessDenied if i was at work. You would have been a dead cabler

Is it the outlet coming out of the top of the solonoid(with the restrictor) the one that you would connect an aftermarket boost controller(like turbosmart) to.

Just want to be sure before I go pulling hoses off

Thanks
Russ

_________________
Russ

Only remove the bit of hose the arrow is pointing to in the above picture, when you pull it out you should see a lil metal thing on the inside with a small hole.

The Gains are definitely there.....but i don't know if it's save or not ...best to have a boost gauge before doing this.

_________________
This is a block of text that can be added to posts you make. There is a 255 character limit

ahh yeah make sure you have the new pipe very secure. the last thing you want is that pipe popping off at 6k

i used a cable tie at both ends of mine just to be sure! I couldnt seem to find the same diameter inside and out as the original pipe.

i just bought some cheapo stuff being the tight ass that i am lol

I have previously researched this subject and this is what I found.

If the car is stock you will notice a big difference in power from removing the restrictor. I have seen dyno results showing a 20 RWKW increase. It seems to vary from car to car but peak boost will rise by 2-3psi. The problem is it will cause the boost to spike by a few psi, usually on hard gear changes.

If the car is modified the increase wont be as much as boost will already be higher from the mods, however depending on the car still good for about 10rwkw. The problem is bigger boost will cause bigger spikes.

How dangerous these boost spikes are I am not sure. I think it depends on how high they are.

_________________
A computer beat me at chess once.
But, it was no match for me at kick boxing.

Sooo which hose would you connect a boost controller like a Turbosmart or GFB manual dial adjustment boost controller.

Don't want to rise spikes by removing the restrictor.


Regards
Russ

_________________
Russ