i'll try not to make this drag on too long. You gotta read this for things to make sense. LOL

I'm running the Stillen Stage 3 SC. I started out with stage 1, and when i was installing stage two i noticed something odd.....When you get the kit they send a tube of this sealent made by locktite that seals the upper and lower "plenum". (for those not familiar with Stillen, you do away with your stock upper and lower plenum when you get the blower. The new "plenum" is more like a box with a lid. The heat exchanger sits in the "box" part, and the blower is mounted to the "lid") This sealent, according to them, is the ONLY think you can use to seal the upper and lower plenum together. They claim that anything else would blow out under boost. (Be aware no gasket is used either just metal to metal with this sealent in between.) So far this makes sense. But here's where things get wierd. The claim that this sealent ONLY hardens in the absence of oxygen, and is the only thing that can take the boost.

Now someone please prove me wrong, i may be all f'd up. Normaly RTV is used to seal the minor gaps between two mating surfaces. It hardens and makes an air/water tight seal. Now this stuff they send ya stays liquid where there are gaps. Because with gaps comes air and oxygen thus it never hardens! (remember they claim it only hardens under the absence of oxygen) I confirmed this when i opend my "plenum" up to do the stage two upgrade. Nearly all of it was missing, and only a few spots were totally hardened. What remained that wasn't hardened was still just as liquid as the day it came outta the tube.

The reason this all really started to concern me is because i installed a boost gauge today for the first time since i went FI. And under ideal conditions the most i could boost was 5.5 to 6 PSI. It's a brand new autometer ES series mechanical gauge. Bare in mind i should be running 7 PSI @ stage three. There's only a couple places you can leak on this setup. Thus i feel the weak link is the crappy seal on the upper plenum using the crap they sent with it to seal it.The other being the hose to the SS box. But i have listened all under the hood with a hose to my ear and could hear no signs of leaks. But obviously i can't be under the hood at full boost which is probably when it's loosing it.

So to wrap this up.....FI is FI when it comes to PSI. I'd have to believe that the guys with turbos or pro-chargers etc., have to be using normal RTV and not blowing their plenum seal. Any suggestionns?? Am i stupid?!?!
Can boost gauges be off that much??

 

i make 5.8 psi and i should b at 7psi.... but they say i lost 1.2 psi due to my headers.... thats a lot of psi to be losing due to headers i heard it should be like 1/2 a psi.. not 1.2psi.. i think mine might be leaking too?


take it off and reseal it and see if it helps :P then let me kno so I can do the same..


But stillen inspected my supercharger and everything to look for problems and said everything is normal... but with stillen i dont know what to believe

 

Yeah i don't think headers should make ya loose that much either!
I think i'll use regular RTV and seal it at some point this week and see if it makes a difference. I'm stock except for Nismo cat back. So should be seeing close to 7psi.

 

It is a known fact with this type of s/c that you will loose boost with a free flowing exhaust system.1.2psi of lost boost i would say is normal with headers as this s/c was designed for the stock exhaust.I never saw more then 8psi even on stage 4 and if i recall on stage 3 i dont think i made 6.5psi.
I wolud think you could use the grey silicone and not have any problems cause that is what i had to use.I never had a problem with the grey silicone but it was only on for 2 months and then i put the turbos on.

 

use the copper rtv its much stronger than they gray type for this type of application.

 

Great i'll give it a shot.

 

i boosted 8 psi on the stage 3 gold pulley.... :P

 

Wow!! No wonder it was making wierd noises!! I think i know why you were running lean now!! lol My A/F gauge is pegged at rich at WOT on stage three. I think once/if this RTV issue resolve some of my lost boost, it'll be a lil less rich.

 

Interesting side not on having aftermarket exhaust with tthis set up....

I only have a Nismo cat back. Headers/cats are stock. BUT i also have an electric exhaust cutout just before my muffler. And open or shut, at least in the 1/4 mile, made no difference other then being deafiningly loud inside at WOT. I ran consistant.
So i think the biggest issue is changing out headers/cats with the Stillen, at least in my case. Not sure abotu other aftermarket exhausts.