I installed a FAST 102 intake on my 1997 C5. 1st I had to drop the motor 1/4 inch to get it to fit under the wiper cowl at the back of the motor. Then after pulling it off several times because it wouldn't seal I figured out the front of it was resting on top of the water pump. I had to grind off the top of the Water Pump and some of the casting around the top mounting bolt. I then noticed the LS2 throttle body didn't completely cover the seal to the manifold at the bottom. I made a plate to put between the throttle body and seal completely. I switched the bolts out with the button heads on the valley plate like you are supposed to, torqued everything in the correct order and used blue locktite on all the bolts. During all this I took the intake completely apart, cleaned it and replaced all the seals. Re siliconed the area at the back where the seal comes together. Every time I start up the car it runs fine and I don't hear any vacuum leak. After about 20 to 30 minutes of driving I can start hearing the whistle come back. I am at a loss as to what is going on. I have tried spraying carb cleaner around the intake to see if I could find the leak by a change in the idle. I also made up a pressure tester that I saw in another thread. I couldn't find any leaks using soapy water. I haven't noticed any place where the intake is hitting on the bottom but I saw in the LS1 TECH site a person counter sunk his valley plate and put in flat head screws. That is my next step unless someone has any other ideas. I am very frustrated with this thing. I have never had a problem with any other intake I ever changed. I will say this is the first composite intake I have ever done. Has anyone ever had this issue before, a vacuum leak that develops once the engine fully warms up. I will be contacting FAST again tomorrow. I don't know if I am missing something. This is really bugging me.

 

Which steam lines are you runnning? On my FAST 90, I had to gently bend down the front line as the intake was contacting it.

 

Sure sounds like a no fit piece of crap to me!

 

I am running the new style. Front only. Yes I did bend it down. It is clear.

 

What mods do you have to support the need to run a FAST 102??

Can you plug all the manifold inlets and outlets and try to pressurize it and see if it holds pressure. What shape are the manifold intake O rings in. If there flat, they may not seal very well. I used FELPRO replacement intake opening O Ring Seals and they seemed to fit fit a litter better than stock.

 

As far as mods I just have a honker cai and installed AR headers. I was doing the 102 to get ready for a HC combo. From all the suppliers and FAST they said it was fine to do first. I got rid of the air pump junk. I pressurized the manifold and can't find any leak. It only does it after the car is totally warmed up. I replaced the PCV tonight and unplugged the EVAP soleniod and switch. I plugged the manifold where it connected and plugged the evap line. The only thing that did for me was throw a code and I still have the noise. I am to tired to look at the codes tonight. I replaced all the interior gaskets and FAST is sending me a new set of port gaskets to use.

 

I finally figured out the problem. It is in the PCV lines or the valve. I replaced the valve but didn't play with the lines to much. After disconnecting one of the lines going into the valve cover on the passenger side the sound completely stopped. I am wondering if the air flow has picked up enough that I need a bigger PCV valve. Anyone have any ideas?

 

NO! The PCV valve flow rate is designed around Crank case volume and normal piston ring blow by. The PCV valve controls the air flow thru the engine crank case during part throttle and idle conditions. At wot, the valve is wide open and the gasses flow out of the valve and into the intake without regulation. The Variable Volume PCV valve maintains proper flow thru out the RPM Band.

Unless you have badly worn rings and have excessive blow by, your good to go.

BC

 

I figured that out after talking to someone with experience. This is my first car with all electronic throttle control. After thinking about it. Unless you tell it to do something different it is going to keep right on doing the same thing. I have an appointment with a tuner Saturday. I have it rigged to run with a vent breather. Thanks for the reply.

 

Had the car tuned. It is running great. Some people say the 102 is to big for stock. I really think getting these LS1 motors to breath first is the right way to go. My biggest issue wasn't even what I thought it was. It was just a fitting on the PCV lines collapsing. Another lesson learned.

 

Obviously, the shop that sold that intake is far from un-biased, and the tuner is being polite.

That sewer pipe size of an intake opening is hardly needed on anything but the wildest n/a 346. Even with crazy FI builds people have better control over their rear tires with the smaller/stock throttle body.

Reminds me of the people who buy (and I have one guy in the middle east constantly PM'ing for advice) those "crack pipe cams" with duration way beyond what any 346 can use on the street. Sure the hp numbers look great, because they are being revved to the moon. Funny how the actual TORQUE is no better than a normal/aggressive 224-230ish cam.

Same with intakes. Spending a cool $grand on intake and Tb, to have a sog-mobile when an LS6 wouldve been crisp is beyond me. Most people rarely follow through on future mods (and it takes a lot to need a 90/92 or 102) to make sense.

Hell, I bought a near complete Procharger for 2300 with the total cost for an upgraded setup no more than $3200 total all sitting ready to go.

I'd advise before you get the cart before the horse (the path you've started on) you look at the used section and ask plenty of questions before your next purchase.

Just saying I've been where you're at many years ago and I'm trying to save you money while giving more power and Torque for your cash.

P.S- your screen name brings back memories of both the the '57 283/270 I restored to 997 points out of 1,000 and the '57 Bel Air that took 6 years to complete. BUCKETS o' parts to make them complete.

 

some people can be harsh yes. The reason some people state these facts is bc some individuals will get parts not needed and then wonder why their car doesnt perform as it should. Personallyyou didnt do any wrong in getting the intake. If and when you do your H/C setup its just one less piece of the pie....understandble. However like someone has posted. A lot of guys never make it to "said" setups and end up stuck. These guys are just simply stating for a mainly stock 346, its overkill by a long shot. You may lose a lil torque on the low end. They just see the same thing posted time and time again and everyonce in a while, some will get aggitated. Its all good

 

Every car I ever moded (25 years ago) I made the motor breath first then started on the big stuff. I am doing the H/C package I am just researching what is best for my needs and saving my money. I have been talking to people that I know have real experience not just what is posted in a forum. After that its a new clutch set up and a set of 410 gears. I don't owe a dime on the car or any of this stuff. This car only has 51000 miles on it. When I am done with all new parts. I will have what I personally want and be able to say I did all the work myself. I guess I am old enough to know it isn't worth getting upset over. Life is way to short to be nasty. I am just trying to have fun while I still can. Hopefully I will be able to leave this car to someone who will appreciate it and know the man who made it that way.

 

Then "some" need to either answer the question and be helpful OR move on to a topic that is more interesting to them. If those individuals are having trouble with that concept I will be happy to help them move along. Trust me as a 10+ year member and Moderator I see a whole buncha crap over and over and over again but everyday we have new members who have questions and even old members with a "new to them" problem and sometimes the search doesn't get you the answers you are looking for. Everyone was a n00b once and everyone is not an expert if they were we wouldn't be here.

If you are not being helpful you are in the way. If you want to be sarcastic we have an Off Topic section.


Carry on