I think I'm having problems with my fast intake leaking boost. I was told that the fast had to be siliconed in order for it to hold boost, is this true or just a myth. I was reading on here that people were having good luck with their fast 90/90 setups boosting like 16-20 pounds. I'm only making like 4 lbs of boost at 6500 rpm, waste gate has a 11 pound spring in it with a manual boost controller. My question is do I need to get rid of the fast and go with the LS2 intake or should I just break out the silicone and start glueing the pieces together?

 

Anyboby have to mod their fast intake to hold more boost?

 

I did lots of checking and there are lots of cars running pretty high boost on the fast intakes. Some things I did on the fast are I used loctite on the hardware holding it together. I did put some rtv on there where the factory gasket runs into each other.Its not one solid gasket. I didn't rtv the entire thing. I also put loctite on the
intake manifold bolts and make sure they are torqued to spec..the spec is inch pounds!
Also hope you used the correct valley bolts otherwise you may have cracked the fast.

You have a couple of options.you can make a boost tester out of like home depot piping and bicycle valve and connect up compressor and try to find leak or you can go to a place with automotive smoke machine they are the best for finding leaks.It may be your fast it may be a coupler or leaking somewhere else. Maybe your turbo is toast.Crack in exhaust housing few other things can cause low boost. I likely won't try to boost past 20psi on my fast but not going to be overally worried going to 15psi or so. I should have not used the burst panels.As don't think my direct port can give a damaging intake backfire like a wet single nozzle could. I maybe can just put in solid plates if have a problem or might upgrade to 92 fast ,get it painted maybe ported.

Anyway you can take off the fast and go to ls6 but it might not be the fast. I wanted the option for the direct port.

I could quote a lot of guys that have run the fast no problem. Tony Mamo the guy that ports the fast and afr has lot of experience. I have not tried to go up past 7.5 psi on mine yet.

Aps used fast to like 20psi on their upgraded test mule.Afr has couple of 1000hp fast intake fi engines on their website linked to mag articles. There are many boosted fast engines in the ls1 dyno book.And one company stinson? is running their rx7 ls1 into the 8s with a fast.

 

I'll try the bicycle air test on the intake to see if it leaks, what did you do about the map sensor grommet to tighten it up. My main problem is the boost comes in very late and I can't get anywhere near the waste gate spring pressure. I'm beginning to wonder if the 3in charge tubes are too big.

 

Not sure bicycle pump can do the job compressor is better but can't hurt to try. Auto smoke machines are ultimate . I found leaks on my 97 talon in seconds.

I tapped and drilled the fast intake and put in a big fitting which use as main vacuum feed to ebay vac manifold.So no leaking there at the map.That could be your problem area its crap how the fast don't hold the sensor down like stock intakes.

I will shortly be going up some maybe on my boost levels possibly to 10 or even 12 but may stick low this season just to minimize any potential problems. I was thinking get the 92 fast over winter, get it nicely painted up ,maybe ported. Likely leave off burst panels this time as don't think they are necessary with direct port setup.
And don't really trust them to much. I am not giving up on my fast right now possibly in the future would get a one piece manifold if it can also be drilled out for direct port and use the same kit as have now.
Zex kit is made for the fast intakes. And it wasn't cheap.

 

Ebay vacuum boost manifold actually good quality.





Think switched to 45 fitting after this pic but same idea.

 

I may use my air compressor for the test, how can I measure the amount of pressure the intake will hold. I'm sure it will leak out since the engine is not running. How fast does your boost come in, is there a lot of lag? I can't seem to make any off the line on trans brake.

 

I have a 408 twin turbo with smaller turbos. Boost comes in very quick. Maybe too quick.
I think with compressor it should still hold it for a bit then will leak down of course.I don't usually bother with tests with compressor on my car.I take them for smoke machine test and seal any leaks. It don't of course tell me how much pressure something will hold though. There are numerous fast intake cars that boost to hight teens for sure not sure how many past 20psi.

I don't have a trans brake or auto in my car yet and havent' tracked it so no idea why you can't seem to make any boost off the line. With an auto it should build some.

 

I'll test the intake for leaks tonight and see what happens. I have one big turbo so it takes a while to spool, but I don't think it should take that long. I would expect full boost by 3500 rpm.

 

unless you remove the rockers there will be a valve open somewhere in the valve train and you won't be able to pressure test inlet.

 

If you use a air compressor you will still be moving enough air to build plenty of boost. I always block off the inlet to the turbo and use the nipple on the compressor housing...test the whole turbo kit as well as the intake.

 

If you were losing that much boost from a leak, you'd need to be deaf not to hear the leak.

 

x2 I agree, just did this actually. I had plenty of air volume to maintain a continuious 10 psi. Doing it this way also keeps the bov shut since you have equal presure pushing through the vaccum line.

Just make sure you hold the throttle blade open with some vice grips or something.

 

Well I think I found my issue. I did the air test with my compressor and was surprised, there were no leaks on the charge side at all. What I found was a big a$$ hole on the hot side. It looks like someone put an 02 bung on the crossover tube for a wide band sensor and covered it up with exhaust wrap. I got lucky, cause it was nowhere near where I was searching, go figure.
I put an old 02 sensor in there that I had lying around and it was a perfect fit. My tranny didn't like the extra horse power I found and took a dump on me as soon as I went for a test run. It started slipping at about 5000 rpm, and would pull any further. Before it would pull all the way to 7500. The extra hot air must have really made a difference. Oh well, I guess its on to my next mystery.
Thanks guys for all your help, I really appreciate it.

 

Excellent you found it. Now you can see how that fast holds up . I will likely be taking mine up a bit soon when get my eboost2 installed but likely only to 10psi or so. Only have 60s in my car right now.

 

How could you not hear such a leak ?

 

Well I probably did hear it, but didn't know it was a leak. This is my first turbo car so I was just glad to get it running. At least now I know what a leak sounds like.

 

Top five LS related pieces of Internet folklore.....

#1.....Cant run a 90/92 mm FAST on a 346 because its two big

#2.....Can't run a FAST on a boosted combination because it will leak

#3.....Every ported LS head flows well over 300 CFM

(I will let you guys can have fun picking the other two....)

Real world info.....

I have a handful of customers running my ported FAST intakes with boost levels approaching 20 PSI. No problems besides trashing drivelines and spinning tires. IMO, its not an issue at anything under this figure.

At some level of boost Im sure there would be slight leakage but it likely wouldnt be enough to notice and hurt performance. The internal O-rings do a good job sealing....especially if it has never been opened up disrupting the OEM seals and silicone applied in key areas.

-Tony

 

Are any of these guys running nitrous also and running those burst panels.I am a bit worried they might blow out prematurely on me.
I think will get a 92 over winter and get it all painted up and then leave the burst panels out .Or guess could simply put solid plates in place of the current burst panels??
I dont' think need burst panel with direct port. don't think direct port can cause explosion like single nozzle puddling in intank can or am I wrong about that?