I installed the AAM fuel system with 650 cc injectors and after a few runs to dial down the injectors, we made a full run under boost at 7 psi, I have a perrin boost solenoid installed as well as a bleeder valve to control boost, anyway the 1st run at 7 psi yielded 395 whp and 380 wtq, an improvement on tq and a 5 whp loss from last time no biggie really, because I wanted to get the car tuned between 9 and 10 psi, so Kevin at Knowledge turned the car to let it cool down. As soon as he turned the car back on for a 8 psi run, the most hellish, loud, hissing noise ever came from the engine, I was scared to death, the boys at knowledge thought it was a vacuum leak of some sort or the fuel pressure regulator had went bad, so we took it off and Mike and Noah at AAM were kind enough to overnight me a new regulator, but unfortunately to no avail, this wasn't the problem. Instead of paying the labor rate that Knowledge performance charges, thankfully my friend Jonathon the same guy who installed the kit for me was there, so we drove the car home and this turned out to be the problem:



This pic was taken after the manifold and the plenum were removed, it shows where the two screws lifted the gasket just enough to blow the gasket.

The next two pics show the aftermath and explain the vacuum loss and minor loss in power at the same boost.



I honestly don't know, but this appears to be either a design flaw on behalf of AAM or RC injectors, for all of the bolts were torqued to spec, if you plan on running this set-up, seriously consider grinding these screws down flat before proceeding with a tune. Hope this helps somebody, and if anyone else has anything to add please do so, while the engine is apart and I can check your suggestions. Although, I am certain to an extent this was the culpret. Yes there is a lot of silicon and next time there will be more, lol

 

is this the gasket that goes directly under the lower plenum?

 

My gasket doesn't look anything like that?????? I've never had a problem and I have the AAM fuel system as well.

 

Yes it is the gasket directly under the plenum, and I glad your gasket doesn't look like this one .

Your aren't using RC injectors either, this may be why. In the pics you can see the screws and the cold spots on the manifold pics as well.

 

That gasket does look different, not sure what it is.

I have the CJ Motorsports fuel rails with RC 440cc injectors and no problems, those are on with countersunk bolts though.

 

My gasket goes nowhere near the bolts. Where the hell did you get that thing?

:edit: oh, I get it, you used silicone. Why did you use silicone, it's not necessary?

 

Doesn't look right. Is it upside down and backwards????

 

Are you sure they didn't install the gasket backwards?'

edit: looks like we posted this simultaneously

 

Looks like he put the gasket down, then slathered it in high temp RTV. If it were backwards or upside down, it wouldn't fit on there at all.

Anyway, the problem is that he didn't grind the bottom of the lower plenum down to compensate for the raised fuel rails.

 

I likey the new av, taurran

 

Thanks.

The only reason why I sugested it might be backwards is that the couple times I had mine off I noticed the alignment was close if it was upside down and backwards... but then again this might not be the case... Maybe they ran out of gaskets and cut their own...

 

I believe it's a stock gasket, fitted correctly. If you look in the first pic, you can see the outline of it underneith the black RTV.

 

Interesting ----If Im understanding right ,,, U were lucky u didnt crack or deface the plenum ----Seems like u simply had a bad mating surrface and right ---It is a little ,,,if not impossible to reverse the gasket-----BTW --I shy away from the silicon on highly machined surfaces and simply oil precision or spray with lower viscosity sealent. If I use silicon I use the RTV silicone Rubber sealant distibuted by International Harvester (P/N 1 830 858 C1) that they use on their Diesels

 

- We countersunk them for a very specific reason

 

+1 and I have used RC440's, RC550's, and RC750's.

 

I did the install of the fuel system.

The gasket is on correct. You can't put it on wrong. Well I guess if you're a complete idiot, you could. I use RTV on my own car for the simple fact that I run over 30+psi so I have a tendency of over doing it a little. You can blow a stock intake gasket without RTV on it at higher boost levels. This is why I use RTV on all the intake gaskets I install with forced induction.

The spacers that I used were for the RC injectors. The spacers that came with the kit will not work with the RCs.

The bolts need to be counter sunk. I am going to grind the bottom of the intake a little and also the shoulders on the bolts to compensate for the problem. The manufacture of the kit should explain this in the install.

craigo'sznprgrs just wanted to try and save some people some problems.

As far as the injectors not being in far enough. The bolts bottom out when the spacers bottom out on the lower intake. This is what controls the depth of the bolts. So I guess if you use the stock injectors with the spacers that come with the kit you would not have a problem with the bolts. But I still think that the bolts need to be counter sunk just incase you do use RC injectors.

So whether it’s an RC problem or an AAM problem, I’m not getting into it. I am just letting everyone know what problems we ran into on this car with this set up so they can watch out for it.

 

When using the half inch fuel rail spacers that come with the Greddy kit or RC injectors and the AAM rails, all you have to do it grind the corner of the intake manifold flange off where it touches.

Those of you saying you dont have a problem, well thats believable, because it doesnt typically create a problem. But it is a fact of physical dimensions that the stock fuel rail bolts will be hitting the intake manifold where he is showing with that combination of parts. It is very easy to remedy before initial installation. I had only personally seen this actually cause an intake leak once on a customers car that came in last year with the combo already installed by someone else, and it took maybe 30 min to remedy. If your not currently experiencing an intake leak causing higher idle and low engine vacuum, i wouldnt worry about it.

it is not a flaw in anyones design. If not using those RC spacers, those rails fit perfect. If not using those rails, the spacers fit perfect. This is just a fact of life in this industry.

 

I agree 100%.

 

I also noticed that the bolts are not countersunk which makes a difference. I still had to grind some off of my manifold with my CJM rails and 550cc RC injectors. Other than that it was perfrect.