Well, I dyno'd the car on Friday (382 rwhp before upgrade) to get a real bolt-on hp increase number after today's FAST LSX install. I had a dyno session time today and was ready to go except...

Today's install went south slowly. After waiting at a shop for 7 hours, I'm back to my original setup for now. To start, the FAST supplied bolts that didn't fit just right and adjustments had to be made. Once installed, my carbon fiber valve covers didn't fit on correctly. The intake actually touches the firewall. It is overall much bigger than the LS1/6 intake manifolds.

Start up and test drive...engine sounded extremely more noisy with the hood up. Didn't sound like a whistle (hinting towards leak), but just louder engine noise. Any ideas?? Took it for a ride and interior noise was very much different. Sounded like air flowing through a hollow tube without the whistle. (hard to describe). Engine during acceleration was smooth, then I pushed in the clutch. :confused: Idle wouldn't drop below 2k rpm and was extremely rough. Shut it off, restarted, and idle around 900 rpm, but rough to be point of near stall.

Could I have gotten a bad intake? I realize I took a risk with such a recent release, but didn't expect this problem. I'm guessing this manifold shouldn't cause anymore noise than my LS1 intake. The shop was very helpful and decided to buy another intake and compare. More to follow...

Anyone else heard of issues like this...Thanks!

 

Please keep us posted on the final results. :nonod: :cheers: :smash: :thumbs:

 

im waitin for mine to come in the mail. hope it works out for ya

 

First I have heard of fitment problems but so few installed to this point hopefully it was just defective--I will know soon I guess-

 

Could your idle issues be fixed with a idle relearn? Maybe just driving the car around and allowing the PCM to learn the new airflow will correct this? Just a thought, Kaley.

 

Did the intake touch the back of the firewall or did the top of the intake touch the overhang?

 

Gorgeous car, what's involved w/ the 435 package? Is it H/C?

 

You have a vacuum leak.

 

get some data. sounds like a leak. would explain the noise. Hook up to Ease and look at map, since that is the sensor in the manifold. do let us know what is happening.

 

I only had one fitment issue and it was with the fuel rail covers. They need to be slightly trimmed up to fit perfect, but as they are now, the're not going anywhere. As far as the bolts, the ones supplied worked fine on my car. Good luck to you!

Matt

 

Glad to hear that--do you have to retune or need to, any dyno info on gains or needed tuning would be great

 

Bill,

The fuel trims didnt change so no need for a retune i suppose. I did not dyno it because i had a broken valve spring that i replaced. I had to put the 3 heat cycles through it first before dynoing. Here in the near future i will dyno it again.

 

Thanks for your reply, Kaley. I thought about the relearn for 88 miles or whatever magic number it is. However, the loud engine noise made me question the install. I called another shop and they said it should sound the exact same and they said no idle trouble was reported. I'll keep ya posted.

Chris

 

It touched the back of the firewall. It didn't touch the overhang, but is pretty close.

Chris

 

Yeah, I'm leaning towards that too. The tech was even questioning if the sensor in the back of the manifold was even seated well b/c you can't get to it once the intake was bolted down. No check engine light though. I wonder if the $100 discount was for a reason. :confused:

 

Silly question, did you put the intake port seals on?

Did you hook up the sensor on the back of the engine, and the two vaccum hoses?

If your idle won't drop you have a leak. I ran into none of the issues you described.

 

Thanks! 435 package details can be found at http://www.mallettcars.com under conversions. Basically, it's a 6.1L 372ci. Different rods, pistons, crank, cam, ported head/intake, etc... Suspension side received lots of work too. Fun car!

 

Thank, J-Rod! I had a 'corvette only' shop perform the work, so I know most of what they did. The sensor on the back can barely even be felt once the intake was bolted down. I assume the check engine light would go off if the sensor was not in correctly. I had no check engine light. I will ask them about the vacuum hoses.

I guess this rules out that the PCM had to learn about the changes causing the rough and high idle.

Chris

 

J-Rod, do the 78mm and the 90mm share the same outer dimensions. My intake is a 90mm and need some cleaning up. I'd prefer to do that in advance, but I'm concerned that if the 90mm doesn't fit my doing some shaving will mean I bought it. Joe

 

My understanding is htey are identical witht he exception of the "top". One has a 78MM, and the other is a 90MM. This allows you to upgrade with a top switch rather than a whole intake.