[Fraxum]

The install took the better part of today.... You have to figure out a few things

1. One of the front vacuum connections needs to be replaced using a 3/8 hose fited to the stock connectors.
   
2. The Rotofab does not like the stretch. But I think it is sealed properly.
   
3. The valley cover has to be removed
   
4. You have to pop out the manifold bolts

But late this after noon I fininshed. Just in time for Atco! But when I started it, it fired right up, then revved a bit and started popping. :( I rechecked everything and everything seems connected and good to go.

Is it possible not all of the trimming was done or not enough trimmed off? I guess I will have to take it off and look. I did see some evidence of light grinding.

I will have to pull it off to check. The manifold seemed seated and the bolts lined up fine. All of the connections seemed right.

Drivers side:


Passenger side:

[Dvs510]

Originally Posted by Fraxum

The install took the better part of today.... You have to figure out a few things

1. One of the front vacuum connections needs to be replaced using a 3/8 hose fited to the stock connectors.
   
2. The Rotofab does not like the stretch. But I think it is sealed properly.
   
3. The valley cover has to be removed
   
4. You have to pop out the manifold bolts

But late this after noon I fininshed. Just in time for Atco! But when I started it, it fired right up, then revved a bit and started popping. :( I rechecked everything and everything seems connected and good to go.

Is it possible not all of the trimming was done or not enough trimmed off? I guess I will have to take it off and look. I did see some evidence of light grinding.

I will have to pull it off to check. The manifold seemed seated and the bolts lined up fine. All of the connections seemed right.

Drivers side:


Passenger side:

A couple places that offer the “bolt on” services don’t seem to b removing enough of the ribs on the bottom side.. Out of the 3 lt2 im’s I’ve installed so far, I had to shave off the ribs on the back corner edge that they didn’t remove(circled in picture). With the rib still there it was bottoming out on the fp. Probly still would have sealed but I didn’t like the pressure it would have put on the fp... other then that they fit great

[Fraxum]

Originally Posted by Dvs510

A couple places that offer the “bolt on” services don’t seem to b removing enough of the ribs on the bottom side.. Out of the 3 lt2 im’s I’ve installed so far, I had to shave off the ribs on the back corner edge that they didn’t remove(circled in picture). With the rib still there it was bottoming out on the fp. Probly still would have sealed but I didn’t like the pressure it would have put on the fp... other then that they fit great

Thanks! I will pull it and check mine tonight and get out my dremel. I still don't like that the Rotofab does not fit. In order to close up the RF I had to pop the RF base out of its seat. To fit it needs a longer mid tube section. I wonder where I can find something like that? And alhtough I bought a Corvette cover I think it will hit the hood. But even at best there would be little room for air around the motor. I will only put that on if it has to go to the dealer.

[Fraxum]

Okay decided to pull it off now and paused my day job.

That back section looks flat. Maybe a bad MAF extension? I can test with the stock IM. Or I wonder if I created some other problem. So I will put the stock one in and see if that works.

Is the valley cover needed? It looks like it keeps dirt off all that stuff mounted on top of the motor. I am leaning towards this was not a good idea. But it is a fun project. If I go back to the stock IM, I will go back to a stock TB Port matched to a stock ported IM from Pray. I find the new TM V2 ported IM interesting. He says 100 additional cfm. But expensive.



Passenger side:

[gmcvt]

So did you install the valley cover?

[Fraxum]

Originally Posted by gmcvt

So did you install the valley cover?

It was preventing the IM from seating in the rear of the motor as far as I could tell. Maybe I could work on that by smoothing ot out. I want to keep if possible. So my test start was without it.

[Matos1LE]

Originally Posted by Fraxum

It was preventing the IM from seating in the rear of the motor as far as I could tell. Maybe I could work on that by smoothing ot out. I want to keep if possible. So my test start was without it.

Someone correct me if I'm wrong, but the valley cover is the metal plate under that. The black rubber material is a heat barrier.

[madkat7134]

well some one with the same problems i was having i snapped 2 bolts so i had to get rid of sleeves for the bolts cause they stick out not allowing intake to seal up and also shaved off all ribs on the bottom of intake put it back on runs like a champ. also get rid of the heat barrier and use a heat shield.

[Fraxum]

I had no bolt problems, and yea I guess it was the heat shield, not the valley cover under all that stuff bolted in the valley. The heat shield also helps keep things clean under there.

After all I went through though ditching the heat shield, having to mod my Rotofab, and a more crowded under the hood I am shelving this project for now. If anyone is interested in my LT2 IM + Corvette cover let me know, especially near South Jersey to avoid shipping. I am going with a stock ported IM and TB. I will be sacrificing about 10 + rwhp, but I am okay with that. I did test the MAF extension on my stock setup and it worked fine. I do think the LT2 over all is a better option than a MSD or ported stock IM for a mild build.

[gmcvt]

Thank you for taking the time to share the details. Hate that it didn't work out.

[Fraxum]

Originally Posted by gmcvt

Thank you for taking the time to share the details. Hate that it didn't work out.

Maybe there are solutions. I am sure the IM will work and is working for most.

I looked carefully for the seal and it looked good. I may have missed something on the install with the MAF. It was plugged in to the new location. But now back to stock running fine. I wonder now though if I had both ends of the extension fully clicked in.

If I still have the IM I will try it again in the spring.

[m6-lt1]

If you didn’t disconnect your battery before install, that could possibly be why. That being said your symptoms sound like a vacuum leak. Things I’ve seen people post they messed up on when installing this are, literally forgetting to install the TB gasket, and the 2 back intake manifold bolts not being tightened all the way. If you didn’t use the LT1 manifold torque sequence and only torqued it in one pass, that could also be why your car acted that way.

[Fraxum]

Originally Posted by m6-lt1

If you didn’t disconnect your battery before install, that could possibly be why. That being said your symptoms sound like a vacuum leak. Things I’ve seen people post they messed up on when installing this are, literally forgetting to install the TB gasket, and the 2 back intake manifold bolts not being tightened all the way. If you didn’t use the LT1 manifold torque sequence and only torqued it in one pass, that could also be why your car acted that way.

Hmm I forgot to disconnect the battery, good point. But when I put the stock setup back in it purred like a kitten. All I had to do was clear the codes. I used the applicable MSD pressure and startring at the middle working out and 2 stage tightening. I did not end up using any loctite. And I did the same with my stock IM. I reused the stock bolts with the sleeves. I can't imagine they have been stressed.

I also disconnected the MAF and started it stock. Like you said, that mimicked the problem. I did test the extension with the stock setup. It was fine.

For those of you new to modding the LT2 IM does not throw codes as far as I know. The IM was correctly modded by GPI, I did something wrong most likely. I just gave up for now. Ted is doing one of these soon and most likely will share his opinions.

[lt4camaro]

Originally Posted by Dvs510

A couple places that offer the “bolt on” services don’t seem to b removing enough of the ribs on the bottom side.. Out of the 3 lt2 im’s I’ve installed so far, I had to shave off the ribs on the back corner edge that they didn’t remove(circled in picture). With the rib still there it was bottoming out on the fp. Probly still would have sealed but I didn’t like the pressure it would have put on the fp... other then that they fit great

Can you show me where you drill and tap for the brake vacuum port. Also do the stock bolts work OK? are they long enough? . Any other quirks as I am going to do this myself. Thank you in advance.