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This is just an FYI post...I just picked up another FAST 90 from a CF member that lives about an hour south of me. Thanks again brother!
Sooo...it looks like either the previous owner, the original owner or a mechanic likely over torqued the bolts or used the wrong bolts during install and cracked the intake. Did they replace it? Nope! The cheap bastard simply epoxied the cracks. It became my problem when the epoxy repair finally failed. My RPMs were crazy erratic, idling super rough and shaking and when cruising it's like the cruise control was on. As soon as I let off the brake it would jump to about 2k. My amazing Vette Tech troubleshot it, talked to my tuner, smoked the intake and found the leak.
Yes it is a 3 piece plastic assy: upper shell / lower shell / 8 internal runners
Apparently it’s an accepted practice by some to seal any cracks with an epoxy rather than dropping over $900 on a new one.
I will say one thing I don't really care for about the C5 is it seems to have an over abundance of plastic parts...Really, a plastic intake? You'd think they could've made it out of some light weight alloy...
I will say one thing I don't really care for about the C5 is it seems to have an over abundance of plastic parts...Really, a plastic intake? You'd think they could've made it out of some light weight alloy...
What is wrong with a plastic intake? No coolant is going thru it. Your only sealing air.
Clearly this was installed wrong. Ive seen ears broken off of aluminum intakes before.
I will say one thing I don't really care for about the C5 is it seems to have an over abundance of plastic parts...Really, a plastic intake? You'd think they could've made it out of some light weight alloy...
This is not a C5 intake. This is a F.A.S.T. intake made for an LS engine.
What is wrong with a plastic intake? No coolant is going thru it. Your only sealing air.
Clearly this was installed wrong. Ive seen ears broken off of aluminum intakes before.
There's probably nothing wrong with it, it's just to me, plastic parts scream cheap...
Not to mention the real reason the manufacture's switched to a glass reinforced polymer material - a low heat transfer rated, which helps to keep the intake charge air cooler and more dense, resulting in more consistent power over a wider range in engine/compartment temperatures.
Plus you can make some pretty wild thin wall designs with injection mold material that are just not possible with a cast aluminum alloy.
Last edited by JHrinsin; Dec 12, 2017 at 11:52 AM.
Thanks to CF member Cutlassmaster for the 'new to me' FAST 90. New intake is installed and RPMs behaving nicely now. All betta!!!
As mentioned above, you did switch out the valley cover fasteners for the low profile button head units that would have originally came with the FAST when you installed the new to you replacement manifold, correct?
Repair FAIL
on getting the problem tracked down and fixed with a new intake. Sounds like you have a pretty competent Vette tech to work on your car.
