That manifold really sounds like it has been painful. I'm sorry :( Maybe BEGI had it right when they made their intake out of iron :/

I'm with the other guy - bad penetration on the welds or the material is too thin. It's a balloon with sharp corners. Bad design idea. :-) Making it thicker (heavier) would work, or even just adding material at the corners would help. Posts through it could help, too.

FYI, the OEM intake can handle serious backfires. :-) A guy once came down the street 6 houses cause he said my garage scared him and he came to offer medical assistance, the last explosion he'd heard like that was in an iraqi war zone. :-)

Perhaps (though I'd hate to mess with the flow) putting a bolt or two through it would really help hold it together, to keep it from ballooning? Or a clamp/strap on the outside? Seems iffy, really good high res close ups of the weld would help someone who knows welding (and I know a few if you don't) tell you if it's the fault of the weld.

From the looks of the pic, it looks like it could easily be fixed.

Are you planning on building another intake?

I'm fairly certain that it could have been easily welded back up, but it would have just failed again. 17# is what I run on low boost and on high boost it needs to withstand upwards of 32#.

I felt the best course of action is to let the guy that designed it have the first opportunity to come up with a fix for it. So currently the manifold is back at Flipside as of last Monday. Rob took a look at it and listened to my concerns. Not sure what his plan is going to be, but I will post up about it when I get the manifold back.

As much as I like the Flipside manifold, I decided to put a 99 intake manifold on the car this week. I'm in the process of finishing that up this weekend. I wish it was as easy as just bolting it on, but I need to re-work my cold side piping, a bunch of wiring, etc... Having a reliable car that I can actually drive is of utmost importance to me right now. I'll most likely sell the Flipside manifold when I get it back.

Its funny, because I showed my boss that pic and he thought it was caused by backfire as well. I hope flipside figures it out. Shitty you had to go all this length to find out you don't even want it.

I think a backfire would have completely ripped that manifold apart, after all it's only made out of 1/16" aluminum.

Have you considered using the Edelbrock manifold. There are some mega horsepower Miatas running them, I bet they are relatively inexpensive compared to sheet metal. It does not look as good a sheet metal intake, but it should handle any amount of boost you can throw at it.

The tubed Miata that is going low 9's at 150+mph is using that manifold. I have seen it on a few other cars. I think it is worth checking to see what kind of flow and boost they can handle, and if it is still available.

I can't wait to see how the car runs when it is back together.

At this point I'm going to just take it easy for a bit and see what happens. If I don't start driving this car soon, I'm going to end up selling it. With that being said, I finished everything up and the car is ready to drive again. I'll go over it again tomorrow to make sure I didn't miss anything and then it's time for a drive. I hope it doesn't rain.

Attachment 198787

What a wonderful day. I took it out and beat the ever living shit out of it, all the way to the gas station and then back home the long way. The plan was to go further, but I left the hood at home and it was starting to rain.

Overall it's a bunch quieter now that I'm not running an open dump tube. I also installed an aftermarket exhaust cam. When I get back on the dyno to do some tuning I'll get it dialed in and see if it will give me any extra power.

Don't you mean... Seeing what power hit you took with the OEM mani? :-)

I've seen people take a dremel to them and hollow them out. Might be something to consider, though this edelbrock suggestion is a good one.

If you or anyone wants to buy my mostly polished and hollowed out NB manifold (hollowed top and bottom) it's FS.

DYNO! What difference did you see before/after/compared to an aftermarket unit?

Did a few pulls on the dyno to see what the car is putting down with the 99-00 intake manifold. VICS was locked in the open position and this was at 19# (wastegate).

Attachment 198531

holy shit

It also sounds quite a bit different with the dump tube plumbed back in. Ben was nice enough to do a flyby in it today so I got to hear it from outside the car and I think it sounds awesome.

What RPM do you hit 19psi at now? 15psi? 9 psi?

It's fully spooled at 4500. As for the other boost levels, I'm not sure and I don't have a log available. With a mbc or ebc I should be able to get it spooled a few hundred rpm earlier. When I do put a boost controller on it I will shoot for a solid 20.5 and call it a day on pump gas. I haven't done this yet because my injectors are already maxed out up top.

Comparison for those that can't scroll back a couple pages...

Aftermarket mani at 17.5 psi

Attachment 198498

99 intake at 19psi

Attachment 198499

More power coming soon...

Attachment 198464

I thought you kicked the habit?:bowrofl: