Join Date: Dec 2004
Location: Orlando, FL
Posts: 20
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Props to Red on Hyundai Aftermarket. Check this out.
There's been a very large rift between some of the aftermarket companies claimed horsepower on the new DELTA 2.7L V6's, versus what some of our Korean friends have been telling us about the life expectancy of such setups.
Quite a few aftermarket places have been touting 240, 280 and 300+ horsepower setups on the V6 for a little while now. Key Motorsports claims 240, but doesn't say if that's measured at the flywheel or at the tires. Thundercharger folks were, for a while, claiming 280 horsepower on their supercharged abomination -- no word on if that's flywheel or tire numbers either. And there have been a few stories of 300+ horsepower V6's rolling around South Africa, Australia and even in Korea.
The problem is, the Korean race market hasn't seen any of these wonderful setups. They have instead been watching the 2.7L DELTA rip apart at the seams: breaking crank caps, cracking sleeves, bending rods, breaking piston ring lands, and spinning main bearings.
Well, while doing a small bit of battle with some of the n00bs on NewTiburon, I dug up this picture here...
[IMG][/IMG]http://www.hmaservice.com/xml/graphics/ed/edja500a.jpg
This is an exploded diagram of the 2.7L V6 motor from the Tib and Santa Fe. Pay notice to the main caps (for those who aren't part literate, at the very bottom see the Bearing Cap (main cap), Bearing Cap Bridge (girdle) and the one line that says M10: 14-16 (140-160, 10-12) which is in reference to the main cap bolts.
What you have here is a fully girdled block with four bolt mains. (For the new people: notice, four bolts hold down each crank main cap, that's a four bolt main) This would usually indicate great strength; if you're talking about a Chevy 350 with four bolt mains, then you've got a very stout motor to build. But our 2.7L also has that full girdle setup (all mains are bridged) which provides even better lateral and anti-vibration support to the block.
Wow, so you'd think with all this cool stuff, the 2.7L should be pretty damned strong right? Well, is it strong, or was Hyundai suddenly making up for something they found after the original casting design?
Look at this diagram now:
[IMG][/IMG]http://www.hmaservice.com/xml/graphics/EC/ECBB001B.jpg
This is the same diagram, but for the 3.5L V6 out of the XG 350. Look again at the bottom end of the picture, and notice the differences... Instead of two seperate parts, the mains and girdle are one integrated unit... And look closer to find that the mains are only two-bolt design. Also check out the bolt specification: M10: 90-100 (900-1000, 65-72) Actually, they're missing the M10 notation, but those bolts ARE a metric 10mm.
Ok, so here's the deal:
The 3.5L V6 has more rotating mass, produces more horsepower, and yet only is needing 2 bolt mains and a smaller girdle. Also, take a look at the bolt specs I provided on the 2.7L:
M10: 14-16 (140-160, 10-12)
M10 is the bolt size, Metric 10mm.
14-16 is tightening torque in Newton Meters
140-160 is tightening torque in kg/cm
10-12 is tightening torque in lb/ft
Ok, now since most of us here are yanks look at the pound feet... Hyundai is wanting 10-12 pound feet of torque to completely tighten down the main caps on the DELTA. Compare that to the number on the 3.5L of 65-72 pound feet! For reference, the I4 BETA motor needs around 43-50 pound feet...
There has been speculation as to how exactly the main crank caps break on the DETLA: Do they indeed fracture and break apart like a piece of pottery? Or do they simply rip out of the block?
If you ask me, in light of the way Hyundai is treating the Delta, it looks like the tapped sections of the block that hold the main cap bolts is far too weak and the bolts are physically ripping themselves out of the block casting.
We do know, 100% for sure, that the bottom end of the DELTA has been shown in multiple cases to come apart in large expensive pieces when dealing with horsepower around 240+ to the tires, depending on a few circumstances. What we haven't been able to fully verify is HOW it comes apart...
But my guess, again just by looking at the Hyundai technical manuals, is that the block itself is weak. Not much you can do to strengthen this thing; even newly helicoiled threads in the block wouldn't hold the necessary torque.
Thought I'd share, since this has been the source of heated debate on nearly any site that deals with the new Tiburon. You can guess how much I'm loved over on NewTiburon forums
{Keep in mind this is not my post, I only copied it and post it here. Enjoy,....or.......not
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: just drill and tap the main bolt holes another inch or 2 and see if you can get the crank to stay put. 
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