: Lets make a frankenstein... LY7/LLT...



DavidBoren
07-02-13, 05:58 PM
Something we are throwing around in the Gen1 CTS forums, is putting an LLT intake on a LY7. Nobody I know of has the parts laying around to test the fit, but we are hoping we can experience some of the awesome performance gains seen with ported/polished LLT intakes on Camaros.

The LY7 only has a VMAX spacer, and soon a RX performance throttle body, available for it. And no one has really messed with porting the LY7 intake (that I know of).

The LLT intake is a far better design and has more available for it. RX has a throttle body for the LLT, as well as a VMAX spacer. MACE engineering makes a whole host of spacers, each with their own purpose and proven results. And MACE has a US-based shop that offers a porting/polishing service for the LLT intake.

I am currently waiting for the RX LY7 throttle body to come out, and when it does I am installing it and my VMAX spacer and RX catch can on my LY7. I am hoping to pick up an LLT intake just to see if it lines up when I have everything torn apart.

A couple issues we are facing is port position, bolt locations, and PCV/vacuum lines.
Also need to know if throttle wire connectors are similar, or can be spliced/modified between the two. Anyone interested in contributing to this mad-scientist cause is welcome to chime in.

I will gladly accept donations in the way of LLT intake manifolds. :)
Or if anyone has access to a LY7 and an LLT intake, if you could see if it looks likes its possible, that would be greatly appreciated as well.

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Here is a link to the other thread. It has some information pulled from Camaro forums discussing the LLT intake modifications we want access to. Link:
http://www.cadillacforums.com/forums/cadillac-cts-first-generation-forum-2003/316993-llt-intake-ly7.html

DavidBoren
07-15-13, 05:27 PM
Also thinking about the LFX rotating assembly and valvetrain. The LFX has 38.3mm intake valves Vs. the LY7/LLT's 36.96mm valves. And I read somewhere about a materials change in the connecting rods for the LFX that made them stronger.

With this sort of complete engine rebuild, obviously some head work will be done, especially if we switch to larger intake valves, it will be necessary. I think shaving a couple thousandth off the heads to change the compression ratio from 10.2:1 up to 11.5:1 (like the LFX) might help, too. Valve clearance on the pistons might need to be addressed at that point.

DavidBoren
07-22-13, 11:35 PM
Intakes wont swap. Bolts are backwards.

On the LY7 intake, the rear-most intake manifold bolt is on the PASSENGER SIDE:
128738
On the LLT intake, the rear-most intake manifold bolt is on the DRIVERS SIDE:
128746