LFX Manifold on LLT
 

In the original thread ( http://www.camaro5.com/forums/showthread.php?t=303283 ) Jason@JacFab found a GM OEM piece that would allow the use of a LFX intake on a LLT motor. He asked me to test this setup out. This thread will cover the actual install and any increases gained.

For reference, my mods are as following:
IPF Supercharger with 3.48" Pulley (12 PSI of boost @ 7300 RPM)
Snow Performance Methanol Injection
Custom IAT relocation using the screw-in type (less heatsoak)
LFX Intake Manifold from Jason@JacFab
American Racing Headers 1-3/4" Tuned Length Headers
ARK DT-S 2.5" Catback Exhaust
Hex Vents

Install:
Easier than doing a LLT manifold, mostly from the huge weight difference. The LLT EVAP hardline required replacement with a LFX one, and that one required a little bending to get into the correct position. Also the electrical plug for the LFX EVAP Solenoid had its wires a little too short, so you may need to cut the tape around it to expose more wire. You can't get too much though because the wires go separate ways in the bundle.

I hated cutting the PCV line at the intake manifold plug, but I had to since I require that use of a check valve with a custom catch can.

You don't use the LLT throttle body gasket, the LFX has an O-ring attached. Just tighten down the 4 bolts just enough to where the O-ring starts to be smashed.

I just finished the install, I'm about to start a boost leak test to make sure it will hold at least 12 psi. After that I will reload a tune and test it out.

The best time I've gotten with a LLT Intake Manifold is a corrected 12.7 @ 113 mph (13.1 @ 110 in 2800 DA). I believe the LFX manifold will beat that. During normal driving my LLT manifold is able to keep cool and I can get 20-21 degrees of timing at WOT. At the track after sitting in the staging lanes I can only get 15 degrees of timing, some times worse. The heat from the headers and supercharger are just too much and even with a Ice-olator it couldn't keep cool.

Interesting to say the least.

Sounds like it was an easy swap! :popcorn: :clap:

I see your IAT sensor is located in the intake tube which is aluminum... I'm wondering if perhaps this could also be a problem with your heat soak/pulling timing issues? Random thought... What if you were to relocate the IAT into the MAF sensor hole in the LFX intake? It would insure the sensor would not be effected by the aluminum at all, and probably give 100% accurate temps as measured right before the air is ingested (forced?) into the engine? This could be a down the road mod of course.

That is what I thought at first, but the IAT I have on there now doesn't heatsoak. I think the sensor is surrounded by ceramics because even sitting in the pits it will still read the correct air temperature. I used to have a push-in type that would heatsoak like crazy, reading over 130 degrees after a few minutes waiting in the staging area. Thought that was the reason why I couldn't get the full 20 degrees of timing but even when the IAT is reading low I was still getting only 15 degrees. That is why I think the intake manifold is the culprit, aluminum transfers heat very fast.

I would like to put the IAT in the manifold but it is a 3/8th NPT type and it needs to be in the direct path of the air to read the meth cooling.

Boost leak test was completed and I took it for a test drive, car ran great. Felt just like having my ported intake manifold on, but I will need to test it more tomorrow and eventually at the track next Friday. DA might be around what I normally race at, so it will be a direct comparison.

this is awesome! Can't wait to hear how it goes!

Sounds like good news so far!

For those at home that haven't been following the various threads this has been discussed in, this is a STOCK LFX intake he is trying out, not one of my ported jobbers.

Okay, I'm watching but I just can't get past how darn butt ugly that manifold is. I guess at least now maybe I understand why my headers & tune did not help me at the track from that opening comments on the thread. :frown: :pout:

Hey Magnum! Glad to see you were able to finally complete the project that I had hoped to complete with Jason a while back...but it never happend and so well thats history now lol. I think this could end up really helping you out at the track, and I also believe that the ported LFX intake is probably the very best performance option out there as far as intakes go for both the LLT and LFX. Only issue is that the swap can get a bit expensive.

I didn't say anything in your other thread Ruby, but I definitely think that heat soak plays a big part in how these cars can run at the track. The Ice-o-lator does a good job of keeping heat out of the intake especially when the car is moving, but if you are sitting in the staging lanes for a good while even that will not keep the intake from heating up.

The LFX intake should help curb that even more. But yes...it is butt ugly.

Can someone explain the differences to me like I am 5? I know very little about the LFX.
That intake looks plastic? Is that why there is less heat soak? I know the LLT is quite heavy and definitely gets pretty hot..

The LFX manifold is basically plastic so it doesn't heat soak as much as the LLT one. It's also a lot lighter and doesn't have the dip that the LLT one has.

Could be your problem, I know LFX's don't slow down the longer they wait at the track from what I've observed. My wife's Mustang V6 has a composite intake and it stays the same and gained 0.5 seconds from headers.

Mine heatsoaks extremely fast, within a minute due to the supercharger and headers.

Might be worth the swap if the times are there, but mine will be an extreme example since I'm supercharged and using meth. A N/A might not see as much gain but when not in boost it feels like a little more torque has been gained. It looks like it flows better than my stage 4 ported intake since my LTFT's are running richer. Hard to tell today though because we had a cold front come in and it is 60 degrees, about 20 degrees cooler than normal. A promising sign though was when I stopped on a private road and started giving it gas. Even with traction control on the tires were screaming at low RPM, normally it only starts to lose traction at 5000 RPM when my peak torque hits.

Track will tell the true tale though.

The LLT manifold is aluminum which transfers heat extremely well, that is why it is used as a heatsink in a lot of components. When the air goes through the manifold it has a huge surface area to absorb the heat from the manifold, raising the temperature of the air charge. It will also gain some heat from the cylinder heads but it won't be as severe as the manifold due to the surface area. Once this heated air is in the chamber it begins being compressed, raising the air temperature even further. When the spark plug is ignited there is a shockwave that expands out from the ignition point and begins to consume the air-fuel mixture in the chamber. This is happening on my engine at 21 degrees before Top-Dead Center, so while this flame and shockwave are expanding the piston is still moving up, compressing the air-fuel mixture even further. The shockwave also compresses the air and heats it up, at this point areas around the chamber walls can auto-ignite without a spark, they will just heat up to the point that the air-fuel mixture ignites. When that happens there will be 2 or more shockwaves in the chamber, and when they collide there is a low frequency noise that is transmitted from the chamber that is picked up by the knock sensors on either side of the engine. When and how loud this noise is determines how much timing the engine control unit removes from the base timing.

I know that is a lot of information about what happens when Detonation happens (Pre-Ignition is when the air-fuel mixture happens before the spark plug ignites and is usually fatal to an engine) but now I can explain what a composite intake does for our engine.

The composite intake will still absorb heat, but it will not transfer heat as fast as aluminum, so this means when the air charge passes my air intake temperature sensor it reads 70 degrees, by the time it reaches the combustion chamber it might be 75 degrees. On the aluminum intake it could be well over 100 degrees by the time it hits the chamber. Might be a small number but when you are talking about chemical reactions you have to be precise with the environment to get the desired outcome. When I said my engine runs 21 degrees of timing, it will hit its peak pressure at 14 degrees after top-dead center, pushing the piston down with the most power. 14 degrees is the sweet spot, when the ECU removes timing due to detonation this peak pressure will be moved to around 20 degrees after top-dead center, meaning the piston is already well on its way back down when the main pressure is hitting it, resulting in lost power.

One thing to remember about all this information, this is happening all within the time of a few milliseconds.

My intake manifold is usually heatsoaked at the start of a quarter mile run, but within 10 seconds or so it is cooled down enough to where it isn't warming up the air charge as much. During this time though the damage is down and the ECU has pulled all the timing, it only adds 0.7 degrees of timing back every 1 second, so if you pull 5 degrees it will take 7 seconds to gain it back, the race is over at that point. This is evident in my timeslips for my car, my trap speed is 110 mph, but I'm only running a 13.1. When I race V8's I'm trapping slower than them at the 1/8th mile mark, but by the 1/4 mile I'm trapping faster, all due to the timing starting to be added again, gaining me more power.

Hopefully this will explain it a little about why we are testing this. Explaining this also helps me because it makes my brain go through all the steps that is happening and visualize how it is working to see problem areas. I use this method at work since I'm a system analyst for computer servers.

I think I might be the only one that prefers the look of the lfx manifold over the llt. I always thought the aluminum one was butt ugly. Just opinions though.. and we all know what those are like.

:bow:

http://www.rantlifestyle.com/wp-cont...d3_3292376.gif


What about dressing up your stock engine cover? There was a guy making some cool aluminum plasma cut engine covers floating around here somewhere.