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Here is the info I was looking for where the LT1, L86 and MSD manifolds were tested and found that the LT1 doesn't provide a benefit over the L86. Definitely not worth having to reroute the belts to make a manifold fit.Quote:
Originally Posted by big_sapper
http://www.gm-trucks.com/forums/topi...2#entry1914381
Not too sure how accurate that thread is, but going from a L83 to a LT1 manifold and throttle body gains upwards of 25hp from the research Ive done :shrug:
The guy dyno tested all three intake manifolds, L86, LT1 and MSD on a 6.2l. I'd be interested to see where people are making 25hp from the LT1 vs L86 manifold. Maybe from the L83, but just looking at the L86 vs the LT1 you can tell it will flow better. The LT1 isn't the best design, it just fits under the hood.Quote:
Originally Posted by HeavyChevy305
I have a tendency to trust a Boeing engineer who has concrete data to back up his statements over the majority of the internet doing bench dynos.
What's the difference between the L83 and L86 intake manifold besides the throttle body bore size?
I don't know if anyone has cut them open to see. Or even flow tested them for that reason.
There are a few threads on performancetrucks.net. Rerouting the belt is just putting a pulley using the alternator mounting bolt and a little longer belt. I did it on my truck, no problem.
You used the same part numbers they posted for the pulley and longer belt?Quote:
Originally Posted by big_sapper
Now Harlech has me second guessing on which manifold to go with :banghead:
The manifold isn't the issue, even the L83 isn't your restriction on air flow, your intake is first and foremost. The gains you are going to see on a NA application aren't going to be HP/TQ gains so much as throttle response gains by being able to run the larger TB. Look at the MAF curves between the LT1 and L86, the LT1 breaths better because it is a better intake design and a better exhaust from the factory, not a better intake manifold. There is a reason the Corvette guys are aren't making as much HP on an CAI as the truck guys are. You might pick up a couple HP on the top end with the LT1 manifold, but you are going to lose some torque in the midrange compared to the L86. Pick your poison.
I already modified my air box and cut the hole out in the sheetmetal fender. I also have a k&n drop in and Air Raid MIT tube. With those mods it's only pulling 1-1.5 kPa of vacuum at WOT. :shrug:Quote:
Originally Posted by Harlech
The Vacuum PID on our trucks aren't worth a damn. While waiting on my blower to show up I did some pulls through the tubing and intercooler and hit 0 on the Vacuum PID so I am not sure how that is being calculated, but if you looked at my MAP pressure it would get to 79 kPa or 21% vacuum which seems about right for that setup. Where as before all the piping with just the airaid MIT tube and filter along with the L83 manifold and TB I was seeing 87 kPa which is closer to 10% vacuum so I lost quite a bit of airflow through all the piping and intercooler. In hindsight I wish I would of did some logs with the new intake manifold/tb with the MIT tube and filter.Quote:
Originally Posted by HeavyChevy305
101 kPa is 0% vacuum, no restrictions and of course above that you are in boost. All this is based on a 14.7psi atmospheric.
Where are you located elevation wise? The default scanners spark advance graph is set with a MAP axis and I hit 100 kPa at WOT (key on engine off it's at 102 kPa). Cylinder Airmass (g) goes to .84/.88 by 4k to redline.
If that is the case you won't benefit anything as you already have as much air available as your motor can move on the intake side. Maybe do headers/exhaust and see if that drops showing that you are then going in to a vacuum.Quote:
Originally Posted by HeavyChevy305
Stock headers,cat delete and true 2.5" duals are already on the truck. My Pacesetters actually get here tomorrow :pray:Quote:
Originally Posted by Harlech
Anybody have codes with this swap. I just installed an L86 intake and Katech ported LT1 throttle body and got P0123, P0222 and P2119 as soon as I turned the key on. Reduced engine power and the codes just keep coming back. Any ideas?
What all did you update after swapping?Quote:
Originally Posted by MattofEarle
I haven't touched the tune yet. I wanted to start logging first, but it is not even drive able. It will not run without throwing codes and even throws codes before I start the engine.
Update these two parameters.
Attachment 69852Attachment 69853
And double check your TB connection.
What year is the truck you did the intake and throttle body swap on?Quote:
Originally Posted by Harlech
I am asking because I am messing with a 2017 L83 and doing the intake and throttle body swap onto, and there is no Fuel/Transient tab.
Did you ever try it with the stock value inputted into the manifold volume table? If so, did it seem to affect it much?
Just curious, if that is going to be a big deal if I am not able to be adjust that to the proper value.
Thank you
Damn he's right. I don't have that tab as well...
I played with the stock value and the LT1 value. Didn't see any effects that stuck out all. No real difference in my mind.