6.2 intake on L83 problems

[Estep40511]

Has anyone else had any issues after putting the 6.2 intake and TB on a L83? My truck just hasnt been the same since. retuned for the intake etc. I should rephrase, it runs great when its cool out, but when warm leaves alot to be desired. Only thing I can see on the scanner is MAP is high. but, no vacuum or exhaust leaks and compression is good (I think, no misfires) so Im at a loss. Been running alot of E85 this spring and summer. Dont know if that would affect it or not. But it just seems that since this intake has been put on, it hasnt been the same. MAP sensors are same part number, so I dont think its that. I have noticed my IAT being really high when truck is sitting. but its been very warm outside. Usually reads 125 or so after its been sitting out in 90 plus degree heat. Is that normal? thanks in advance!

[TriPinTaZ]

The LT2 manifold may simply be too much for a 5.3L engine. It will slow down the velocity of airflow and could be responsible for the sluggish feeling as it may be down on torque lower in the RPMs. Maybe it makes more power up top, but I would bet its down on power down low. As for the MAP readings going higher at low RPM, that support exactly what I was saying. The engine can't maintain a higher vacuum at low rpm which reflects in the MAP reading closer to ambient pressures (100KPA). You may be able to clean some of this up by altering the Virtual Torque Tables and adding a little timing.

[Estep40511]

thats kind of what I was thinking. its just the L86 intake I have on it with the L86 throttle body. Im thinking about switching back to the original intake and retune my virtual torque and timing and see what happens. too big of runners I guess

[Shane Hewitt]

I just did the L86 manifold swap on my L83 2 weeks ago............truck runs phenomenal, probably the best mod I've done to the truck. Post your tune and log.

[Estep40511]

heres the most recent idle log.

22-07-06 12-38-24.hpl

[Ben Charles]

L86 on an 5.3 is one thing, lt2 on a 5.3 I haven’t actually tested, but like said above, could be too much

[Estep40511]

It seems to run great when the temp outside is down. So it makes me wonder if something in tuning couldnt be adjusted? No vacuum leaks found, smoke tested it. Map just stays high, 80-90 and pulls timing down. but then, MAP goes down some and it idles like it should. Weird. can not figure it out lol

[Ben Charles]

Naturally ANY engine is going to lose power when it’s hot outside..

[Estep40511]

makes sense.

[WadeKauffman]

I know this was a few months ago, but do you have a stock cam? Your idle rpms seems to move around a lot.

[Estep40511]

No its a LSXceleration stage 2.1 cam