[cmitchell17]

Originally Posted by 6spdhyperblue

I ended up just adding the 3L to the original manifold volume so I’m running 16,420cm^3 and is looking ok. The transients are looking pretty good. Fuel comes right in and levels off. I want sure if the 1.27 multiplier was a bit too much and made it feel a little more lazy on the hit, but the data looked good. I ended up dropping it to the 16,420 we’ll see how I like it.. If anyone tries it let me know if you notice anything.

Also, my throttle was closing over 6,000 incrementally toward 6,800. I must’ve had my tune torque values set right up to the limit for the old combo, but I worked that all out, and it’s open to 6,800rpm. Yeah it’s pulling hard up top now

Have you noticed any unexplained toque management advance pulling timing? I just noticed it on mine after my LT2 manifold install. However, I think its because I tried increasing the peak torque values, I had the values from the LT535 crate engine tune in them before so they were about 60-80lbft above stock. I increased them more since I figured my motor made more torque than a LT535 given it has the LT2 manifold, increased compression, etc. When I put it back to the crate engine tune values I don't think I have seen it happen, expect for like 1 or 2 degrees in a small spot at WOT.

I haven't even adjusted anything in the tune for the manifold, I just kind of lost morale after I saw from the logs and times I had it didnt do much improvement. I didn't even think of the manifold volume table, though not sure what if anything that actually does in the tune.

[cmitchell17]

Also, I mean to measure when I had my manifold off but I don't have a set of calipers or something to measure with, but does anyone know the stock intake port taper? Also are they pretty well matched form the head port to the intake manifold on stock LT1s?

[6spdhyperblue]

The manifold volume effects two things that I can tell. Start up and tip in (and potentially decel and dfco)
For tip in, where does fuel actuals usually land right after the hit? and duration of time to reach commanded. When you change the intake manifold, I would use this parameter to have that response return to where it was before the swap. I am not suggesting manipulating this parameter to compensate for things that should be addressed elsewhere.

For the throttle closing -
I had my peak torque higher than stock in those areas, then I just went 20 higher. It didn’t do anything,
No, my timing was not effected alone, only along with the throttle closing
I raised the dd only in the 100% row to 455 and it’s staying open. The rest of the table is stock. Maybe I should return the peak torque back to stock with the dd table and see what happens. That was my next move but the 455 in the 100% did it and pulled hard AF. So I left it.

[6spdhyperblue]

Originally Posted by Highland

Got my manifold from GPI and it looks fine. Went with the modified to fit but unported.

Question...has anyone considered replacing the vac. hose barb up front? Sticks up like a flag pole or something! Lol!

Or is it not that noticeable when installed?

They make 90* fittings that clip on there. That’s what I’m thinking. Maybe we get JLT to make their catch can as an option with the 90 instead of the straight. Two birds

[cmitchell17]

Originally Posted by 6spdhyperblue

Pray said 1.580 in his Facebook. The LT2 was most definitely less than that at the friction weld.

Are you saying Pray said the intake port taper was 1.580? I assume that would be degrees, I couldn't find the LS1 intake port taper specs either for any GEN III or IV.

The manifold volume effects two things that I can tell. Start up and tip in.
For tip in, where does it usually land right after the hit? and duration of time to reach commanded. When you change the intake manifold, I would use this parameter to have that response return to where it was before the swap. I am not suggesting manipulating this parameter to compensate for things that should be addressed elsewhere.


I had my peak torque higher than stock in those areas, then I just went 20 higher. It didn’t do anything,

I raised the dd only in the 100% row to 455 and it’s staying open. The rest of the table is stock. Maybe I should return the peak torque back to stock with the dd table and see what happens. That was my next move but the 455 in the 100% did it and pulled hard AF. So I left it.

Yeah thats why I am so confused, I thought ever since I just went back to using the peak torque and DD settings from the "OEM GM tuned" GMPP crate engine LT535 tune it seems I have been having no issues with stock virtual torque tables (except for me tweaking them lower at idle range) stock just like the GMPP tune.

I know I had issues before with it pulling timing and it corrected it after I got help on the HP Tuners forum by adjusting virtual torque, but ever since I found out and used the settings for the GMPP tune I have been having no issues. I actually did see at low RPMS around 2500 in a WOT second gear pull from a stop I saw the throttle blade close a couple percent at WOT, however I will probably just attribute that too a weird MAP to throttle angle torque calculation since its not going to make that much of a difference at that low RPM if the throttle blade shuts a little.

Now that I think about it, maybe the manifold is working better and we actually need to increase DD tables a little.

[cmitchell17]

Originally Posted by 06 4.8

Your car with the cam setup made no gains deleting the cats? That's very surprising.

I wasn't able to verify myself with the equipment I have available to see a gain. I haven't' had a track to run on either. But reviewing logs I didn't see any "gains". However you will only be able to really see increases in volumetric efficiency when monortoring logs, some of the supposed power gains from the cat delete may come from decrease pumping loses. Basically the gains are probably so small it would be hard to tell becuase your at the limit of error of what you can measure to with a dyno and definately on the track given you have to have perfectly consistent launches.

[Highland]

I ordered 8/19/20, i think. So less than a month.

I'm thinking cut off the top of the fitting, then drill out the rest. Thread the hole.

Then turn an aluminum lower fitting to screw in and only stick up high enough to thread an upper fitting (a barb) in at 45 degrees or so. Easy couple evening job.

If you have the time and a lathe! Lol!

I got the lathe, but not sure I want to find the time!

[s346k]

Originally Posted by 6spdhyperblue

I am thinking the 1.27 multiplier was a bit too much and made it feel a little more lazy on the hit, but the data looked good.

i didn't touch the tune on mine. it felt about the same (vs stock ported LT1) from 50 mph in 2nd. 70* around midnight and it would spin the tires maybe 30'. on back to back hits it still chattered them a few feet. first gear at any speed is completely useless unless it's 90* out and the tires are clean and warmed up a bit. running 32 lb on the stock wheel/tire combo.

the msd definitely feels a bit softer from idle to 3500 or so. ill reserve an educated opinion until after the car gets dialed in again. i feel that the 95 mm tb is contributing to the soft cruising, as well. i say soft but the car still has a lot of tq. i'm thinking the msd will pick up 30 whp or so with a fair extension of power above 6k.

[OB0001]

Originally Posted by Chemist

I ordered on 8/21. I received an email on Friday that it was in process. Didn't feel like too long of a wait for me.

Thanks!

[RobbyBeefcake87]

Originally Posted by Dvs510

Yea it Definately sticks upwards.. I used the push connects from the stock hose and put them on a 3/8” hose.. one of the push fittings is a 45 degree. So I used that one on top to help angle it down.. looks good and clears fine.. my bad with the first pic, don’t know how to rotate

Did you have to modify your strut brace to fit the LT2?

[6spdhyperblue]

I have to look at my old slips but I think my fastest mph at this track was 121.5 mph

[Dvs510]

Originally Posted by RobbyBeefcake87

Did you have to modify your strut brace to fit the LT2?

Yea I modified my brace a little bit. The welder at my work notched it and filled back in... without modifying, the brace litteraly sat on the top of the manifold.. it would bolt on but I was keeping in mind any movement of the motor wouldn’t b good.. probly could just get away with shaving off the 2 ribs where it hits tho. That would Definately b the easier route

[BlackbeastSS2]

Originally Posted by Dvs510

Yea I modified my brace a little bit. The welder at my work notched it and filled back in... without modifying, the brace litteraly sat on the top of the manifold.. it would bolt on but I was keeping in mind any movement of the motor wouldn’t b good.. probly could just get away with shaving off the 2 ribs where it hits tho. That would Definately b the easier route

What about just adding a few washers to increase the height where the strut tower brace bolts on?

[Dvs510]

Originally Posted by BlackbeastSS2

What about just adding a few washers to increase the height where the strut tower brace bolts on?

I don’t actualy know how much the motor moves. I’ve been meaning to have someone hit the gas a couple times while I look. But u gotta consider its gonna move a lot more when it’s under an actual load and especially on launches.. so I feel most comfortable giving it as much space as I can wich is why I notched the brace and will also soon be shaving the ribs on manifold in that area. The washers is a good idea but it’s your call if that will be enough space.. I was wondering tho, the bmr brace looks like it would possibly clear a lot better. Need to find someone that has one so I can take a couple measurements