dr_whigham

iTrader: (49)

That's not ENTIRELY true. Some of the LS6's did in fact get balanced AFTER they were assembled. This is Corvette specific ONLY though. And yes, it's a nightmare bc it then throws EVERYTHING off unless you xfer over.

OP... Have you actually measured PR length yet?

G Atsma

Was it more like a "fine-tune" balance? Because what I was getting at was engines like SB Fords that ARE externally balanced had flywheels/flexplates with balance weights from the factory, where LS engines have (normally) zero-balance flywheel/flexplates as OEM.

dr_whigham

iTrader: (49)

Correct

Some have been worse than others, unfortunately.

G Atsma

I'll buy that…..

one4torque

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one4torque

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one4torque

Deleted a bunch of useless trouble shooting above.....

Here's my latest update:::::

I feel and hear a good bit of vibrations/trans noise through the floor......
I checked drive shaft clearance (ALL GOOD), and verified engine and trans not hitting the frame.

Next I rev'd the engine in neutral.... no serious vibes.
then I ran the car in all gears on jack stands....... in all gears... no noise... or vibes.

then I pulled the shifter boot and drove the car with open trans hole open down to the trans.... and went through the gears.
the noise appears just to be loud *** poly mounted T56!........ I get this bearing whirring noise on accel in all gears...... it's super noticable due to the solid mounts.

So question---- is this gear noise just the sound of my T56 going through my very thin 5/8" thick rear poly trans mount and my ultra thin poly 3mm mm's?????

I'll get some of my ls1 buddies to drive the car with the trans cover/shifter cover off..... so they can see/hear/feel it ........ I'm starting to think this thing is just noisy race-car like with the poly mounts.......

does anyone have an LS/T56 in a race car??? that they can confirm your hear the trans gears during accel in the car.... and they feel it?

one4torque

May have found my t56 issue

bought dex 4 or 6 don’t remember... but it said it superseded dex3........ only put 12 miles on it.. will put d3 back in tonight.... hope I did not screw up my trans.

Che70velle

iTrader: (6)

I’m running solid engine mounts I built and a solid aluminum trans mount I built, in my Chevelle. I have no noises like what you describe. Mine is quiet, but it could be the difference between mine being a full frame car and yours being a sub-frame car? I think your trans mount actually bolts to the cars floor? My Gen3 Camaro, the trans mount bolts to the floor on either side. Someone with a poly mounted t56 in a 4th gen will pop in here...

mintws6

I have poly mounted T56 in my 4th gen with poly motor mounts. I have no vibration or noise what so ever. I put GM recommended AC Delco Dex 3 transmission fluid in only, I'm sure some others have used upgraded fluid but I have not. I hope the fluid change solves your issues.

one4torque

I only put 12 miles on it... si fingers crossed.

one4torque

Fluid made no difference. So now suspect trans hitting tunnel somewhere under load. Will keep u posted.

one4torque

7.4.19 Update -

Pulled the (ebay) T56 and trans shop did full rebuild.... at only 59k ebay miles... it needed all bearing replaced.

Going back together in the next few weeks.

Thanks all for the help and support......

Next Steps:
1 - while eng out, drop pan, inspect oil pump p/u o-ring. (make sure right one),
2 - re-install eng/trans,
3 - alignment,
4 - dyno-tune.....
5 - shake down miles.......
6 - ac
7 - drag strip..... not trying to get best 60' with M3 axles and diff..... but want to check mph,
8 - local autocross....
9 - then some track time at COTA...... at first with stock susp/brakes.... then as funds allow.... BBK, new wheels/tires, wide body, coil-overs...... race seats....... harness.... cage.... etc... etc...

one4torque

8.4.19 Update -

Finally got a proper highway road test after re-installing the rebuilt t56, no overheating, no fires, no leaks. No issues with hot restart.
It is pretty gutless right now. LSX told me my mail order tune would be close enough to drive to the shop.... but to get it dyno tuned.
I did not realize it would be so gutless..... but suspect timing/fuel are super safe with the mail order tune.

quick question on placement of IAT sensor..... my old 5.0 days we wanted the IAT to read the true temp of air entering the intake.... so I installed in in the rubber elbow that connects to the stock TB.
Since this is not forced injection I"m happy I've got a good seal on the fitting.

Other people will mount the IAT in the bottom of the air filter.

Is my location fine for my dyno session.... or should I buy a new elbow (sans hole), and relocate the IAT in the bottom of the filter?

Also I have not had time to fabricate a custom cold-air box to isolate the filter.... it is just sitting behind the psgr headlight.... so in traffic it will get some hot air... but ok when Moving.
Do I need to make this change before dyno tune?

thx.....

Oh side note..... pretty funny to see the faces of camaro, mustang, and challenger drivers when I pull away from a light in my GMW...... can't wait to get it tuned...

Darth_V8r

iTrader: (4)

Move the sensor to get fresh air temps. Where you have it, the elbow will heat soak, temps read artificially high. It'll cut fuel and timing.

one4torque

THx Darth -

My troubleshooting plan tonight after work:

1. Check fuel pressure @ fuel Rail.. Make sure my custom fuel system is not faulty.
2. Check fuel trims with my u-scan OBD reader.
3. Reclean my MAS. Will test with MAS plugged and unplugged to see if diff.
4. Check for any codes on OBD.
5. Test Relocating IAT.

Talked to LSX perf about my mail order tune, then reviewed each engine assumption with me a gain... (inj, mas, etc..) and said this tune should be close. They suspected a fuel issue, has new O2 sensors. Good new grounds all across chassis and engine to custom LS harness.

I hear no detonation..... but motor just does not rev out...… it's pretty gutless.

I've checked compression, and oil pressure. Has new plugs gapped .05, new sp plug wires, all holes firing (verified with water squirt on each header tube), new wiring spec custom harness.
Fuel inj are new 36# bosch FIC.
Fuel pump is new 255lph.
Fuel filter is new corvette return style.

one4torque

Alright LS guru's here's what I did and the result tonight:

1. Scanned ECU:
Eng Spd: 848
Calc Load: 3.1 (idle)
MAF: 1.14 lb/m
MAP: 17.1 HG
Coolant: 198
IAT: 126
Ign Adv: 24.5
Sec Air: Atm
ST FTRM1: 1.6
ST FTRM2: 1.6
LT FTRM1: -10.9
LT FTRM2: -9.4
Veh Spd: 0
Fuel Sys 1: Closed
Fuel Sys 2: Closed
O2S B1S1: .085
Fuel Trim B1S1: 1.6
O2S B1S2: .435
O2S B2S1: .12
Fuel Trm BsS1: 2.3
O2S B2S2: .455
OBD2 STAT: CA

Observations: IAT ran hotter just sitting in engine compartment VS in the intake tubing (so for next test left IAT in inlet tract).
Fans turn on (F body dual fan setup) @ 189, 2nd fan @ 195.... then seem to keep cooling system at steady 195f
O2 Sensors seemed OK cycling voltage between .1 - .5 sinusoidal
I tested unplugging the MAS, engine idle dropped, then engine idled ok lower.... gave MAS code 102, then speed density code 103 (so happy MAS is OK).
Also cleaned the mas w CRC.

Test Run AFTER clean MAS - no change. low on power... doggy slow. Barely spin tires in top of 1st.
No CEL, no engine codes.
Just down on power.

Checked fuel pressure with KOEOFF..... 50psi.. so happy fuel system working. Will test fuel pressure running when I get a non-leaking p gage (LOL).

I'm starting to think I need to throw this on a dyno and get someone who knows tuning to run it through gears and see what's up.
I don't have a AFR.... I bought a blue-tooth unit... but it's inop.

LMK any other things to check.

In the back of my mind I'm thinking something mechanical.... like bad crank bearings....... it does make some funny noise under load which I thought was trans.... but after T56 rebuild still makes some groaning under load....
either bearings... or header rubbing frame... will investigate.

After 1st start checked oil P - all good.
After 1st start check comp - all good.

Will a way off tune give above conditions????

that's my next move.

Jeff

trilkb

iTrader: (4)

Any chance the cam is off a tooth?

It may just really need dyno tuned lol.

Darth_V8r

iTrader: (4)

pressure should be 58

one4torque

Check fuel p running—. Steady56psi.

cam installed w marks at correct spot.

suspect it’s the scaling of maf and Bosch 36# inj

dyno date 8/15