I have both sides vented to fresh air. I hope the motor isn't hurt. it only has around 1500 miles on it and this my second wot run. Is possable that rings havn't sealed??

Well the motor only has 1500 miles on it. Looking at log file the ls6 cam doesn't like to be spun to 6k. I will do a compression test see where it stands.
thanks

 

If the rings haven't sealed yet they never will and it's a bad build. Not sure how your PCV system is setup but you may have a bad check valve allowing excess pressure into the crankcase. I personally will not run a closed PCV system on a performance turbo build.

Not sure what kind of cubes your motor is but an 02+ LS6 cam should spin up to 6400 rpm and peak around 6000 rpm on a 5.7. If it's peaking way earlier than that than your turbo is too small.

 

not from any builds ive seen with a ls6 cam. they peak by 5500 and dead drop by 5900


thats with a gt4202 with a 1.15 ar

 

Not sure what to tell you other than I can't remember how many LS6 cammed 5.7 turbo cars I have tuned and every one of them has peaked around 5900-6100 rpms with an appropriately sized turbo. That graph you posted shows peak HP at 5100-5300 rpm which I have never seen with a 5.7 and an LS6 cam.

 

foose04... had to use your thread for a visual here lol.

Quick.... https://www.performancetrucks.net/fo...d.php?t=465591

 

Not sure what that dyno graph has to do with his problem but OK.

53RUSSELL, I would start with a leakdown test to see if anything looks amiss and go from there.

 

just showin quick and the OP that the LS6 cam spins just fine up to 5600-6100 with very minimal drop off lol.


here is another https://www.performancetrucks.net/fo...9&postcount=32


If the engine is vented correctly and there is nothing wrong with the tube itself, then considering the engine was just built, id assume something is wrong there. like said, compression test and go from there.

 

Well that's a 5.3 with a fairly small turbo so it isn't the same but the op sounds like he has a mpt-70 with the old wheel which is small for a 5.7 so it may be closer. The last 6.0 with the LS6 cam I tuned peaked around 5500-5600 rpm with a 76mm setup so it's definitely around there.

Either way yes it needs a leakdown to see what's going on with vents and popping dipsticks.

 

ive seen a good bit of ls6 cam setups die off way before 6k. there was a post awhile back in the FI section of this site how the ls6 cam drops off horribly. im not a fan of the ls6 for boost if your looking for topend.
that ls1 above had 4" all the way back, and is truck manifold setup

unless the cars you tuned were different then others that have had bad luck


also foose truck is a 4.8. a cam that is designed for a larger motor will carry further then it does in the larger motor in a smaller motor. thats why my cam pulled close to 8k.

 

I agree with quick. Block everything off and vent it. I would also vent the oil fill cap. I was blowing the dipstick out until i closed the pvc and vented everything. I might have $30 invested in vent filters. Thats my .02. Good luck!