BlackdaHLIALs6

hey guys...im in desperate need of help ....i just finished a custom rear mount turbo kit on my 2004 cadillac ctsv...i been having boost issues....my wastegate is set a 7 psi and im only getting 1-2 psi when i floor it from a dead stop thru out all gears..but when i floor it on the freeway on a high gear i get around 6-7 psi...my current setup is a single to4e 60-1 w/ .96 a/r....wastegate is a 38mm tial,exhaust size is 2.50" down each header to a Y and 3.00" all the way to turbo.The intercooler pipeing is 2.00" from turbo to the intercooler(10"x30"X3") then after the intercooler is 2.50" and after the MAf is 4.00" for fuel system i have F.A.S.t 60lbs injectors and kenne bell boost a pump...i have zero boost leaks from the turbo all the way to the Throttle body and the pcv has a check valve..so far i think my turbo might be too small, what do u guys think might be the issue?



(short video of semi-done turbo setup...gauges are not connected & exhaust tip on the turbo side still needs to be done)
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JAX04

iTrader: (17)

The turbo is a touch small yes, but your charge pipe from the turbo to the IC, is too small as well. Maybe that run of 2" is choking you?? I was always told not to use a pipe smaller then the outlet of the turbo.

BlackdaHLIALs6

my mistake i ment 2.25" not 2.00" for the intercooler pipeing from turbo to intercooler..the inner diameter from the turbo outlet is 1.75" and the pipeing's inner diameter is 2.00"..so the pipeing is not restrictive at all...but like u said turbo might be too small..but i dont get it..this turbo is rated at 550whp for a ls1..i dont mind buying another turbo i just want to make sure this is my problem

JAX04

iTrader: (17)

what type of wastegate are you using??

BlackdaHLIALs6

i have 38mm tial..wastegate spring is 7 psi...with no boost controller....btw i decided to disconnect my wastegate and i blocked off the vaccum lines..then i did a short run being extra carefull not to overboost..and nothing...still 2-3 psi..... and of course on the highway i got the 7 psi and psi was going up..so i let go of gas right before it hit 8 psi...yeah i kno it was really risky!

hawk584

iTrader: (1)

60-1 w/ .96 a/r < small vs. to big?

BlackdaHLIALs6

what do u mean "small vs. too big"?..are u talking about the a/r?..if so, i had the .81 a/r and changed it to a .96 a/r and still have the same issue.

hawk584

iTrader: (1)

i was.. you got me fellow sts brother, hope you get yours figured out... my car's on jack stands with unknown issues

BlackdaHLIALs6

dang sux to hear that...just wondering have u done a boost leak down test on ur car before??

OUTLAWZ RACING

iTrader: (9)

What have u done for valve springs?

BlackdaHLIALs6

right now everything is stock..once the turbo setup is boosting properly with kno delay im im takeing my car to get the heads done...but i find i kinda pointless right now boosting only 2 psi, get me?..one more thing..i did a boost leak down test by putting a coupler w/ a cap and compressor fitting @ beginning of intercooler pipeing....i set the compressor at 10 psi(while car is off of course!) , pcv and all lines to the Tb blocked off...and it doesnt hold any psi i tried this with the car both cold and warm. Theres no air coming out of exhaust only from dipstick and the pcv line coming from the block!..is this normal?

longrange4u

iTrader: (2)

Hmmm... not building any boost? I am curious about what your backpressure is. A 60-1 on a LS6 motor is not just a little small... its very small, but that shouldnt cause your problems. What kind of clamps have you used for your setup? Are all the connectors new? (I have seen the silicone elbow's collapse onto themselfs under WOT)

All STS parts for this build or custom?

BlackdaHLIALs6

everything is custom..but specs of setup (exhaust,IC pipeing,etc.) are similar to the sts...the only thing sts is the turbo..its a to4e 60-1 and w/ the specs ment for a ls1 camaro ...all the clamps are t-bolt..the couplers are the silicone kind that are reinforced w/ string type material , so they are not the cheap rubber kind...the intercooler pipeing they all have a bead at the end to prevent the claps from slipping, i have zero boost leaks form the turbo to the TB....guys i really appreciate u guys showing interest in helping me out, this is driving me insane!

longrange4u

iTrader: (2)

Other then the small turbo... You are dealing with a restriction somewhere in the line. I have delt with issues where from dig... the chassis on car twisted enough to seperate one of my connectors allowing boost to leak...

You may be dealing with a similar issue... if you see boost on highway but not from dig... eliminate what changes between those two times.

BlackdaHLIALs6

ive checked all the pipeing and no leaks...and since u mentioned restrictions maybe my intercooler is not properly sized? ive seen camaro's gto's etc. setups w/ much bigger intercoolers than what i have..so im going to do a test and delete the intercooler w/ a straight pipe in place to see if it changes anything..if there was a restriction that would be the only place i can think of, since all the pipeing is bigger than the turbo outlet

BlackdaHLIALs6

so i ended up deleting the intercooler and it did'nt make a difference!!!....i was so confident that this was going to be a the problem!.......now i think its time to buy a bigger turbo im just a lil undecided to go with a tc78 or tc76?..what do u peeps think? or do u guys still dont think that will solve the boosting problems?

longrange4u

iTrader: (2)

I think you have a different problem.. I am suprised that none of the guys that know more then me have chimed in. Your turbo size wouldnt prevent you from building boost... that's not a symptom.

Going to a TC76 on a stock cube LS1 isnt a bad idea... its just that I dont think thats your only problem. I didnt think it was the intercooler... if anything that causes you to loose boost pressure if its too large... not too small.

I still think you have a piping issue somewhere... or a waste gate that wont stay closed?

BlackdaHLIALs6

longrange4u ur right, today i called sts and i perdy much Bs'd and told them i had a 2001 sts camaro w/ a ls6 swap to get some info from them... anyways...according to them, the symptoms my car is having is due to a bad wastegate, or a really bad exhaust leak or boost leak and not the turbo size....so i decided to literally block off the wastegate..i took it for a ride and still the same issue only 2 psi!!!!!...so its not the wastegate, and all the pipeing is good (intercooler & exhaust)..so it has to be something in the motor...if it was my intake manifold gaskets that are bad will i be able to hear the boost leak? i have a feeling it might be a vacumm leak since my rpms float around from 600-800 rpms when im on idle

BlackdaHLIALs6

peeps trip out on this....so i decided to connect a boost gauge right off the the turbo compressor...these r the numbers i get now + 0.20 psi on idle and 7 psi from a dig..before gauge would read of the intake -17.00 psi on idle and 1 or 2 psi from the dig..sounds to me like theres a restriction somewhere..but where?! throttle body(electric) plate maybe not opening completely????

speedcrazy2

iTrader: (1)

sounds like a restriction or boost loss except that it gets 7psi in the intake from a roll

double check your boost gauge on the intake might be faulty or
could also be a pinched boost line to the gauge(if it is mechanical)

what does the car feel like when the gauge says 2-psi(does it feel like it is making 7psi)

if not then maybe as stated earlier it is a silicone connector flexing when launched other than that maybe a faulty blow off or waste gate