Power question. Turbo guys come in!
Originally Posted by alwaysinboost
what kind of wastegate are you running and are you using a boost controller or just running of the WG spring pressure?
another thing you might want to try is a pressure test to see if you have any leaks in your charge piping.
another thing you might want to try is a pressure test to see if you have any leaks in your charge piping.
I am see 15psi at the manifold so I doubt there is a leak that is affecting it this much.
TECH Regular
Joined: Jan 2007
Posts: 408
Likes: 0
From: boostville
Originally Posted by phildo
I am using a e-boost 2 now but have tried the waste gate spring only and even tried pulling the boost reference line off of it. All with the same results.
I am see 15psi at the manifold so I doubt there is a leak that is affecting it this much.
I am see 15psi at the manifold so I doubt there is a leak that is affecting it this much.
if you said you pulled the boost reference off the WG and felt no difference what so ever I would suspect there is a problem with the WG not staying shut. with the Tial units there is a fire ring @ the base where it would connect to the manifold/collector, often times that ring is left off and the result is simular to what you are experiencing.
also a boost leak test is never a bad idea. it takes a short time and you would be really suprised what you would find.
TECH Regular
Joined: Jan 2007
Posts: 408
Likes: 0
From: boostville
Originally Posted by phildo
I have turned the meth off and it ran the same. There was no knock retard either. I have tuned numerous turbo cars on the street w/a wideband and get them pretty close before I take them to the dyno for the final tweaking. It is not in the tune. There is something mechanically wrong. I am wondering if it is blowing the spark out.
I was just hoping someone had a similar situation and could shed some light on the situation. I am sure once I figure it out it is going to be something stupid but I will try anything to get to the bottom of this.
I was just hoping someone had a similar situation and could shed some light on the situation. I am sure once I figure it out it is going to be something stupid but I will try anything to get to the bottom of this.
Originally Posted by alwaysinboost
what kind of WG are you running and what is the spring pressure?
if you said you pulled the boost reference off the WG and felt no difference what so ever I would suspect there is a problem with the WG not staying shut. with the Tial units there is a fire ring @ the base where it would connect to the manifold/collector, often times that ring is left off and the result is simular to what you are experiencing.
also a boost leak test is never a bad idea. it takes a short time and you would be really suprised what you would find.
if you said you pulled the boost reference off the WG and felt no difference what so ever I would suspect there is a problem with the WG not staying shut. with the Tial units there is a fire ring @ the base where it would connect to the manifold/collector, often times that ring is left off and the result is simular to what you are experiencing.
also a boost leak test is never a bad idea. it takes a short time and you would be really suprised what you would find.
The spring is set to 6psi and I saw 15.5psi with it pulled.
TECH Regular
Joined: Jan 2007
Posts: 408
Likes: 0
From: boostville
Originally Posted by phildo
Sorry I didn't clarify that, boost definetly increased but the power output gain was minimal compared to the boost jump. The car has the best sound and torque at about 3-4psi, anything more and I loose torque and the engine starts to sound weird. Like the timing is retarded or something.
The spring is set to 6psi and I saw 15.5psi with it pulled.
The spring is set to 6psi and I saw 15.5psi with it pulled.
again I'll ask what kind of WG are you running?
u said its a new motor...the car runs nice at 3-4psi to redline?just making sure its not a motor issue.rule out the controller if u ran it on wastegate and the same thing happened.where are your references at for the WG and BOV?u shouldnt be blowing out spark at those levels,maybe try gapping them at .030
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Verdad Gallardo
Awesome K5 Blazer Restomod Comes With C7 Corvette Power
Verdad Gallardo
10 Camaros You Should Never Buy
10 LS Engine Myths That Refuse to Die
Verdad Gallardo
Originally Posted by code4
What valve springs are you running? What size cam?
I am starting to think the push rods are too long. I am going to pull the valve covers and check lifter pre-load. I was told to just run the stock ls1's I had. I was rushing to get it done and to my stupidity I never double checked them.
It is the only thing that makes sense so far. I will keep you guys posted. Thanks to all that helped! Last edited by phildo; Jul 30, 2007 at 08:56 PM.
TECH Resident
Joined: Jan 2004
Posts: 832
Likes: 0
From: Castro Valley, CA
Way simple, I know, but I've had some partially-burnt plug wires that allowed the car to run OK until pushed. But never at the expense of THAT much power.
Plenty of boost going in but no power? It does kinda sound like a valvetrain problem.
Plenty of boost going in but no power? It does kinda sound like a valvetrain problem.
I have a customer with an APS kit on a C6 that took off his bone stock 243 heads and installed the L92's and lost power. Most turbo kits have more exhaust pressure than intake pressure. Bigger intake valves cause intake port charge dilution from exhaust gases, as the exhaust gases back up into the intake port during overlap. What cam duration and LSA are you running?
Last edited by Brian Tooley Racing; Aug 1, 2007 at 07:23 AM.
TECH Enthusiast
Joined: May 2006
Posts: 631
Likes: 0
From: Metairie, LA
Originally Posted by Brian Tooley
I have a customer with an APS kit on a Z06 that took off his bone stock Z06 heads and installed the L92's and lost power. Most turbo kits have more exhaust pressure than intake pressure. Bigger intake valves cause intake port charge dilution from exhaust gases, as the exhaust gases back up into the intake port during overlap. What cam duration and LSA are you running?
Originally Posted by Brian Tooley
I have a customer with an APS kit on a Z06 that took off his bone stock Z06 heads and installed the L92's and lost power. Most turbo kits have more exhaust pressure than intake pressure. Bigger intake valves cause intake port charge dilution from exhaust gases, as the exhaust gases back up into the intake port during overlap. What cam duration and LSA are you running?
I'll give a few suggestions.
1- the valves are floating or the pushrods are too long.
2- both 02 sensors in the 1 crossover pipe in a no-no. 1 bank could be way off from the other which causes the car to run like complete crap.Have seen it many times while closed loop tuning.Move 1 02 to the downpipe.
3- The turbo is not a back pressure problem at such low boost but the rest of the exhaust could be.Run an open downpipe to check.
4- the dyno could answer alot of questions and save time.
1- the valves are floating or the pushrods are too long.
2- both 02 sensors in the 1 crossover pipe in a no-no. 1 bank could be way off from the other which causes the car to run like complete crap.Have seen it many times while closed loop tuning.Move 1 02 to the downpipe.
3- The turbo is not a back pressure problem at such low boost but the rest of the exhaust could be.Run an open downpipe to check.
4- the dyno could answer alot of questions and save time.
Originally Posted by Pro Stock John
Can you change the AR to a bigger one? If not, turn it down and leave it alone until you can fit a bigger turbo. Why not do a T4 88, T6 is a bigazz turbo, mine is almost 12x12x12 inches.
Originally Posted by Pro Stock John
I'd check the pushrods, and then I would also think about whether you have valve float. How much preload is ideal, .050? I'm running the ETP valvesprings, but I ran Comp 977's at one point, and I ran Crane 832's before then. When I was a blower + 230/236 cam the Crane 832's were fine, but when I went to a 236/246 cam I had valve float. Rule of thumb is to run a lot of spring pressure to get those valves to open under high boost conditions.
I have the day off today so I am going to get to the bottom of this. I will keep you guys posted.
Thanks for all the good suggestions!
My crossover is shaped like a W w/ the turbo in the middle and 0'2 at the top of each outside peak right after each manifold. Is this o.k. or should I take one out?
Originally Posted by Slowhawk
I'll give a few suggestions.
1- the valves are floating or the pushrods are too long.
2- both 02 sensors in the 1 crossover pipe in a no-no. 1 bank could be way off from the other which causes the car to run like complete crap.Have seen it many times while closed loop tuning.Move 1 02 to the downpipe.
3- The turbo is not a back pressure problem at such low boost but the rest of the exhaust could be.Run an open downpipe to check.
4- the dyno could answer alot of questions and save time.
1- the valves are floating or the pushrods are too long.
2- both 02 sensors in the 1 crossover pipe in a no-no. 1 bank could be way off from the other which causes the car to run like complete crap.Have seen it many times while closed loop tuning.Move 1 02 to the downpipe.
3- The turbo is not a back pressure problem at such low boost but the rest of the exhaust could be.Run an open downpipe to check.
4- the dyno could answer alot of questions and save time.
Those springs are marginal at best with the big valves with anything over .560 lift with boost but I doubt that is the problem at 4lbs.
You say timing is steady at 16 degree's and A/F is 11-1 read from a wideband?Unless the tranny is slipping I'll say it's valve trane.
You say timing is steady at 16 degree's and A/F is 11-1 read from a wideband?Unless the tranny is slipping I'll say it's valve trane.