Why Am I Losing Boost - Incon Setup
Thread Starter
TECH Resident
Joined: Jan 2002
Posts: 956
Likes: 0
From: Phoenix, AZ
Why Am I Losing Boost - Incon Setup I thought it was the wimpy 4.5psi actuators, so I swapped them out for an 8psi set. Boost seems to come on harder/faster now. With the boost controller on and turned all the way down, it hits around 14psi, but by 4500rpm starts dropping, down to about 11 at redline.
cablebandit has stated he never had this issue. Could it be I'm getting valve float? I'm running Comp 918's in it now. Could I have so much pressure on the hot side to cause this condition? I'm really scratching my head on this one, I've been chasing this issue for a couple of years now.
Please help!
- Dug
cablebandit has stated he never had this issue. Could it be I'm getting valve float? I'm running Comp 918's in it now. Could I have so much pressure on the hot side to cause this condition? I'm really scratching my head on this one, I've been chasing this issue for a couple of years now.
Please help!
- Dug
Thread Starter
TECH Resident
Joined: Jan 2002
Posts: 956
Likes: 0
From: Phoenix, AZ
This is the 'Stage 2' kit but the turbos I believe are the same as Stage 1, I think they're .86AR? Got dual exhaust, no cats, and bullit mufflers ( I know they are a problem too ). My next thing to try as you asked onfire is to disconnect everything after the gates and take that out of the equation. Did not plot, but I took video of the gauges and it hits 14-15 and immediately starts to drop, then stays at 11.
mahhddgtp if you are right, then there's really nothing I can do aside from larger turbos then? Not worth it if that's the case.
mahhddgtp if you are right, then there's really nothing I can do aside from larger turbos then? Not worth it if that's the case.
TECH Enthusiast
Joined: Mar 2004
Posts: 604
Likes: 0
From: Loganville, GA
It's gotta be choking... Getting larger turbine housings is one fix. There's the .64 A/R and the .86 A/R. Even the 0.86's have seemed to be way too small.
You can always de-stroke to smaller cubes...
You can always de-stroke to smaller cubes...
Originally Posted by ChevyNo1
This is the 'Stage 2' kit but the turbos I believe are the same as Stage 1, I think they're .86AR? Got dual exhaust, no cats, and bullit mufflers ( I know they are a problem too ). My next thing to try as you asked onfire is to disconnect everything after the gates and take that out of the equation. Did not plot, but I took video of the gauges and it hits 14-15 and immediately starts to drop, then stays at 11.
mahhddgtp if you are right, then there's really nothing I can do aside from larger turbos then? Not worth it if that's the case.
mahhddgtp if you are right, then there's really nothing I can do aside from larger turbos then? Not worth it if that's the case.
If the ar is 86 (Look at the castings) it's not the housings. I've seen GT2871R's (What you have) hit 20 psi on bigger motors than you have.
Are you sure the boost controller is set up properly. I ran 17psi with those turbos with a very steady pressure line with the EB2 controller.
Trending Topics
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
TECH Enthusiast
Joined: Mar 2004
Posts: 604
Likes: 0
From: Loganville, GA
Originally Posted by onfire
If the ar is 86 (Look at the castings) it's not the housings. I've seen GT2871R's (What you have) hit 20 psi on bigger motors than you have.
Are you sure the boost controller is set up properly. I ran 17psi with those turbos with a very steady pressure line with the EB2 controller.
Are you sure the boost controller is set up properly. I ran 17psi with those turbos with a very steady pressure line with the EB2 controller.
Originally Posted by mahhddgtp
17psi on what size motor? IIRC you had a 427 with the incon kit at one point in time.
427ci
ALL of LPE +400ci builds used GT2871R turbos on the "standard" builds. Their 9.5 at 145mph Vette that ran the plane in MT was a 427 with GT2871R's same as the Incon base....those baby turbos make some great power for their size. My best was 9.9 at 141 at Bristol (+4000ft DA)
Now running GT3582R's.
onfire, how did you get such big turbos to fit on the incon kit? I thought, even the bigger turbos, the biggest you could get was a gt 3071r? Also, how's the car drive with the upgraded turbos?
I remember he was trying to get the bigger 13 cartridges to fit into the housings but I couldn't remember how well that worked out. Are these the turbos with the bigger 13's or are these turbos with the adapter plates to fit t-4 turbos (I think) onto the incon manifolds? sorry to hijack the thread BTW, just always interested in getting more incon info.
Originally Posted by anarchy99
onfire, how did you get such big turbos to fit on the incon kit? I thought, even the bigger turbos, the biggest you could get was a gt 3071r? Also, how's the car drive with the upgraded turbos?
Originally Posted by WARPNOVA
If I am not mistaken he is no longer running the incon manifolds but instead he uses the speed inc twin turbo street kit manifolds that he got before they haulted the building of them due to some small problems. He is still using parts of the old incon setup but that is all I believe.
Thread Starter
TECH Resident
Joined: Jan 2002
Posts: 956
Likes: 0
From: Phoenix, AZ
no worries on the hijacking guys, I too gobble up any Incon info I come across.
Took a look at my controller last nite, it is the original Greddy Profec-B. Now here's the interesting part. It of course has the balance ****, and low and hi boost *****. Supposed to tune by putting the balance in the middle and adjusting low/hi to your liking. It you get boost spikes you turn the balance **** clockwise to sharp until it stops. If you get boost hunching ( falling off ) then you turn counter to mild. IF you still have spike issues, there are 4 dip switches on the back giving 4 possible settings. Two are for actuator type, two are for external wastegate type. One of the options for both setups is if you get boost spike you can adjust the dip switch. Mine is flipped for actuator type in overboost situations, so I'm thinking that is why it's falling off on the top end. Hope to do some tests today after the roads dry up.
Took a look at my controller last nite, it is the original Greddy Profec-B. Now here's the interesting part. It of course has the balance ****, and low and hi boost *****. Supposed to tune by putting the balance in the middle and adjusting low/hi to your liking. It you get boost spikes you turn the balance **** clockwise to sharp until it stops. If you get boost hunching ( falling off ) then you turn counter to mild. IF you still have spike issues, there are 4 dip switches on the back giving 4 possible settings. Two are for actuator type, two are for external wastegate type. One of the options for both setups is if you get boost spike you can adjust the dip switch. Mine is flipped for actuator type in overboost situations, so I'm thinking that is why it's falling off on the top end. Hope to do some tests today after the roads dry up.
