10-5-5 boost problem (SOLVED)
11-25-13, 08:01 PM
#1
10-5-5 boost problem (SOLVED)
Thought I'd share my experience to help out anyone with a similar issue..
95 PEP, catback & downpipe only. 68.5k mi
After getting my gauges installed (finally), I was able to monitor my boost and noticed I was only getting up to 5 psi after the secondary transition (10-5-5 or so). I also noticed a howling/whistling noise (not as high pitched as a whistle, but somehwere between) when i really got on the pedal. Testing was mostly done at night so I'd get up to 12 psi occasionally on the primary (attributing this to cold/dense air).
I installed a downpipe (finally), and came across a brittle CRV hose that cracked as I was removing it. Replaced it with OEM, hoping that may add to the boost, but the needle never went past 5. I inspected the valve when I did my DP install and it was fine. I was afraid it was my CRV solenoid not activating and causing it to stay open after transition.
Decided I may as well dig in as I have a bunch of silicon tubing ordered from hiperformancestore.com (which seems to be very good quality), as well as viton check valves from Dale.
Removed my pressure chamber, inspected my IC hoses, couplers, Y-pipe coupler----nothing visible.
Found this website:
Symptoms
I took a look at the pressure chamber hoses described and they seemed intact, plugged in the mityvac and the valve held tight in one direction, and air would flow in the other direction, but a distinct hissing/whining noise could be heard. Not sure what to make of that. Tossed it and the hoses, replaced them with viton and silicon, as well as the other tube that goes from the pressure chamber as it easily accessible.
Put it all back together. Took her for a spin (cold and dark again)..
She is now eagerly boosting 12-14 psi when I got WOT in 3rd---as soon as I saw that I left off the gas. Still hearing that howling noise, could it just be the WG? Happy I solved it, but somewhat bittersweet as I cannot do WOT runs safely...... such a finicky b*tch! lol
This is with apexi N1 duals, stock cat, and pettit downpipe. I put silencers back into the apexi to hopefully kill some of the exhaust flow and it seems to have SLIGHTLY helped the overboost. Soon enough I'll polish up my RB dual tip and throw that on there, but until I have 1900 for a PFC and tune, manual boost controllers are next on the list.
thanks for reading, hope this helps someone!
95 PEP, catback & downpipe only. 68.5k mi
After getting my gauges installed (finally), I was able to monitor my boost and noticed I was only getting up to 5 psi after the secondary transition (10-5-5 or so). I also noticed a howling/whistling noise (not as high pitched as a whistle, but somehwere between) when i really got on the pedal. Testing was mostly done at night so I'd get up to 12 psi occasionally on the primary (attributing this to cold/dense air).
I installed a downpipe (finally), and came across a brittle CRV hose that cracked as I was removing it. Replaced it with OEM, hoping that may add to the boost, but the needle never went past 5. I inspected the valve when I did my DP install and it was fine. I was afraid it was my CRV solenoid not activating and causing it to stay open after transition.
Decided I may as well dig in as I have a bunch of silicon tubing ordered from hiperformancestore.com (which seems to be very good quality), as well as viton check valves from Dale.
Removed my pressure chamber, inspected my IC hoses, couplers, Y-pipe coupler----nothing visible.
Found this website:
Symptoms
I took a look at the pressure chamber hoses described and they seemed intact, plugged in the mityvac and the valve held tight in one direction, and air would flow in the other direction, but a distinct hissing/whining noise could be heard. Not sure what to make of that. Tossed it and the hoses, replaced them with viton and silicon, as well as the other tube that goes from the pressure chamber as it easily accessible.
Put it all back together. Took her for a spin (cold and dark again)..
She is now eagerly boosting 12-14 psi when I got WOT in 3rd---as soon as I saw that I left off the gas. Still hearing that howling noise, could it just be the WG? Happy I solved it, but somewhat bittersweet as I cannot do WOT runs safely...... such a finicky b*tch! lol
This is with apexi N1 duals, stock cat, and pettit downpipe. I put silencers back into the apexi to hopefully kill some of the exhaust flow and it seems to have SLIGHTLY helped the overboost. Soon enough I'll polish up my RB dual tip and throw that on there, but until I have 1900 for a PFC and tune, manual boost controllers are next on the list.
thanks for reading, hope this helps someone!
11-25-13, 09:15 PM
#2
Don't put off the boost controllers. With just a Pettit downpipe and a Racing Beat cat back, my '94 would hit the over-boost cut in 3rd gear after transition due to a boost spike somewhere around 6K rpm.
Too cheap to put in even a manual boost controller, I took out the stock restrictor pill in the wastegate control hose and replaced it with a 0.064" Holley carb jet. That didn't do the job, so I tried larger jets until finally I stuck in a jet with an 0.0755" orifice. That got the boost down from 12-10-11 to 11-10-9 in cold weather and more importantly, it lowered the rpm at which the transition spike occurred by almost 1000 rpm. The overboost cut curve is more generous at lower rpm (12 psi at 5K vs. 11 psi at 6K), so that solved the problem -- until I get around to another mod.
Too cheap to put in even a manual boost controller, I took out the stock restrictor pill in the wastegate control hose and replaced it with a 0.064" Holley carb jet. That didn't do the job, so I tried larger jets until finally I stuck in a jet with an 0.0755" orifice. That got the boost down from 12-10-11 to 11-10-9 in cold weather and more importantly, it lowered the rpm at which the transition spike occurred by almost 1000 rpm. The overboost cut curve is more generous at lower rpm (12 psi at 5K vs. 11 psi at 6K), so that solved the problem -- until I get around to another mod.
11-26-13, 12:41 PM
#3
^+1
Just a friendly piece of advice:
It would be a good idea to verify that your boost gauge is accurate. In any case, get a boost controller ASAP. Now as far as a PFC and tune costing $1900: Not really you can pick up a used set on here for like $700 and get it tuned for $250.
IMO get a good electronic boost controller and set it to 10 psi (rock solid, no spiking nor creeping). As you add components (CAI, IC ect..) re adjust your boost controller back to 10 . Once you are done adding boltons get the PFC or some other ECU and tune it with your final configuration.
Just a friendly piece of advice:
It would be a good idea to verify that your boost gauge is accurate. In any case, get a boost controller ASAP. Now as far as a PFC and tune costing $1900: Not really you can pick up a used set on here for like $700 and get it tuned for $250.
IMO get a good electronic boost controller and set it to 10 psi (rock solid, no spiking nor creeping). As you add components (CAI, IC ect..) re adjust your boost controller back to 10 . Once you are done adding boltons get the PFC or some other ECU and tune it with your final configuration.
Last edited by Montego; 11-26-13 at 12:45 PM.
11-27-13, 01:01 AM
#4
does an electronic boost controller work just as well as the manual ball-spring valves? For some reason I was under the impression they did not
and yeah, I know I could buy a used PFC--but it is risky, as there is no way to verify it works 100% before purchasing....
and yeah, I know I could buy a used PFC--but it is risky, as there is no way to verify it works 100% before purchasing....
11-27-13, 05:00 PM
#5
Well my greddy spec II has has controlled my boost perfectly for years. I love it for several reasons.
-Gives me a real time boost display
-Warns me if I'm over boosting
-allows me to adjust my spool time ( to a point)
-the ability to fine tune my boost response while I'm driving. Add an intake? no problem go for a drive and adjust as necessary. Too cold of a night causing elevated boost? Problem fixed in two seconds.
-Gives me a real time boost display
-Warns me if I'm over boosting
-allows me to adjust my spool time ( to a point)
-the ability to fine tune my boost response while I'm driving. Add an intake? no problem go for a drive and adjust as necessary. Too cold of a night causing elevated boost? Problem fixed in two seconds.
11-27-13, 05:43 PM
#6
The reason a lot of FDs made it past 30k miles on the original engine is because the second turbo was not coming on line, which is what was happening in you situation. A couple big spikes in 3rd Nd 4th and the factory seals will crack/break.
The best thing to do is to eliminate the turbo control/per-control solenoid that are connected together on the front if the UIM. Loop together/block off the two nipples in the. 3 o'clock position in the waste gate and pre-control actuators. You can run this way for the time being safely and will see 7-9lbs of boost and the car will be faster than it was when the second turbo wasn't transitioning.
Order two Hallman Pro RX manual boost controllers and get the system dialed in to 10lbs.
The best thing to do is to eliminate the turbo control/per-control solenoid that are connected together on the front if the UIM. Loop together/block off the two nipples in the. 3 o'clock position in the waste gate and pre-control actuators. You can run this way for the time being safely and will see 7-9lbs of boost and the car will be faster than it was when the second turbo wasn't transitioning.
Order two Hallman Pro RX manual boost controllers and get the system dialed in to 10lbs.
Thread
Thread Starter
Forum
Replies
Last Post
rgordon1979
3rd Generation Specific (1993-2002)
40
03-15-22 12:04 PM
tiger18
3rd Generation Specific (1993-2002)
9
09-03-15 08:27 PM
