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Discussion Starter #1
Hey guys, this all started when i installed my ebay downpipe and speed-factor intercooler a couple weeks ago. I had seen this thread about problems with the wastegate hitting the flange on these downpipes. I figured this was the problem but after a couple grinding sessions I was left with the same problem....

Here is a list of my relevant mods:
ct20b, 3" downpipe, tko 2.5" exhaust, intake, speed-factor intercooler, twosrus mbc and throttle-body inlet.

This really seems more like a boost creep problem via insufficient wastegate flow but i'm sure there could be other factors. Previously the boost would drop slightly toward redline on the stock gutted cat and intercooler. Now it spools well and hits around 11psi at about 3k but once it reaches 4.5K+ the boost climbs with rpms up to about 14 or 15psi. I can adjust the boost controller so it hits 14psi around 3k but it will creep to over 17psi before reaching redline, and i haven't tried anything higher. Here are a couple pics showing the setup and where i grinded the downpipe.



If anyone has any insight or has had similar problems please let me know. Thanks,
John
 

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When I installed my ct20b and XS power downpipe I had a very similar problem, after changing the downpipe to see if that was the problem (it wasn't) I discovered a big leak between turbo and wastegate actuator. If you have access to a compressor, disconnect the line that goes from turbo to actuator and blow compressed air in to it (with one end still attached to actuator, obviously). See if the actuator arm is moving (might have a leaking or jammed actuator), and listen for the hiss of an air leak
 

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I installed my 20B with RPM 2.5in downpipe, I also have an N1 and Twos R Us MBC. I set it for 15psi and it would hold rock steady at 15 all the way to redline.
 

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Discussion Starter #5
Thanks, I'll be checking the actuator to make sure its working correctly. I checked it using an air compressor and bleeder valve when I installed it and it opened right around 12psi. However, things may have changed since then. Unfortunately I'm 2 hours away at school so I can only make a checklist for when I get home and work on it.

Thanks,
John
 

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My gen 3 has been doing this to me.
I have the ct20b mated with an Aussie DP.

Before my boost gauge was installed (VSV disabled ready for my EBC to be installed) I figured I would be at 6-8 psi..the wastegate pressure.
Though, when I would get on it after breaking in the clutch it felt to me that it would hit what felt like WG pressure (no way of knowing exactly then with no boost gauge installed yet) then by around 4,000 rpms it would have an incredible increase in power.

Now with my aftermarket gauge, I can see that (with VSV disabled) if I am driving along in 2nd/3rd around 3000 rpms...I will go WOT and hit 8psi right away then by 4,000 rpms the boost continues to increase with rpms to redline to about 14psi.


When my GReddy Profec B was hooked up earlier this week, I had no control over the boost...I thought it was the WG but apparently if the WG were bad it should boost to the moon.

I will have to start digging.

-Brendan
 

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what sort of wasteagtedoes the 20b come with? one of the reasons I went with the CT27 was because the wastegate it comes with it large enough and of high enough quality as to prevent boost creep in most situations. since it was internal, i had my doubts but after looking around and talking to ken and arron that worry was put to rest. Is the problem you are having with the 20b similar to that with the greddy TD-0H w/ the stock wastegate (e.g. not the upgraded version or a welded one with an external added)?
 

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MisterMister said:
what sort of wasteagtedoes the 20b come with? one of the reasons I went with the CT27 was because the wastegate it comes with it large enough and of high enough quality as to prevent boost creep in most situations. since it was internal, i had my doubts but after looking around and talking to ken and arron that worry was put to rest. Is the problem you are having with the 20b similar to that with the greddy TD-0H w/ the stock wastegate (e.g. not the upgraded version or a welded one with an external added)?
It is a factory stock internally gated CT20B. I am not sure if it has the original Wastegate actuator (CT20B design), or if it has had a CT26 actuator adapted with washers to work (which I have read can create boost control problems with the actuator not opening enough). PO built the car so I am a little fuzy on what was used in some areas.

When I received the car max boost with my controller off (Profec B, orginal style) or byassed was 8.5psi. This was consistent without creep, but I had alot of boost leak issues that have now been fixed. Before fixing (not knowing I had them) the boost leaks, I went to between 15-19psi. No real creep issues in these ranges, but it would fluctuate a little (+/- .75 psi) from my setting during a single boost event. I went from my setting at 17-18psi (was there for a long time) back down to 15psi (which I will run for track days) and noticed that it was a completely different setting on my boost controller to get it to 15psi. Was a mid/low range setting on the "High" knob, but now was a very low setting on the "low" knob (which used to be about 11psi when I got the car). Even with the controller off or bypassed it was hitting about 14psi. I had a inline filter for the line from the turbo to the inlet on the boost control solenoid and it looked pretty gunked up with oil. After removing it and still bypassing the boost controller (lines looped back to themselve from turbo to actuator), minimum boost dropped from 14psi to 12.5 psi. It seems to hit 9 psi for a moment between 3-4K rpm and then slowly rise to 12.5 by 5.5-6K rpm.

It one time in testing (during the same test session) held lower boost (bypassed controller setup) at about 9psi rock solid, but the very next time I hit the gas pedal at WOT it went back up. This is what has thrown me for a loop.

I am not sure if the higher minimum boost is because I fixed quite a few boost leaks (since I have not check it since then), or it is because something is going wrong with my wastegate or actuator. The fixed boost leaks is really the only thing that has changed during this time period. Otherwise the car runs great when it is boosting (at both low 12.5, or higher 18 psi levels).
 

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Discussion Starter #11
I am going home to get everything sorted out tomorrow. Have to replace the hose from hell, then get to work on the boost issue. It may be the hose from the actuator to vsv not tight enough, but thats only speculation. Haven't driven the car in over a month...
John
 

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Discussion Starter #12
Well unfortunatley my problem still exists. I've fixed any other problems with my car, and secured all the vacuum hoses on the boost controller and actuator with zip ties so I know they are secure. Same exact problem. Even with the boost controller bypassed, it will creep to about 14 psi by redline.

Man, I'm tired of these little things... I REALLY don't want to pull the turbo off again in order to port the wastegate. Seems this is a very rare problem with the ct20b that I've had the fortune of coming across. Thanks for all the help, any other ideas are appreciated but I think I've exhausted all the possibilities.
John
 

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I found out mine was pretty simple. I can now hold as low as 9psi with the boost controller off. My problem was that the line from the turbo to the boost controller had a lazy spring clamp. I used the same spring clamp when bypassing the controller so that I think it still caused the problem with that configuration. Although I saw improvements when bypassed. probably because the barbs on the plastic adapter I used helped it to seal better than to the smooth connector on the solenoid. I added some better clamps to all the connections from the turbo to the solenoid and it seems fine today. That was the only change I made.

Are you sure the zip ties are sealing it well enough. The spring clamp that relaxed too much still made some pressure (enough to keep the hose from popping off completely) but seems it still allowed to much of a leak. Might be worth getting a pack of the small hose clamps just to make sure before you pull the turbo off.

Good luck.
 

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Discussion Starter #14
Glad to see you got yours sorted out.
I'm fairly sure they are secure, but i'll be checing that with an air compressor over the next few days. Hopefully it will be something simple, but these have never given me any issues before as zipties can get pretty tight around the hose. I'm sure the airflow has been increased greatly since the downpipe and intercooler, thats why i'm suspecting insufficient exhaust bypass through the wastegate...


John
 

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daddylonglegs said:
Glad to see you got yours sorted out.
I'm fairly sure they are secure, but i'll be checing that with an air compressor over the next few days. Hopefully it will be something simple, but these have never given me any issues before as zipties can get pretty tight around the hose. I'm sure the airflow has been increased greatly since the downpipe and intercooler, thats why i'm suspecting insufficient exhaust bypass through the wastegate...


John
FWIW I have an ST205 IC core (very free flowing straight shot from turbo to TB inlet) with free flowing exhaust. Exhaust is a 2.5in KO DP with 2.5" exhaust the rest of the way through (single 7" magnaflow muffler with 2.5" in/out). No cats in the system. I really don't think you should see creep with your set up. I would think it would take head work/OS valves, etc... to cause any problems. I don't think external bolt-ons would do it.

Good luck
 

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califcarm said:
FWIW I have an ST205 IC core (very free flowing straight shot from turbo to TB inlet) with free flowing exhaust. Exhaust is a 2.5in KO DP with 2.5" exhaust the rest of the way through (single 7" magnaflow muffler with 2.5" in/out). No cats in the system. I really don't think you should see creep with your set up. I would think it would take head work/OS valves, etc... to cause any problems. I don't think external bolt-ons would do it.

Good luck

Well, adding a catless DP + free flowing exhaust and intake will get boost creep on the GReddy TD-0H turbo set-up on the MKII due to insufficent wastegate properties. It SOUNDS like he is having the exact same problem given the fact that this started after installing said downpipe and exhaust.

Granted you dont heart about this problem as much as you do with the GReddy kit, but Im sure its bound to happen once in a while if the wastegate isnt upgraded from the CT26, as he said previously.
 

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daddylonglegs said:
Well unfortunatley my problem still exists. I've fixed any other problems with my car, and secured all the vacuum hoses on the boost controller and actuator with zip ties so I know they are secure. Same exact problem. Even with the boost controller bypassed, it will creep to about 14 psi by redline.
I don't think 14PSI is an unreasonable minimum boost, given that you have removed all of the restrictions from your setup. I couldn't run less than 14PSI on my CT26/T04E-46 once I had a down pipe, exhaust, and upgraded IC.

I'm not really sure why anyone would WANT to run less than 14PSI anyway.

Ken
 

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KBlake said:
I don't think 14PSI is an unreasonable minimum boost, given that you have removed all of the restrictions from your setup. I couldn't run less than 14PSI on my CT26/T04E-46 once I had a down pipe, exhaust, and upgraded IC.

I'm not really sure why anyone would WANT to run less than 14PSI anyway.

Ken
His problem is that he says if he sets 14psi boost, it will creep to 17psi by redline. Strange problem, it that it is not a min boost issue, it is a creep issue (I wasn't aware that they could be different, but seems so?).
 

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Discussion Starter #19
I'm fine with 14psi... it's just that if i set the boost controller for 14psi, it will reach 17-18 by redline. If I set it to 17psi i'm sure i would see 20+. I would like to be able to hit 16psi by 3k and hold it to redline without creep. I'm missing that midrange I would have if I could set the boost and keep it. Like I said, it seems a very random incidence, which lead me to believe it was the vacuum lines. I'll test them with my air compressor tomorrow and post back.. hopefully.
John
 

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daddylonglegs said:
I'm fine with 14psi... it's just that if i set the boost controller for 14psi, it will reach 17-18 by redline. If I set it to 17psi i'm sure i would see 20+. I would like to be able to hit 16psi by 3k and hold it to redline without creep. I'm missing that midrange I would have if I could set the boost and keep it. Like I said, it seems a very random incidence, which lead me to believe it was the vacuum lines. I'll test them with my air compressor tomorrow and post back.. hopefully.
John

what EBC are you running? When I installed my Spearco IC, I had been running a Marc Summers ball and spring MBC. With the screw backed out all the way, I was still unable to control boost, much like you are describing here. I installed a Blitz DSBC Spec R, and I was suddenly able to regulate boost again. I still couldn't run less than 14PSI, but I was able to set it for 16PSI, and run 16PSI from as soon as the car could make it (about 3k RPM, IMS) to redline.

Ken
 
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