CBRD wins the least expensive power mod award...
How did you ultimately get it back on?
3.5 turns was worth 5-6 psi on my car across the board.
I drove it to work today, 80 miles round trip, and used a combination of cruise control and just regular driving. I spent long periods of time (as long as possible at least) in part throttle high boost situations, transient low boost to high boost part throttle, and lugging the car along at low RPMs letting boost come up to 15-ish psi in fifth at 2500 RPM part throttle, etc, all in an attempt to get the car to throw a cell. Never got a cell. Hope it continues like this.
3.5 turns was worth 5-6 psi on my car across the board.
I drove it to work today, 80 miles round trip, and used a combination of cruise control and just regular driving. I spent long periods of time (as long as possible at least) in part throttle high boost situations, transient low boost to high boost part throttle, and lugging the car along at low RPMs letting boost come up to 15-ish psi in fifth at 2500 RPM part throttle, etc, all in an attempt to get the car to throw a cell. Never got a cell. Hope it continues like this.
I have tried from 22psi to almost 25psi peak. No matter what, the turbo tapers to 17psi at the rev limiter way up top. Power difference between 22psi and 24psi is negligable, she's blowing hot air in the midrange. This car likes fueling changes more than anything.
So I spent some time messing around with this mod yesterday, here is what i found. I have an intake, exhaust, boost gauge and a mbc. I was getting a 23->17 boost curve with my mbc.
I first tried 1.5 turns, readjusted my mbc to maintain my stock boost level, and didn't really notice any difference. I tried again with 3 turns, then 3.5. At 3.5 turns, i was able to make an additional 1psi at redline, giving me a 23->18 boost curve. However, it seems to hold boost better the entire way through, and it seems faster all around. I wasn't able to make 19psi at redline like some of the others, however, I am in denver, at 5280 feet the stock x turbo is probably struggling for air.
Unfortunately, i had a couple problems on the way to work. My car started idling at 2k rpm, unless i had the ac on. (If i turned the ac on the car idled fine.) Once i turned the car off and back on this went away and hasn't come back. However, i'm fairly sure this is related to my cone air filter. The other issue was my SES light came on...I haven't checked the code but i didn't notice any gimp mode.
This mod is really easy to do, if i continue to have problems I can reverse it in about 20 min.
I first tried 1.5 turns, readjusted my mbc to maintain my stock boost level, and didn't really notice any difference. I tried again with 3 turns, then 3.5. At 3.5 turns, i was able to make an additional 1psi at redline, giving me a 23->18 boost curve. However, it seems to hold boost better the entire way through, and it seems faster all around. I wasn't able to make 19psi at redline like some of the others, however, I am in denver, at 5280 feet the stock x turbo is probably struggling for air.
Unfortunately, i had a couple problems on the way to work. My car started idling at 2k rpm, unless i had the ac on. (If i turned the ac on the car idled fine.) Once i turned the car off and back on this went away and hasn't come back. However, i'm fairly sure this is related to my cone air filter. The other issue was my SES light came on...I haven't checked the code but i didn't notice any gimp mode.
This mod is really easy to do, if i continue to have problems I can reverse it in about 20 min.
The high idle is a side effect from the code.
You don't feel the effects of the limp mode because your ECU boost is disabled. If it was hooked up, you would be seeing 12psi.
Evolving Member
Joined: Apr 2003
Posts: 297
Likes: 0
From: Raleigh, NC
Its not going to throw a CEL because you are using ECU controlled boost still. The P1235 CEL happens from an MBC and like 22psi from like 20% throttle where the car is in cruising load cells and fueling set at stoich. It sees it as an unsafe condition with the MBC because well, it is.
My car does not like 24+ psi in the midrange on 93 octane with the way its tuned and tends to get fussy and detonate. Yours will too when you lean it out. With boost correction and barely tapping 23psi in the middle, its smooth as silk.
Newbie
Joined: Apr 2008
Posts: 13
Likes: 0
From: Illinois
How did you ultimately get it back on?
3.5 turns was worth 5-6 psi on my car across the board.
I drove it to work today, 80 miles round trip, and used a combination of cruise control and just regular driving. I spent long periods of time (as long as possible at least) in part throttle high boost situations, transient low boost to high boost part throttle, and lugging the car along at low RPMs letting boost come up to 15-ish psi in fifth at 2500 RPM part throttle, etc, all in an attempt to get the car to throw a cell. Never got a cell. Hope it continues like this.
3.5 turns was worth 5-6 psi on my car across the board.
I drove it to work today, 80 miles round trip, and used a combination of cruise control and just regular driving. I spent long periods of time (as long as possible at least) in part throttle high boost situations, transient low boost to high boost part throttle, and lugging the car along at low RPMs letting boost come up to 15-ish psi in fifth at 2500 RPM part throttle, etc, all in an attempt to get the car to throw a cell. Never got a cell. Hope it continues like this.
I've still got no cel and I've also tried to drive it at various throttle positions in different gears. It sounds like it's pretty clear that there is no cel as it is still using factory boost control. I'm still not sure if this is a better way to increase boost than using an MBC. I think in a few days I will put on my MBC and mess around with it a little bit. Again thanks for the help guys.
Evolved Member
Joined: Mar 2008
Posts: 972
Likes: 0
From: Mid-West IL
So this is producing these great results with out the MBC? I am going to skip on the MBC anyways. I just wanna now what would be safe to turn. 25psi seem a bit much for peak boost. I wish it just tapers a lot less. I wanna get a boost gauge before I do this anyways.
Is there any way you could more or less specify what "better" fuel means. Where I live we have BP, Shell, Mobil1, Marathon. Which one of these you think wouldn't cause the loss of power or which one would you tank up.?
Is there any way you could more or less specify what "better" fuel means. Where I live we have BP, Shell, Mobil1, Marathon. Which one of these you think wouldn't cause the loss of power or which one would you tank up.?
Last edited by love9sick; Jun 24, 2008 at 04:19 PM.
Evolved Member
Joined: Oct 2007
Posts: 1,849
Likes: 1
From: USA
Did you by any chance have an mbc on your car and he didnt on his? The factory boost control system does a pretty good job of preventing boost cut by preventing the boost from spiking too high.
I'm not a fan of MBC.. very crude plus I like to run multiple settings for street, wife and track ..
As compared recently .. my TOTALLY STOCK (for now) car spiked to 27psi versus my friend's 23 psi .. BUT his tapered to 15-16psi whilst mine tapered to 13-14psi .. This could be due to the boost sensor we use but his upper rpm ranges corresponds to what you guys see here ..
Newbie
Joined: Mar 2008
Posts: 89
Likes: 0
From: Denver
Remember this mod is about getting a better boost curve, which is all determined by the wastegate on your turbo. the wastegate can be controlled mechanically, via a mbc, or adjusting the wastegate actuator, or it can be done electronically, via the ecu or a ebc. If you've gotten a tune then it's been set electronically via the ecu to have a specific boost curve, this mod shouldn't be necessary.
Evolved Member
Joined: Mar 2008
Posts: 972
Likes: 0
From: Mid-West IL
Does the Clevis rotate in the negative position at all? If you loosen the jam nut bolt does it spring or does it just sit there and wait till it is turned? Can it be turned in the opposite direction? I should expect 25 psi and about 18-19 psi taper after full turn? Did you guys drive it fulled turned and give it full load in fifth gear on the high way and lower RPMS? no CEL or SES lights? No boost spikes?
It seems like this mod is better than an MBC because it tapers less boost up on top of the rpms and doesn't throw check engine and SES lights. Right?
It seems like this mod is better than an MBC because it tapers less boost up on top of the rpms and doesn't throw check engine and SES lights. Right?
Last edited by love9sick; Jun 25, 2008 at 04:32 PM.
Evolving Member
Joined: Apr 2003
Posts: 297
Likes: 0
From: Raleigh, NC
This is what happens in my car. I can't gaurantee every car is exactly the same.
It will rotate in both directions. It is not spring loaded, if you remove the clevis from the actuator while the jam nut it loosened, and you do not turn the clevis by hand, then the clevis just sits there and does nothing.
I got 25-ish psi in fourth gear at WOT at about 4000 RPM. Haven't gotten 25 psi in third or fifth. It seems to taper down to 18-19 psi, on my car, at WOT, between 6000 and 7000 RPM, in third, fourth, and fifth gears.
Yes, that is how my car is set up now. It seems to get to about 15 psi in fifth at low engine speed (2000 - 3000 RPM?, not sure exactly on the range) on the highway. No CEL on my car.
This is why I'm not installing my MBC. Whether or not it's "better" is open to interpretation.
I should expect 25 psi and about 18-19 psi taper after full turn?
Did you guys drive it fulled turned and give it full load in fifth gear on the high way and lower RPMS? no CEL or SES lights? No boost spikes?
It seems like this mod is better than an MBC because it tapers less boost up on top of the rpms and doesn't throw check engine and SES lights. Right?