I was curious what could be causing this. power kicks in at about 2700 and pulls until 4500 and then it just "gets lazy". I just replaced exhaust with 2.5" catback, because I thought it was a flow issue and Im still having the same problem.
could it be the CAT. I still have the stock cat, because the retards that made me a 2.5" dp decided to weld it directly into the cat, even though I asked for a flange there. so that could be a bottleneck?
could it be compression? when I installed KAT I had 170+-5 across the board. I would imagine a loss of compression would cause a general decrease in power, but I dont feel that everywhere. Im going to be checking this tomorrow.
could it be manifold exhaust leak. I have a hole in my gasket that goes from manifold to turbo. I would think this would cause slow spool, but wouldnt effect anything at high rpms. I got a new SS one in the mail, so that will be replaced shortly as well.
any other thoughts would be appreciated as Im chasing a gremlin that I cant seem to find.
Thanks,Steve
high rpm KAet lacking power, help appreciated
I have the same turbo, and the same problem as you. Power kicks in good at around 2700, but loses some steam at around 4500 just like yours. Mine seems to pick up just a bit right around 6000. It bothers me, because I think I'm making peak power at about 3500 rpm, but then it doesn't pull as hard in the upper rpms.
I think my problem is that I haven't tuned the car yet. I expect the power dip to go away with some tuning. I also have a stock cat, and that could be a bottleneck, but I haven't made a test pipe yet to find out.
Ftrs13, what do you have as far as fuel management/tuning, and have you done any tuning on a dyno yet?
I think my problem is that I haven't tuned the car yet. I expect the power dip to go away with some tuning. I also have a stock cat, and that could be a bottleneck, but I haven't made a test pipe yet to find out.
Ftrs13, what do you have as far as fuel management/tuning, and have you done any tuning on a dyno yet?
-
Checkered-Member
- Posts: 1593
- Joined: Wed Sep 24, 2003 7:14 am
- Car: 1998 Nissan Altima (modded)
2003 Audi A6 2.7T (stock) - Contact:
Here is the thing, a KA by its very nature isn’t very efficient at top end, unless off course you do major modifications to achieve such a goal.
the stock exhaust is not helping, the sidemount is also not helping, neither does the stock cat, and your compressor is simply too small. yes getting a cat back and better fuel management will help, but not as much as you are hoping
the stock exhaust is not helping, the sidemount is also not helping, neither does the stock cat, and your compressor is simply too small. yes getting a cat back and better fuel management will help, but not as much as you are hoping
just installed a temp catback that I got for cheap, 2.5" mandrel. sidemount will be replaced in a week with a starion, and cat is on for a while because the crazy guys at the exhaust shop decided to weld it into my downpipe.
I was thinking of swapping out the T3, for T3/T4 in the future, with a new dp. but dont really have the money now, as I have to save for the year of school I have ahead. I was planning on building a motor and upgrading turbo next summer, when I get a little more cash.
would gutting the cat increase flow significantly? I know its bad, and we dont have emissions here. but Im looking for better flow. this will help a lot?
Steve
I was thinking of swapping out the T3, for T3/T4 in the future, with a new dp. but dont really have the money now, as I have to save for the year of school I have ahead. I was planning on building a motor and upgrading turbo next summer, when I get a little more cash.
would gutting the cat increase flow significantly? I know its bad, and we dont have emissions here. but Im looking for better flow. this will help a lot?
Steve
-
C-Kwik
- Moderator
- Posts: 8070
- Joined: Thu Aug 01, 2002 9:28 pm
- Car: 2013 Chevy Volt, 1991 Honda CRX DX
A T3 turbo is rather small. At high airflow rates, the motor is choked because the compressor has to spin at a high speed to acheive the airflow and pressure you desire. To spin it this fast, the turbine needs a lot of exhaust energy. In order to get this much energy, the wastegate must stay shut longer and force more air through the turbine. The backpressure in the manifold is subsequently increased causing a loss in power. Also, to add to that, the T3 compressor is not going to be at a very good efficiency the closer you are to redline. When this happens, the air will be heated more and there is more internal aerodynamic drag which means the turbine needs to work that much harder. While increasing airflow all around helps, ultimately, it's your turbo that is going to be the biggest restriction.
Also, as far as where in the RPM band you will feel the most forward acceleration is always the point you have the most torque, not HP. HP tells you more about the big picture of acceleration. But using the peak HP figure is not going to be where peak acceleration occurs(in a given gear), unless peak torque and peak HP occurs at the same RPM.
Also, as far as where in the RPM band you will feel the most forward acceleration is always the point you have the most torque, not HP. HP tells you more about the big picture of acceleration. But using the peak HP figure is not going to be where peak acceleration occurs(in a given gear), unless peak torque and peak HP occurs at the same RPM.
ftrs13 wrote:just installed a temp catback that I got for cheap, 2.5" mandrel. sidemount will be replaced in a week with a starion, and cat is on for a while because the crazy guys at the exhaust shop decided to weld it into my downpipe.
I was thinking of swapping out the T3, for T3/T4 in the future, with a new dp. but dont really have the money now, as I have to save for the year of school I have ahead. I was planning on building a motor and upgrading turbo next summer, when I get a little more cash.
would gutting the cat increase flow significantly? I know its bad, and we dont have emissions here. but Im looking for better flow. this will help a lot?
Steve
I'd be willing to bet you it's your stock catalytic converter choking the power output at higher rpms. Does your boost stay constant to about 6000 rpm or does it drop off too? Exhausts on a turbocharged car make HUGE differences in how the car performs...
I had a full 2.5" mandrel bent exhaust fromt he downpipe to the back, NO catalytic converter, and my boost would be a steady 9 psi to around 5000 rpm and then drop to 7 psi by 6000 rpm and stay there above that range. I couldn't figure out what would be causing a restriction because the muffler is a straight-through tanabe. Then I thought about the resonator--when I looked at the inside of the resonator I realized how necked-down it was and figured it'd be a restriction. So I just brought the car to a muffler shop, had them chop out the resonator and weld in a straight 2.5" pipe. Yesterday when I took the car out it held 9 psi to redline, and before i did that, it'd be at 7 psi at redline.
Every little bit makes a difference.
Just my $.02
ok, thats the conclusion that I came up with. the psi stays constant, but Im only running 5 so it can still make that.
I was thinking of cutting out the catalytic converter, and replacing it with a straight pipe, then everything would be 2.5" turbo back. but I need to find the flange for the cat entrance. after I have one, Ill just put some straight pipe in there
I was thinking of cutting out the catalytic converter, and replacing it with a straight pipe, then everything would be 2.5" turbo back. but I need to find the flange for the cat entrance. after I have one, Ill just put some straight pipe in there
-
sonorous986
- Posts: 44
- Joined: Sat Feb 21, 2004 7:21 pm
- Contact:
-
twotirefryerwa
- Posts: 107
- Joined: Thu Dec 11, 2003 8:49 pm
setting up turbo now:87 lebaron t3 .48 a/r stock boost ka24e(rebuilt)stock added piston squirtersRRFPR, SAFC2, 4g63 440ccsaab intercooler
Ziggy, interested in your website. a couple of questions for you;
the blow thru maf...better than mounting MAF in intake side of turbo? I've heard of this but dont understand why. I understand the MAF can't read pressure. do you have an SAFC???
also, i plan on only running maybe 7 lbs, will stock ka24e injectors support that?
Ziggy, interested in your website. a couple of questions for you;
the blow thru maf...better than mounting MAF in intake side of turbo? I've heard of this but dont understand why. I understand the MAF can't read pressure. do you have an SAFC???
also, i plan on only running maybe 7 lbs, will stock ka24e injectors support that?
While an MAF can't read pressure, it does read the increase in airflow provided by the turbo. Whether it's the fast moving air before the turbo, or the compressed air after the turbo, the MAF will read the actual mass of air, which is the same before or after the turbo. The main advantage of a blow through MAF is that you can mount the BOV before the MAF and vent the BOV to atmosphere. Also, some people say that a blow through MAF is a bit more accurate because, when the MAF is before the turbo, it won't account for the increase in intake temperatures when the turbo heats up the air. In a blow through, it will read the actual temperature of air that the engine will get.
Yes, I run an SAFC, but the tuning for a blow through MAF is no different than with a draw through MAF.
I wouldn't recommend running any boost through stock injectors. They will almost instantly max out when you hit boost, then your engine will run lean and possibly detonate.
Yes, I run an SAFC, but the tuning for a blow through MAF is no different than with a draw through MAF.
I wouldn't recommend running any boost through stock injectors. They will almost instantly max out when you hit boost, then your engine will run lean and possibly detonate.
-
twotirefryerwa
- Posts: 107
- Joined: Thu Dec 11, 2003 8:49 pm
-
twotirefryerwa
- Posts: 107
- Joined: Thu Dec 11, 2003 8:49 pm
I have a DE not an E, but I can run open atm BOV without any issues, although mani pressure does climb faster between shifts when I have the BOV routed back. Some people do have issues with the open atm BOV, some don't. It depends on the car.ziggy682 wrote: The main advantage of a blow through MAF is that you can mount the BOV before the MAF and vent the BOV to atmosphere.
Quote »I wouldn't recommend running any boost through stock injectors. They will almost instantly max out when you hit boost, then your engine will run lean and possibly detonate. [/quote]
No they won't. Theoretically you can run almost 4PSI of boost on stock injectors. I know I ran 6PSI without any issues... although a bit lean.
-
twotirefryerwa
- Posts: 107
- Joined: Thu Dec 11, 2003 8:49 pm
huguetpj wrote:I have a DE not an E, but I can run open atm BOV without any issues, although mani pressure does climb faster between shifts when I have the BOV routed back. Some people do have issues with the open atm BOV, some don't. It depends on the car.
No they won't. Theoretically you can run almost 4PSI of boost on stock injectors. I know I ran 6PSI without any issues... although a bit lean.
venting ATM straight into atmoshere is ghetto, IMO. asking for trouble. and 4 psi...who runs 4 psi?
and a bit lean is too lean. while i appreciate the advise and experience, and want to save money, blowing engines is not cheap. getting back on thread topic.....does the ECU temp sender problem that the DOHC has pertain to the SOHC ka also?
Dustin