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Discussion Starter #1
2.0 litre Turbo, charge tubes, GMPP intake, Trifecta tuned, Solo HFC, Solo Race Exhaust.

ive developed a bog/choke/loss of power when into boost. Car pulls up to 21 lbs of boost and then a sudden loss of power. Let off and it’s fine. Almost like the fuel gets cut off. No codes. No lights.

Checked all the connections, All claps tight Including the throttle elbow. Intercooler is not ballooned. Don’t see any cut vac lines to the boost controller.

Tried turning off the Trifecta tune, still get a bog/stumble but not as pronounced.

Have also tried cleaning the MAF. Had a DDM braised line fuel filter on, though it might have been clogged. Took it off with no changes to above condition.

Thought it was the fuel. Used up the old tank and refilled with 94 octane. No change.

Any thoughts on the condition? Thanks.
 

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Discussion Starter #3
Yes, no where near redline.
stead cruise, onto the throttle It pulls hard and falls flat of its face. Like the fuel has been cut, an intercooler tube blew off or loss of spark.

pulled the plugs and checked the condition, all less than 5000 miles, air filter clean, MAF is clean, Solo cat has about 7,500 on it. Don’t typically beat on it, just doing a pass on the highway so got into the throttle. First time I’ve noticed it.
 

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You would need a data logging tool. For serious logging, I use HP Tuners but you may not want to drop $300 on it. You can get a Bluetooth OBDII dongle and the Torque app to scan and see what your AFR is. Basically have someone watch your Torque app and see what the AFR is when you are experiencing this issue. It can also tell you if you have any codes. Not all codes trip the Check Engine Light.
 

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Discussion Starter #7
HP Tuners might be a bit much for now.
generally the A/F ratios look good on the aeroforce gauges, but the issue happens so quickly it doesn’t necessarily show that quickly on the gauge.

Any other thoughts? I could swap the cat back out to see if that makes any diff. Anything is plausible, but I thought it unlikely a new cat would go south.
 

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I would look at mass air flow.
 

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HP Tuners might be a bit much for now.
generally the A/F ratios look good on the aeroforce gauges, but the issue happens so quickly it doesn’t necessarily show that quickly on the gauge.

Any other thoughts? I could swap the cat back out to see if that makes any diff. Anything is plausible, but I thought it unlikely a new cat would go south.
Okay, if you have Aeroforce gauges that'll work. If it is a fuel condition, the AFR will go SUPER lean immediately when it happens. We're talking the value will show the maximum lean value. My AEM gauge maxes at 18:1 So a reading like that or greater means your fuel is either cutting out or so little is getting to the engine that it's cutting out.

MAF can very possibly be a problem but you'd still see the AFR go lean if that is the case. A dirty or damaged MAF will report less air entering the engine than is actually entering it but to be this far off you should be seeing some kind of check engine light error code.

If it isn't going lean. then that may rule out fueling as being an issue. You could look for blockages in your exhaust at that point and it could be beyond the cat but it could also be before the cat. Looking at what your AFR is doing (maybe have someone film the gauge as you drive???) will help give you some things to look at or rule out.
 

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Discussion Starter #10
Thanks Troy and John. I’ve give the MAF another good cleaning, take it out for another drive to replicate and watch the A/F ratios. Shouldn’t be a restriction beyond the cat as it’s a solo race exhaust.
 

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I am not suggesting that you have a bad MAF sensor, although that may be the case.

I am suggesting that you read the mass air flow so that you can find out if the problem is happening at a specific air flow with both the stock and added tunes.

You mentioned year-old gas in the other thread. I also suggest that you clean out the fuel tank and try some fresh gas to see if there just isn't enough energy in the fuel.
 

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I was thinking about upgrading my 07 redline to get more hp.
I think you all scared me out of doing that.
I have about 45,000 miles on her and never any problems.
 

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If you are not an experienced mechanic, I would recommend that you don't do performance upgrades yourself. However, if you know someone who has done successful performance upgrades on a kappa, I would ask them for help.
 

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I was thinking about upgrading my 07 redline to get more hp.
I think you all scared me out of doing that.
I have about 45,000 miles on her and never any problems.
Modifying your car isn't for everyone. A simple tune will give you more power without much risk as you can always put the tune back to stock and you're not physically changing anything mechanical on the car.
 

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Sometimes even little things.... like changing to a K&N air filter can make a difference..... with little or no risk
Changing the air filter will not give added performance on our cars - the factory one has more than enough flow. Also, changing to an oiled filter can have deleterious effects on the MAF from oil blow by.
 

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sahein post: 1319781 said:
If you are not an experienced mechanic, I would recommend that you don't do performance upgrades yourself. However, if you know someone who has done successful performance upgrades on a kappa, I would ask them for help.
thank you.
while I am mechanically inclined, I am not auto mechanically inclined at all when it comes to performance of the engine enhancments.
Do I start with the exhaust, if so what without being to obnoxious on the street. Then mentioned the air filter.
What steps should I take before hiring a specific tune?
 
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