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power surge at 7000 RPM

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Old 01-07-2008, 04:53 PM
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power surge at 7000 RPM

Today I pulled out to pass a car and noticed that it felt flat on acceleration. When the revs got to about 7000 rpm it was like a turbo kicked in. I pulled over and stopped then pulled out and accelerated hard again. Same thing happened . 7000rpm it kicked in hard. Can someone explain to me what the heck is happening? Thanks.
Old 01-07-2008, 05:00 PM
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final 2 ports opening up.
Old 01-07-2008, 05:02 PM
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LOL - search SDAIS
Old 01-07-2008, 05:07 PM
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Actually, it goes like this:

3750 SDAIS Secondary intake ports open (SSV)
5500 SDAIS VFAD may open (Yamaguchi p 115)
6250 SDAIS Auxilary intake ports open (APV)
7250 SDAIS Primary intake ports interconnnect (adds a second shorter path) (VDI)
7250 SDAIS VFAD opens on WOT

Last edited by Nemesis8; 01-07-2008 at 05:10 PM.
Old 01-07-2008, 06:09 PM
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I had the same thing happen atleast 50 times.....I like it so I'm not complaining. First time it happened I was like..."Hell ya"....reminded me of going into vtec in my old SC'd 02 civic Si.
Old 01-07-2008, 06:20 PM
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^^*sigh*
reminds me of the good times. at least the good times i've had with piston engines in my H22a. though the TL is also vtec, but not as aggressive like the vtec's we've got...and its auto. C series suck unless its one in the NSX.

*sigh* it was 8k rpm goodness when i had it... too bad cops were all over me when i had it. damn i'm not young anymore or in high school. so i sold it.
Old 01-07-2008, 06:57 PM
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Originally Posted by Nemesis8
Actually, it goes like this:

3750 SDAIS Secondary intake ports open (SSV)
5500 SDAIS VFAD may open (Yamaguchi p 115)
6250 SDAIS Auxilary intake ports open (APV)
7250 SDAIS Primary intake ports interconnnect (adds a second shorter path) (VDI)
7250 SDAIS VFAD opens on WOT
Ok, I understand about the ports opening up , but this was different . It's like engine power is down from what I am used to . Always before , it has been a smoother transition .This time it was rather weak until it hit 7k, then it was boom kick in the ***. I read rotary gods post . Very informative. But I still don't understand why all of a sudden I feel such a large increase in power. Is it possible that some other port is not opening when it is supposed to? Sorry if this sounds rudimentary, but I am new to rotary engine technology having grown up with large V8's. Thanks

Last edited by rled; 01-07-2008 at 07:26 PM.
Old 01-07-2008, 06:58 PM
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check the plugs and ignition coils.

plugs = brown is okay, black is not so good
ignition coils = white burn marks on the bottom can potentially be a sign of them failing. Here's a method for testing them: http://www.finishlineperformance.com...16-07-1793.pdf
Old 01-07-2008, 09:57 PM
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I wouldn't bother, his car runs fine
Old 01-07-2008, 10:03 PM
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I'm not good at troubleshooting the valves. But if you say it behaves differently than before, then maybe something is up. Ask the experts to chime in.
Old 01-07-2008, 10:08 PM
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Originally Posted by rled
Ok, I understand about the ports opening up , but this was different . It's like engine power is down from what I am used to . Always before , it has been a smoother transition .This time it was rather weak until it hit 7k, then it was boom kick in the ***. I read rotary gods post . Very informative. But I still don't understand why all of a sudden I feel such a large increase in power. Is it possible that some other port is not opening when it is supposed to? Sorry if this sounds rudimentary, but I am new to rotary engine technology having grown up with large V8's. Thanks
If it is different to what you remember then it could be related to ports not opening ....
OR
someone slipped a turbo in there while you weren't looking ....
Old 01-08-2008, 04:56 PM
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Originally Posted by Brettus
If it is different to what you remember then it could be related to ports not opening ....
OR
someone slipped a turbo in there while you weren't looking ....
Yeah I wish! The car is behaving differently. Like I said before ,power felt down until I hit the 7k rpm and then it was a real noticeable instant power surge.I don't have any misfiring or stalling, . It always pulled strong all the way up to 9k. Any one know where I can find an exploded view of the intake? I don't know what the different port abbreviations mean, or where they are located in the intake tract.It idles a little rough though. It makes my horn button on the steering wheel vibrate . Aggravates the crap outa me. Thanks
Old 01-09-2008, 05:55 AM
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Lightbulb

Is this what your looking for?
Attached Thumbnails power surge at 7000 RPM-intake2-large-.jpg  
Old 01-09-2008, 06:00 AM
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flat spot

same , i notice the same thing , but it doesn't always happen , it feels like a power boost around 7 grand.
Old 01-09-2008, 06:00 AM
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same , i notice the same thing , but it doesn't always happen , it feels like a power boost around 7 grand.
Old 01-09-2008, 10:05 AM
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cats clogging or coils going. i place my money on cats
Old 01-09-2008, 03:47 PM
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Hey Thanks Darkmoon. Thats just what I was looking for.

Last edited by rled; 01-11-2008 at 05:36 PM.
Old 01-12-2008, 07:05 PM
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somone told me that the old 7s had a similar set up... @ WOT or a specific RPM range, two more ports would open up not unlike the old school four barrel carbs. that those of us that grew up on old American motors are used to. He also mentioned that there was a way to make both or all four ports or whatever anyway.. all of them open all the time... would this be possible with the ren? Another question... should this mod be possible... would it actually help? Or would it just add to the already ... less that desirable fuel consumption?

Last edited by nordichunter; 01-12-2008 at 07:09 PM.
Old 04-14-2016, 05:40 PM
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Originally Posted by rled
Hey Thanks Darkmoon. Thats just what I was looking for.
Hi Rled,
I'm noticing the same issue - did you find out what your problem was?
Old 04-14-2016, 06:00 PM
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rled is probably long gone by now .

This symptom is usually related to a stuck ssv . When the APVs open the engine can suddenly breathe again so you feel a surge in power .

Have someone turn the engine off while you watch the ssv actuator . It does a check cycle a few seconds after the engine is shut down. Also: activate it by hand and make sure it moves freely ....

Last edited by Brettus; 04-14-2016 at 06:03 PM.
Old 04-15-2016, 04:26 AM
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Originally Posted by Brettus
rled is probably long gone by now .

This symptom is usually related to a stuck ssv . When the APVs open the engine can suddenly breathe again so you feel a surge in power .

Have someone turn the engine off while you watch the ssv actuator . It does a check cycle a few seconds after the engine is shut down. Also: activate it by hand and make sure it moves freely ....
Thanks for your help.
Silly question but how do I find the SSV actuator? I've looked on Youtube and here but can't find proper pictures...where do I put my hand?

Cheers,
Jon
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