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New intake and exhaust//power loss?

Old 09-24-2015, 03:02 PM
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New intake and exhaust//power loss?

Hey rotor heads I'm new to the club but I came here seeking help as most people do. I recently installed a full racing beat rev-8 intake, exhaust header, dual resonated midpipe, and catback system. Car sounds incredible but it feels like the acceleration was cut in half. I can't even spin the tires without dropping the clutch. It's an 07 rx8, motor was replaced 35k miles ago under the warranty so it's a 2013 motor. i smell more fuel smell outside the car than before the install but I don't know if that's because of the cat conv removal with the midpipe or not. Please help!
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Old 09-24-2015, 03:08 PM
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Do you have the two screens installed in the intake?
Are they both in good condition and not damaged?
Might want to start there and double check that because if the air flow isn't smooth across the MAF, that can cause you problems.
And yes, by removing the cat, you will get that "fuel smell".

Also, do you have the VFAD nipple capped behind the throttle body?
I assume you also have the Racing Beat ram air duct too, which would remove the VFAD assembly and require you to cap that nipple.
If you don't have the ram air duct, then don't worry about capping.

Last edited by Jon316G; 09-24-2015 at 03:19 PM.
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Old 09-24-2015, 03:24 PM
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Pretty much what he said^^ Also make sure there are no vacuum leaks, more than likely from the VFAD nipple that NEEDS to be capped if you install an aftermarket intake. If there is a vacuum leak as big as that, the car is likely to stall out or hesitate and feel like theres not power on tap.
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Old 09-24-2015, 03:30 PM
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Installation guide said only one screen was needed and to use the better of the 2 so I did, vfad is properly capped as well. I thought maybe plugs/wires/coils maybe? But idk. A guy a Firestone who was replacing my tires said I may need to reflash the ECU. He used to race an rx8 in Puerto Rico so he may be on to something.
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Old 09-24-2015, 03:38 PM
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It isn't uncommon for AFRs to go to **** after an intake install (AEM is bad for this-) . Get yourself a logging device so you can check AFRs under load . My guess is it's running pig rich .

Last edited by Brettus; 04-05-2016 at 03:36 PM.
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Old 09-24-2015, 03:40 PM
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Originally Posted by Ovr-9000 View Post
Installation guide said only one screen was needed and to use the better of the 2 so I did
Oh yeah... you're right. Been awhile since I messed with my RB intake.
I would still take a peak at the screen and ensure its still upright and not damaged.
Also take that time to clean the MAF with some MAF cleaner.
Both are quick and easy to do so why not.

Originally Posted by Ovr-9000 View Post
A guy a Firestone who was replacing my tires said I may need to reflash the ECU.
You should not have to reflash the ECU.
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Old 09-24-2015, 04:10 PM
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This is kind of off topic but when the Mazda dealership replaced my motor under the warranty they put 5w-20 synthetic blend in it. The user manual specifically says not to use synthetic oils...is this okay? I've been putting that back in there since the swap with regular oil changes cause I figure the "master tech" wouldn't do something to destroy the motor...right?

I'll clean the maf and do plugs and wires this weekend and let you know but keep the ideas coming
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Old 09-24-2015, 08:10 PM
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I'm a noob, but AFR is short for air fuel ratio yes?
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Old 09-24-2015, 08:18 PM
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Also a little off topic, but when the dealership put in the new motor they put 5w-20 synthetic blend but the owners manual says absolutely no synthetic...any thoughts?
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Old 09-25-2015, 07:55 AM
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Originally Posted by Ovr-9000 View Post
Also a little off topic, but when the dealership put in the new motor they put 5w-20 synthetic blend but the owners manual says absolutely no synthetic...any thoughts?
Synthetic oil in an RX-8
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Old 03-28-2016, 12:37 PM
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Bump
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Old 03-28-2016, 01:52 PM
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In the past 6 or so months since this issue began, have you done anything to troubleshoot the issue? Did you verify the parts that previous posters have recommended?
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Old 04-04-2016, 06:54 PM
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Yeah man I went back through the install process. The only thing I could think of was maybe the exhaust header bolts weren't torqued to spec. I got them as tight as I could but without a torque wrench I'm just guessing. I've also replaced plugs and wires, hell actually it's running worse now. I can dump the throttle in 6th at 60 mph (for on ramps to interstates) and she just creeps, when before all the power was there. Sometimes I actually drop gears for the acceleration I need for interstate driving. And high end launch is kinda what the rotaries are known for since they really have no low end. I'm going to replace the coils and see what happens, and maybe go back through the install again. Would an exhaust leak cause such a dramatic loss in power? The car still runs 3000rpm at 60mph which is what it always has so idk if coils will really change anything, she sounds like she is running normal the power just isn't there.
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Old 04-04-2016, 09:15 PM
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Rpm @ speed don't change without changing the transmission, so don't use that as an indicator.

Look, coils are a common failure point. If they have more than 30k miles on them, change them as a precaution.

When you installed the Revi, did you block off the VFAD vacuum line? If it's just dangling open, the engine will have all kinds of problem.

Did you also use the metal screen in the intake? You're supposed to carry it over from the stock intake.

Last edited by Loki; 04-04-2016 at 09:19 PM.
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Old 04-04-2016, 10:22 PM
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Good point bout the rpm. I let that one slip through my cognitive reasoning skills. Anyway I was thinking of upgrading to the bhr coils, and yes I have the Vfad capped and the metal screen. Ima clean the MAF sensor and do the coil upgrade. If it was a vacuum leak I feel like it would be having trouble idling but she stays a smooth 750-800 when warmed up.

Thanks for all the help guys I really love my car, I have an FD as well so rotary is my life I just don't know as much as I need to know yet
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Old 04-05-2016, 05:32 AM
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Wait, Everyone stop. Did you say the car had 35K miles and when the dealership installed the motor they used 5w20? Have you changed the oil since then?
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Old 04-05-2016, 03:37 PM
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It isn't uncommon for AFRs to go to **** after an intake install (AEM is bad for this-) . Get yourself a logging device so you can check AFRs under load . My guess is it's running pig rich .
In case you missed it the first time...............
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Old 04-06-2016, 03:02 PM
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I change the oil about every 3500 miles and I was thinking about getting the Cobb tuner?
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Old 04-07-2016, 01:16 PM
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Should o get a compression test just to be on the safe side?
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Old 04-07-2016, 01:27 PM
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You can, it certainly won't hurt but what would make a big difference, IMO, is to see what the OBD2 logs look like. You're looking for AFR, airflow volume, rpm and short and long-term fuel trim (stft, ltft) both at idle and when the car is experiencing low power.

You can get that via a Cobb, but also via a Blutooth/OBD2 connector and the Torque smartphone app, or from any other kind of OBD2 reader.

That would help diagnose what the car is seeing and we can diagnose from there. Please post results.
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Old 04-07-2016, 02:38 PM
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I have a P0420 code (cat conv, cause I don't have one with my dual res mid pipe)
And a U0167 code ("lost connection to immobilizer", don't know what this actually is but I think it's like a theft deterrent thing, and doesn't appear to be causing me any current issues, except maybe the occasional airbag light that comes on every now and then then goes away)

I literally just got back from advance, gonna seafoam and clean the MAF. Wish me luck.
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Old 04-07-2016, 02:40 PM
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While I'm under the hood Ima go back through the instal and make sure everything is good with the intake screen and Vfad nipple. seafoam will also help me locate an exhaust leak if there is one.
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Old 04-07-2016, 02:54 PM
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Codes are one thing, but the actual values for stft and ltft would go a long way and avoid guessing.
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Old 04-07-2016, 11:19 PM
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Okay I put in some work today: Vfad nip is correct, screen was damaged so I replaced with the spare from stock intake, cleaned MAF sensor, performed seafoam, and confirmed exhaust leak at the header. I'm going to try to get a torque wrench and get those bolts to spec and see what's up with the bhr coils. But it really just may need a quick tune for the AFR.

I must say the car runs a lot better after the seafoam, cleaner smoother sound, almost no backfires at all from 7k em back to idle.

Anymore tips are appreciated but in the meantime I'll keep you posted

Thanks
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