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I just bought a 2008 Series I, with the 6 speed MT. I expected not-so-great gas mileage, but I'm getting around 11.5 MPG... surely this can't be normal! I do like to redline the car about once or twice every time I drive it, but I'm not thrashing it everywhere I go. Also, this is mostly suburban driving, with some highway and city thrown in here and there.
The car has under 19k on it. I just replaced the plugs, coils and wires. No white or black buildup on the plugs; just the usual light brown. I also cleaned the MAF sensor and the air filter. It seems to idle ok - the revs sit at around 850 and there will be a very slight pop or drop in revs every half minute or so, but it runs pretty well otherwise. The cat doesn't glow after a hard drive. No CELs. Power seems fine and it starts hot and cold instantly.
Only mods worth mentioning here are a catback exhaust, and a K&N v2 air intake.
I just bought a 2008 Series I, with the 6 speed MT. I expected not-so-great gas mileage, but I'm getting around 11.5 MPG... surely this can't be normal! I do like to redline the car about once or twice every time I drive it, but I'm not thrashing it everywhere I go. Also, this is mostly suburban driving, with some highway and city thrown in here and there.
The car has under 19k on it. I just replaced the plugs, coils and wires. No white or black buildup on the plugs; just the usual light brown. I also cleaned the MAF sensor and the air filter. It seems to idle ok - the revs sit at around 850 and there will be a very slight pop or drop in revs every half minute or so, but it runs pretty well otherwise. The cat doesn't glow after a hard drive. No CELs. Power seems fine and it starts hot and cold instantly.
Only mods worth mentioning here are a catback exhaust, and a K&N v2 air intake.
Any ideas?
Get rid of the K&N intake.
They're known to mess with the MAF sensor.
Dammit. That was my first thought as well... I was hoping there was another answer haha. As an aside, this intake came with the car when I bought it. I know the K&N gets a lot of hate here for various reasons (power loss, air filtration, poor design, etc.) but man, it sounds incredible at WOT. I'm also a little concerned about the water issues that the AEM intake has. Anyone know how it sounds compared to the K&N? I haven't heard it in person.
If you want an aftermarket intake, go with the racingbeat revi intake + duct.
I've had the AEM, it's great at wot but under 7k rpm, sounds ricey. Racingbeat sounds better, performs better and not as sketchy in the rain. The little dust cover on the AEM falls off a lot as well, I've had to replace it like 4 times, as filter is located in the front of the car.
I love my AEM at all speeds.. had it for over 1yr with zero issues including in snow and rain. I've taken the filter off to clean it once, and it didn't really need that. I'd vote that one.
On most tanks of gas I get about 10-11 most I've gotten is 15 but I drive fast I run it through the gears and I run 93 octane and higher weight oil gotta learn to live with it since I've fallen too deeply in love with my car
On most tanks of gas I get about 10-11 most I've gotten is 15 but I drive fast I run it through the gears and I run 93 octane and higher weight oil gotta learn to live with it since I've fallen too deeply in love with my car
That's still not normal.
I drive very 'enthusiastically', fast starts, hard stops, downshifting constantly, high speeds at high revs and I average 14-15 mpg.
If I drive normal where I'm not taking off every time I stop and red lining once per red light then i get about 14 I drive my car very hard and my gas mileage shows it
Thanks for the input, everyone. I'd been on the fence about getting rid of the K&N for a while now - like I said, it came with the car - but this was the nail in the coffin. I went ahead and ordered an AEM CAI with the sock yesterday. That said, what are the chances that the poor MPG is not intake-related? What are the other possibilities?
Thanks for the input, everyone. I'd been on the fence about getting rid of the K&N for a while now - like I said, it came with the car - but this was the nail in the coffin. I went ahead and ordered an AEM CAI with the sock yesterday. That said, what are the chances that the poor MPG is not intake-related? What are the other possibilities?
Do you still have a cat?
If so, drop it and inspect it.
Especially if you've had any misfires.
This is normal for me most of the time, unless I use the AC or am in like stop and go traffic. Or if I'm just beating on her hard for the entire tank, then I'll get 190 or so. This is also on Ethanol free gas. Engine has.. 21k on it.
Just for reference..
Last edited by Dominarian; 06-20-2016 at 02:07 PM.
This is normal for me most of the time, unless I use the AC or am in like stop and go traffic. Or if I'm just beating on her hard for the entire tank, then I'll get 190 or so. This is also on Ethanol free gas. Engine has.. 21k on it.
Just for reference..
My car won't even do that with highway miles. Best I've managed on the highway is somewhere around 18.
Do you know where I could find pictures of what a healthy/clogged cat looks like? I haven't been able to find any on the forum.
There may be some in the new members section.
Sometimes it's obvious like it can be melted, cracked, or broken up.
You can try shining a light through it to see if it's clogged.
I have not heard of these aurelio tech coils, where'd you get them? as a rule of thumb oem coils are recommended if you are not going the upgrade route of bhr/sakebomb/etc/etc/etc....
I have not heard of these aurelio tech coils, where'd you get them? as a rule of thumb oem coils are recommended if you are not going the upgrade route of bhr/sakebomb/etc/etc/etc....
Haha they're just some random ones I found on Amazon. They've got a lot of good reviews though, so I figured I'd give them a shot.
There may be some in the new members section.
Sometimes it's obvious like it can be melted, cracked, or broken up.
You can try shining a light through it to see if it's clogged.
Yeah I figured it would be pretty obvious if it was clogged, but I don't know the first thing about them so I thought it wouldn't hurt to ask
Haha they're just some random ones I found on Amazon. They've got a lot of good reviews though, so I figured I'd give them a shot.
Were the good reviews from RX8 owners, or just other car owners using that brand? Ignition health is critical to a rotary engine. Not saying your coils are anything but fine, but anyway here is some coil advice from the club:
You have a number of options for coils:
- The Cheapest option: BWD/Intermotor coils from auto parts stores like Advance Auto. 4 coils, 4 plugs, and 4 wires can be had for around $190-220 total based on whatever promotion is running at the time, shipped to your door for free. They are considered to be the first coil revision and you should expect to need to replace them around 20,000 miles, 30,000 miles max. They often come with a "lifetime warranty" by the auto parts store, which could potentially be leveraged for perpetually new coils.
- The Best Upgrade: The BHR ignition coil upgrade can be had for around $500, which eliminates the need to continue replacing coils periodically, as well as deliverying a significantly stronger spark for minor mileage and power gains. It is a proven kit with top notch customer service supporting it. It includes the wires, you still need to add plugs ($80)
- The For-Sure OEM: Mazmart sells all 4 coils of the latest OEM coil revision (C) for around $250, (just the coils, you still need to add plugs and wires) Supported by top notch customer service. They will likely last longer than 30,000 miles, but we don't have much solid data on how long the latest coil revision will last.
- The Most Expensive option: Buying from a dealer will run you around $300+ for the coils, $500+ for coils, wires and plugs, and if you have them do the install, expect to get a bill for anywhere from $700 to $1,800. You may not get the latest coil revision. Yes, you are getting shafted if you take this option, so bring lube.
- The Highest Risk option: Ebay coils continue to pop up as counterfeit, mislabeled, dead on arrival, and have zero post-purchase support largely. They are the "cheapest" listed price, but when you add that $92 or whatever to the price of anything in the list above from having to do it over again, you can see that they are no longer the cheapest option. Do it right the first time. "Motor King" coils are popping up at an attractive price on Ebay, but are being proven as ineffective, to the point of being unable to get the engine fired. "Mazda" branded coils on ebay are almost always counterfeit. Check the seller's name though, since some of our vendors sell legitimate coils there. The price will be $200+ though. Anything sold as "Mazda OEM" under ~$26 per coil should really be considered as suspect and probably counterfeit.
Be wary of "LSx D585 coil upgrades", as not all D585 coils are created the same, and the standard generic D585 coil is not properly designed internally for the RX-8's ignition needs. They generally "work", but there are anomalies and performance issues that have to be solved, if they can be solved. Definitely NOT a plug and play option, even if it is advertised as "plug and play"
Last edited by gwilliams6; 06-21-2016 at 06:56 AM.
Were the good reviews from RX8 owners, or just other car owners using that brand? Ignition health is critical to a rotary engine. Not saying your coils are anything but fine, but anyway here is some coil advice from the club:
You have a number of options for coils:
- The Cheapest option: BWD/Intermotor coils from auto parts stores like Advance Auto. 4 coils, 4 plugs, and 4 wires can be had for around $190-220 total based on whatever promotion is running at the time, shipped to your door for free. They are considered to be the first coil revision and you should expect to need to replace them around 20,000 miles, 30,000 miles max. They often come with a "lifetime warranty" by the auto parts store, which could potentially be leveraged for perpetually new coils.
- The Best Upgrade: The BHR ignition coil upgrade can be had for around $500, which eliminates the need to continue replacing coils periodically, as well as deliverying a significantly stronger spark for minor mileage and power gains. It is a proven kit with top notch customer service supporting it. It includes the wires, you still need to add plugs ($80)
- The For-Sure OEM: Mazmart sells all 4 coils of the latest OEM coil revision (C) for around $250, (just the coils, you still need to add plugs and wires) Supported by top notch customer service. They will likely last longer than 30,000 miles, but we don't have much solid data on how long the latest coil revision will last.
- The Most Expensive option: Buying from a dealer will run you around $300+ for the coils, $500+ for coils, wires and plugs, and if you have them do the install, expect to get a bill for anywhere from $700 to $1,800. You may not get the latest coil revision. Yes, you are getting shafted if you take this option, so bring lube.
- The Highest Risk option: Ebay coils continue to pop up as counterfeit, mislabeled, dead on arrival, and have zero post-purchase support largely. They are the "cheapest" listed price, but when you add that $92 or whatever to the price of anything in the list above from having to do it over again, you can see that they are no longer the cheapest option. Do it right the first time. "Motor King" coils are popping up at an attractive price on Ebay, but are being proven as ineffective, to the point of being unable to get the engine fired. "Mazda" branded coils on ebay are almost always counterfeit. Check the seller's name though, since some of our vendors sell legitimate coils there. The price will be $200+ though. Anything sold as "Mazda OEM" under ~$26 per coil should really be considered as suspect and probably counterfeit.
Be wary of "LSx D585 coil upgrades", as not all D585 coils are created the same, and the standard generic D585 coil is not properly designed internally for the RX-8's ignition needs. They generally "work", but there are anomalies and performance issues that have to be solved, if they can be solved. Definitely NOT a plug and play option, even if it is advertised as "plug and play"
Thanks for the rundown! The reviews were from other RX-8 owners using the same coils. I'd love to have the BHR kit, but I only have so much $$$ on hand right now. Hopefully I'll make the switch at some point. The previous coils/plugs/wires had been in the car since it was born (it's actually the same car as yours - a 2008 40th Anniversary Edition) but for only 18,000 miles. Given their age, I figured switching them out wasn't necessary, but probably prudent. When I put the new ones in I did notice that it ran a bit smoother, but I think the old set was probably good for another few thousand at least based on what I saw.
Last edited by slowismooth; 06-21-2016 at 02:22 PM.
06-17-2016, 04:57 AM
