Lock & Load
10-26-2003, 03:52 AM
Here is what canzoomer has said in the tech garage sectionn of the forum.
Sorry, I was away a couple of days at the beginning of this week, and then had to deal with my engine problem on the way home.
Add to that a tooth problem last weekend, and this has been a bit of a stressful week.
I am now sitting here with a decent glass of bordeaux, and life is *MUCH* better!
1) Aftermarket exhaust breaks down to 2 categories:
A] Cat-back. Might help a bit in reducing restriction.
To do so will be louder. As stock maps for fuel are overly rich at rpm over 6,000 this will likely increase airflow, and gain a bit of power by leaning the mixture. The gains to be made are similar with stock maps or modified. Flow is flow. It adds HP, unless you are running too lean, which is not what will happen in either case, at the top end. It might make it a bit hooter with stock ECU maps as Mazda has set this a bit lean to start with.
B) Mid-pipe. This is where the big gains are to be had. The RX-8 uses fairly large cats, so small flow gains are there by going to a straight-thru midpipe. Much more gain is to be had as you can then run fuel maps that are leaner, and ignition timing that is more aggressive. With cats we can only do so much, as the exhaust temperature rises with power output. Beyond 1750F you will vaporize the catalyst coatings on the cat bricks.
Stok the engine peaks around 1600F. But we have seen the temps rise pretty quick as we add ignition advance.
By removing them you can run more aggressive tuning without this risk.
The trade-off is that you will make more emmissions, and will be illegal in most jurisdictions for road use.
If you want to do this ONLY in off-road(track) use, then it is permissable and recommended. Removing and replacing the mid-pipe is a 10 minute job.
However in doing so you are removing the O2 sensors, so the O2 feedback to the ECU is then in open-loop mode, and you have to add feedback to the ECU to fool it into believing that the O2 readings are OK, and that costs money as it is more logic.
Hence the added costs of our stage 2 and stage 3 tune options.
The stage 2 also includes the ignition mapping control, so is a more extensive component and map device.
This is really aimed at a track application. I am not the thought police, so you can run this on the street if you wish, but I would prefer that you did not.
As for trade-ins we have decided that this is something we will do. There will always be much more demenad for the Stage1 kit, so we will end up re-packaging trade-ins and selling them as used and re-certified at a discount. There will be a trade-in cost of around 50% to cover the discount and costs. We have to test the returned units, clean up anything that is damaged or messed up, and re-package them.
As Stage2 REQUIRES 91 octane or better, and voids ANY warranty and emmisions we WILL require the purchaser to sign a disclaimer form.
87 octane is perfectly safe on a stock RX-8.
To use our Stage1 kit we require that you use at least 89 octane fuel. We have tested with 89 at 3,000 feet altitude and it will not make for knock.
On 87 there would be definite risk of pre-ignition knock. With stock apex seals that could possibly kill your engine.
To take the FC out of the car for emmissions tests you have 2 choices:
1) remove the unit ( a 15 minute job)
2) One may optionally wire in a defeat switch. This requires wiring and a switch that we are not including, but we will include instructions. A 4 pole, double throw switch is required.
Switching must be done with the car turned off, or you will trigger an ECU check engine event, and this will be detectable by dealer diagnostics.
Once switched you need to let the car idle for 5 minutes, and to run gently for another 10 to allow the engine ECU to "re-train".
Generally it is simpler to unplug the unit.
One MUST remove the unit for dealer service, or you risk them voiding your warranty if they find it.
Forced air induction by turbo or supercharger requres tuning maps that can deal with intake positive pressure. A non-FI setup is only zero or negative pressure mapped. It is an ENTIRELY different condition. Running FI with no appropriate map would be suicide for the engine and make limited power gains.
More air in requires more fuel.
In some cars you have to upgrade the fuel injection equipment for more flow capacity, but i do not think this is necessary on the RX-8.
Based on our testing, running boost with no proper positive pressure tuning is going to risk killing your engine and cause constant check engine status. I am confident that anyone who makes a boost kit and is competent will have to include fuel/air control to deal with this requirement. We hope to offer this in our kit options so the vendors for chargers don't have to.
We also are recommending that the engine be rebuilt with ceramic apex seals. Further we advise using re-machined rotors to reduce the compressionratio to 9.2:1 or lower. Any other actions will likely result in severely limited seal and engine life.
This is a 10:1 compression engine. Even 4 pounds of boost may be bad if run on stock seals.
If you look at the 2nd gen and 3rd gen RX-7's the boosted models had lower compression ratios.
High flow cats are not too expensive as you mentioned, but they are not "magic".
They use coatings which can only take heat up to around 1750 degrees.
If you run aggresively re-mapped ignition AND fuel maps, it is NOT a legal street tune. Don't do this unless you are COMPLETELY sure about what you are getting into.
One good run of WOT through the gears will produce 1800F exhaust temps. A few of these and your cats have no coating left. They then become expensive non-efficient resonators.
Only by keeping the temps below 1700 can we reliably know that they will still be working.
If Mazda does release a flash to update the ECUs I can not see any reason why they would limit to one group of cars over another. I think their biggest obstacle is self-created. To do a new ECU map they have to comeup with a consistent and credible reason. Doing this only for power reasons would contradict what they have said.
Fuel economy may be an alternative.
Anyway, for now we are setting the first target for releasing a device with fuel/air maps to produce roughly a 25HP gain, to preserve the cats, and to help on mileage if you drive aggressively.
Once that is done we will return to the direction of ignition timing as well. Starting with a non-cat midpipe we willwork on a kit with timing plus fuel control, and with O2 sensor simulation to keep the ECU happy.
I had said i was interested in working on a supercharger kit before, but after looking that over, we can certainly do it, BUT:
1) It is not a cheap project. Probably around a $30K investment.
2) If others are doing it as well , that is a stupid move for us to make.
3) I do not want to experiment with boost on the engine at 10:1.
I hope to get re-machined rotors at 9.2:1 or so before I try this. I also want ceramic apex seals. Perhaps I am being overly cautious, and maybe this is not necessary, but I would hate to find out the hard way. I am already becoming the leader in broken parts. Sure that is the price you pay, but I don't enjoy doing it if it is not needed!
4) As it is now I know of 5 parties working on releasing an RX-8 kit for turbocharging or supercharging. I would much rather work with the results of their work, add our tuning to this, and Adams machining and parts, and make these into reliable mods.
Finally, thanks for the kind words. As for the "Rock" part, well, I am 47 years old, and this is a hobby. I am having a hell of a good time doing this, and I appreciate that some of you are looking forward to it.
As I said a while ago, when I decided to keep the car, it is a great machine, and if I have to spend a few thousand dollars to make it what I want, and enjoy myself on the way there, I think that is just fine, thank you.
In hard cash, even if I DID blow an engine and had to pay for it I would still be at less expense than if I had bought a 350Z Track Pack, and about $5K below buying an A4 or TT. And $25K below a 'vette.
That is not too bad, because this is a cooler car than any of those.
Sorry, I was away a couple of days at the beginning of this week, and then had to deal with my engine problem on the way home.
Add to that a tooth problem last weekend, and this has been a bit of a stressful week.
I am now sitting here with a decent glass of bordeaux, and life is *MUCH* better!
1) Aftermarket exhaust breaks down to 2 categories:
A] Cat-back. Might help a bit in reducing restriction.
To do so will be louder. As stock maps for fuel are overly rich at rpm over 6,000 this will likely increase airflow, and gain a bit of power by leaning the mixture. The gains to be made are similar with stock maps or modified. Flow is flow. It adds HP, unless you are running too lean, which is not what will happen in either case, at the top end. It might make it a bit hooter with stock ECU maps as Mazda has set this a bit lean to start with.
B) Mid-pipe. This is where the big gains are to be had. The RX-8 uses fairly large cats, so small flow gains are there by going to a straight-thru midpipe. Much more gain is to be had as you can then run fuel maps that are leaner, and ignition timing that is more aggressive. With cats we can only do so much, as the exhaust temperature rises with power output. Beyond 1750F you will vaporize the catalyst coatings on the cat bricks.
Stok the engine peaks around 1600F. But we have seen the temps rise pretty quick as we add ignition advance.
By removing them you can run more aggressive tuning without this risk.
The trade-off is that you will make more emmissions, and will be illegal in most jurisdictions for road use.
If you want to do this ONLY in off-road(track) use, then it is permissable and recommended. Removing and replacing the mid-pipe is a 10 minute job.
However in doing so you are removing the O2 sensors, so the O2 feedback to the ECU is then in open-loop mode, and you have to add feedback to the ECU to fool it into believing that the O2 readings are OK, and that costs money as it is more logic.
Hence the added costs of our stage 2 and stage 3 tune options.
The stage 2 also includes the ignition mapping control, so is a more extensive component and map device.
This is really aimed at a track application. I am not the thought police, so you can run this on the street if you wish, but I would prefer that you did not.
As for trade-ins we have decided that this is something we will do. There will always be much more demenad for the Stage1 kit, so we will end up re-packaging trade-ins and selling them as used and re-certified at a discount. There will be a trade-in cost of around 50% to cover the discount and costs. We have to test the returned units, clean up anything that is damaged or messed up, and re-package them.
As Stage2 REQUIRES 91 octane or better, and voids ANY warranty and emmisions we WILL require the purchaser to sign a disclaimer form.
87 octane is perfectly safe on a stock RX-8.
To use our Stage1 kit we require that you use at least 89 octane fuel. We have tested with 89 at 3,000 feet altitude and it will not make for knock.
On 87 there would be definite risk of pre-ignition knock. With stock apex seals that could possibly kill your engine.
To take the FC out of the car for emmissions tests you have 2 choices:
1) remove the unit ( a 15 minute job)
2) One may optionally wire in a defeat switch. This requires wiring and a switch that we are not including, but we will include instructions. A 4 pole, double throw switch is required.
Switching must be done with the car turned off, or you will trigger an ECU check engine event, and this will be detectable by dealer diagnostics.
Once switched you need to let the car idle for 5 minutes, and to run gently for another 10 to allow the engine ECU to "re-train".
Generally it is simpler to unplug the unit.
One MUST remove the unit for dealer service, or you risk them voiding your warranty if they find it.
Forced air induction by turbo or supercharger requres tuning maps that can deal with intake positive pressure. A non-FI setup is only zero or negative pressure mapped. It is an ENTIRELY different condition. Running FI with no appropriate map would be suicide for the engine and make limited power gains.
More air in requires more fuel.
In some cars you have to upgrade the fuel injection equipment for more flow capacity, but i do not think this is necessary on the RX-8.
Based on our testing, running boost with no proper positive pressure tuning is going to risk killing your engine and cause constant check engine status. I am confident that anyone who makes a boost kit and is competent will have to include fuel/air control to deal with this requirement. We hope to offer this in our kit options so the vendors for chargers don't have to.
We also are recommending that the engine be rebuilt with ceramic apex seals. Further we advise using re-machined rotors to reduce the compressionratio to 9.2:1 or lower. Any other actions will likely result in severely limited seal and engine life.
This is a 10:1 compression engine. Even 4 pounds of boost may be bad if run on stock seals.
If you look at the 2nd gen and 3rd gen RX-7's the boosted models had lower compression ratios.
High flow cats are not too expensive as you mentioned, but they are not "magic".
They use coatings which can only take heat up to around 1750 degrees.
If you run aggresively re-mapped ignition AND fuel maps, it is NOT a legal street tune. Don't do this unless you are COMPLETELY sure about what you are getting into.
One good run of WOT through the gears will produce 1800F exhaust temps. A few of these and your cats have no coating left. They then become expensive non-efficient resonators.
Only by keeping the temps below 1700 can we reliably know that they will still be working.
If Mazda does release a flash to update the ECUs I can not see any reason why they would limit to one group of cars over another. I think their biggest obstacle is self-created. To do a new ECU map they have to comeup with a consistent and credible reason. Doing this only for power reasons would contradict what they have said.
Fuel economy may be an alternative.
Anyway, for now we are setting the first target for releasing a device with fuel/air maps to produce roughly a 25HP gain, to preserve the cats, and to help on mileage if you drive aggressively.
Once that is done we will return to the direction of ignition timing as well. Starting with a non-cat midpipe we willwork on a kit with timing plus fuel control, and with O2 sensor simulation to keep the ECU happy.
I had said i was interested in working on a supercharger kit before, but after looking that over, we can certainly do it, BUT:
1) It is not a cheap project. Probably around a $30K investment.
2) If others are doing it as well , that is a stupid move for us to make.
3) I do not want to experiment with boost on the engine at 10:1.
I hope to get re-machined rotors at 9.2:1 or so before I try this. I also want ceramic apex seals. Perhaps I am being overly cautious, and maybe this is not necessary, but I would hate to find out the hard way. I am already becoming the leader in broken parts. Sure that is the price you pay, but I don't enjoy doing it if it is not needed!
4) As it is now I know of 5 parties working on releasing an RX-8 kit for turbocharging or supercharging. I would much rather work with the results of their work, add our tuning to this, and Adams machining and parts, and make these into reliable mods.
Finally, thanks for the kind words. As for the "Rock" part, well, I am 47 years old, and this is a hobby. I am having a hell of a good time doing this, and I appreciate that some of you are looking forward to it.
As I said a while ago, when I decided to keep the car, it is a great machine, and if I have to spend a few thousand dollars to make it what I want, and enjoy myself on the way there, I think that is just fine, thank you.
In hard cash, even if I DID blow an engine and had to pay for it I would still be at less expense than if I had bought a 350Z Track Pack, and about $5K below buying an A4 or TT. And $25K below a 'vette.
That is not too bad, because this is a cooler car than any of those.