Lock & Load

RX8-- friend

Any clues as to how more power could be achieved at lower rpm using the stage 1 kit??????

michael

RX-8 friend

It's not a matter of a lot more power. The stock program runs about as much power as is available. Well, maybe a little bit more . It's the little hesitations we're really trying to get rid of.

Oh, and the Stage 2 prototype box works! Installed it last night. Now we have to work on the program to put into it (it has a very "mild" Stage 2 program right now). Maurice tried to test it on the road but the weather was not co-operating. It snowed again. So his test showed just how much wheelspin you can get.

SCiMMiA

Mine only really hesitates when the car is cold. It's pretty smooth after it warms up.

RX Guy

So is the bump at 4k rpm universal to all (or most) cars? Or is it individual car specific? I got the Stage 1, but have not install it yet. I'm waiting for the on/off switch. Would we all have to get the Stage 1 upgrade?

canzoomer

Some things:
As rx-friend said, spending a lot of time on filling Stage1 stuff right now.
Also, winter up here is a bitch.
You can't do this stuff completely on a dyno. You run on the road, with the wideband in play, measure, tweak, test, repeat..
At low temps, ice and snow on the roads, I have 2 choices:

1) Leave DSC on, get no power as the DSC cuts it.
2) Turn off the DSC, go sideways most of the time.

Went on a bit of a run last night.
Daytime high had gone a few degrees above freezing. It was then night, below freezing, tiny bit of freshpowder snow falling. Maybe 1/4" of it on the ground.

I left a light with a lady next to me in a Chevy.
I started gentle to avoid just spinning my tires.
DSC was off.
I then rolled on harder late in 2nd gear.

I passed her on my 2nd-3rd gear shift.
I was going almost perfectly sideways.
I looked out the windshield at her face.
She looked back at me.

You should have seen her expression!

There actually is no "bump" at 4K. what there is can be described as a lack of "bump". At 4,000 we start to gain a bit. At 4200 we are up about 5HP over stock. It then falls off and at 4500 to 4900 we are pretty well exactly back to stock.
Then it hits hard and starts to take off. We gain about 5hp again at 5,200, then it comes up really fast, bringing us up to 22HP over stock within 400rpm at 5,600.

We kept the original mapping in the 3 to 4 k range pretty well stock. It is already pretty lean, and this is where your rpm is on the highway. We are revisiting that, along with the 3 dips where the intake tracts change over to try and smooth them.
At 3,750 the 2nd intake opens, and we worked hard to smooth out that dip. Problem is that at 4,500 the extra shot of fuel puts some latency in, and to get back to lean takes a moment, and in low gears, full throttle you are already at 5,000 before we can catch up. With fuel there is a certain amount of lag or latency on any larger adjustment. In low gears you gain a lot of rpm before your map change has a noticeable effect.
In 4th gear it is much smoother, with almost no noticeable dip.
For those who are already running Stage1, try that for yourselves in 4th or 5th.
I can bring the "dip" up a bit higher, thenm we lose about 6HP at that magical 5,500 spot.
It''s a choice. Personally I prefer the 5,500 punch.
Below that you are in the rpm range that does not matter. Less than WOT. In 1st you are clutch slipping and tire spinning real quick.
In 2nd and on igher your shift point brings you right back into above the dip rpm, so what difference does it make?


I don't think we can do much better than that with fuel only. It will take a bit of advance as well. Ignition timing effects are much more rapid in effect. Lower latency of response.

Back to the road testing scenario..

Anyway, we can make a Stage2, with a bit more aggressive fuel/air map, and a gentle bit of ignition advance, which would be suitable for road use on 91 octane of higher.

It would put you at about +35hp (rear wheels).
Peak A/F at around 13.6:1. 7 degress of peak advance increment over stock.
Pretty safe stuff on good fuel. 91 or higher octane.
Pass on the cheapy no-name stuff please!

Add full exhaust (cat-back and midpipe with low restriction high temp cat) and you can get this up to around +45hp. That is free horsepower (other than buying hte parts of course!)
Do an intake if you really want, but i stil lthink it is a waste of money. Just "sounds cool".

But I do not want to send these out to the public, pre-loaded, until we get some more time in on smoothing it, and some testing done at sea level at higher air density.

In the Stage1 tune we really have a big margin of error. In Stage2 it will be much less, and I am taking time on it, and being cautious.

We will also be selling the Stage2 with the programming port accessible, and offer the tuning software kit as an option.

That way, (ASSUMING YOU OWN A WIDEBAND SENSOR and LOGGER!!!!!!) you can tune it up and see how close to the edge your ***** will allow.

Frankly that is not aimed at the people I see posting here.
Don't take it wrong, but can you afford to say "Whoops, guessI should have backed off earlier" ??

Remember that video of the kid with the 350Z ?
Maybe not as spectacular, but the same result can happen with too lean/too much advance.

The tuneable option is for those who actually have the tools, the skills and the deep enough pockets for the risk management.

Racers.

Also, after about a gain of around 50HP, I wonder when clutches, transmissions, diffs, and so on are going to start going ballistic.
Remember, we are already at a 30% gain in rear wheel power at that point..

A good comparison on what this means is like going in some car from the 4 cylinder to the 6 cylinder option. Most of those have a pretty beefed up powertrain to go with it.

Anyway, at about 50HP, we are at the end of the run for naturally aspirated power gains on a stock Renesis.
From here on in we need engine porting, matching header, and time to scrap that cool multiport intake manifold.

Or go to boost.

success07

Great write up Maurice!!! Thanks, as always, for your time and effort!!

I have a question concerning the Stage 2. You mentioned - "Anyway, we can make a Stage2, with a bit more aggressive fuel/air map, and a gentle bit of ignition advance, which would be suitable for road use on 91 octane of higher." - "It would put you at about +35hp (rear wheels). Peak A/F at around 13.6:1. 7 degress of peak advance increment over stock.
Pretty safe stuff on good fuel. 91 or higher octane."

Does this mean we could use the Stage 2 in every day driving like we can with the Stage 1 and it not harm the factory cat.? If that's the case I'll take one!!! :D

Scotchee

Rx-8 Friend - question,

In another thread a couple of weeks ago you mentioned that you thought the stage 1 kit leans out idle a little bit. According to an e-mail that I got from Maurice, the maps are only altered for WOT (>85%) conditions which would mean that idle was not messed with. Could you clarify?

Thanks,
Scott.

rxeightr

CZ,
I guess the better question to ask is this - can we run Stage 2 without decreasing the cat life to mere days, weeks or months?

Thanks for your most excellent post.

canzoomer

I can not tell you exactly how long the cat would survive.
That would require destructive testing.
Would you care to volunteer your cat for this?

Seriously speaking as temperature rises, cat life will drop quickly.
When Random Tech first equipped and RX-8 with one of their high temp cats, it started to fail after a couple of months.
They subsequently went to one of a larger diameter, which dissipates the heat more evenly and over a larger area.

I have a freind who has run one for over 3 months so far with no problems.

The rotary, and especially the Renesis, has a very high exhaust gas temperature.

Part of the reason the stock cat costs so much is due to this.

If a cat only cost about $100 it would not be such a big deal, but at around $1,500 for the stock one, and the Random at about $300.

As Dave at Random said to me last fall, and which recaps it quite nicely:

"Maurice-

Exhaust temperatures obviously play a role in determining converter life and durability, but the biggest issue is the amount of raw fuel in the exhaust system.
A converter typically operates at approximately 1200 degrees (F) and failures typically occur when core temperatures exceed 2000 degrees.
However, problems most typically occur when these temperatures are created within the converter itself. In instances where a faulty fuel injector or ignition problem allow unburned fuel to enter the exhaust system, the converter attempts to oxidize it and that's what "fuels" the extreme increase in temperature. Frankly, I'm not sure what the results would be if 1800-degree inert gas was passed through a converter. Problems should be minimal because in that case, the converter would act as a heat sink and dissipate the heat, as opposed to creating it.

The only way to find out for sure is to do some testing. Our metallic substrate converters have significantly higher flow capacity and much better heat dissipation than ceramic substrate converters so that would be my recommendation. We can supply you with universal style converters, or build direct fit models according to your preference. Let me know how you'd like
to proceed and we'll get something in the works."


Dave"

canzoomer

Further to the above we are actually fighting two different problems in a cat on the RX-8:
On a stock 8 the exhasut gases are very rich in fuel, and this fuel will burn in the cat, causing it to get very hot.

In a tuned 8 the temperatures happen before the cat, and the heat can also cause havoc.

Random have put a lot of time and effort into this, working with us to come up with a solution that will flow high volume, AND survive the two different conditions.
In early testing on a STOCK RX-8 we burned up one of their cats due to the first reason. Subsequently we found that an even larger cat allowed better heat distributuion, and this seems to survive.

Again, a quote from Dave:
"Relative to capacity, these converters have a higher flow than anything else available. However, we've found that a 2-1/2" diameter pipe is a restriction. These converters flow 582 cfm with 3" diameter inlet and outlet, but only 435 with 2-1/2" inlet/outlet. That may be more than adequate for the RX-8, considering there are two converters, but if you need more capacity, you'll have to increase pipe diameter.

Also, the air/fuel ratio isn't all that much of an issue, except that when it drops below about 11.5:1, there's an extremely high probability that some unburned fuel will pass through the engine. That's really the converter killer. Combusted fuel doesn't have enough unburned hydrocarbon content to create much of a problem, but at 10:1 or so, there is a fairly high hydrocarbon content. However, if a stock converter can survive this
environment, ours should as well.

Dave"

zoom44

ok i am very confused now. maybe i've missed something. you just wrote:

On a stock 8 the exhasut gases are very rich in fuel, and this fuel will burn in the cat, causing it to get very hot

i have been believing for some time that this pig rich map we have stock was the result of tuning done for cat-longevity. dumping the fuel in to reduce the temp of the exhaust gases. now what i quoted is saying the unburned fuel gets burned in the cat causing higher temps and shortening cat life. care to explain?

Omicron

Yes, please. I was thinking the same thing.

red_rx8_red_int

I guess if both are right then it works like this: Increase fuel somewhat over stock to cool the cat, but if you keep increasing fuel then you end up with fuel being burnt in the cat and it heats the cat. It sounds like there's a difference between "unburned fuel" which will cause damage versus "combusted fuel" where even with a low A/F ratio (which causes partial combustion??) will act to cool down the cat? That's my take but I know nothing about all this.

Gyro

I'll bet anything that the EPA regulation for CAT longevity is EGT based. Mazda was probably forced to lower the exhaust gas temps to within spec for the EPA. Richer fuel mixture as we know will do this...

Catch 22. So Mazda did it.....and we benefit even less than what I originally thought. The results of Mazda's "adjustments" are actually counter productive to the original goal of CAT longevity. Is this rich or what!?!......ok bad pun.

zoom44

f@$%ing government in action. i hope that is not correct

RX-8 friend

The explanation is easy. The stock RX-8 does dump excess fuel through the cat. It does so WITHOUT O2 to burn it. You can see the result in the carbon muck that decorates the exhaust pipe. All a cat. does is promote the chemical joining of supplied O2 and HC, NOx, and CO (to H2O, N2, and CO2). What Dave is talking of is "normal" cat. operation, that is, lots of O2 to eliminate HC, NOx, and CO. Mazda is cheating to cool the cat. by not injecting enough O2, at the expense of excess HC (in an RPM range that EPA tests don't look at).

One possible way around the temp. problem is to move the cat. farther back in the exhaust system. This would increase the time before the cat. starts working, but the exhaust gas would be cooler. As Maurice stated, the cat. is heated by the exhaust gas and the fuel burning inside it. Lower one source by moving it further back, and lower the other with Stage 1. This would also apply to Stage 2, of course. We haven't gone this route, as the exhaust system is space constrained. Lots of design work might be needed.

StealthTL

iTrader: (1)

I have graduated to the 'production version' of the 'Zoomer Mod, and just wanted to check in with an update....

During the testing phase, I was greatly impressed by the difference the mod made - for me it was 100% improvement in the power delivery, just what the car needed.

However, I worried that Canzoomer might 'back off' some of the "boost" to err on the safe side, and avoid any issues with heat / detonation.

I wanted to make sure that the settings I had in the prototype made it to the finished product.

I can tell you that the final tuning is every bit as awesome as anything from the tests!

Someone posted that it's hard to tell it's there unless you are in 2nd or 3rd - all I can say is, I can feel ALL the 'push' in ALL the gears..... In 6th, the push comes on nice and strong at 107 mph......(roughly 107, I was too busy to take good notes!)

I am going to get in SO much trouble when spring comes to these parts!

S

zoom44

thanks for that explanation. but that suggestion i quoted won't work for our merry freinds in california. the cat is as close as it is in the first place because of the requirement in cali that says the cat needs to reach operating temp in 5 minutes.

like i said f@$%ing government at work again. bastards.

StealthTL

iTrader: (1)

O.K., forgot to mention in my last post - wanted to put the 'cost-per-horse' in perspective.

I was reading the Porsche options for the new convertible 911, there is a mod option for the turbo on the list that adds about 30hp,

the cost is $18000.

S

93rdcurrent

Yeah, stealling our hp and gas mileage all to save a stupid cat that I would replace at 30k miles if I could have the first two things back.

oh and did I mention the enviromental impact.

canzoomer

Sure!
Like many things it is a matter of what degree.
If there is a bit too much fuel the cat burns it, getting hotter.
If there is WAY too much fuel, the ratio is wrong for proper combustion, and it burns incompletely, and passes a lot of the fuel through the cat unburned.

Basically too much gas and not enough oxygen will quench it.
If we run the engine really lean the gas temps start to rise, in the header output, BEFORE the cat. This will strip the coatings off the cat, as it comes in hot, gets even hotter in the mid-cat combustion.

So, in steps:
Very lean mixture: Gases going into the cat are very hot, what fuel is left gets burned in the cat, making it too hot. Input gas temps around 1,700F to 1,850F. What a Stage2 tune does.
A high temp cat can survive this as long as it is big enough to dissipate the heat.

Moderate mildly tuned mixture: Gases come in a bit cooler, residual fuel burns in cat, suitable temps for cat operation and survival. But still, hot enough that cat life will pass the 50,000 mile mark, but maybe not much more. Input gas temps around 1,400F to 1,650F. Similar to JSPEC and what a Stage1 tune does.

Too rich mixture, lots of gas gets burned in cat, input temps are relatively low, and it is rich, it has enough O2 to burn most of the fuel, and the temperature inside the cat rises very high.
Cat lasts a fairly short time as it is running too hot.
Input gas temps around 1,300F to 1,450F. What we want to avoid at all costs, as it will eat any cat.

Pig rich mixture but as input temps are low, and it is so rich, it runs out of O2 before it burns all the fuel. Cat lasts a long time, as it is getting quenched by all the fuel. Makes lots of soot. Telltale sign is lots of carbon on the tailpipes. What Mazda did to meet EPA2. AS there is tons of fuel available the internal "burn" in the cat heats it up quickly, then as temps rise it runs out of O2. Helps the cat get up to full operating temperature quickly.
However the price we pay is a large fuel consumption, carbon not completely burned resulting in plug fouling, flooding, and sooty exhaust.

canzoomer

It, like many things, is a trade off.
EPA wants to cut down on CO and Nitrous products as they are most poisonous.
In return we burn more fuel, make way more pounds of carbon output, pollute a lot more, but with more harmless by products.

Either way, the days of the internal combustion gas engine are numbered.

Of course it is all a total waste of fricking time.
People in China are starting to buy cars in increasing numbers now. Give them 20 years at this progrssion, and you could park all the cars in N. America, and still be making more pollution.

Know why a lot of business ( and your jobs) are going to China?
Sure, labour is cheap, but that does not last so long.
But their environmental laws are almost non-existant.
It's a lot cheaper to do business when you can pollute at will.

With Stage2 I am pushing people towards using a cat, even if it is not as clean output as the stock one, it is stil better than nothing.
It is also a lot easier to use a cat, rather than trying to make the car happy with an O2 fooler circuit.

We all have to breathe this crap.

smrx8

iTrader: (1)

when will your stage 2 be ready, ill be the first to buy it .iam waiting and waiting patiently ok not that patient :D 45 + hps thats sound like a killer mod.

zerobanger

you bought the wrong car.

CanZoomer JR

No kidding, This is a good bang to the buck. I have friends who pay alot more for less horses as well. Even if u shouldln't be having to get these horses back. :p