Random Tech High Flow and Temp Cat
 

I dropped my car off today at Random Technologies in Atlanta, GA for them to design and install a prototype high flow catalytic converter. I am doing this in hopes of running a cat with the stage 2 'zoomer mod. I would rather run clean here in downtown Atlanta than just run a mid-pipe. I stayed there while they removed my old cat and began to design the new one.
They are going to make a prototype by hand bending everything, test fit it, build a jig for producing them, and finally build and test fit another one on my car. This means that after they have produced mine, they should be able to easily produce the setup for anyone interested.
I forgot to mention that this replacement will be bolt-on so that I can swap the cats for service or emissions. I will not, however, have to fool the 2nd O2 sensor like you have to with a mid-pipe. The major benefit of using a Random Tech cat is that it should be able to withstand the extra heat generated by the stage 2 mod. I believe Maurice is already doing some testing with a cat he got from Random Tech, but no updates have been posted about that. I am sure he is still busy with getting Stage 1 out the door.
I am hoping to do some Dyno runs after the new setup is installed to see what the car produces with a Borla and high-flow cat.

Great! Keep us informed on the progress. :D

Yes Xavier, please keep us posted. I'm interested in doing the same thing. You might want to email Maurice (maurice@harddata.com) with what you're doing... I suspect you may be saving him a lot of leg work.

I connected with Dave at Random Tech through Maurice originally, so he is aware of this development. I have just emailed him with an update. Random Tech has already sent a High-Temp cat (only the cat, not the mid-pipe with cat installed)up to Canada for testing, but as far as I know there has been no update on it.

You are the man! Hopefully itll be out soon so i dont have to run straight pipe!

Re: Random Tech High Flow and Temp Cat
 

The 2nd O2 sensor may still need to be fooled, because most high-flow cats, by their design, will not provide the same level of O2 your current cat does.

I think the sensors are pretty simple, easy to fool.

yes all you usually need is some tiny resistor in order to fool an 02 sensor :)

After hearing some concerns about tripping a CEL, I gave Dave at Random Tech a quick call, and everything is just peachy. They may not have the car ready till Thursday, but if we do trip a light, he has all the equipment needed to fix the problem. I am ofcourse hoping the car doesn't have a problem with the converter, since Dave said many cars don't, but their is no guarantee of that ofcourse. Just have to wait and see.

Did talk to Maurice via email last night, and a sister cat to mine goes on his car next week. He is suggesting I try a Stage 1 mod with the high flow and Borla before upgrading to Stage 2 since it seems the exhaust mods greatly enhance the Stage 1 upgrade. We shall see. I am greatly looking foreward to seeing what the exhaust combo will do on the Dyno.

Well, after a few issues with a broken pipe bender at Random, I have gotten my car back, complete with new high-flow cat. I do have to warn everyone, without the stock cat and resonator, it is louder. Not unbearable, but louder, especially with the Borla. Still nice and deep. My car does have a prototype on it, which will probably be switched with a production version when they are ready. In the mean time I will be evaluating the performance, sound, and testing to see if I get a CEL.
The protoype is very good looking, with nice smooth bends. Dave has told me to give the car a few days and decide whether it needs a resonator to quiet things down a bit. The mid-pipe is 3 inch tubing the whole length, and uses a very small looking, but effective, high flow random cat. I asked a few questions on behalf of fellow forum members, and found out the production version should start shipping in Mid January, depending on the success of the prototype and whether it needs a resonator. When I get the first production version, the car will then be dynod with Cat and Borla. I am hoping to do a base run with Borla and one with high-flow cat and borla, but we will have to see. As soon as I get them, I will post them.
Anyone in the atlanta area interested is welcome to see/hear the combination. Also, if anyone has the equipment to do a sound clip, I am sure some people would like to hear it. Glad to answer any questions.

This is something that I too would like to do in addition to the stage 1 and a new exhaust. Even though we dont have emissions here in FL I would like to run legally and still get as much as can out of the car. Of course like all the rest I await with baited breath any new tests/developments.

Xavier, do you have access to a digital camcorder? That would do a nice job of recording the sound with the new cat + Borla (which would be the same as my setup :D). Also curious as to the price Random is thinking of charging for this unit, if it is a bolt-on, and if they will be providing new O2 sensors to prevent CELs. Thanks...

No price yet. Bolt-on. 100 miles so far with no CEL. I am hoping it stays off, but only miles will tell.
I do not have a digital camcorder, probably a few digital pics is the best I can produce. I will do that when the car is on the lift getting a production version soon.

Yes, pics would be good. Also would bet that Random would have the capability of making a sound clip available. Just a thought.

Still curious though... are you using the stock O2 sensors?

Bump

QUOTE]Xavier, do you have access to a digital camcorder? That would do a nice job of recording the sound with the new cat + Borla (which would be the same as my setup ). Also curious as to the price Random is thinking of charging for this unit, if it is a bolt-on, and if they will be providing new O2 sensors to prevent CELs. Thanks...[/QUOTE]

DITTO

i just wanted to say ditto lol!

500 Miles and No CEL! Very happy. Update from Random soon.
Aaron

Been reading alot of negatives on random tech.I think I will get a carsound.Im more comfortable with them since i had one on my supra.4 years of kicking the hell out of it and it never failed.

Care to share what negatives you've heard? Just need to be informed.

How about an update, Xavier296? Thanks...

bump

Finally, an update. Haven't seen Dave over at Random in awhile, as holidays and other circumstances have prevented it. Per my request he is building a new prototype with a resonator since I believe without it the car attracts to much negative attention. I DID end up throwing a CEL, and we are going to work on that this week or early next week. May be loose connections or flanges, not converter efficiency. We shall see.
No dyno. Have been advised against till I can find a dyno operator nice enough to let me unhook the rear ABS units while hooked up. I really want to dyno, especially with/without CZ stage 1. I believe my exhaust setup will yield large gains with the better fuel maps. I will update again after I make it up to Random again.
Aaron

Cool. Please keep us posted.

Hey Xavier, any update?

bump

Update:
Took the long trip to Random today, and ended up spending the better part of the day there. I tripped my CEL after 600 miles of driving, and after resetting the ECU, again after 60 miles. The test pipe with cat was removed at random, and the cat had melted on the outside of the substrate. It had melted enough to allow the converter to move around inside its housing. Dave was VERY surprised, and asserted that he had never seen this happen in a N/A car. The area around the cat had blued quite a bit, which is a sign of excess heat. So, new prototype, this time using a 5" diameter cat rather than a 4". Hopefully this will give more surface area for the cat to cool and keep temps at check. My CEL had tripped because some of the catalyst had already been burned off and the converter efficiency was not what it was suppossed to be. I will run this cat for a while and see how it performs. It is not an everyday part, and was rather cut out of test setup.
Other options were discussed, including moving the cat to the end of the midpipe and extending the lines to the O2 sensor. Time will only tell if these have to be implemented.
Obviously the rotary motor puts out lots of heat, even though Dave said he had never seen this happen in an RX7. I drive the car like it should be, try to never shoot flames, and put alot of HW miles, so I do not believe I was abusing the Cat horribly. Now the question is: How is Maurice using this setup without a hitch? Does the ECU Stage 1 mod actually lower AVERAGE temps by reducing the amount of unburned fuel entering the cat? We shall see...

Thanks for the update. Sounds like more time is needed to work out the details.

Make sure to keep us posted.

Generally, when one leans out the mixture of fuel, the exhaust gets hotter. Mazda made our mixture rich in the first place for cooler exhaust gases. It is indeed odd that Maurice is still running his random cat and yours has melted. One possibility may simply be that Maurice hasn't been driving much because of the cold temperatures in Canada, but only he knows that for sure.

Xavier, let me get this straight: You have the stage I and a Random Tech Cat melted from that setup? That seems weird. I mean, I thought Random Tech's cats were supposed to withstand more punishment than stock? How can our stock cats hold up so well if an aftermarket one doesn't cut it?

I am NOT running stage I, I hope it arrives soon. So on a stock car I have melted the 4" random cat in about 500 miles. No one has been able to explain it. It has been postulated that the small random cat cannot dispell excess heat like the giant stock cat. The stock cat is at least 6" in diameter and 3 times longer than the random cat. This gives it a large amount of surface area to handle all of the heat generated by the Renesis. My midpipe section was VERY blue around the random cat, demonstrating how hot that area had been. When an exhaust pipe overheats, the color of the pipe gets a slight blue tint to it. Half of my pipe looked like this.
As of now I am running a 5" prototype random cat, trying to take the same course at the stocker buy greatly increasing the surface area that the exhaust gases meet. A 5" cat is 50% larger in its cross section than a 4" cat. Now all I can do is drive the car normally and see what this cat does.
All I know is: I melted a cat, Maurice has not. What's different, I'm not sure. I just hope others who install these cats on their cars don't have the same problems I have. The only 2 variables that are different that I know of are the Borla and the chip tuning. I have a Borla, he has chip tuning. hehe.

Maybe the extra rich stock fuel maps are to blame. It would be interesting to see the exhaust gas temps just after the cat on your car versus another with the Random Tech and Stage 1. If all of that extra fuel is igniting in the cat your exhaust temps are going to go through the roof! :eek:

It's funny you should say that. I know that Mazda supposedly richened the mixture to cool the cat temps, but it doesn't make sense to me how. Less efficient burn?

My first car was an '89 Mazda 323. I screwed up the spark plug wiring one day and the end result was a car that ran on two cylinders for about 20 miles before I made it to a mechanic...Yeah, I was a dumb-ass for not figuring out what I messed up on. Anyway, all that unburnt fuel made that cat glow cherry red during my little trip. How hot was it? Well, my carpet inside my car was smoking.

Surprisingly, the cat survived, but that's why it doesn't make sense to me why a richened mixture lowers cat temps

It sounds like Mazda has gone way beyond rich and is bordering on just plain drowning the engine. I believe that Rotary God said that if there was not enough O2 present in the exhaust the gas would not be physically able to ignite completely while passing through the cat and thus cool it off.

With your new cat, the flow dynamics have changed and it may be creating a situation where the gas is now able to ignite and thus drive up the temps. This would also make sense because the same Random Tech cat has been used successfully with the leaner Canzoomer Stage 2 ECU (leaner = lower EGT).

It isn't that rich. The A/F ratio is in the 11:1 range (very rich) but only at WOT.
At lesser throttle positions (mostly 50% to 70%) the A/F is closer to 12.5:1.
Optimal (in my estimation) is about 13.7:1 and I tune to 13.5:1 for a margin of safety.
Drowning the motor would be more like 10:1 which is what the STI does. Amazing that it runs, but every motor is different.
I think 9:1 is where there isn't enough O2 for combustion at all.

BTW, leaner A/F = higher EGT. I imagine that was just a typo on your part.
Advancing the timing will reduce EGT to some degree also, despite what I have seen written from time to time around here.
Retarded ignition timing raises EGT.

I made a trip to Random yesterday and had the stock converter put back on. I need to take the car in for an oil change, recalls, and ECU reflash. While I did throw a CEL with the 5" cat, it looked perfect when we removed it, unlike the extremely blued and destroyed 4" cat. Maybe this will be a more permanent setup, and the answer for other RX8 owners.

So where in the process are you now?....i will be heading up to Suwanee during the next few weeks and would like to drop by and see your setup if you have been back to RT to test more...

Yeah, I'd like to know this too. And maybe you could throw a pic or two of the new cat up?