maxcooper

Dynatech and Random Technologies are the two brands of commonly-available metal substrate cats in the U.S. (there are certainly others available, but these two are available at Summit, Jeg's, Martel, etc.). They both have short, round 4" bodies and are available with various inlet and outlet sizes (3", 2.5", etc.). The Random ones are also available in 3.5" and 4" sizes. But keep in mind that despite the different inlet and outlet sizes, the middle of the cat is the same (within the offerings from a single brand). So ordering a 4" cat won't get you a larger substrate than ordering a 3" cat.



The Dynatech cats are $150 (though I saw one site with a 10% coupon and free shipping -- $135 total). The Random cats cost more at $215 or so. They are not exactly the same cats, since the overall length is different between the two brands. I wouldn't be surprised if it turns out that they do have the same substrate (and are thus essentially equivalent), but there do seem to be some indicators that the Random cats flow better (based on not-all-that-comparable flow tests published on the manufacturer sites). In other words, I suspect they are essentially the same, but I had enough doubt to pay more for the Random cat, which might flow better. But this is all just speculation -- I don't know for sure if they are the same or differrent, or how they really compare to each other in terms of flow. The Random is also a little shorter overall, which should be easier to fit with a separate muffler in my midpipe.



I got my 3" Random metallic cat today from Martel Brothers and it looks great.



-Max

FikseRxSeven

hey max, would you mind taking pics of the random tech. high flow that you have. so we can compare it to the picture that dynatech has in their site. also, where can we find that coupon that you are talking about.



another thing... i know it changes the quality of the sound, but does it change the decibel level, im guessing it does because of how it will somewhat restrict the air, but if there are any feedbacks about it, that would be great.



here is the picture of the dynatech

FikseRxSeven

just so max dont have to type whatever he already typed...



here's the link to rx7club where a lot of info are also discussed

http://www.rx7club.com/showthread.php?t=410581

ccarlisi

Here are a couple pictures of mine. Although the core looks rather dense in these pictures you can see newspaper text through it if you look into it straight on.



Notice that in the pictures provided by Dynatech the transitions appear to be part of main casing. However, on both Dynatech cats that I have seen the transitions were welded onto the main case and there was an abrupt lip on the inside where the two sections joined. I removed the transitions and had the edge ground down before we welded the cat into the 3.5" exhaust system.

FikseRxSeven

i think im gunna go ahead and buy either the dynatech or the random technology cat, i will also buy a resonator (which i intend to place after the cat, so the packing wont melt).



ill also keep my 3.75" greddy resonated midpipe til after i do one of those blower tests. i was thinking of just using a blower and sealing off the the one end and either hooking it up to one of my boost gauges, or maybe even my map sensor so its accurate and has peak hold (im just worried that i might damage the map sensor). but we'll see ill go order the cat and resonator this week.

Rob x-7

seems like all high flow cats buy the guts from the same place, they all look like that one pictured

FikseRxSeven

i think the boost gauge idea is no good.. ill find a way to measure flow though

treceb

let me know when u want to do the testing. i might have a flow metter at work.

FikseRxSeven

[quote name='treceb' date='Apr 4 2005, 11:20 AM']let me know when u want to do the testing. i might have a flow metter at work.


[/quote]





well first of all, i gotta get the high flow cat, if you can get the flow meter that would be great...



i plan on measuring the flow of:



-high flow cat

-resonator

-racing beat dual

-treceb's exhaust

-straight pipe 3"

-high flow cat w/resonator

-3.75" greddy resonated midpipe

- ^ with high flow cat



and thats all i can think of

rfreeman27

the point being? Just for ***** n giggles?



i shipped the ign box today btw.