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Collapsed Metalcat

Craney

By Craney,
in Engines & Forced Induction

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Tangles Grand Master

Tangles

Posted
Posted
When it collapsed, what did the car actually do? Did it just lose all power and not make any more? What made you know it was the cat?

was on the dyno for a tune, but made same as before with too much timing

as soon as I picked it up it felt restricted, could tell really, tuners said check the cat and fix the fmic pipe

so checked the cat, was all warped inside and bent, cleared it out, then back on the dyno to fix the crap tune

206kw at 14psi, but the turbo is now the restriction - then redid the fmic so it works real well now, as 1 corner was warped and not letting thru 100% volume

now with 16psi feels fantastic, reckoning around 210kw dynobum

down 25kw with the turbo, so looking for a garret bb I can alter with my housings to harness 235awkw (auto heavy stag)

headwork makes the engine feel like a 25/30 so Im happy as larry, just need to get a better flowing bb turbo

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GTRsean Grand Master

GTRsean

Posted
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I had a metal cat (barrel type) last for two years then finally kark it on a dyno tune. Went from 20psi to 11psi due to guts of cat blocking the exhaust a little. It was rattling around due to it separating from the body. Bits were shooting out the back lol.

Anyway, ended up getting a new one and this seems to be the mark II. It has a rod welded across the back of the matrix to stop the guts moving around I guess when it heats up and cools down.

I'll see how it goes.

Fastrotor Proficient

Fastrotor

Posted
Posted
I reckon thats more work than unbolting the exhaust from the front pipe (because you've gotta get a pressure sensor then :P)

Yeah i guess so for those , but its something to keep in the tool box forever once its done...... i should make a heap up and sell them i think !

I do far to many cars to not have one with me..... and ALL dyno shops should have one anyway ! So easy to just whack it in and log on a second map channel. !

Hey i just re-read your comment and you said "you've gotta get a pressor 'sensor'" ...... all i mean is make up an adaptor (18*1.5mm thread to hose barb adaptor, and using some silicon hose , plumb it to a spare, or your current, "BOOST" gauge ...) ...can't get much simpler than that !

Gary

badhairdave Proficient

badhairdave

Posted
Posted

my 5inch catco went the same way as sean gtr's.

It just worked it's self loose around the edges and proceeded to unravel from the outside of the substrate.

The outsides of the cat didn't have a mark on it from scraping or anything so i figured it was a manufacturing fault. other than the separation the guts looked good, no melting or whatever. It got punched out and flames started to appear on over run :D

Fastrotor Proficient

Fastrotor

Posted
Posted (edited)

Turbine Inlet Pressure. Anothers words, measure the pressure in the exhaust manifold. This will give you the info to work out the MIP to TIP ratio ( boost to exh mani pressure) , If its over 2:1 then your in trouble.

With high exh backpressure, due to small turbo housings or restricted exhaust, larger overlap cams just give it more time to pollute the intake charge more, and drop the knock point, resulting in less power.

Hence why changing to a larger exh housing generally allows more timing to be added, due to less intake charge poluting.

If you've run out of things to check, this is the ultimate thing to check to check the turbo sizing to the job your asking it to do. Bit of an effort , but its quality data when you get it.

Gary

Edited by Fastrotor

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