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Frequent flyer Silver
Posts: 62
 
| Ive seen white on petrol too, especially ones with blown head gaskets or running too lean..........
Its a well known fact that excessive heat, usually caused in petrol engines running lean or LPG engines where the exhaust temps are higher than normal, can and eventually will crack headers/extractors, most commonly around the welds.
Genie as an example tells people on certain models that have a tendency to go lean after freeing up the exhaust, that if their mixtures are not reset, the headers will develop cracks from the excessive heat.
Also one more point, cat converters, with headers, always run metal substrate cats as the cheaper ceramic ones will get too hot and crumble inside from the higher temps brought down the pipe from the freer flowing headers, obviously if going LPG same story.
Combine LPG and headers....hand on and a supercharger .....man your looking for trouble. LOL |
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Frequent flyer Gold
Posts: 1092
 
Location: An island off southern Tasmania. | Godzilla - 27/10/2011 22:18
Ive seen white on petrol too, especially ones with blown head gaskets or running too lean..........
Its a well known fact that excessive heat, usually caused in petrol engines running lean or LPG engines where the exhaust temps are higher than normal, can and eventually will crack headers/extractors, most commonly around the welds.
Genie as an example tells people on certain models that have a tendency to go lean after freeing up the exhaust, that if their mixtures are not reset, the headers will develop cracks from the excessive heat.
Also one more point, cat converters, with headers, always run metal substrate cats as the cheaper ceramic ones will get too hot and crumble inside from the higher temps brought down the pipe from the freer flowing headers, obviously if going LPG same story.
Combine LPG and headers....hand on and a supercharger .....man your looking for trouble. LOL
yeah the cheap ceramic cat failed whithin amonths and they replaced it under warranty with a metal unit a while back....
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Frequent flyer Gold
Posts: 1092
Location: An island off southern Tasmania. | Well i bit the bullet today.
Started at 3pm and had the stock exhaust in by 6 pm.
But it took to 9pm to get the oxygen sensor that someone had cross threaded in the rear cat out....re-threaded and a bung put in.
Absolute ball breaker of a job, but brute force and lotsa trips to the bench and it is now a full three catalytic system.
And it sounds sooooo stock, I forgot what a GT is supposed to sound like.
Might have lost 5 kw atw...MEH...who cares, it sounds great now and still pulls like a pack of mules....no rattles or vibrations....
If I was doing the extractor upgrade again me thinks custom stainless will be the go...
The RPW extractors are definitely a bad, bad move. |
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Frequent flyer Silver
Posts: 62
| On a supercharged LPG setup i think any mild steel header will fail.
I dont know if stainless will be any better, however you could be right. |
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Frequent flyer Gold
Posts: 1092
Location: An island off southern Tasmania. | Godzilla - 31/10/2011 23:06
On a supercharged LPG setup i think any mild steel header will fail.
I dont know if stainless will be any better, however you could be right.
the stock pipes are welded completely differently, but it sounds and drives so much nicer....bugger the extra few kw me thinks... |
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Frequent flyer Gold
Posts: 1092
Location: An island off southern Tasmania. | Rang RPW yesterday and spoke to David there to let him know of my disappointments with the $700 extractor kit.
After a bit of brain storming we found the problem.
RPW have used the existing MAGNA front headers for the 380 kit and the accompanying jig.
The rear bank are completely new and are mated to the front MAGNA ones, and...a different person welded the rear bank.
It could even be that the fronts are old stock and the new have been fabricated later to make up the kit.
The two different people had different welding techniques....I had no problems with the front bank...only the rear bank. |
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Frequent flyer Silver
Posts: 62
| Sounds plausible.
Did you mention the LPG and S/C setup, if so what was his opinion for the extra heat generated?
No problem?
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Frequent flyer Gold
Posts: 1092
Location: An island off southern Tasmania. | Godzilla - 7/11/2011 22:19
Sounds plausible.
Did you mention the LPG and S/C setup, if so what was his opinion for the extra heat generated?
No problem?
His response was that he was prepared to weld them again for me....but the freight to WA and back?....nahhhhhhh |
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Frequent flyer Bronze
Posts: 33
| I had a set of RPW Extractors installed a couple years ago and ever since it's just had a raspy metallic rattle. I have had the crossover point welded so that the pipes don't rattle. I know the welds along the flanges are all fine, I checked them before they went on. Could be the flex pipes broken or cracked internally, or even the two flex pipes rubbing together since they do sit almost right up against the one another. I don't know, but I'm thinking it could even be an exhaust leak also since it reeks of exhaust when I start it up cold.
I have a feeling it could be the exhaust manifold gasket, although a manifold gasket leak is usually very loud isn't it?
The reason I feel like it might be a leak at the manifold is that the dodgy exhaust place I went to (I will never go there again) just wanted to get the car out of their shop because they soon realised how much of a pain in the arse it is to get the headers on. I reckon they just chucked them on, did a half arsed job of tightening it all up and just gave the car back to me.
What's the best way of getting to the rear header bolts without having to resort to taking the drive shaft out? Obviously that's one of the biggest obstructions, but I'd like to avoid that if possible. It's so tight I can't find an easy way to get anything up there. I was thinking maybe taking the inlet manifold off, I'd be able to reach the bolts from the top? If there is an easier way without having to remover anything, please let me know. Even just the bolts on the flanges near the flex pipes have clearance issues and I can't get a socket around some of them.
Edited by Perry's 380 VRX 26/8/2016 01:14
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Frequent flyer Gold
Posts: 1092
Location: An island off southern Tasmania. | the rear manifold bolt furthest on drivers side can be got at with a double extension and a universal on a socket...but requires patience...has to be threaded through steering and other stuff.
you will never get it back on to reinstall though.
take the drive shaft out and its a piece of cake...can be done in an hour...
I know what your problem is...
the welds have failed on the pipe to flange..the front ones were the magna ones...the rears were fabricated by a schoolkid...mine failed same way.
trust me taking the shaft out is the easiest way...not rocket science either. |
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RPW extractors/headers
