i have an early scoobysport up-pipe on my MY01. following various comments on here, and a certain amount of paranoia on my part, i removed it and checked it as i was sure it was blowing slightly when hot.

having removed it, i machined the faces flat at each end and refitted it, and it's been fine since.

i'm led to believe that this was the problem with some of the early ones ie. faces not machined accurately, and that the later ones do not suffer the same.

although the scoobysport one seems expensive at £120ish it's a bargain compared with some of the others, considering they do the same job.

simon

ps. i'm sure pete or dave t-s may have something to add.

[Edited by RRH - 8/1/2002 5:09:58 PM]

 

Caronte

I do not agree with your suggestion of gutting the standard catted uppipe for the following reasons;

• it is very difficult to remove all of the cat, and any remaining may come loose and pass through (and damage) the turbo
• the remaining pipe will have both a restriction (at the sleeve) and an expansion section (where the cat was) causing poor gas flow.
• the bellows joint remains, so is a potential weakness.
• in the UK, unlike the USA (where this mod is done a lot), we don't have an inspection to check we haven't modified the exhaust, so we don't need to stick to OEM parts.

Unlike D T-S, I'm no longer convinced by the flexi-jointed option, and will continue down the solid option for the meantime.

Duncan

[Edited by BugEyed - 8/1/2002 10:12:32 PM]

 

Wondered on ya thoughts1
going to get a decat for my01 wrxppp
don't know wether i should get a flexie jointed up pipe, as much as £340 or stick with the ridged one!
any ideas or thoughts

steve

 

please

steve

 

BTTT

Still won't beat me m8 at the rr day

 

Thanks for the constructive coment Kev
someone out there must have an opinion on this , i wouuld have thought1
steve


ps Kev wrx ppp full decat see rr results in dyno , think it can be as high as 270/287

 

Steve

I have a PPP'd 01 with full decat. Just for your info my car which is poorly at the moment topped out at 270bhp with 22 degrees C in the workshop.

I have the fixed pipe, I think the concern was regarding the lower joint which can cause the gasket to fail.

I'm sure the flexi pipe would stop this but it is a lot of money.

Nathan..

 

Hmm

The jury is well and truly out on this question.

On one hand, Subaru in their infinite wisdom have always fitted a flexible joint in these pieces. However, this is the company that gives us the "brightness" button .... Equally, the bellows type joint on the standard item is not unknown to fail.

On the other hand, a number of people (me included) have had problems with gasket failures on replacement items (as stated above, the lower 2 bolt joint gasket). These have been both due to manufacturing problems (wrong length, warped flanges, etc) and, possibly, due to the fixed nature of them. However, a high spec. stainless pipe is claimed to self-anneal, and should flex without cracking or warping.

More questions? Well, how about the quality of the welds, the options of extra reinforcement around the welds, bolts vs. studs, etc. With flexible joints, the main question (other than cost) is how long the joint will live. It is "rumoured" that MRT changed their design of flexible joint due to failures. TSL have yet to release their version because of similar concerns.

And another option? TurboX-S (in the USA) do a cast iron version with superior expansion characteristics (and simpler machining on the flanges), but it weighs approx 7lb so is similar in weight to the the standard piece.

So, no answers, just a lot of questions!

Duncan

 

empty the original. much better.

 

As my name was mentioned....

We put a solid replacement up pipe on Carolyn's STi7 when it was just 60 miles old.

The lower gasket blew within 2500 miles. It's a 1.5mm thick triple layer steel gasket - pic here.





I had the up pipe taken off and put back to standard. I now would ONLY fit a replacement up pipe if it has a flexi joint in, not a solid one.

This is merely a statement of the facts, I am not criticising any suppliers, and this is ONLY my personal opinion

 

steve,
270 bhp, i've got no chance against that

may have to get the new downpipe a bit sooner.

Kevin

 

Duncan,

if you have fitted a PPP the original cat in the uppipe is likely to be broken(even if you maintain the Oe DP). At this point drilling it away is a fair stright job. there won't be any remainings of it in the pipe.
the important thing is to change the bolts and mostly the gaskets with new ones.
The problems regarding the gas flow are very relative since it's a turbo engine. the section of the uppipe will have the same overall pressure when the engine is running . the turbo will "suck" the exhaust gasses at the same speed compared to a straight pipe. and in any case much faster than with the cat.
last reason in my opinion is that being the pipe original, it will have the characteristics (dimension and torsional rigidity)studied at the time of the project of the car.

C.

 

intresting coments chaps !
keep them coming
still not sure which to go for!!!

cheers
steve

 

Looking at this from a slightly different perspective (first establish what the potential problem is, then find an engineering solution to the problem), the problems with replacement lower up pipe gaskets blowing appear to be for three potential reasons:

1) Flanges that are not exactly flat.
2) Flanges that do not mate exactly due to slight tolerance issues on manufacture.
3) Flanges that *may* move under exposure to heat on a solid up pipe due to having no expansion joint, and there being a bend in the pipe which may cause it to try and straighten out when exposed to 900c or thereabouts.

Solutions?

1) A quality control issue that should be dealt with at manufacture i.e. ensure the flanges are precisely ground flat after welding.
2) Can possibly be dealt with at manufacture, but every car probably has slight alignment differences anyway so a flexi joint would allow for this.
3) Much discussion on here about the expansion coefficient of annealed stainless steel; but, again, a flexi joint will allow for this.

Some of the above is fact, and some is theory. I believe it is likely that an up pipe with a flexi joint in would be less likely to exacerbate problems 2) and 3) above.

As always, IMHO only

In closing Steve, you could try emailing APS and MRT and asking why they feel it worth going to the trouble of fitting a flexi joint in their up pipes. I for one would be interested to see their answers.

[Edited by Dave T-S - 8/2/2002 8:21:16 AM]

 

cheers dave

not sure which way to go!
will try emailing option!
steve

 

Dave TS

Where's that luvurly pic of the MRT up pipe gone?

Oh and did you get a price?

F

 

£340

 

o and see dealer 3rd party questions for pete's coments.
looks like ridge one is ok!
steve

 

Mr emery
Please email me so I can discuss this offline

 

yhm dave

steve