Up-pipe pre-cat removal and map

is need remap if will replace up-pipe with cat to up-pipe without. rest exhaust standard with prodrive back box

i would say yes as it will spool up quicker but thats just my opinion ,what i did was take out the original uppipe and opened it up and removed the cat then rewelded it and refitted it with a full decat exhaust and a map my car is on full boost by 2500-2600rpm i tried it with a decat uppipe and it spooled later

Absolute waste of labour unless upgrading turbo at same time.

[quote author=davelegacy™ link=topic=38135.msg436742#msg436742 date=1370041362]
Absolute waste of labour unless upgrading turbo at same time.
[/quote]

it might be waste. as some work doing by myself so would be only time waste
but my question wasn't about it.

There's no easy answer here.

1) If the up-pipe is narrow enough (either standard one de-catted like Wagon Dec's, or other aftermarket that is sized right for your application), then you will see much faster spool up. Faster spool early on will mess with fuel:air ratio and as you rev higher can see boost spikes etc. So... you would need a remap to a) keep it safe and b) see full gains available.

2) However, if the new up-pipe is a bigger diameter than stock it will not improve spool and will actually make it more laggy (See the last part of Wagon Dec's comment). In this case, as per Dave's comment, you'd need a bigger turbo to get the most out of your bigger diameter up-pipe.

Note: If you do put a bigger diameter de-cat up-pipe in and keep the stock turbo you "might" get away without a remap if you are "lucky" enough that the de-cat gain is exactly cancelled by the bigger diameter canceling the gains in spool... however, then you'd wonder why bother as it's just work without any gain with the risk that your standard map still isn't able to cope to keep your engine safe. Seeing that it exactly cancelling eachother out through the entire rev-range is unlikely then eitherway, you'd need a remap.

If you are getting a remap then it would make sense to address the rest of your exhaust system first (de-cat or free flow sports cat) to get the most out of your investment in a new map.

Hope the above helps.

thanks for reply.

it doesnt really matter now. as engine gone. big end bearings

sorry to hear, was it before or after u changed the uppipe?

bad luck lad was that the cause of the boost problem

no i didnt change up-pipe. just was thinking about it. everything was stock with 86k miles

That sucks!

Any idea what caused the failure?

[quote author=Keadeen link=topic=38135.msg436891#msg436891 date=1370189485]
That sucks!

Any idea what caused the failure?
[/quote]


no ideas no engine light. no oil light. recently oil changed.
it was some knocking sound in morning but a lot garages said that piston slap. with that little knock on cold engine was going as long as i have car 6 months. might this thing somehow caused engine failure

Really sorry to hear that man that was the knock u were showin me at the octaine meet
Hope you get her back on the road soon

[quote author=Ciaran WRX link=topic=38135.msg436938#msg436938 date=1370246186]
Really sorry to hear that man that was the knock u were showin me at the octaine meet
Hope you get her back on the road soon
[/quote]


yes that knock
hope will back on road with her at end of august

how did you go about the oil change???

did you dry crank it to build up pressure 1st

oil was changed not same day. couple hundred miles ago.

p1impreza what do you mean?
i did like : drain oil, remove filter, fill new filter with oil, put filter back and refill engine with oil

Re: Re: Up-pipe pre-cat removal and map

[quote author=Federal link=topic=38135.msg1#msg1 date=1370297063]
oil was changed not same day. couple hundred miles ago.
[/quote]


What grade ?

Any bearing particle in the old oil ?

Re: Re: Up-pipe pre-cat removal and map

[quote author=davelegacy™ link=topic=38135.msg436997#msg436997 date=1370297304]
[quote author=Federal link=topic=38135.msg1#msg1 date=1370297063]
oil was changed not same day. couple hundred miles ago.
[/quote]


What grade ?

Any bearing particle in the old oil ?
[/quote]

castrol gtx 10w40 didnt notice any praticles in old oil

Was it collected and checked? Camera inspection?

[quote author=davelegacy™ link=topic=38135.msg437000#msg437000 date=1370297478]
Was it collected and checked? Camera inspection?
[/quote]

yes it was checked as i drained oil myself to clean empty dish didnt see any metal or any particles . no camera inspection

Sudden oil pressure loss so.

Check oil pump upon removal.