Lexurf IV.

[Wolfracer]

http://www.lexls.com/info/ls400.html

Exhaust sound is all down to design on a 'V' engine. H or X pipe, chambered or straight through silencers, seperate pipes etc.

Mine is two into one 2.5" with two straight through silencers and a 3" outlet.
Lexurf II has a stainless system fitted with twin outlets.
Lexurf III has two seperate 2.25" pipes with a NASCAR type silencer on each outlet with 3" tailpipes.
Lexurf IV has two 2" pipes, linked with a 'H' pipe and two chambered silencers at the back.

So far, Lexurf III is the loudest, but impressive.

250 FWHP.... not mahoosive but more than enough for the surf i would imagine. Wouldn't like to try stopping mine with that power!
IMHO, twin pipes with a proper X pipe - ie full bore crossover not "kissing pipes" promoting scavanging from the cylinders is the best set up. Sports cats and smallish rear boxes are all that is required...!
Pipe diameter is really determined by exhaust gas flow - bigger is not necessarily better - even for 6 litre LS2's 3" dual pipes can be too big for the gas flow. Gas flow, scavanging and back pressures are beyond me, but all I know is you CANNOT beat a good V8.

[Albannach]

Sports cats and smallish rear boxes are all that is required...!

What's the rationale behind fitting cats.?

[BUSHWHACKER]

What's the rationale behind fitting cats.?

Sports cats are just free flowing and twice the price versions of the standard ones.

Cats aren't needed on Lexurfs.

[BUSHWHACKER]

250 FWHP.... not mahoosive but more than enough for the surf i would imagine. Wouldn't like to try stopping mine with that power!
IMHO, twin pipes with a proper X pipe - ie full bore crossover not "kissing pipes" promoting scavanging from the cylinders is the best set up. Sports cats and smallish rear boxes are all that is required...!
Pipe diameter is really determined by exhaust gas flow - bigger is not necessarily better - even for 6 litre LS2's 3" dual pipes can be too big for the gas flow. Gas flow, scavanging and back pressures are beyond me, but all I know is you CANNOT beat a good V8.

Yeah, I know!

[Albannach]

Sports cats are just free flowing and twice the price versions of the standard ones.

I know.

Cats aren't needed on Lexurfs.

I know that too. Which is why I'm asking why he would fit them to a Lexurf.

[BUSHWHACKER]

Who knows?!

[stormforce]

i don't know

[Bogus]

Why dont you need the cats then ? I thought that cats had to be fitted to any vehicle manufactured after Aug 1992. Another thought, how would that work if the Surf is a 93/94 vehicle and the lexus engine comes from an earlier ( 91/92 say)?

Bogus

[flounderbout]

As far as I can see, there is recent legislation requiring that only type approved cats be fitted when replacing cats (so no more cheap substitutes that aren't approved). Not really relevant here.
But I can't find anything to suggest that cats must be retrofitted to older cars (whether or not pre 1992). There is some conflicting stuff about whether you need a cat to pass your MOT if it is registered post Aug 1992 (and some anecdotal evidence that people have been failed for removing cats). But the more reliable sources make clear that there is no requirement for the MOT that there be a cat, only that the emissions test be passed.
So I can't see why you would have to have one provided the emissions are OK

[Albannach]

Why dont you need the cats then ? I thought that cats had to be fitted to any vehicle manufactured after Aug 1992. Another thought, how would that work if the Surf is a 93/94 vehicle and the lexus engine comes from an earlier ( 91/92 say)?

Bogus

They had to be fitted, but weren't tested until later (2001?), so could be removed. AFIK, the vehicle year determines whether-or-not the cat(s) is tested.

[flounderbout]

There are a whole series of flow charts which get used to determine what the test levels are. If the vehicle was first used between 1 Aug 1992 and 31 July 1995 then it gets a CAT test if it shows up as an exact match in their database. See http://www.dft.gov.uk/vosa/repositor...01992-2002.pdf. So presumably a Lexurf would thoroughly confuse it and throw it back to the non-CAT test.
Having said that I haven't got any idea at all...
God I must be bored at work...

[Albannach]

I may be way wrong here, but aren't the Pre 8 2002 tests merely emissions tests (in which case the cat need not be there), whereas post 8 2002 the cat its self is part of the MOT?

[gwh200]

I may be way wrong here, but aren't the Pre 8 2002 tests merely emissions tests (in which case the cat need not be there), whereas post 8 2002 the cat its self is part of the MOT?

Yes that's correct. A 2001 ford excursion required to pass an emissions test only. A 2004 model required the cat to be present.

[Bogus]

I think the LEXURF question has been answered. No match in the db, non cat test, but other questions now come to mind.

If testing a vehicle with a cat because thats what the flowchart says ( post Aug 1992 and on the database) how could you do a test if it had no cat, dont they fit a lead to the lambda sensor for the test ? Are the allowable emissions for test purposes not different depending on whether a cat is fitted or not. Would that not mean you were almost certainly doomed to fail ? If the vehicle has no cat yet the database says it should have, would that not be a fail in itself?
Is this too much of a thread hijack ? Should I delete this and move it to general?
Bogus

[gwh200]

No...it's all very relevant. When a vehicle also falls just short of an sva test, but undergoes a major modification( á la lexurf), you have to take into account, the original vehicle was uncatted.