VR Decat

[Kevin Bacon 5]

Just formulating some ideas for my next batch of engine work. The car feels like it's throttled at high rpm in 5th and I'm wondering if it now needs a decat and more air? It's currently on the standard exhaust, standard air box and filter and standard cat.

 

I've got some 268 cams to go in at some point and they will be pulling more air in at mid to high rpms, so will I *need* a freeflow exhaust? Will I always get this 'holding back' sensation with the standard induction/exhaust?

 

It pulls well in the lower gears, but the slug of torque in 5th is a lot less pronounced, which I find dissapointing as it's got the AMD throttle and AMD remap.

 

There are no VAG-COM errors and I'm assuming the Schrick is working properly.

 

Ta

 

Kev

[dazzyvr6 0]

mine pulls like fcuk in 5th

[Scott 0]

Standard Exhaust and standard filter are the problems.... you need to concentrate on getting more air into the engine and more out of the back..... had the same problem when started modifying an old valver a few years ago.... felt breathless at top revs and required decent exhaust and filter to sort it....

[Kevin Bacon 5]

Cheers mate. Trouble is, I've been down the exhaust and filter road too many times in the past and not found much of a difference. You're probably right though, but it's an expensive way to find out!

 

I might try boring the cat out first as the engine effectively sees that as a 40% blockage in the exhaust.

 

K

[PhatVR6 0]

change into 6th then?

 

oh, sorry....I forgot :-P :wink: :mrgreen:

[Kevin Bacon 5]

Aha, that wasn't the response I was expecting from you Mr H! Thought you'd come back with "Get a 3.94 diff in the box" :lol:

[dr_mat 0]

We like to mix it up a little bit. Keep you on your toes.

Talking of which, I think you should get a cold air intake, mounted at about ground level under the wheel arch. The VW one is rubbish, makes the car sound like a complete wimp too.

If it's uphill enough, no grit and rubbish will get sucked in either, it's a winner! ;)

 

* - I take no responsibility for anyone taking this crap seriously!

[Kevin Bacon 5]

A sterling idea for sure. Surely a very large bonnet scoop would be more effective, fed straight into the air box? You'd get a positive pressure of 0.589 psi at 100mph then.

 

K

[Kevin Bacon 5]

Update: I put some BP ultimate in tonight and it feels a lot stronger. Must have picked up a shoddy tank of Optimax or something previously. Still might gut the innards of the cat next week at Stealth though, if Vince reckons it might help.

[corradovr6sc 0]

don't you need the cat for the mot?

[emax 0]

kevhaywire,

 

Are you running on the standard paper filter or a K & N panel??

 

I'm sure I heard that the standard exhaust is relatively free-flowing anyway, can anyone confirm this?

 

My car is on its original exhaust but when it dies, I'm not after a loud exhaust. I was even thinking of an OEM system again as they seem to last for 10 years! Either that or a Magnex. Ideally a free-flowing exhaust without the extra decibels...

[Kevin Bacon 5]

CorradoVR6SC, you do but I was thinking of just removing the catalyser plates. They're very brittle and should be easy enough to break with a long metal bar. My local MOT tester won't query it, unless he detects a distinct lack of sulphur odours! Just make sure the car is good and hot when you take it in! Standard cats only yield a 60% 'open' area which is going to throttle a shrek'd and cam'd engine somewhat, but only in the upper rpms. A Sports cat has fewer cells per square inch (100 - 200, as opposed to 500-600) and gives an open area of 75-80%, but they're pricey.

 

Emax, I was running the paper filter for a while until I could be arsed to clean the K&N, but now I've dropped that back in and put some BP ulimate in, the engine is way more responsive. The Schrick torque is now a lot more pronounced, so the paper filter is obviously quite restrictive.

 

Yes the OE exhaust is more free flowing than people give it credit for and obviously the fit and finish is perfect, especially if you've got uprated ARBs like I have, which aftermarket back boxes tend to knock on. If you want free flow less the noise (my preference too) then look no further than Supersprint or Miltek.

 

K

[16VG60 1]

You can smash out the ceramic matrix that forms the internal structure of your cat if you like, but i would check out replacement cost first!! The new item is enough to chill the blood, and to buy second hand you will be looking at at least £50 for something halfway decent. As an MOT tester i can tell you that we do not give a hoot as to whether or not a presented vehicle has a cat fitted or not. A cat not being fitted is not a reason for rejection, failing the relavant emissions test is. If you are seeking better flow from your exhaust system and are obligued to comply with the cat emissions at MOT then you have choices. firstly fit a performance cat back system to give improved flow. Keep the oe cat to meet the emissions test with 100% certainty. Fit a cat by-pass pipe for 364 days of the year then replace the oe cat for MOT testing purposes. Fit a sports cat which will give you much improved flow and meet the MOT emissions test without the annual shananigans. With regards to what aftermarket system you chose, well i'm biassed but for good reason Milltek is the only choice for me, that's why they are fitted to all my cars and i sell them to my customers. Why Milltek? They are built to the highest standards, they fit very well as good as the oe system and do not knock on the chassis, they are not loud and booming but instead give a deep subtle tone that purists and racers find acceptable, they offer a full range for all Corrado models and are guranteed for life.l

[Kevin Bacon 5]

John, cheers for that. I was looking at Milltek's site today and is where I got the 'cells per inch' info from (honest bloke aren't I?) and I have to admit, I am very very impressed with Milltek's knowledge and products. They're not your average supplier of boy racer tubes. I have heard a milltek system on a VR and you don't get the usual stainless boxy boom that you used to get with cheapy Scorpion systems. Instead you get a nice SuperSprint style bassy idle tone that's remains till about 3000 rpm and then you just get the factory system's refinement thereafter.

 

I would prefer the sports cat route but in addition to the rest of the Milltek system, it's expensive. Especially as you can get the OE rear and middle section from G&SF for £155. I've still got a year or so left in the standard system (after 10 years, how bloody good is that?) so I shall be considering a Milltek in the near future.

 

K

[16VG60 1]

For the original system that is truly incredible service life, my own lasted for 7 years. Give me a call when you decide what move to make, i'm sure there is a Milltek system in my stock room with your name written upon it :lol: Have you seen the price that i can offer a Milltek Sports Cat for?

[scruffydubbers 0]

its a shame, i sold a cat a few months back for about a £5 on ebay, you could have used it to play around with.

 

i used a cat bypass pipe on my VR from motech was about £40.

 

my friend has the same one fitted to his mk3 16v and he got a flange welded on the other end of the bypass pipe, and on the other end of the cat, making it much easier to change come mot time.

[kieron 0]

Kev,

 

Your car sound very similarly spec'd engine wise to mine was especially as you have the 268s going in.

 

Mine was VSR, AmD t/b and remap and Schrick 268s with Milltek back box and ITG/Eurosport induction kit. I always felt the engine had more power available and it did seem to run out of breath a bit at high rpm. I can't remember why I considered the Milltek sports cat, maybe Scott realised I hadn't spent any money for a month or two and suggested it :lol: , but believe me it REALLY opened up the engine.

 

Suddenly the engine felt waay more powerful especially at 4500rpm+. It did actually feel like the engine was being choked before.

 

It is also possible that your Schrick isn't switching over as mine wasn't until Geoff Everett waved his magic wand (well plugged something in :lol: )

 

BTW, my VR6 has no problem with emissions come MOT time.

[Kevin Bacon 5]

Cheers Kieron. It's always handy having someone on board with the same spec engine!

 

Yeah it's definitely in 4th and 5th past 4K that the cat feels like it's throttling the engine, especially as the Shrek and cams pull more air in. Below that and with standard cams (which have been designed with the cat in mind) it feels OK.

 

I think I'll try bashing the catalyser plates out first and see what that yields! If nothing then I'll try a complete system with sporty cat :lol:

 

My engine doesn't feel like it's suddenly had the bakes applied at 4000rpm, so I think the Manifold flap/controller are behaving themselves.

[stevemac 0]

How old's your VR Kev ??

 

Although CAT's were fitted to new cars by law from August 1992, the MOT emissions requirement was not enforced until August 1994. Meaning that if your car was first registered before August 1994, you can safely remove your CAT & still pass the MOT test.

[Joe M 0]

Doesnt that just mean they never started checking for a cat until after aug'94, but since then they check all cars newer than aug'92? :?

They failed (2 different mot stations) my 16v for no cat and it was a '93 K plate. :mad:

[stevemac 0]

Doesnt that just mean they never started checking for a cat until after aug'94, but since then they check all cars newer than aug'92? :?

They failed (2 different mot stations) my 16v for no cat and it was a '93 K plate. :mad:

The CAT info was supplied to me by a reputable MOT tester in Leeds. Is it possible that your car was emitting too much even for the pre 1994 levels ??

Cars don't fail MOT's for not having a CAT, they fail because the emissions are beyond alowable limits relevent to the age of the car.

[CorradoVR6-Turbo 0]

CorradoVR6SC, you do but I was thinking of just removing the catalyser plates. They're very brittle and should be easy enough to break with a long metal bar.

K

 

I've tried this with a spare Cat ,they are not soft and will not shatter,believe me,unlike fords were you drop them and the guts fall out.

I had to gut mine like a fish then weld it back up.

[Bobbywhacker 0]

Bahn Brenner do a sports CAT for £130 notes ( I think thats what it works out to )... As for Miltek systems, looks good, sounds good, don't fit too good.... I've had to make up all new mounts out of box section to stop it crashing about... and my car isn't lowered!

[16VG60 1]

With my personal experience of fitting numerous Milltek systems, many of these to VR6 Corrados, i am suprised to read your comments regarding your own application. You say that you had to make all new mounts just to achieve a fit that was acceptable? Are you sure you were supplied the correct system for your car? I have spoken to another Corrado owner who told me on the outset a simillar tale. Later upon inspection it transpired that the Corrado in question had originally been supplied as a 16V and had been converted to VR6. Hence the hangers were all wrong to accept the later VR6 system. Did you contact the supplier to question your difficulties with the system? If so what was the outcome? I know that if Milltek had been consulted at any stage regarding your issues they, as indeed so would i, not rest until you were satisfied with your investment. I have never experienced any difficulty with fit or installation of a Milltek system, it is this fact coupled with their proffesionalism that inspired me to become an agent. I would not sell a system knowing that such difficulties would be experienced, and niether would i expect my customer to go to such lengths to achieve the desired result.

[NormanCoal 0]

CorradoVR6SC, you do but I was thinking of just removing the catalyser plates. They're very brittle and should be easy enough to break with a long metal bar.

K

 

I've tried this with a spare Cat ,they are not soft and will not shatter,believe me,unlike fords were you drop them and the guts fall out.

I had to gut mine like a fish then weld it back up.

 

I have one of these going Gratis should anyone want one.......