Modify your Pre-CAT

[max and andy]

I didn't bother looking at Peco . Thought they had gone bust . Max

[max and andy]

Is a stiffy a PCE ? And whats the veiw on exhausts Peco Or Piper whats the best ?

[rip]

Is a stiffy a PCE ?

Yes.

And whats the view on exhausts Peco Or Piper whats the best ?

If you want a 2¼" without the extra silencer or sportscat, then I don't thing there is a lot to choose between them. If you are really keen to compare the two, you'll have to have a look & listen to Elans with them already fitted.

Peco don't offer a silencer or 2nd cat or 2½" system, so a Piper would have to be the one to go for if you want any of these.

[max and andy]

How many types of PCE are there i think Ive seen three now .From a big chunk of metal to a lump of pipe with heat shield rapped around it. Is there any difference in performance .And is there much difference in price ? Andy

[Elanlover]

Is a stiffy a PCE ? And whats the veiw on exhausts Peco Or Piper whats the best ?

Technically, the "stiffy" is a combination PCE and turbo exhaust manifold all-in-one piece. The PCE is only a replacement for the pre-cat and doesn't include the turbo manifold - it bolts to the bottom of it.

[max and andy]

If i get a PCE.Will the old exhaust manifold fit? Andy

[Elanlover]

If i get a PCE.Will the old exhaust manifold fit? Andy

Turbo exhaust manifold - not exhaust manifold. Just trying to be clear

No reason why not. I'm not aware of any differences bwteen the Fed pipe versus the UK pipe. Anyone know for sure? The parts guide doesn't seem to indicate a difference.

[nitroman]

Yes there is: Cybox (PECO) (whoops, Mini was ahead of me, but see my message a few posts up )

The Ring stays, true, but compared to the 2"restriction it is a restriction beyond measuring capabilities. It is possible that it makes the flow even better. The ring brakes up the flow, causing turbulence. The trubulence makes it easier for the mainflow to pass the 2"orifice restriction.

Complex matter that cannot be answered without FEM analysis, backed up with actual experimental measurements. Luckily even without analysis it is safe to say that you cannot feel if the ring is still in place or not while driving

I'd say the removal is worth a couple of HP. Air is lazy. It doesn’t like going around corners, squeezing into tight spaces, or expanding to fill larger spaces. That is why good port jobs straighten out the bends as much as possible and keep the port size as consistent as possible throughout the airflow path. Obstructions like the insertion of an upside down-U right at the point where the precat begins funneling-down from 4" would cause an F1 team owner to hand out pink slips!

http://www.extrudehone.com/auto/auto-performance.php is a business entirely devoted to reducing air turbulence. I've wished more than once that I had the kind of free cash to justify sending a cast intake to them.

[HJ2]

When you are talking about a swap from empty pre-cat housing to a stiffy: Absolutely true!
I however talked about empty pre-cat with, or without the ring. The difference is not a couple of HP in this situation...
I am sorry if i didn't make myself clear

[nitroman]

When you are talking about a swap from empty pre-cat housing to a stiffy: Absolutely true!
I however talked about empty pre-cat with, or without the ring. The difference is not a couple of HP in this situation...
I am sorry if i didn't make myself clear

Ah contraire, the PCE is worth much more than 2hp. Have you had occasion to scientifically compare the before/after effects of replacing this one component only? I have. Those 2 horses must be Clydesdales! Turbo lag is also almost eliminated. I had the 2.5" exhaust on first, with a hollowed precat. Only after experiencing this did I install the PCE.

[Elanlover]

When you are talking about a swap from empty pre-cat housing to a stiffy: Absolutely true!
I however talked about empty pre-cat with, or without the ring. The difference is not a couple of HP in this situation...
I am sorry if i didn't make myself clear

Ah contraire, the PCE is worth much more than 2hp. Have you had occasion to scientifically compare the before/after effects of replacing this one component only? I have. Those 2 horses must be Clydesdales! Turbo lag is also almost eliminated. I had the 2.5" exhaust on first, with a hollowed precat. Only after experiencing this did I install the PCE.

At the risk of putting words in someone's mouth I think he meant the difference between a ring-in and ring-out hollowed pre-cat couldn't be more than a couple of HP.

[HJ2]

THANK YOU ELANLOVER

Obviously my English is a bit too rusty to explain myselve
So... this is exactly what i was trying to say

[alexg]

I noticed a marked improvement after fitting the piper 2.25 exhaust with sportcat and PCE on my S2, it now feels much more like I remember my old SE. My memory might be a bit tainted as I had the SE over 10 years ago.

Looking at the precat it seems very restrictive and is probably where the 10hp is lost between the cars, but I'm not an expert. I would recommend replacing the precat it has transformed the car.

[max and andy]

Alex did you ever think of trying the exhaust without the sports cat. Andy

[alexg]

after Reading the exhaust threads on here I decided that it would be too risky to run without any cat at all as the car may fail the MOT on emissions unless set up perfectly and then there is no guarantee. So choose to remove the precat as it is mainly there to control emissions on warmup and has the most restriction.

[Siegreen]

I had the full exhaust sytem removed from my S2 and the Peco system installed (no main cat) and it still passes emissions for MOT, given that the pre cats job is just to heat gases up quickly on cold start (i hope thats right?), does anyone reckon it would be ok to hollow out the pre cat also or better to repace it. And being a complete mechanical biff does anyone around South yorkshire area have any experiece or recommend some to do this, thanks in advance.
Si

[GeoffSmith]

My S2 passes the MoT with no cats and a Peco Si.

[HJ2]

Pre CAT is for a cold engine only.

Hollow out the pre cat is easy and can be done in situ, just with the downpipe removed. This gives great results and is the best bang for the buck . From a flow point of view a replacement with a part with smooth internal curves is better. This also gets rid of the orifice in the pre-cat wich acts as a restriction.
However, i am quite happy with the improvement of just hollow out the bugger (85%) the pre-cat replacement gives another 15% gain
(disclaimer: i have NO data whatsoever to back this up I do have some experience with rocket engines internals though... )

[max and andy]

How easy is it to remove the pre cat? My kwickfit didn't want to know. They said they would have to drop the front sub frame to fit the exhaust. Andy

[Elanlover]

How easy is it to remove the pre cat? My kwickfit didn't want to know. They said they would have to drop the front sub frame to fit the exhaust. Andy

Better look for a new shop then. There's NO reason to remove any parts of the car to fit the exhaust. It may be "easier' to do it but not necessary. My shop replaced the entire system from the turbo exhaust manifold (right off the turbo) down without removing anything. You'll pay a lot to remove the sub frame by someone who has no idea how to put them back again.