4.5" Body Venom Cat

[luvpsi]

Hey guys I have searched and noticed most people got the 5" body cat from venom I'm going to order a cat from venom but not sure what one to get I think the 5" body will be overkill as I'm still only running stock turbo but will soon be upgrading and looking at 300kw would the 4.5" body be a better bet for my application Oh my exhaust is a 3" from turbo back

[boostn0199]

Well bigger the better so you might aswell go 5 now.

[luvpsi]

Thing I'm worried about is the body hitting the floor of car as I'm fitting it to a fairly newly made exhaust

[luvpsi]

I spoke to George at venom and he mentioned the 4.5" for my application

[Hanaldo]

I would go the 5" man... That extra half inch would make a world of difference to flow, but won't make much difference to your ground clearance.

[KiwiRS4T]

I got the 5in. Just make it fit. Flow is everything. In and out is 3in but you can cut the taper to acheive 3.5 or 4in in and out if you need to later.

[Harey]

Yeah I went the 5" as well. I reckon the 4.5" will be fine though.

[luvpsi]

Problem my car sits on the limit for height as is George reckons it will be overkill for a 5"

[Room42]

Just some food for thought about flow. My R33GTSt will turn the tires for about 100m in 3rd when it comes on boost at 110kph. I'm still using a stock cat.

[luvpsi]

yeah i went the 4.5 as george said becuuse he doesnt have any 5" in stock til next week anyway and i need it asap

[R31Nismoid]

Just some food for thought about flow. My R33GTSt will turn the tires for about 100m in 3rd when it comes on boost at 110kph. I'm still using a stock cat.

So? Same as the people that say a 3" exhaust flows 350rwkw.

Swap it to something that flows better and then they pick up power, torque and response. 40rwkw is not uncommon when the restriction is that bad.

Less restriction = happier motor, tune and everything associated.

Just because something "makes XXXrwkw" doesn't mean it can't be better for simple changes.

[Room42]

So? Same as the people that say a 3" exhaust flows 350rwkw.

Swap it to something that flows better and then they pick up power, torque and response. 40rwkw is not uncommon when the restriction is that bad.

Less restriction = happier motor, tune and everything associated.

Just because something "makes XXXrwkw" doesn't mean it can't be better for simple changes.

I generally agree with everything you say in your post.

One of the points that I implied in my previous post is there was that the OP has a stock turbo and worrying about a 4.5 or a 5 inch cat should be way down the list. Getting one or the other is not even worth considering. Just get either. If the OP is chasing power then there are plenty of better ways to get it.

I have dyno'd a 600hp engine that with a 3 inch system. It lost power with a 4 inch system. It wasn't a turbo engine but the overkill principle is still the same.

Someone might pick up 40rwkw (maybe me when I pull my finger out and swap the cat) but it wont be the OP with his current setup.

I took a couple of guys for a drive the other day and the first thing they commented on was how quiet my car is. The next thing was how it surprised them by how well it went.

Cop bait is not always best and a loud exhaust is one of the primary thing you will get picked up for.

[zebra]

I picked up 2mph in the 33 just by running a cat delete pipe over the standard cat...no change in the tune, but would pull harder from 6k to 7krpm.

side note - changing from the standard dump pipe with 3" front pipe to a 3" bell mouth dump/front made no difference.

Done back to back on the same day at Heathcote

Edit - all on standard turbo

[TiTAN]

Just some food for thought about flow. My R33GTSt will turn the tires for about 100m in 3rd when it comes on boost at 110kph. I'm still using a stock cat.

so would mine with a 2.5" emissions cat but you will find that you are building up a lot of pressure in there before the cat, mine blew out both gaskets pre cat.

[Room42]

I picked up 2mph in the 33 just by running a cat delete pipe over the standard cat...no change in the tune, but would pull harder from 6k to 7krpm.

side note - changing from the standard dump pipe with 3" front pipe to a 3" bell mouth dump/front made no difference.

Done back to back on the same day at Heathcote

That isn't a lot of difference. Sure, it is something though.

Gotta love changing a hot exhaust

[zebra]

forgot to add that was with a standard turbo at 14psi

Im sure there wouldve been even bigger gains with a larger turbo

[R31Nismoid]

I have dyno'd a 600hp engine that with a 3 inch system. It lost power with a 4 inch system. It wasn't a turbo engine but the overkill principle is still the same.

N/A & turbo are not the same by any means. Comparing the two is misleading.

And 2mph from removing a CAT is actually quite a big gain realistically for a stock turbo.

[luvpsi]

Well put it this way I'm running a Decat now but sick of the smell and having to turn car off when pulled over so mr plod cannot smell it

[R31Nismoid]

It'll still smell even with a huge CAT in it

Not as bad, but ye - cruise behind a car with a hi-flow CAT and you can certainly still smell as if it was not running one.

[rondofj]

I picked up 2mph in the 33 just by running a cat delete pipe over the standard cat...no change in the tune, but would pull harder from 6k to 7krpm.

side note - changing from the standard dump pipe with 3" front pipe to a 3" bell mouth dump/front made no difference.

Done back to back on the same day at Heathcote

Edit - all on standard turbo

I just picked up a JJR 3" dump/front last week, are u saying it will make stuff-all difference to my set-up with stock turbo?? (see signature below for my set-up).. Just realized I have a 4" body 3" inlet and outlet 100 cell metal cat (Lobokka brand off ebay), instead of a 5" body which people recommend, is this going to restrict my exhaust when I get 280-300rwkw down the track later???