My vx220 project

vocky

the mapping lambda is after the cats because whenever I've asked they say it doesn't really matter as long as they know where it is :crazy:

winstar

vocky said:
I cannot fit the new exhaust just yet, the coolant system mods need to be done before fitting the manifold

The length of your secondaries after the cats is irrelavent they will kill any reflected wave from the 2-1 junction, there will be a reflected wave that occurs from when the flow hits the cats. The system will act more like a 4-2 than a 4-2-1.

Looking at the design i can't see why you just didn't just use a single cat after the 2-1 junction.

vocky

I must admit to thinking the same whilst making the 'twin cat' system, my original plan (I actually bought all the parts required) was to make the 2-1 section the same length as the 4-2 (so 500mm) and then use a 2.5" U bend, then a single cat.

Trying to find a single cat which will take a 250bhp normally aspirated engine is quite hard, so I had a mad idea of using a 'twin cat' system like many 6 cylinder cars.

I may end up converting back to plan A but will give plan B a try first, the tc system will certainly flow better, but whether that means more or less bhp will have to be seen.

As with all my cunning plans, "It seemed a good idea at the time" :lol:

winstar

vocky said:
I must admit to thinking the same whilst making the 'twin cat' system, my original plan (I actually bought all the parts required) was to make the 2-1 section the same length as the 4-2 (so 500mm) and then use a 2.5" U bend, then a single cat.

Trying to find a single cat which will take a 250bhp normally aspirated engine is quite hard, so I had a mad idea of using a 'twin cat' system like many 6 cylinder cars.

I may end up converting back to plan A but will give plan B a try first, the tc system will certainly flow better, but whether that means more or less bhp will have to be seen.

As with all my cunning plans, "It seemed a good idea at the time" :lol:

Jetex do one but it's expensive, but then again 2 cats instead of one isn't cheap either!

vocky

plan B sucks :thumbdown:

I need to rebuild the tc section due to clam 'issues' :oops:

So I will be going back to my original plan; matching length secondaries, single cat and a 2.5" U bend rather than twin cats and twin 2.25" U bends.

I have to say it did sound really really nice, the engine just revs so smoothly without the mechanical water pump and you could tell by the exhaust note that the system flowed very well :clap:

vocky

anyway, back to more fun stuff 😃

I removed the mechanical water pump, chain, tensioner and guides. I had to make a blanking plate for the balancer chain tensioner oil feed.
Whilst the oil pump was off I fitted my 'GM racing' oil pump gears - much better quality, the standard have cast gears and the 'GM racing' are machined from steel (y)

I made the water pump blanking plate, I decided to use the thermostat housing cover as the new water inlet, works very well :clap:
outer hole shape - to match the pipe fitting

inner hole shape - to match the block

the pipe fitting modified to match the hole

and fitted, I used sealant between the plate and block and between the pipe fitting and plate

exhaust manifold fitted

alanoo

That looks very good

Got some pics of the GM oil pump gears ? Have been curious about those as depending on the source they are described either as "hardened" (which could be done on the stupid sintered OE stuff) or "billet"

vocky

I didn't think to take any pics of the GM oil pump gears :oops:

they were billet, but then they should be at that price :wtf:

Matt

More good work there Neil.

TheHood

vocky said:
I didn't think to take any pics of the GM oil pump gears :oops:

they were billet, but then they should be at that price :wtf:

Were they the ones from karo at allecotec.com Vocky?

I'm putting together a shopping list....

vocky

yes they are the GM racing oil pump gears available from www.allecotec.com

http://www.allecotec.com/product_info.p ... cts_id=118

update;
I have made the 2-1 section, just need to fit the U bend and single cat

sdbutler10

nice work again need more pics

vocky

this is how I originally planned the exhaust [aka plan A], equal length primaries and secondaries - 500mm

the modified piper 2.5" backbox, the pipe has to go at an odd angle for clearance

the cat sits quite tight to the backbox - for clam clearance [viewed from underneath]

just the U bend to make, I need to buy a pair of tight 90 degree elbows as the U bend I bought is too wide a radius (n)

JohnnyN

Have you had that Piper backbox for long? I believe that you have a repackable one too like what's being advertised in this months TV?

vocky

it is my 6 month old piper repackable backbox Johnny, nothing escapes being vocky'd :lol:

JohnnyN

I reckon that I need to bring up my Milltek for you to open up and make repackable????

;-)

vocky

JohnnyN said:
I reckon that I need to bring up my Milltek for you to open up and make repackable????

;-)

easiest way is to chop open an oblong section, repack the silencer and then weld it back up :thumbup:

vocky

I managed to get the exhaust heat shield modified today, I chopped off the lower subframe section and mounted that with the three standard mounts, then modified the rest so it allows more air over the exhaust

blue_se2

all that work and it gets covered up lol

Matt

Good work Neil as usual.

« Previous Page Next Page »