92 replies to this topic

[slindborg]

I don't know many other (high perf.) engines running 1+2 & 3+4 primaries, so I'm still convinced that a proper designed 1+4 & 2+3 manifold will be beneficial for the 2,2...

this could lead toa nice question then...

Would an unequal length 1+4.2+3 manifold be better than an equal 1+2.3+4 (or even 4-1)

[vocky]

one thing I do know is the standard cast manifold is not good for performance

I doubt there would be much difference on a road car between;

an unequal length 1+4/2+3
an equal length 1+4/2+3
an unequal length 1+2/3+4
an equal length 1+2/3+4

or between an unequal length 4-1 and an equal length 4-1

you should be able to notice the differnce between a 4-2-1 and a 4-1

[Jameshs]

one thing I do know is the standard cast manifold is not good for performance

I doubt there would be much difference on a road car between;

an unequal length 1+4/2+3
an equal length 1+4/2+3
an unequal length 1+2/3+4
an equal length 1+2/3+4

or between an unequal length 4-1 and an equal length 4-1

you should be able to notice the differnce between a 4-2-1 and a 4-1

I really need to get a manifold to finish the exhaust off. What are these Dblias ones like?

[vocky]

dbilas are better than the standard, but heavy a tubular type manifold will be the best option, but unless you buy the £1k tms manifold then you won't find a direct fit replacement

[Jameshs]

dbilas are better than the standard, but heavy

a tubular type manifold will be the best option, but unless you buy the £1k tms manifold then you won't find a direct fit replacement

Whats the regal one like??

To be honest i would rather not spend £1K on a manifold

[MaDFreeBiRD]

Is the Diblias heavier than standard? If it is but gives better gains then usrely its worth it for the £££ i personally wouldnt be able to justify spending £1000 on a manifold as pretty as it may be

[Winstar]

There are arguments on both sides as to the benifits of sequencial (1+2&3+4 or 1+3&2+4) or non-sequencial runner configurations, the thermodynamic principles behind sequencial runner arrangments is sound, but race headers are non-sequencial or 4-1. The design I came up with used 1+2 & 3+4 confifuration as it was the easiest to package while getting equal (and they are equal to the mm) and long primary runners and reasonable length secondaries. What's more it's the only configuration that's proven to work there's alot of speculation of 1+4 & 2+3 but I'll belive it when I see a dynoplot. I was going to try to organise a GB but I gave up on that as people want the goods but don't want to pay the going rates the number of bends required to fit the package runs into the hundreds of pound then add a sports cat and you above what most of the new VX oweners are willing to pay before you've even welded the bits up. I did have to compromise the design slightly to ensure it would fit with the miltek backbox, so I am tempted to go back and start with a blank sheet design port face to tail pipe.

Edited by Winstar, 10 September 2008 - 12:42 PM.

[MaDFreeBiRD]

It would be awesome, like you say a fair few will not be up for paying £££'s for the product. For example i only recently bought a piper catback, so i would only need the manifold and cat section. Were you thinking of designing a system that you could have in pieces or would the whole thing have to be bought and installed?

[Jameshs]

There are arguments on both sides as to the benifits of sequencial (1+2&3+4 or 1+3&2+4) or non-sequencial runner configurations, the thermodynamic principles behind sequencial runner arrangments is sound, but race headers are non-sequencial or 4-1.

The design I came up with used 1+2 & 3+4 confifuration as it was the easiest to package while getting equal (and they are equal to the mm) and long primary runners and reasonable length secondaries. What's more it's the only configuration that's proven to work there's alot of speculation of 1+4 & 2+3 but I'll belive it when I see a dynoplot.

I was going to try to organise a GB but I gave up on that as people want the goods but don't want to pay the going rates the number of bends required to fit the package runs into the hundreds of pound then add a sports cat and you above what most of the new VX oweners are willing to pay before you've even welded the bits up.

I did have to compromise the design slightly to ensure it would fit with the miltek backbox, so I am tempted to go back and start with a blank sheet design port face to tail pipe.

Out of interest how much was it going to be?

[slindborg]

plus with the location of the exhaust (ie its well protected) and the fact most exhaust manufacturers use utter dog sh*t stainless steel. I'd be inclined to have one made from a high grade of Mild. Costs are lower due to materials and labour etc, a Good grade of Mild will last 5-6 years.... more than most people dream of a VX let alone own one lol

[vocky]

Whats the regal one like??

they don't sell it anymore

[Jameshs]

Whats the regal one like??

they don't sell it anymore

Its still on there website though??

[NickB787]

I was going to try to organise a GB but I gave up on that as people want the goods but don't want to pay the going rates the number of bends required to fit the package runs into the hundreds of pound then add a sports cat and you above what most of the new VX oweners are willing to pay before you've even welded the bits up.

I am still looking into this, there must be a way to organise a cheap(ish) 4-1 replacement for the oem cast one.

one of the guys did one on the z22se site but when the company he used to weld it up, they didn't save the design

clicky

[drpau]

I was going to try to organise a GB but I gave up on that as people want the goods but don't want to pay the going rates the number of bends required to fit the package runs into the hundreds of pound then add a sports cat and you above what most of the new VX oweners are willing to pay before you've even welded the bits up.

I am still looking into this, there must be a way to organise a cheap(ish) 4-1 replacement for the oem cast one.

one of the guys did one on the z22se site but when the company he used to weld it up, they didn't save the design

clicky

Like the sound of this Nick, Most I want to spend really is about 400ish though (yes I am a tightwad lol, house to do up and mortgage to pay), otherwise I will go for the dilbert which must give some improvement over the standard cast one..

[Winstar]

I was going to try to organise a GB but I gave up on that as people want the goods but don't want to pay the going rates the number of bends required to fit the package runs into the hundreds of pound then add a sports cat and you above what most of the new VX oweners are willing to pay before you've even welded the bits up.

I am still looking into this, there must be a way to organise a cheap(ish) 4-1 replacement for the oem cast one.

one of the guys did one on the z22se site but when the company he used to weld it up, they didn't save the design

clicky

to be fair that design was pretty poor, the 1&4 runners are about twice the length of the 2&3.

I also love the fact there's no pictures of it not wrapped.

[NickB787]

I was going to try to organise a GB but I gave up on that as people want the goods but don't want to pay the going rates the number of bends required to fit the package runs into the hundreds of pound then add a sports cat and you above what most of the new VX oweners are willing to pay before you've even welded the bits up.

I am still looking into this, there must be a way to organise a cheap(ish) 4-1 replacement for the oem cast one.

one of the guys did one on the z22se site but when the company he used to weld it up, they didn't save the design

clicky

to be fair that design was pretty poor, the 1&4 runners are about twice the length of the 2&3.

I also love the fact there's no pictures of it not wrapped.

Yea I know what you mean about really seeing it. I do think though a simple 4-1 design would be best though.

[Winstar]

Yea I know what you mean about really seeing it. I do think though a simple 4-1 design would be best though.

if you want it cheap then it's the only way your going to get it.

But it will be far from ideal for NA performance, SC on the other hand just needs to be able to get the gas out quickly.

[slindborg]

what RPM is your design tuned for Rob?

[Winstar]

what RPM is your design tuned for Rob?

It's not tuned for any rpm, the aim of using long primarys in a 4-2-1 is to reduce the intensity of the reflected wave such that you don't get the constructive or destructive interferece therfore you get a more even spread of torque through out the rev range. Plus the fact that there's so little room for manover on what you can fit while maintaining a good runner diameter you pretty much get what you can fit, it took me literally weeks and over 10 configurations to get somthing that would fit and have long equal length runners. Starting from a complete blank sheet would allow you to tune the runner lengths better though.

Edited by Winstar, 11 September 2008 - 12:45 PM.

[NickB787]

Yea I know what you mean about really seeing it. I do think though a simple 4-1 design would be best though.

if you want it cheap then it's the only way your going to get it.

But it will be far from ideal for NA performance, SC on the other hand just needs to be able to get the gas out quickly.

Yep