Planning to build a custom 4-2-1 manifold

[kevo]

I'm newbie in this site, I have a 172 and I'm planning to build a custom exhaust manifold just like the 182 one, already used the Search but I still have a few questions.

I saw that the 182 one does not fit and i don't feel the k-tec one is a good deal 'cos it's pretty expensive, so do you think that a custom made could give me at least 8whp? already got a Magnaflow exhaust system.

Thnx

 

[thedoc]

ebay - Item number: 4620448063

 

[Fred@BTM]

no chance in hell are you going to better the 182manifold

 

[Ricardinho]

what do you need to use from the manifold back if putting the 182's on the 172? 182 or 172 system, or custom?

 

[Fred@BTM]

172 system with a link pipe

 

[Ricardinho]

has anyone done it yet?

 

[BenR]

Why cant you better the 182 manifold, its better than the 172, but its most definately nowhere near 'great'.

And magnaflow!? are you in the states?

 

[Fred@BTM]

in terms of the cost Vs performance benjarmen

 

[BenR]

cost to us, or cost to customers?

 

[Fred@BTM]

£250 for a 182 manifold (hard to get hold of admittedly)

how much is a new designed one gonna be? at least £500 inc fitting (and that's a conservative estimate!)

 

[BenR]

If i were to make one, would probably end up around £700 for the manifold alone.

 

[Fred@BTM]

yeah, we've looked into it, but don't think its worth it

 

[Big Iain]

so can u buy these link pipes anywhere?

 

[Englebert]

I was thinking of getting k-tecs 182 manifold with sports cat but then noticed it costs £225+vat. That's like 5 hours of labour. Is it really that difficult to unfit/fit the manifold?

 

[BenR]

you have to drop the suframe

 

[Fred@BTM]

so can u buy these link pipes anywhere?

yep

all you have to do is ask

 

[MarkM]

If i were to make one, would probably end up around £700 for the manifold alone.

What would you hope to gain over a 182 manifold?

 

[Big Iain]

im askin lol, pm me prices if u like I know ur a busy guy.

 

[BenR]

What would you hope to gain over a 182 manifold?

A truely efficient manifold is built to enhance the engine it is being bolted to. It will only truely work for an engine to which it is designed.

Factors such as displacement, peak rpm, Peak torqure RPM, cam profiles, compression ratio, cylinder head specification and the engines average operating region.

So a manifold for a stock engine will be nowhere near good for one running 1500rpm more rpm and peak power is 1000rpm higher up. Its all about timing exhaust pulses exactly to generate a beneficial scavenging effect. However, any manifold will only be working spot on over a very narrow rpm range, so it needs to be decided where you want this 'peak' to be, and/or decide where you want the corresponding 'trough' to be.....as you will ALWAYS have a high and low point to deal with.

Even for a std engine, there should be another 5-7bhp and enhanced torque. But for a high specificaiton engine, the difference could be as much as 20bhp.

 

[MarkM]

Even for a std engine, there should be another 5-7bhp and enhanced torque. But for a high specificaiton engine, the difference could be as much as 20bhp.

Worth doing then.

How many manifolds would you have to design to cover different engine specs. Or would you just do a middle of the road one?

 

[Andy GDI]

i think testing would play a large part in propper development of it.... hence why there are not alot out there....