Extractors for 20v silvertop

[quicklvn]

Im thinking of putting some custom extractors on my 20v Silvertop. I have a 2 1/4" exhaust to bolt them up to.

I was just wondering what is the maximum sized pipe I could use for the extractors as it is going to be a 4 to 1 set up. I've heard there are certain 'rules' as to the size of the pipe you can use for the extractors based on the size of your exhaust pipe.

Any help will be good.

Cheers

[Lanius]

Waste of money imo. The factory 20 valve extractors are pretty damn good, and you'd have to spend a fair bit of money to get anything better in there. Even then, you'll find minimal gain for the cost involved. There are other places you could spend the money for more gain (put your car on a diet, tyres, suspension, brakes etc).

Of course, if you've already modified everything else on the car, and extractors are the only remaining piece to be upgraded, then go for gold

[quicklvn]

The extractors are going to be made by a friend who is an engineer and has just done some for his 400ci V8 , I was also thinking of getting a blacktop head to replace my silver top. Is there any mods to be made with that? cost involved and power gains?

[Stealer Of Souls]

Considered make a dual length system?
Complex. But has some very distinct advantages...
Plenty of modern cars are starting to use them...

[Lanius]

Would be cheaper / easier to just buy a blacktop and install it.

Fair enough to get your friend to make the extractors, at least you'll get them for a good price. Just make sure to keep a hold of your factory extractors in case you're not happy with the new ones

Don't forget that 4-1 extractors tend to encourage torque at the top end of your revs, while 4-2-1's are aimed more at the bottom to mid range revs. The result will be a bit more pull when you ring it out pulling onto onramps, or dropping into third on the motorway, but less when driving around town or in traffic.

[KinLoud]

4 into 1 = a bit more top end but less midrange torque!
Lord knows the silvertop needs more midrange torque not less!!

Think about doing what I did when I put a 3sge into my racecar (AA63 rwd Carina).
I got it made as a 4:2:1 with slip joints so I could either:
- extend pimaries
- extend secondaries
- go 4 into 1
This means that if I want to I can tune my exhaust to suit any mods I do to the engine without the mains expense/effort of getting everything remade.

Made by Action Dan in steel then HPC ceramics coated.

Ken
Ham
021 408 863

[AceSniper]

best you could prolly get with out spending ages with R&D is put some blacktop 4-2's on and then re make the 2-1 same length... just better(no squish)

Blacktop head can go on but you would wanna run blacktop pistons aswell, or measure the combustion chamber volumes between silvertop and blacktop an try to get the blacktop close to the volume of silvertop (if you can safly skim that much off)

[quicklvn]

ok i'm looking at buying some blacktop extractors now, do they bolt staight on or is there customising to be done?

[AceSniper]

they bolt on, but if you have the time re-pipe the 2-1's that go over the cross member

[neo]

Damn, there some preddddddy extractors Ken!

[quicklvn]

If I put these new blacktop extractors on can I expect any noticable power increase or is it not really worth it? Cause if its not gonna do much then I probably won't bother.

[ROBODISCO_20v]

A popular mod to do in ozzy on the silvertops is just extend the secondaries. The top half seems to be good enough.

[Crampy]

I've seen in the latest NZPC mag some extrators and prices for various cars. The 20V 4AGE ones were $1000