Thread: 3.9l Extractors...gains worth it?

Originally Posted by Rezley

G'Day All,
My 97 S1 seems to become quite asmatic above 3500-4000rpm. It completely standard but Im considering getting a set of aftermarket extractors for it.

Is there noticable gains to be had in the way of more power, free-er revving engine and better fuel economy or am I wasting my $'s if my std manifolds are still servicable?

Any opinions would be good.

Cheers,

Definately leave the manifolds alone. You would be better off changing cams and port matching etc than fitting headers. The EFI manifolds flow plenty enough for a 3.9, even cammed and chipped they are still OK.
Have you had a decent tune by someone who knows these engines yet? Ignition timing is important(10 Deg BTDC is a good start) and also check that the distributor mech advance isn't siezed. This will make these engines flat and unrevable, and is a fairly common problem.
IF you go for headers, HM make a good set for the D1, by far the best quality for the $ I have seen, and the ports are very well finished too.

JC

Originally Posted by Rezley

G'Day All,
My 97 S1 seems to become quite asmatic above 3500-4000rpm. It completely standard but Im considering getting a set of aftermarket extractors for it.

Is there noticable gains to be had in the way of more power, free-er revving engine and better fuel economy or am I wasting my $'s if my std manifolds are still servicable?

Any opinions would be good.

Cheers,

something is wrong with your tuning,
i have a 95 3.9 auto and foot flat it runs past 6000 [which isn't on the tacho] every time,
have a look at your tuning.
don't **** with the factory manifolds, they work.

and if you were to go with weeant extractors that don't do anything for your money, you will be weeded off with the extra noise from under the bonnet.

Originally Posted by Rezley

G'Day All,
My 97 S1 seems to become quite asthmatic above 3500-4000rpm. ....

Any opinions would be good.

If I was to pick on anything to cause this ... Exhaust wise ... It would be the catalytic converters ... & / or the internal condition of the muffler

Mike

Originally Posted by mike 90 RR

If I was to pick on anything to cause this ... Exhaust wise ... It would be the catalytic converters ... & / or the internal condition of the muffler

Mike

No Cats on our D1's Mike, but yes the main muffler on these has been known to drop baffles etc...

JC

I fitted Hurricane extractors to mine, mainly cause I had the opportunity to when the heads were off and because the manifold studs were had it on mine thanks to previous maintenance (rough mechanics)

Didn't really chance my performance for good or bad, but made it sound a teeny bit better. Anyhow, I have this deep down desire to build an angry sounding engine for it at some stage, so I guess I've saved myself the hassle of doing the exhaust leading up to it.

Thank you to all for the replies. Looks like you've saved me $450-500 which I'll now put towards a decent tune up.
Nothing beats personal experience.

Cheers

Originally Posted by justinc

No Cats on our D1's Mike, but yes the main muffler on these has been known to drop baffles etc...

JC

I have been quite surprised about the "No Cats" fitted on the early unleaded models ... As I am use to seeing them on "other brands" that use this fuel (example ... Ford EA 1988)

My understanding on the concept of the cats, is to super-heat the exhaust and burn off excess fuel & gases ... so they get rid of the rotten egg smell & to also help meet the emission's standards /// and for such thirsty engines, They met the standards without cats?? ..... ....


and Yep ... I know of a couple of folks, in the past, that have had restrictions of the exhaust system due to the baffle coming loose and blocking the exhaust passage

Mike

i had an outstanding result on my 4.0L carburetted V8 with a set of extractors.
post fitment and rejetting of the carby's to suit, my 25yr old 110 had a new lease of life, then i had the gearbox rebuilt!!!