Thread: 3.9 v8 sports exhaust options

Originally Posted by Meccles

I fitted Perry extractors to the manual 3.5 in 1986. There was a noticeable difference in performance we had a steep hill to go up leaving house which prior to extractors we had to be in second. After they went on it would go up in 3rd. Same on other hills. No other change made. Currently running ceramic coated headers they’re cooler than cast manifold back into y piece then single 21/4” to muffler and resonator.

That is interesting, I would have though extractors would help only at high revs. Your feedback says they increase torque at lowest engine speeds. You didn't fit a torque cam at the same time ?

seeya,
Shane L.

When I fitted extractors nothing else was changed. Not cam, Carbys or Ignition. We picked up a gear going up hills. The big hill from bottom of Hasting St past Noosa pub used to be a second gear hill, it became a 3rd gear hill. Same as hill on way from Tewantin to Cooroy.

extractors with long secondaries increase torque( I've seen a dyno comparo using 35" secondaries), short or no secondary (4 to one) increase HP at top end

Some very interesting comments on here which suggests that what is being suggested by the O.P. may not see any gains in performance, indeed may result in a loss, unlike in some other vehicles, V8 Holdens, Fords etc where there are tried & tested "over the counter" systems which will show a gain.
Many years ago we owned a 351 Bronco, & I was going to fit extractors but was advised against because of heat issues, so I left the original manifolds on, just fitted a straight through muffler with bigger tail pipes,..probably no performance gain, but it sounded ok, looked ok too with chrome exhaust tips!
There's all sorts of funny things that can occur with exhausts, some of the V8 Holden/Ford systems I've seen that use extractors etc, still have the pipes joined at one point, usually just behind the gearbox, in a sort of cross piece, then resume with two pipes....something to do with back pressure?
So, in this case, unless a tried & tested system is available, I'd just fit a straight through muffler & a big bore tail pipe?
Pickles.

Originally Posted by Pickles2

So, in this case, unless a tried & tested system is available, I'd just fit a straight through muffler & a big bore tail pipe?
Pickles.

Its pretty crap honesty, only gain is noise volume. Everything else is a loss, less power, less torque worse fuel economy.
I wanna go back to stock pipes maybe with 4-2-1 extractors, otherwise stock without a resi for a bit of burble.
Cheers Jim

I just pulled the trigger on the system, the main reason is that the PO had done a bodgie hack job exhaust and on idle it banged against the body. It looked like he had used plumbing pipes. There is a massive amount of rust chunks coming off the cast manifolds and some leak out of the passenger side manifold.
I love the sound of the v8 and I believe that the only part not needing replacement is the driver side manifold. So I went for a complete replacement.
This is not a daily driver and will be used on club rego.
I'll try and get some photos on here when I get it delivered but my computer illiteracy is dismal.

Oh and my wife's D1 has a nice sounding system on it so I can't just follow her around in my quiet RRC, that would be a shame job.

Originally Posted by Pedro_The_Swift

extractors with long secondaries increase torque( I've seen a dyno comparo using 35" secondaries), short or no secondary (4 to one) increase HP at top end

Pedro do you remember the figures?
I was wanting to fit this system, photo attached. Not if its a waist of time though.

This was going to get bolted to a 3.9 which is getting dropped into an 89 Rangie