Decent set of AE86 headers ??

[touge_ae101]

Wow those are really good gains! our current fgk headers are 41mm primaries all the way through and 45mm secondaries. hopefully the step in the primaries and having a tuned length should gain us 2-3kw and a beefed up mid range.

geez that is good gains from increasing exhaust size! I think it would be worth trying to see if we can break 140kw atw on a standard engine with cams.., ill have a look into making a New exhaust before it goes on the dyno.

[1I1]

I think it would be worth trying to see if we can break 140kw atw on a standard engine with cams..,

That runs over 12:1 CR!

[touge_ae101]

I think it would be worth trying to see if we can break 140kw atw on a standard engine with cams..,

That runs over 12:1 CR!

Still standard pistons, rods, block and head though.. nothing a bit of machining/too many rebuilds by people who don't know what they are doing can't achieve!

[Flannelman]

Haven't a picture of first dyno, but it was 78kW STOCK headers with 2 1/2 exhaust AFTER the factory crush, with a single resonator in the center.

http://i591.photobucket.com/albums/ss35 ... 004AGE.gif

RED line is FGK header, 1 3/4in primary, 2in secondary and 2 1/2 after the merge and straight through to the muffler, with 2in outlet
BLUE line is above, muffler replaced with straight 2 1/2in pipe

This is on a ST 20V, dyno dynamics dyno. Same setup recorded 98kW in palmy

[jondee86]

Dragging this back to life as I just realised that I never posted anything about the
setup that I finally finished up with. So here are some pics...









I had the headers ceramic coated to keep them looking tidy and to try and reduce
the amount of heat that reaches the CAS. Seems to do a good job as the CAS does
not get as hot as it did with the OEM cast manifold, and underhood temps feel to
be quite a bit lower when I pop the hood after a drive.

There is a flexi in its own flanged section and then a 60 dia s/s over-axle exhaust
with the obligatory cannon muffler. The muffler says Apexi brand and it came off
a Jap import. Kind of loud when you get on it, but not too bad if you take it easy.

Can't really comment on the performance as there were a lot of changes to the car
around the time the exhaust was built. It's the standard MacBilt rally proven design
upgraded with proper merges and a couple of small changes that I requested. Mac
says that the header was dyno-proven to be good for 10hp on a 4AGE and I have
no complaints. Previous 50 dia system seemed to be a bit restrictive at high rpm
whereas this one works great at all rpm's

Cheers... jondee86

[Flannelman]

As an experiment, I changed the lower section of the FGK headers to this.

Its up from 1 3/4in to a short 2in joining into a 3in collector. Its short and designed for higher RPM.

It is backed up by a 3in exhaust. Home made, flared joins for strength.


I also decided to have a go at building a muffler. It looks like this.


Dyno time came. So did the disappointment...


As Dyno Man Mike called it before the engine was let loose on the the rollers, Flowmaster or any similarly designed mufflers KILL power. He has seen a 3in flowmaster kill as much as 30kW on a turbo powered car. In my case, 13kW at peak with lots of mid range gone too. The lower speed level I will put down to the shorter header but I will be building a straight pipe and chasing this up. I can also flow test the muffler and straight pipe for a validated restriction too.

No, not AE86 headers but lessons are there for those willing to apply the knowledge being shared.

[jondee86]

The factors that allow a muffler to stop noise getting out the exhaust are also the
factors that create resistance to flow. So generally speaking, any muffler that makes
your car quiet will hurt power. Or putting it another way, performance mufflers (that
are usually of the straight thru design) will make your car LOUD

Abrupt changes in cross sectional area/gas velocity and sharp changes in direction
cause resistance to flow (back pressure) which hurts power. Building/tuning a decent
muffler for a stationary engine that runs at a constant rpm is easy, but doing the same
for a car engine that operates over a wide range of speeds is far more difficult. That
is one of the reasons the cheap holden mufflers I used (instead of the hugely expensive
OEM Toyota mufflers) sounded like crap.



I personally like this Magnaflow design which looks as so it should stop the fiberglass
absorbtion material from getting blown out in a hurry. But good luck with building a
better mouse trap I can see what you were trying to do, and with a few hundred
hours of dyno time and dozens of prototypes, you may get it to work.

Cheers... jondee86

[1I1]

When deciding to change the rear muffler on my Corolla I spent a lot of time researching options and ended up with a Magnaflow muffler like you've posted John. It is an offset inlet and centre outlet one. There is a good little promo vid by them explaining how their muffler can flow as good as a straight piece of pipe while still being able to absorb noise.

Seems to flow just as good as the straight pipe - while we never did back to back dyno tests, going off the AFR's when road tuning I believe it was pretty damn good.

This is on a 20v with 2.5" piping, two straight through resonators and the Magnaflow muffler. I have more issues with road noise than I do with exhaust noise when driving normally around town or sitting at 100km/h in the country. Factor in with the straight pipe instead of the muffler the car is heard on the old club section of Taupo circuit when standing in the new pits.