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AT171 exhaust manifold question
May 6, 2010
Hey folks. I'm the proud owner of a 1992 Carina II (UK model) with 4AF engine. Would there be any better exhaust manifolds out there from other similar engines that'll fit my engine and let me free up a little bit of torque and power?

Thanks in advance:D

May 7, 2010#1
They make aftermarket tubular exhaust manifolds that could help out. Of course you have to balance that with appropriate modification on the intake side as well.

Not sure what availability or access to certain brands you have there - but most of the aftermarket ones I've seen for the 6th generation 4AF engine are also compatible with the 7th generation Corolla - as they also use the 4AF series of engines.

May 7, 2010#2
Who would "they" be, Toyota? I've seen a 4-2-1 Celica mani' on fleabay which I'm thinking about but I'm not sure it'll fit the exhaust outs exactly :s

I have a K&N panel filter (not listed for this car but for engine) but WOULD rather have better induction certainly; I've found the exhaust manifold 4-2-1 REALLY helped my 1993 1.6 Eunos Roadster out a lot with standard intake so I presume the same would be the same for the 4AF!

May 7, 2010#3
Some generations of Celicas had the 7AFE engine - who's exhaust manifold is very close, dimensionally, to a 4AFE engine. May not be a 100% bolt on swap (actual length is different, but flange bolt pattern matches), but has been done before. The Corollas 7AFE and 4AFE exhaust manifolds are interchangeable in a similar manner.

I didnt list any vendors - as I dont know which ones you are able to select from in the UK, thats why I mentioned aftermarket header from the 4A series of engine (4AGE, 4AFE) would be potential choices for your modifications. The OEM and aftermarket 4AGE exhaust manifolds are a popular mod to the 4AF engines - some modification is necessary to make the flange area fit.

Keep in mind that you will not see miraclous improvements in performance. Even here in the US, even with quality I/H/E (intake/header/exhaust) bolt on mods on the 4AFE - dyno plots have shown only 3-7HP gain. The major impediment being the cylinder head design and the OEM engine computer air/fuel and timing maps.

As for brands - lots of knock-offs out there, so be wary. Most find themselves through channels like eBay or similar. OBX is near infamous of being one of those knock-offs - sometimes you'll get a decent one, other times, you'll find shoddy workmanship (cracked welds, wrong bolt pattern, etc.)

Pacesetter is the only one that I know of specifically for a 6th gen Corolla. Option Racing and Matrix are two others that I know of, off the top of my head. There are quite a few others, sourced from the Philippines and Australia/NSW regions - that you might have better access than what we have here in the US.

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