HKS Copy AE86 Cast Turbo Exhaust Manifold

Finally ditched the idea of using 1NZ-FE manifold and went with something that will just work. I found out from the measurements that while the second and third 4A-GE exhaust ports matched with the 1NZ-FE's, the first and fourth ports are spaced so wide that about 10-15% of the area will be blocked. It could be solved by grinding the manifold ports about 5mm to the sides but decided it's not worth the trouble. Here's what i meant.

With 4A-GE cylinder head exhaust port being smaller than 1NZ-FE's manifold ports, 35 vs 40mm, there's a bit more tolerance for port-to-port spacing. However, it only goes to an extent and caused the 1st and 4th port to be slightly eclipsed by the manifold shown by the shaded areas.

Decided that it's not worth risking the flow of the exhaust gas with the 1NZ-FE, i went with one that is actually for 4A-GEs. Ebay went to the rescue once again and just today i bought the infamous HKS copy cast turbo manifold for AE86 there, pictured above. They come with T25 flange which should fit my turbo perfectly. Somebody already did a good review on it and so i will just shamelessly copy it here.

Pros: Fits pretty decent, cast manifold, brutally reliable.. Top mount so everyone can see your cool turbo in ya face!! If you got the guts for it, you can put on a t25/t3 adapter and bolt up a t3/t4 and it can stick out the hood and you can make a functional hood scoop. :)

Cons: Top mount causes turbine housing to be too close to the brake booster where eventually the heat will shred the diaphram and cook the fluid in your brake booster YAY. Also causes the downpipe to have a sharp angle and its difficult to route a big downpipe with this setup. These were made originally to be on a right hand drive JDM car. Forces the oil return line to be pretty much right on the exhaust manifold.

Improvements: Angle the turbo slightly with the compressor pointed away from the block to get the downpipe and the turbine housing a bit of room away from the brake assembly. Angle the pipes downward to allow larger turbos to be mounted up without cooking the paint off the hood.

Verdict: Its a buy, it does what its supposed to do, just needs some cleanup as far as spacing and such. Actually its reported that the HKS and knockoff cast exhaust manifolds make some of the best hp around if you can just get the thing fabbed in correctly. I know a considerable amount of people who just gave up on the darn thing because it was hard to make a downpipe fit.

Glad with the fact that The Dog is RHD so the cons mentioning brake booster doesn't apply to me. The sharp angle downpipe still applies though. I already imagined that those Megasquirt relays on my firewall will have to be relocated.

This pic that i got from here shows you the downpipe angle view. Yup.. those relays will have to move somewhere else.

Just how exactly do you execute the suggested improvements mentioned above? Here's one way to do it, also taken from the same page.

With that purchased, a Blow-off Valve, turbo MAP sensor, intercooler and plumbing are next on the shopping list. I wonder if those Ebay universal intercooler piping kit has enough pipes for my Charmant?