Port and Polish or Extractors

[moover]

Has anyone tried/evaluated doing a port and polish. If so what were the results like. Alternatively has anyone added extractors to a 2.8 4jb1?

I am currently replacing my dead 2.8 and will be doing the 3" exhaust (Turbo Back), bighorn turbo and intercooler, losing the EGR setup, adding a snorkel, enlarging air intake from the filter and changing to a free flow filter (probably a K&N), then doing a dyno and fuel adjustment. Just thinking that a port and polish would add that little extra or possibly headers. Has anyone done this, did it produce, ?

[mulover]

I dont think you would have enough room of extractors in there but even if you made a free flowing manifold out of steam pipe bends (which are really tight radius, have thought about this myself) it would probably make an improvement, would be a bit of work though, but if you have the motor right out anyways then why not!!

[geeves]

True headers are not realy an option with turbos although some high performance cars do have much better flowing exhausts than factory. I suspect if you had somthing custom made it would cost far more than the gains are worth.
Port and polish sounds a good idea but be carefull There is not a lot of thickness in the casting and if you make it too thin It could be all over. A light polish shouldnt hurt but I suspect you will be the first to ever try it.
All the other mods are well worth doing.

[moover]

I have been doing a little research and have found this info turbonation.com/header.htm
The page details how to build a header for a turbo quite well and I will use it to build one. And then later use it as a prototype for a stainless one. Mean time does anyone know where I can get ceramic coating done.

[geeves]

My fater in law has had 2 exhaust manifolds done by a crowd in Auckland Ill email him for info.
Its not a true ceramic but is applied in a kiln and on one of the cars still looks new after 12 years. The other car was only finished 2 years ago

[geeves]

This is the reply from my fater in law.
HPC (High Performace Coatings) in Onehuinga>? is the outfit - they advertise in
NZCC, Petrolhead and a load of other places

[moover]

Thanks I'll give HPC a call. Been doing a lot of reading and am now convinced on the headers High Flow exhaust) , just need to get down to it. Will post photos when they're done.

[moover]

Just got the motor back together. The Head has had a port mainly on the exhaust side as it has a large lip on that side. Otherwise just a polish up. That comdined with the addition of Intercooler, Snorkel, K&N filter and the 2.5" exhaust on monday should see a sizeable increase in performance. Ran out of time for the extractors so they'll have to wait for a rainy day however they are possible and the evidence suggests another 15-25hp gain. Not straight forward I will admit though as it requires moving the AC line.

[Jimmu]

Extractors with a decent merg collector made an extra 25hp on my mates 2J powered 180SX.
(Which I think is now the fastest street legal 180 in the country...) I would be pleasantly suprised if they would make anywhere near that differene on a 4JB1T.

I will see if I can get a picture of the collector setup that he had made. The pipes come together to an almost razor sharp edge. It did cost some serious coin though.

I reckon the dump pipe would be the biggest restrictor in my exhaust now and I would like to fit a better one.

I am interested to see how you go with it.

Jimmy.

[Graham]

If the factory exhaust manifold is bad enough then 25 hp or more is possible, but as you say, I couldn't see the factory manifold being that bad.

[superturbocompound]

there are two type of exhaust extractors,one is call a log and the other extractors/headers,from the feed back i got from various 4jb1t modders,they said that there is no difference from the stock log to the extractors, maybe there is,maybe not, but i know that when i removed my stock exhaust, there is some restriction from the extra material that potrudes in to the exhaust pipe for the 4 studs to mount the turbo.from a performance point,extractors are always benificial in a way that they seperate the out going exhaust from the individual cyclinders and prevent other exhaust cycle obtructing each other,but then again because the 4jb1t cam timing is so mild that the over lap between cyclinder in minimal so obtruction is also minimal.i have noticed that high powered petrol engine do benefit from long exractors because of the long duration and this is done to improve pulse and reduce reversion,however in diesels in my opinion is, have extractors but short as possible.