Jump to content
SAU Community

Recommended Posts

hi looking at upgrading my exhaust manifold and wanting some advise form people who have. ive upgraded the turbo to a 500ps unit and it sits on the standard mani with a custom twin dump/front pipe. So if anyone can tell me were to get a good manifold that locates back to the stock turbo position would be great. also the gains they have got from doing it . what is the most hp a stock manifold on a rb25 can support?

cheers guys

hi looking at upgrading my exhaust manifold and wanting some advise form people who have. ive upgraded the turbo to a 500ps unit and it sits on the standard mani with a custom twin dump/front pipe. So if anyone can tell me were to get a good manifold that locates back to the stock turbo position would be great. also the gains they have got from doing it . what is the most hp a stock manifold on a rb25 can support?

cheers guys

Hi i can have made for you a custom exhaust manifold in stainless steal,but its expensive.i all so can supply plenium kits and inlets for rb20,25,30.contact me at

[email protected].I can send pics of all item.good kw gains

cheers steve k

I have one of those china manifolds and they look good dunno if it makes more power but,I guess I'll find out soon :wassup:

Here's some pics of mine

China power 1

China power 2

China power 3

China power 4

I have got one like r31 power's to slap on my rb25 but i have to say it doesn't really look like any sort of improvment maybe even more restrictive then the stock log. It wouldn't really suprise me if people with these things are loosing power....but they look pritty from above. :headspin:

Live and learn i guess but i would be going for something custom next time round or a jap one and not a cheap pre-fab thing.

John

r31 power;

cool let me know how it goes. might be ok because i think there trying to replica a hks. someone was telling me they have problems with them leeking and cracking when getting real hot. thanks for the pics. Did you order it from the site, how long did it take and what was the total cost after shipping?

cheers.

The reports I'm getting about these chinese manifolds via anecdotes is that work better than you'd expect and they are stronger than what you've heard about SS manifolds.

Some grinding is needed to get them to fit but nothing a competant shop can't work out.

T.

Have you ever noticed that these spaghetti leg fabed manifiolds (the locally made ones) look like a nest of snakes ? I have to wonder if the contorted angles that some of the tubes use when they reach the collector are much good . Some US designs merge the primaries into a single tube which then feeds the turbo , the WRC engines seem to do this too . At least then the primaries are facing the desired direction and not wasting gas velocily and heat energy trying to oxy the collector off . On a six cylinder engine I recon the split pulse (123,456) would be easier to produce (than spaghetti special) and give better response and less reversion , also access to the turbo is better .

HKS do cast iron manifolds for RB20/25/26 (single turbo) which are along these lines and usually have provision for an external waste gate . If you can find one of these it would have the advantage of cast iron (less chance of cracking/warping) a guaranteed fit and the opportunity to use a higher performance waste gate system later if you need to . Also if you can do this part for reasonable money it has the potential to open a lot doors to future upgrades . Its no problem to make a cover plate for the external gate mount if you need to use an integral one for cost or cop reasons . You'll stand a better chance of convincing Joe average Wood Duck that its factory rather than the scaffold and ****y poo custom job .

Just my two paseos worth , cheers A .

The reports I'm getting about these chinese manifolds via anecdotes is that work better than you'd expect and they are stronger than what you've heard about SS manifolds.

Some grinding is needed to get them to fit but nothing a competant shop can't work out.

T.

This is good news for me... i was starting to think i'd wasted my money. :D

Now this grinding? where? is there much of it to be done. i have just got my head back and have not test fit it yet.

Also discopotato yes i know there are some horrible aussie custom ones floating around and like you said aussie ones tend to favour the long runner equal length design. I think i saw a few threads on the short runner jap manifolds vs aussie ones on here and performance forums ages ago.

John

ive got one those chinese manifolds, power has gone from 212rwkws at 17.5psi to 224 rwkws at 17.5psi, you be the judge.

Carl,

People also report a much nicer sound and more throttle response. Do you get this?

I love a car that leaps off the line and goes from 60-80-100 in a jump.

T.

Its good to hear people are getting good results from these.

I haven't even got my one on the head yet so i have no practical knowage of how they work in the real world yet.

Its just I was a little bit dissapointed in the clean-up & weld quality inside the runners on my one but if it works. :cooldance:

I will have my engine back together in a week or two so i'll let you guys know how it goes.

John

PS thats a nice markup they are putting on those at autobarn. :uhh:

Has anyone thought about an R31 GTSR original or better copy? To look at they are a damn sight prettier, and normally of it looks right then it works right.

My 2c is no matter which manifold you get, wrap it up in it jammies:) Mine is ceramic coated and it works ok but under bonnet temps still go through the roof, so when i get the car back ill be giving it a once over with high temp exhaust wrap. That and brace the turbo up off the head so that the thin walled 800deg C exhaust isnt relied upon to support the weight of the turbo

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Similar Content

  • Latest Posts

    • No intention of driving the car the way it's set up now, just wanting to make sure I haven't made any mistakes along the way so that the tune can go smoothly, I don't want to waste anyone's time with stupid issues. And of course I intend to get it towed to the dyno in a completed state 😅 I have the base fuel pressure with the vacuum disconnected set at about 40psi, which I believe is at least relatively close to stock fuel pressure, maybe I'll have a fiddle with the reg and see what happens. For all I know I could be wasting my time with this and I should just plumb it in and see what the tuner reckons. I just find it a bit strange that it seems to be under so much load just free revving, but maybe that's just a result of the turbo slowing down the exhaust gasses and making a restriction in the flow, with no boost to compensate.
    • The boy just hit up google translate and it worked a treat, he said step one was "please urinate with precision and elegance", he then sent me the correct translation  I get some new loctite for the small fixtures tomorrow and get some "dort" going after that 🤣
    • Right, so is the fuel pressure the same as it was previously? If not, well, it's not going to work well. I can understand the theory I assume you are going for, which is: "Run it N/A, and if I have the original AFM, and same amount of fuel and intake air as previously, the fact there's a turbo in my exhaust should still make it run" Which it... might? Provided you don't actually change how much air or fuel is going into the car.. or getting out. But if you have changed that, all bets are off. What is the purpose to even have the car run this way? To get it to a tuner? And if the goal is to limp it to a tuner, you're still going to what - plumb up a whole intercooler system and new intake in the parking lot out front before your tune......?
    • Haha yea it's a bit of a weird setup at the moment, just wanted to make sure I sorted out any headaches before dyno day. At the moment I've changed the exhaust manifold, turbo and downpipe, 460lph fuel pump and rising rate reg as well as the previously mentioned headstuds and gasket. The nistune was already mapped for the car as it was and drove around for a few months no worries. The plan is to run flex fuel hence the big pump, which I've wired direct to the battery through a relay to avoid voltage issues.
    • Um. Was the ECU the same as the one previously there? I know R33's needed R32 GTST ECU's or other tomfoolery to run Nistune. This is such a wild setup. Most people would plumb in the turbo then not drive the car (i.e tow it to a tuner). What's actually changed since it last ran?
×
×
  • Create New...