Low Mount Manifold Options

[wolverine]

Yup, but common for them to be re-drilled/tapped to t3.

They came from HKS with pre-drilled stud holes for T3 or T4 afaik.

They are divided.

A GT30/GT35 sized turbo may fowl slightly on the engine mount but a small shave of that is easy enough if necessary.

If you want to use a split turbine housing then they are a good low mount option.

[1400r]

looks only T4 to me

same as the one I had

http://www.skylinesaustralia.com/forums/uploads/post-14974-1151368811.jpg

[Mick_o]

Id say keep the stock manifold for the best response as the shorter runners will simply get the gas to the turbo faster. For the power you're looking to make ya pissing ya money up the wall on headers. I made 336kw on the stock manifold and it was the sweetest RB25 setup you could hope to drive especially for the money spent and being a basic bolt on..

[Mick_o]

Wolverine had a T3 on his car with a 3076 strapped to it

looks only T4 to me

same as the one I had

http://www.skylinesaustralia.com/forums/uploads/post-14974-1151368811.jpg

[Griffin]

The reasons i put a 25 manifold on 26 are: cost ie nothing, just a few hours on a rainy Sunday, turbo placement. The one in using doesn't need a spacer plate, standard heat shield bolts up, hard to find a cast his manifold at the time, and to prove a point. And also cost. It was cheap

[scotty nm35]

This was pretty much my point

I understand your point entirely.

My point is, I make manifolds, dumps and exhausts for a living, and I would simply use the stock manifold for the power you are chasing. If you wanted 400+ I would be steering you towards a HKS or steampipe. Take my advice or not, it won't be keeping me awake at night.

There are always gains to be made, I agree, but it comes down to cost per KW, and manifolds usually add so much cost, not just in buying the manifold, but fitting challenges with highmount setups, compromised angles on the dump bends, wastegate challenges... Remember, I have fitted all types of manifolds before, including twin gate split 6Boost setups, they never install as easily as you would expect.

Here is my favorite RB setup which had it's own challenges. Wasn't cheap either, but the results were great. If you plan to head down that path, find a decent fabricator first, then speak to a few manifold suppliers. Some are more approachable than others.

[wolverine]

Another attraction of the HKS cast manifold is that it is a true low mount (as opposed to stock sidemount) so pipework from the turbine outlet isn't convoluted like top mounts. However there is a cost in fabricating everything to fit and you need to weigh it up.

[Philr32]

I understand your point entirely.

My point is, I make manifolds, dumps and exhausts for a living, and I would simply use the stock manifold for the power you are chasing. If you wanted 400+ I would be steering you towards a HKS or steampipe. Take my advice or not, it won't be keeping me awake at night.

There are always gains to be made, I agree, but it comes down to cost per KW, and manifolds usually add so much cost, not just in buying the manifold, but fitting challenges with highmount setups, compromised angles on the dump bends, wastegate challenges... Remember, I have fitted all types of manifolds before, including twin gate split 6Boost setups, they never install as easily as you would expect.

Here is my favorite RB setup which had it's own challenges. Wasn't cheap either, but the results were great. If you plan to head down that path, find a decent fabricator first, then speak to a few manifold suppliers. Some are more approachable than others.

That setup looks awesome! I understand the value may not be there but I would still like to look into a manifold for later (who knows I'll probably get 350kW then want more). My goal is not outright power, it's torque, drivability etc in good package. The exhaust manifold isn't high on my priority list but I like to do research.

Thanks for the help and advice

[Griffin]

Just put up some pics of my setup for those interested , dunno how to put link up.

[discopotato03]

Actually I think the HKS single cast manifolds were intended for RB20s or RB26s , the cracked one in the pic above looks like an RB26 one and they were all twin outlet T4 mounting pad . The other one was twin outlet with the T3 stud pattern but the pad section is large enough to take a T4 flange and stud pattern .

Original kits had a TA45S for the RB26 and AFAIK a T04E for the RB20 with an O trim turbine and a HKS unique turbine housing .

Possible best case for RB25 is the HKS RB26 manifold if you can get around the different head side stud pattern . These mount the turbo back further and were intended to allow for a reasonably big compressor housing .

Honestly I think the std manifold is way to go unless you have lots of thousands to throw at ideal situations . Hard to argue that a stocky with an IW GTX3071R making 330 plus wasps at the bags is average . Had its 0.82 housing had a Scotty mount 45-50mm external gate on it probably more and with mild cams more again .

With a little effort an IW GT30 hides quite well under the std plumbing , Scotty inlet , and provided you weren't being a moron if the cops bust you about as standard looking as 330 plus gets to look . Affordability , manifolds free isn't it .

A .

[Dale FZ1]

There's no easy or right or wrong answer to the OP's question.

The idea of keeping with the OEM RB25 cast manifold has some benefits, particularly with road-only use where the whole setup never really gets the sort of thermal belting that happens with a race-only setup. Nobody can claim that the OEM manifold makes for an easy or quick process of checking for tight fasteners or (worse) removing the turbo. Normal people couldn't afford the cost associated with paying for a decent mechanic's time.

I grew sick of the difficulties of getting a spanner onto all the fasteners around the manifold and turbo. Trying out the high mount setup at least makes the process of spanner checking all those points much simpler.

And that is the rub for me - I accept Scott's comments about the ability to make power with the right bits attached. But does the ability to check and maintain things count for the OP? I accept Troy's comments about delivery. Does that count for the OP?

Not many things come for free, but if some outcomes are high priority, it can become money well spent.

[KiwiRS4T]

There's no easy or right or wrong answer to the OP's question.

The idea of keeping with the OEM RB25 cast manifold has some benefits, particularly with road-only use where the whole setup never really gets the sort of thermal belting that happens with a race-only setup. Nobody can claim that the OEM manifold makes for an easy or quick process of checking for tight fasteners or (worse) removing the turbo. Normal people couldn't afford the cost associated with paying for a decent mechanic's time.

I grew sick of the difficulties of getting a spanner onto all the fasteners around the manifold and turbo. Trying out the high mount setup at least makes the process of spanner checking all those points much simpler.

And that is the rub for me - I accept Scott's comments about the ability to make power with the right bits attached. But does the ability to check and maintain things count for the OP? I accept Troy's comments about delivery. Does that count for the OP?

Not many things come for free, but if some outcomes are high priority, it can become money well spent.

OP is not looking for a high mount.

[Dale FZ1]

So I see...

Those pics posted up by Callan look like a pretty setup, but don't appear to improve serviceability. Low mount fabricated manifold is difficult to give a rational thumbs up.

If it's just for appearance or to satisfy a personal whim then good luck to the OP. If the aim is to get honest, experience based opinion for low mount and low key appearance then I would follow Mick-o's lead.

[scotty nm35]

With a 3/8 short extension on a long socket, the stock manifold I did the other day was on in about 5 minutes. There is only one nut under the flange I couldn't quite tighten, one turn with the spanner it was done. I don't understand what you mean about it being hard...

The manifold I removed to re-fit the stock one required me to take the rocker cover off, and cut down a spanner, took me over 2 hours to just remove it. It had taken all day to fit, cutting down studs etc, and left bugger all room for a dump and screamer. The 34 has a fair amount of crap in the way compared to a track 32 with no heater of course.

[discopotato03]

Guys for the record Hazet do double ended ring spanners that are sometimes a god send for working around manifold and turbo mounting studs/nuts . I bought a set from Sydney Tools and for pulling apart the old Subie RX Turbos custom manifold and turbo system - super bitch trust me - made it quite easy .

These double ended rings are offset horizontally and let you into places a normal flat ring spanner won't . The ring sections are thin walled compared to some garbage spanners and the shanks not too long .

The part number for the set is 610N/8RS so have a look at them . Not cheap for what they are but if you're doing this kind of stuff all the time then time and knuckles is what you stand to save .

Thoughts Scotty , cheers Adrian .

[Dale FZ1]

There is no doubting the benefit of experience, and having the correct/best tools for the job. Sometimes that includes having one particular spanner modified to get to that one particular fastener.

Running a HKS Pro S IW housing with a custom dump pipe, I frequently found that one turbine flange nut, and two dump flange nuts gave grief during fitup. Generally, having a second set of hands around proved a bonus for this novice. But it still takes time and causes strain on the lower back while leaning into/over the engine bay. The cast manifold was never a real issue to fit/remove because nothing was hanging off it and access was good.

Going over things for pre-event spanner checks while everything is fitted up is the time consuming PITA that I commented about. Not much point leaving 2 or 3 because they're difficult and patience runs thin.

I never had any complaint about how that setup actually performed. Retaining stock heat shielding was another bonus and cost saver.

Perhaps the OP might verbalise what application his car is being used for.

[discopotato03]

By the way that Rajab above was some sort of auto correct . Not out to offend anyone .

[Ben C34]

God forgives.

[scotty nm35]

lol.

All hail Rajab, king of the RB's.

I have about 100 spanners of different sizes and shapes. Some I have modified for particular tasks and some just work perfectly from the shop. The long double ended offset ring spanners are one of my favorite sets, I bought the Snap-on kit after I worked out the KC set was so good.

Retaining stock heat shielding was another bonus and cost saver.

This is the best part of keeping the stock manifold. Nothing beats the stock heatshield, and it is so tight against the engine that i can fabricate dumps and screamer pipes with ease, mount wastegates and still get my hand down there to tighten loose bolts.

I fitted all the water and oil lines/drains after fitting the turbo and exhaust on the 34. I wish all cars had that much room.

[Missileman]

There is no doubting the benefit of experience, and having the correct/best tools for the job. Sometimes that includes having one particular spanner modified to get to that one particular fastener.

Yeah so true, having a selection of rings with different offsets is a must, and still occasionally you have to modify one, turbo out to dump bolts is reoccurring theme...

Edited May 10, 2014 by Missileman