Dump Pipes On R32 Gtr

[lows_13]

Is it worth while installing dump pipes on a R32 GTR RB26 motor?

Or just go a complete front pipe setup?

[itbmils]

I've used custom HKS style non-turbulace dumps on my GTR and I think I got ~25awkw from them - give or take

I'm currently running with R34 N1s (isn't everyone) and I'm getting a solid 300awkw @ 1.0 bar

[lows_13]

What mods do you have on your car to support that power figure?

Are split dump pipes better than single dump pipes?

[itbmils]

I bought my R32 GTR about 18 months ago - and it was clearly a 'renovators delight' - if you know what I mean. The engine was already tired (READ: rooted), but the body work and interior was/are in good shape. So I set about 'renovating'. I replaced the turbos and did a FULL engine rebuild about 6 months ago. This is what I did ....

forged pistons (Weisco – only one size over)

shot peened and balanced everything

ARP rod bolts

std rods (shot peened and balanced)

N1 water pump

N1 oil pump

N1 bearings

port and polished head

the non-turbulance dump pipes

3" (no cat) exhaust

R34 N1s

Apexi PFC

Apexi EBC

Tomei Adjustable CAM gears

Tomei fuel pump (about 130% over the std pump)

Tomei 1.2mm head gasket (yes – that's 1.2mm)

Tomei timing belt

SX fuel regulator

std GTR injectors (but no for much longer)

I have HKS 550cc injectors, RB25 AFMs and probably the Tomei CAMs on my radar for my next power upgrade - and I expect to see 350awkw when I'm done. I may also look at an upgraded FMIC to keep things nice an cooool.

If you have not figured it out yet - this rebuild cost me my left one, but it's a fairly conservative and solid build. I did a lot of research before starting, spoke to guys that have owned GTRs for a long time, and I spent a lot of time looking for a mechanic I could trust. The only thing I would change if I was doing it again would be to use forged rods and stronger head bolts. These items will limit me to around the 350awkw mark – which was kind of easy to get to by the way.

I'm happy to share all the gory details of my experiences if your interested

[hyper knight]

I bought my R32 GTR about 18 months ago - and it was clearly a 'renovators delight' - if you know what I mean. The engine was already tired (READ: rooted), but the body work and interior was/are in good shape. So I set about 'renovating'. I replaced the turbos and did a FULL engine rebuild about 6 months ago. This is what I did ....

forged pistons (Weisco – only one size over)

shot peened and balanced everything

ARP rod bolts

std rods (shot peened and balanced)

N1 water pump

N1 oil pump

N1 bearings

port and polished head

the non-turbulance dump pipes 

3" (no cat) exhaust

R34 N1s 

Apexi PFC

Apexi EBC

Tomei Adjustable CAM gears

Tomei fuel pump (about 130% over the std pump)

Tomei 1.2mm head gasket (yes – that's 1.2mm)

Tomei timing belt

SX fuel regulator

std GTR injectors (but no for much longer)

I have HKS 550cc injectors, RB25 AFMs and probably the Tomei CAMs on my radar for my next power upgrade - and I expect to see 350awkw when I'm done. I may also look at an upgraded FMIC to keep things nice an cooool.

If you have not figured it out yet - this rebuild cost me my left one, but it's a fairly conservative and solid build. I did a lot of research before starting, spoke to guys that have owned GTRs for a long time, and I spent a lot of time looking for a mechanic I could trust. The only thing I would change if I was doing it again would be to use forged rods and stronger head bolts. These items will limit me to around the 350awkw mark – which was kind of easy to get to by the way.

I'm happy to share all the gory details of my experiences if your interested

<{POST_SNAPBACK}>

if you dont mind could you PM me the price of that build? sounds exactly like the 26 I want to build...

[Gav]

I personally think that the best "bang for buck" is to get mild steel dumps and have them ceramic coated.

S/steel is not really needed as they're not prone to corrosion and not visible anyway.

Ceramic coating is recommended because these suckers get REALLY hot and they radiate heat to other underbonnet parts like a bastard. While you're at it, coat the terb exhaust housings and exhaust front pipes as well.

[lows_13]

Can you rap the dump pipes in that thermo rap stuff to

keep the heat down?

[Gav]

Can you rap the dump pipes in that thermo rap stuff to

keep the heat down?

<{POST_SNAPBACK}>

Sort of an awkward shape, but better than nothing I guess. That thermo wrap is still pretty expensive, however, and for the sake of (say) 50 bucks I'd get them coated inside and out - especially if you are doing the terb housings and front pipes at the same time.

[lows_13]

Whats this coating worth?

[Sydneykid]

The replacement split dumps are too short and don't have enough separation, you still get turbulance which affects the turbine response. The combined dump and engine pipe systems have sufficient separation to give a noticeably superior result, both more power and more importantly better response.

This is one of the most discussed subject on here, try a search for "split dumps" under my postings, those threads should tell you everything you need to know.

cheers:)

[lows_13]

So you reckon get dump pipes & front pipe at the same time for there to be significant difference.

[Sydneykid]

So you reckon get dump pipes & front pipe at the same time for there to be significant difference.

<{POST_SNAPBACK}>

Yes, at least 400 mm separation of the turbine and wastegate exhaust is required.

cheers

[lows_13]

Split dumps or normal dumps, in your opinion which is better for a 32 GTR?

[lwells]

Split dumps or normal dumps, in your opinion which is better for a 32 GTR?

<{POST_SNAPBACK}>

What SK is saying (and has said numerous times, as have others) is that split is better as long as the split length is sufficiently long at around 400mm. Too short and you start to get turbulence which negates any benefit of a split style dump.

The HKS style dumps are a comprised design. Basically they made them so you could just replace the original dumps and not worry about the front pipe. Because the OEM dumps aren't very long -- and HKS couldn't change their length without ruining their modularity -- the split is quite short. If you want a sufficiently long split you need to buy a dump+front pipe set.

[Beer Baron]

...like lucien has

C'mon lucien, i'm hanging to see your trust dumps before you put them on! i'll let you see anything of mine you want lol.

[Scooby]

Is it worth while installing dump pipes on a R32 GTR RB26 motor?

Or just go a complete front pipe setup?

<{POST_SNAPBACK}>

and a damn good question it is too. i started a thread ages ago on this issue, particularly wanting to know if anyone had comparable back to back dyno results. the answer as far as i could tell was no; not surprising given the stuffing about it would take to do a proper comparison and that people generally do turbos etc at the same time.

anyhow, the main dump pipe choice issues i encountered were;

most of us seem to agree that non standard dumps are better than stock, particularly if stock is R32 GTR. however there is no dyno evidence to support how much better ie why spend $600 on a 2nd hand set of HKS if they make only 3 or even 5 kw difference. anecdotal evidence ie seat of the pants exists to suggest they're better but i'd like to see figures.

most of us agree that long ie 400mm divorced w'gate style pipes are better (also see long post on here quoting Garret engineer on exhaust design and if you're keen get Corky Bell's book Maximum Boost) but again, no back to back dyno evidence. and this is where the $ really tell, because you won't get a set of these suckers for under about $1500. so we're back to square 1 ie yes it's better but how much/is it worth it.

custom exhaust specialists in bris do the short style dumps and engine pipes and claim 50hp atw (not 50kw as stated on thier web, Trevor confirmed this yesterday) which is quite a bit. they have been promising for 6 months to do a dyno test on an otherwise stock GTR fitted with the long style comp pipes they also do and hopefully it will happen this weekend. ring and ask, it might be the impetus they need to actually do it.

i reckon that those are the issues in a nutshell but in essence the thing that stops me from committing to a particular type is lack of test results. then again i can wait and have a set of R34 GTR dumps handy if i need them. if money is no object and you're in a hurry i'd say go the ces long style.

cheers

ps if anyone has back to back dyno test results please share.

[lows_13]

I'd like to see some dyno results as well. The normal dump pipes look quite large already as standard. If theres little difference maybe i should modify in a different area?

[lwells]

as far as i could tell was no; not surprising given the stuffing about it would take to do a proper comparison and that people generally do turbos etc at the same time.

Yes, its a bit much to ask for a private individual to change the dump/fronts and touch nothing else. There is, however, quite a lot of annecdotal evidence from RB20/25 owners that changing just the dump/front pipe can have quite large improvements. Obviously there are design differences between the two setups, but the basic principles are the same: freer air flow.

most of us seem to agree that non standard dumps are better than stock, particularly if stock is R32 GTR. however there is no dyno evidence to support how much better ie why spend $600 on a 2nd hand set of HKS if they make only 3 or even 5 kw difference. anecdotal evidence ie seat of the pants exists to suggest they're better but i'd like to see figures. 

Well, if you look at the standard dumps its pretty clear to see why they might be a flow restriction, particularly if you upgrade your turbos. Again, there is a lot of annecdotal evidence that comes from the proven gains from freer flowing exhausts on turbo cars and car manufacturers well known preference for restrictive designs to keep power, noise and pollution in check. Also, I would point out its not just about a peak kW here or there: I seem to recall (but can't find with the useless search function) SydneyKid stating that he found a 300RPM improvement in spool time by changing to a split dump setup (and I believe it was the only change).

you won't get a set of these suckers for under about $1500. so we're back to square 1 ie yes it's better but how much/is it worth it.

More like $1200-1300 for the Graddy/Trusts. The CES 'competition pipes' are in the same ballpark IIRC, but more for stainless.

Anyway, that's all a long winded way of saying I'd love to see some dyno evidence too, but I think there is enough circumstantial evidence to say they are a worthwhile investment.

Richard: Sorry, I saw your post in The Mafia's thread but didn't get around to replying. I have the pipes sitting next to me, at the end of my bed I'll take some decent photos shortly, and you're welcome to inspect if you want. Give me a couple days as my honors thesis is due on Friday.

[Beer Baron]

mate, i would love to come and have a look at them before you whack them on. any time is fine.

[shaqrx3]

I would recommend the trust MX dump pipe and front pipe kit. It will cost around $1400, But it is the best design I have seen. The dump pipes are split and about twice the length of HKS ect with a shorter front pipe. These are the ducks nuts.