To 30/26 Or Keep The 26?

[XKLABA]

I dont know how quickly the guy plans on upgrading the turbo, but a customs from Unigroup, also a member on here, is planning to upgrade his T04Z to a 6766. It sounds like he will be running the same turbo as ours only it will be a 26 versus a dirty 30 with a 25 head.

Hopefully he does it some time soon so i will see if i can get a dyno graph of the 2 cars to compare the difference in power and torque

That would be great, I am going to post up the difference from 2.6 with-7s against 3.0 with GT-RSs, my car gets dropped off next Wednesday arvo for mapping and tune

[sky30]

Mine was from a guy on the forums that used to make them, came with bolts etc.

i cant see how people can charge $800 for a laser cut piece of 10mm steel with holes tapped in, i thought $450 was expensive.

[C4a0s]

actually this would be interesting... all mods equal...see which is quicker and faster

[GTRNUR]

That would be great, I am going to post up the difference from 2.6 with-7s against 3.0 with GT-RSs, my car gets dropped off next Wednesday arvo for mapping and tune

Based on my experiences with GT-RS's on the street with stock gearing, RB26's they come on (achieve full wastegate boost, say 1.7kg/cm) at 5500, RB30's at 5000, and my RB315 was 4500 RPM.

Loading up in the dyno is pretty pointless for comparison purposes. I managed 2kg/cm at 4000 RPM doing this, but you could never get that kind of response on the street as you would drive past 4000 RPM before the turbo's could spin up.

[discopotato03]

Sydneys Kid once said to me that an RB30 is the first think he'd do to a GTR and I tend to agree though I'd probably opt for an RB32 or 34 . A pre loved - thrashed GTR - probably needs an engine by now and 30s don't appear to be any more expensive to do than 26s - yair ok the plate ...

Straight away RB34 is going to make stupid torque at low to medium revs compared to a 26 even with cock ups like low static CRs . That sort of capacity is not going to need big revs or boost to make very adequate performance . Turbocharging becomes very easy when there's lots of off boost torque because you haven't got to worry about the age old boost soon cause it feels like a 120Y ATM .

I would have thought it obvious that anything that comes on boost at mid revs and goes ape shit over a narrow rev band would be very hard to drive neatly esp for non race std drivers . This is the sort of thing that gets very intense very quickly and if it's mid corner and or on questionable surfaces AWD (of sorts) is no guarantee that life continues in the seconds that follow . Have a good look at the Grp B rally monsters and note a few who killed or almost killed themselves driving them 11 tenths .

Bigger engines in lower states of tune were almost always easier things to manage because you had far better control of the engines power output . The all time drama with big boost/turbo engines is that you often can't control turbo speed with your right hoof so the dryers going to do what it wants to do given WOT over its boost threshold . Because load on the engine is often inconsistent they can boost differently in different situations . Basically torque modulation can be interesting because of the pumping characteristics of exhaust driven centrifugal air pumps .

If you have a bit of say with gearing , diffs anyway , you can opt for taller ones to have a bit more speed in the intermediate gears and this is something I reckon is to some degree an issue with RB25 turbo powered Skylines .

Anyway almost non existent chance I'll ever have a GTR , not rich enough , but if millions fell from the heavens a 30 something is a given .

I don't need to be dramatic or attention seeking - too old for that , good flexible engine with prod go power more to my liking .

If I truly wanted a Skyline to rev piss and pick handles out of it would be an R32 GT4 or whatever the 4WD RB20DET powered thing was , drive it flat everywhere because it's cheaper to throw engines at than a GT pawper maker R . No , knowing me it would be a Neo Stag engine in the 32 because still cheaper easier than a 26 and probably give a few stdish GTRs a real big hurry up for less money and agro .

Sorry folks but I just can't see past the complexities and at the same time limitations of TT RB26s - on the street .

[Dale FZ1]

Different individual preferences abound, but I reckon any of the awd platforms - thinking Evo, STi, and GTR - don't really shine unless/until on low traction surfaces, running high output engines, or in a competition environment where there are slow speed corners. The weight penalty paid for the extra mechanical bits is not insignificant either. But in the hands of a driver who understands how to handle them, they are so much faster it is ridiculous.

Adrian when it's said and done, once you finally get that GT3076 fitted to your 25DET you will kick yourself for holding out so long.

And if/when you get a run in something with a 30DET you will again kick yourself. But the character of extra cubes and a lower rev ceiling may not suit everyone.

Group B obviously the fatal crash of Toivonen and Cresta was terrible but I think the real issue was around the .and style of events and stages, and engineering focus on light weight prototypes plus pure speed rather than including inherent crashworthiness. Remember those blokes were incinerated upside down at the bottom of a steep gully. The cars took a certain, and very different approach to drive fast - but they are not in the same street as current WRC machines. Engineering has stepped well ahead in 27 years. The best driver ends up driving the best machine, and those with funding can get a run as with other categories ie F1.

Returning on thread, I reckon stock final gearing for a modified RB26 powertrain would benefit from going to a lower (ie numerically higher number) ratio if it's not hitting full boost until 5000 and able to rev to 8500.

[Buraz]

XGTRX

On many occasions you've mentioned about evidence if more capacity is faster around a track than an rb26. You couldn't find any?? Have you looked at the Racepace GTR from mid 2000's which had massive benefits over rb26's around a track. Ben wouldn't have gone through all that trouble to increase the capacity if there were no benefits on the track. That's what Racepace does, build track cars. It was running 1.15 or something around sandown which is bloody quick, you'd be hard pressed to find many people running those times still today. It was stroked to 3 liters so wasn't an rb30 block. There's a massive thread here about it too so have a search.

Their current car is stroked to 2.8 and just have a look at the results they've had recently, it's a track monster. Have a search or go to their website or facebook. I'm just trying to add some evidence you mentioned so many times.

I don't mean to be a smartass at all, I love my rb26 too but I think there's definitely benefits to be had with more capacity street, track whatever... If only I had more money!!!

[XKLABA]

XGTRXOn many occasions you've mentioned about evidence if more capacity is faster around a track than an rb26. You couldn't find any?? Have you looked at the Racepace GTR from mid 2000's which had massive benefits over rb26's around a track. Ben wouldn't have gone through all that trouble to increase the capacity if there were no benefits on the track. That's what Racepace does, build track cars. It was running 1.15 or something around sandown which is bloody quick, you'd be hard pressed to find many people running those times still today. It was stroked to 3 liters so wasn't an rb30 block. There's a massive thread here about it too so have a search. Their current car is stroked to 2.8 and just have a look at the results they've had recently, it's a track monster. Have a search or go to their website or facebook. I'm just trying to add some evidence you mentioned so many times. I don't mean to be a smartass at all, I love my rb26 too but I think there's definitely benefits to be had with more capacity street, track whatever... If only I had more money!!!

We've all but given up explaining to him cause unless you can prove yourself with evidence you have from a build you did with offical times where the ONLY thing that changes is the capacity then I'd guess he'll have an excuse as to why the capacity didn't make any difference except make ya car sound bad

Those that understand - need no explanation

Those that can't understand - there's no explanation possible

[Mick_o]

Come on Mick put the ego aside and quit the personal attacks mate!

[XKLABA]

Haha yeah sorry mate, it just gets away from me some times

[Daz]

Why not have a 500kw 26 running low mounts like me?

[XKLABA]

2.6 with low mounts making 500kw at the wheels on a chassis dyno ?

Any chance you want to post spec and a dyno graph or a build thread

[gtr0321994]

Please share love to know as we'll

[scotty nm35]

2.6 with low mounts making 500kw at the wheels ?

Any chance you want to post spec and a dyno graph or a build thread

I already posted the graph I think.

On this topic, how many of you have tried Vcam? It uses a 350z cam actuator good for 40 degrees inlet cam advance/retard. Are there any before and after graphs? My VQ25det variable cam setup reeled in 1000 revs of lag, making the engine very similar to a 3L the way it comes on boost. If it can be cheaply retrofitted it could be a better option than a 3L bottom end.

[log in]

26/30 here, I find the torque of the 30 so good to cruise at 50kmh in high gears at around 2000rpm, it does it as easy as my 25 with standard turbo that had full boost by 3100rpm, 30 has a t78-33d 17cm and makes full boost by 4200

[XKLABA]

I already posted the graph I think.

On this topic, how many of you have tried Vcam? It uses a 350z cam actuator good for 40 degrees inlet cam advance/retard. Are there any before and after graphs? My VQ25det variable cam setup reeled in 1000 revs of lag, making the engine very similar to a 3L the way it comes on boost. If it can be cheaply retrofitted it could be a better option than a 3L bottom end.

40 deg is a big change but worth the effort of installing it in to a 26 against a well selected properly dialed in set of cams is a different story

What I would like to see is a full VE setup, like the SR20VE, made for the RB engines, that would give interesting results

[Lithium]

Siigh. I have dirty dreams about making lots of money from being awesome and then building RBs with Frankenstein heads shamelessly stealing design cues from Honda's K-series heads and designing a cunning cam swinging/valve lifting logic setup using MoTEC M1 Build (and a M150).

Oh, messy pants.

[XKLABA]

Haha, me to but using the Syvecs S8

That or just drop a VQ37HRTT in the car

[Lithium]

Was discussing Syvecs/Life Racing stuff with someone recently when I was looking into the capabilities of M1 Build - couldn't find a clear indication of whether it had the ability to build your "own" plug-ins like you can with the MoTEC? It's a really fricken cool idea to add to such a well developed base product, if you have the money to throw around.