VG30DETT torgue vs RB26DETT article

Great read, makes me realise why I like the low end torque of my babay..

http://forums.hybridz.org/index.php/topic/28207-vg30dett-vs-rb26dett/

Copied Text below

http://www.ooparts-i...entroof/record/

These are 2 engines both tuned by the same company. They equipped both the VG30DETT and the RB26DETT with identical turbos, TD06-20G-L2 8cm.

With these identical turbos, the VG30DETT made 746 rwhp @ 6550 rpm, and 865 ft lbs of torque @ 4550 rpm, while the RB26DETT made 759 rwhp @ 7820 rpm, and 543 lbs of torque @ 7000 rpm.

First things I noticed were how high the RB had to rev to make its power, and how much of a torque advantage the VG had. The power outputs were very similar, only a 13 hp difference on 700+ hp machines. But the torque output was much different, with the VG having 322 ft-lbs more. So while the RB has 1.7% more power, the VG made 60% more torque, and at a lower, much more streetable RPM.

I doubt this will really change anyones mind about which engine to choose, since the hard part is mounting it and from what I heard, the VG30DETT is a royal PITA to get to fit.

Just thought I'd share.

 

http://www.ooparts-international.co.jp/index/car/listbybrand/pentroof/record/

Proper link to the pentroof article

 

Been posted many times, the message doesn't get through for some people though. Funny thing to see is the GTR running 12x 444cc standard injectors, oldschool jap tuning at its finest.

 

Hmm.... RB is down 400cc, and still made more power. They make a bucket load more power stock for stock too as far as I know.
RB30DETT would make significantly more power than the VG. Perhaps similar or close torque figures?
RB is a race motor, built to dominate and hold up on the track, hence it's dougheyness (in comparison) around town. ITB's>Tuned intake runners. VG is Nissan's streetable motor for a GT car in comparison to an RB26 IMO.

 

The RB manifold and lower capacity is a disadvantage to the VGs manifold length and displacement for torque production.
However the shorter runner and longer rod ratio length enbales the higher power for the RB over the VG.
Both are beautiful motors, and with money both can be made to perform. Remeber the NT90 used a VG30 (single cams) to race. It produced phenominal power figures.

 

So I know there are many build threads to read through but would anyone know offhand an engine locally or on the forum who would have the most torque at say less then 6000 rpm?

Or what turbos would produce the fattest (and most) torque curve - say roller bearing GT500?

So a FUN lazy daily driver lol.

I know when I installed my Profec and played with the Gain to bring the boost in alot quicker it made for a lot more entertaining point and squirt upto 5500 rpm.

http://autospeed.com/cms/title_The-Nissan-VG30DETT/A_109870/article.html



This article is one of my favourites, huge amount of development with the plenum and runners to maximise torque. Would be interesting to see how much torque is possible as opposed to max rpm power.

 

Actually the RB26 powered GTR's will still only push 170-180rwkw when put into RWD mode by way of fuse removal(R32) or front driveshaft removal(R33/R34). Highest i've seen was 207rwkw from a bog standard low km R34 N1 and that jumped to 225rwkw with the boost restrictor removed. Be aware though the N1 R34 is still 80k plus for a nice one.

 

who was it who said Colin Chapman torque wins races, max HP is only for bragging, so youd get done easy with more torque

 

Don't think that the torque difference can be due only to runner lengths at all. My VG30DET has a custom top mounted plenum giving short runners and still delivers great torque on the track as shown by the corner exit acceleration. No VVT either.

 

Note my post the runners are only part of the equation, I mentioned displacement too. There are heaps of other items too such as cams, valve hat shapes, manifolds, rod to stroke ratios, chamber volume, etc. But the major difference between the RB and the VG in respect to torque generation is the displacement and the runners on the VG, and the rod ratio and manifold of the RB.

 

Come on, don't poo poo the RB it is a brilliant engine. Horses for courses I say, it is a constant trade off with cars and their engines (bugatti are the only ones that have got it about right, but that car cost a bit more than the Z). Colin Chapman was not always right, he also said;"You would never catch me driving anything I built." And "Why do you want to take a washer with you for an entire race." (referring to why he wanted to take all of the washers out of his cars).

 

Thoser quoted figures are still just smoke and mirrors and only look good on paper.
Remeber, Hp is more or less a mathematical equasion of torque and RPM.

Its easy to see here. Both engines produce the same outright Hp but the VG does it significantly lower in the rpm range. The RB makes its horsepower by producing LESS torque but at higher RPM... simple right??!!!!
So, the VG should result in the more powerful/driveable car right?....... well, mebbe not! All is still not as clear as it seems.

The RB may produce less torque, peak at higher rpm (hence show the same Hp) BUT in a similar chassis, may (or may not) overall perform better! Yet first glance at the figures alone would indicate a peakier engine........ not necessarily so!!!!!

Peak torque/hp figures look real impressive on paper but in the real world can mean very little if the effective torque peak is spread over a uselessly narrow rpm range.
Additionally, the torque rise can be so steep that the power delivery of the particular engine is uncontrollable and largely useless in the real world.
Think 1100 Hp RB dyno queens. There is no functionally usefull RPM range where it will make controllable HP. Its either is a slug or a fire breather and nothing inbetween!!!

It could be that the RB torque peak is spread over, say 1000 more rpm giving a far more flexible engine, easier to keep in its effective torque peak and so at the end of the day, easier to drive fast and significantly faster overall.


260det.
The length of inlet runners is arrived at to MAXIMISE torque around a given (Tuned) rpm. So your shorter runners are simply maximising torque at a higher rpm is all.
VVT in a zed does nothing more than to advance the closing time of the inlet valves at low/mid rpm to exploit the gains from tuning the runners. The retarded cam timing at high rpm exploits inertia of the inlet gasflow to gain some extra low lift cylinder filling which nicely offsets the loss of torque as a result of the long runners.
Now this works with the relatively mild stock inlet cams but with your tougher cams, especially so if they have been carefull designed and maximised, may extend the closing time of the valves past where any low lift flow is gained and might even work the other way and allow reversion from the cylinders at the very RPM your trying to maximise!!! The reverse could be true at the advanced (low rpm) setting where the inlets may open too soon as to allow excessive exhaust gas under pressure to blow back into the inlet manifolds... not the best scenario.

The kind of improvement, both long inlet runners and simple on-off VVT are exploited at much lower rpm/stae of tune than your engine would see anywhere on a track where it would actually make ANY difference and nothing an extra psi of boost cannot easily account for anyway so the statement is, altho good for your particular race car, is not particularly relevant here.

L8r
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Here's a video that will get that point across, when asked about the powerband this is the answer he gave.

Still against a 600rwhp R33, bloody hell
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What about people that only need 2000rpm to do the type of racing they prefer? Horses for courses

RB's give me an eargasm!!!

 

Personally RB's are the best sounding engines bar none.

 

Better sounding than the BRM supercharged 1.5ltr V16? I don't think so, turn up the volume the screaming starts at 0.22
http://youtu.be/OnEA-m8cVcE

 

sorry i like this better.

http://www.youtube.com/watch?v=He8QmV8mFng

and he has a shocking powerband........but it hammers..horses for courses.

 

PMSL!! The only thing "shocking" about this thing is how WELL its power spread is matched to the transmission....... bejeebus!

E

 

yeah righto

 

Yeh i do think so, personal taste.

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RB26 + T51R SPL = Jizz
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More than likely running an OS Giken "OS 88" Sequential box, a lot of the hi-po GTR's in japan run them.