torque numbers

[jessem]

Has anyone out there got good torque numbers out of an rb? Toyotas make me jelous having torque higher then HP in some cases and gettting it really low in the rpms. Is this obtainable with an rb? More then likely a 25 I would guess.

I think it was chasduran that had decent torque to match his hp numbers, do cams fix this? or can it even be done with just a tune? obvisouly early boost pressure would help. but i would love to have 350hp and 350ftlbs of torque at low rpm.

[Skym]

From what I understand, 4cyl or 2.5-3.0 litre 6 cylinder have longer stroke and more torque. RB20DET is not known for torque due to shorter stroke. Stroking RB20DET with RB26 crank, RB26 conrods, Tomei RB24 pistons can increase capacity, stroke.

Shorter stroke is good for reving a engine higher and is a common mod on NA Nissan V8 racing engines to reach 10,000rpm in Indy cars -

http://www.popularmechanics.com/automotive/motorsports/1269261.html?page=3

Also more capacity helps with 6 cylinder, like this RB26 vs RB30 dyno chart -

http://4.bp.blogspot.com/_vhpEGyEVhes/SE7_1idVURI/AAAAAAAAAzA/BYk7YSej5Sk/s1600-h/****+GTR+powe5r.jpg

Also cam timing can be adjusted to lower peak hp and gain low to mid torque and ECU retuned to suit. Also cams + cam timing can help to gain more hp down low when fitting bigger turbo's.

Then there's higher compression for better off boost performance, like on a stock RB25DET engine.

[falcon]

RB20's don't know what torque is. But a 26 I know of made 480awtq

[jessem]

So skym your saying, with the right intentions good torque can be made. I never thought of running a thin head gasket but it makes sense. I can assume the right cams could make a big difference too?

Anyone know what kind of difference a front facing plenum makes, if i remember right they tend to decrease torque.

[BrianV8]

I had my new rb25 on the dyno last summer. Once we hit peak power we detuned it a bit and i drove off making 380hp and 355 ft/lbs of torque at the wheels

[DrMango]

I read someone say on here that if you go with smaller turbos and a propper tune then you can achieve higher TQ numbers vs Hp but I don't know crap about it. Try searching, it was pretty recent I think

Kyle

[jessem]

I had my new rb25 on the dyno last summer. Once we hit peak power we detuned it a bit and i drove off making 380hp and 355 ft/lbs of torque at the wheels

id be more than happy with that, what kinda set up are you running on motor? is boost pretty early?

[Skym]

JesseM, with the correct mods.

Don't think you need a thinner headgasket, just the stock thinner headgasket, higher compression pistons, etc on RB25DET helps with off boost performance (NA part of engine), as street use is the application engine was designed for.

Staggering the cams, like higher duration on intake, lower duration on exhaust helps with bottom end torque with upgraded turbo's. Tomei mention this in link below -

http://www.tomei-p.co.jp/_2003web-catalogue/e070_cam_RB26.html

The main part where upgraded cams help, is they let more air into engine at lower rpm's and mixed with more fuel from a ECU retune, provides more power at lower rpm's and more exhaust gas at lower rpm's to get turbo to spool a little bit quicker. But higher duration, lift cams shift peak hp, peak torque up the powerband and creates a cross bow look in bottom of power, torque plots on dyno graph. Can adjust cam timing, reduce boost level to reduce this bow look.

Stock R32 RB20DET longer intake runners, stock R32 RB20DET short runner exhaust, small turbo, small intercooler, small diameter exhaust, low duration cams are best for low rpm torque. Basically a stock R32 RB20DET powered Skyline. Same with RB25DET but has the benefit of higher compression, more capacity for better off boost performance.

Shorter intake is more for mid to high rpm hp gains. Exhaust is opposite, where longer exhaust runners are mid to high hp gains when mixed with bigger diameter exhaust.

Good example of low hp but huge torque down low is rally cars -

http://www.mikkohirvonen.com/fordfocus-uk.php

Smallish turbo (about the size of a rebuilt stock RB20DET turbo), longer stroke than RB20DET, small 2.5 inch exhaust with cat.

[BrianV8]

id be more than happy with that, what kinda set up are you running on motor? is boost pretty early?

Running a series one rb25 motor stock internals,
series 2 transmission.
side feed intake plenum
big front mount with 3" intercooler piping
q45 throttle body
top mount turbo manifold w/ holset turbo
550cc injectors w/top feed conversion
N1 oil pump
stock head gasket
arp studs
38mm Tial waste gate
blitz BOV

And i think thats all of it haha. I was making full boost aka 20 pounds at 4200rpm. Over the winter i've discovered a bunch of boost leaks so i'm hoping i can get it spooled quicker around 4000rpm with those fixed up

I can post pics later if you want

[jessem]

thanks skym, and brian

good info, it would be great if you post up some pics.

[mcfly]

thanks skym, and brian

good info, it would be great if you post up some pics.

or a real dyno sheet

[BrianV8]

or a real dyno sheet

I can one up your dyno sheet, i have screen shots :P
This is what i rolled off the dyno with after we detuned the car. I cranked it back up later on lol. Chew on that a bit mcfly.



and ya my bad made 350 torque not 355 my bad:P

Here is a couple pics hooked up to the dyno




Here is a more close up of the motor right after the install

[M13]

Very nice Brian.

[mcfly]

what kind of dyno, i notice weight being factored in which means the numbers are worthless.

[BrianV8]

mustang dyno, weight was factored in during tuning to put resistance agains the drums for a more accurate and detailed power curve for tuning purposes. And the weight on the drums lowers the actual power numbers. Those numbers are dyno jet numbers. They also told me to add about 20 to 30hp to my dyno jet run to compensate for mustang dyno's reading low.

So if anything those numbers are lower than the actual. So there goes your theory mcfly