Upgrade Rb 20 Or Put Rb 25 Or 26 Into My R32 Gts-t?

[JonnoHR31]

the gearing is obviously very different for whatever reasons as your run stops 30-40 k's short of the others even with what i assume would be a higher rev limit?

the green line makes the same or very similar peak power without being anywhere near as peaky. not denying your car would haul nicely from 120-180 but i think overall the other 2 would be faster because of the extra torque and progressive power delivery. but it all comes down to what your doing with the car

[Roy]

The gearing is different, just like cars all run different size rims and tyres with different rolling diameters that affects overall gearing. So i think looking at dyno sheets that look at road speed tell a better story of performance.

There is no question the RB25s make a nicer road. Car, but frankly, if you are upgrading engines to make it a nicer road car, there are far better road cars then R32s. So i generally look at it as a performance upgrade, and based on my experience there isnt really that much to be gained from performance if you setup an RB20 properly.

Re power delivery, its my experience that friends RB25s torch tyres far more then my RB20. Torque tears up tyres wth wheel spin when you punch it out of corners, hell 3rd gear in a straight line some of them. And i dont view my power as peaky, just the RB25 graphs as lazy in how they make their power (if it was a torque curve then i would agree) Mine jsut gets onto making power sooner and holds a good power band, in a slightly different manner,. I suppose this is very dependant on turbos

If you are accelerating from 2,000rpm to redline and you are caught in the wrong gear you will be slower and left for dead. If you are punting along and having a go, the RB20 gives away very little. Especially in a drag race or at the track where you are rowing the cars along, with a 3,500rpm power band making the same average power as other cars who have a 3,500rpm power band. then there is not much in it....and other variables such as tyres, driver, suspension are all a bigger variable then engine

[Nee-san]

The gearing is different, just like cars all run different size rims and tyres with different rolling diameters that affects overall gearing. So i think looking at dyno sheets that look at road speed tell a better story of performance.

There is no question the RB25s make a nicer road. Car, but frankly, if you are upgrading engines to make it a nicer road car, there are far better road cars then R32s. So i generally look at it as a performance upgrade, and based on my experience there isnt really that much to be gained from performance if you setup an RB20 properly.

Re power delivery, its my experience that friends RB25s torch tyres far more then my RB20. Torque tears up tyres wth wheel spin when you punch it out of corners, hell 3rd gear in a straight line some of them. And i dont view my power as peaky, just the RB25 graphs as lazy in how they make their power (if it was a torque curve then i would agree) Mine jsut gets onto making power sooner and holds a good power band, in a slightly different manner,. I suppose this is very dependant on turbos

If you are accelerating from 2,000rpm to redline and you are caught in the wrong gear you will be slower and left for dead. If you are punting along and having a go, the RB20 gives away very little. Especially in a drag race or at the track where you are rowing the cars along, with a 3,500rpm power band making the same average power as other cars who have a 3,500rpm power band. then there is not much in it....and other variables such as tyres, driver, suspension are all a bigger variable then engine

I think the primary advantage of having more cubes for a given turbocharger size and therefore power output, is the transient response of the turbocharger when applying part throttle and also in gear selection when the rev drop between changes may fall in a better range of the power band.

basically, more cubes and therefore greater flow of the fluid (air) through the turbocharger allow the inertial threshold of the wheel to be overcome more rapidly in the situations described above, giving the power delivery a greater driveability but not necessarily tractability which comes down to how your putting your power to the ground.

Cheers,

Mitch.

[SoFreshSoClean]

Re power delivery, its my experience that friends RB25s torch tyres far more then my RB20. Torque tears up tyres wth wheel spin when you punch it out of corners, hell 3rd gear in a straight line some of them. And i dont view my power as peaky, just the RB25 graphs as lazy in how they make their power (if it was a torque curve then i would agree) Mine jsut gets onto making power sooner and holds a good power band, in a slightly different manner,. I suppose this is very dependant on turbos

But Roy doesnt torched tyres = way more tractive effort = more speed if put down on the road? I would say that your guys with RB25's are maybe using too much throttle/shitty tyres & suspension setup..

[Nee-san]

But Roy doesnt torched tyres = way more tractive effort = more speed if put down on the road? I would say that your guys with RB25's are maybe using too much throttle/shitty tyres & suspension setup..

If your overpowering your wheel, tyre and suspension set up then you either have to increase traction OR live with the fact that you can only make X amount of power/torque before it becomes superfluous.

However roy is also correct in that making similar power in a different way can also be beneficial, for one this type of delivery has a far greater degree of mechanical sympathy for your drive line.

[limpus]

I see Roy's back....this is more like the sau of old...rb20 vs rb25....lol...

[mad082]

i've driven a few skylines from stock r33s to 33's with a bigger turbo and a 32 with a bigger turbo. the 32 with a bigger turbo was putting out similar peak power to my stock turbo'd 33 (with raised boost, cooler and exhaust), yet the skyline felt much better to drive because it was making full boost by well under 3000rpm while the 20 wasn't until about 4500rpm. the 20 felt fast while it was on boost, but that may have just been because of how slow it felt off boost. the 20 feels good if you drive everywhere and keep it above 5000rpm, but to drive along normally and then punch it the 25 feels much nicer, and to get the same effect in the 20 you have to start dropping back gears. i live in a hilly area and just for general driving around the 25 was much nicer. less having to drop it back gears once you get to some of the hilly areas where the speed limit just wasn't very suited for the 20. it was either having it sort of screaming in 1 gear or having it bogged down in the next. the 25 you could just stay in the higher gear and it would still just go along nicely (although it has to be said that a big aussie 6 or 8 felt much better than either of them)

my mate has a 25 in his ceffy and his brother is the one with the 20 in his 32 (both putting out about 200kw) and they went to a track for a drifting event and in the 32 you had to enter one of the corners about 20kmh slower because you had to use second gear as it wasn't high enough in the revs when in 3rd gear to keep the slide going. with the 25 you could go into the corner in 3rd and it didn't matter much if the revs dropped a bit as it had the torque to spin back up. they had a go of each others car, as well as another mates s13 and they all agreed that the 20 was the worst of the lot due to the lack of low down power.

[335]

This isnt about 33's being better and 32's being crap. I just want to know what will be the best bang for the buck. Instead of putting money into the RB 20 if buying and putting in a 25 will be better than I will. But if I can get the same power and some better torque than stock with my RB20 than I will be happy. I want 300 hp and good acelaration and better torque than I have now from stock. If that means I need to put in cam gears or put in upgraded fuel pump and fuel injectors and have it tuned than that is fine. If putting in a 25 is good than fine. Easier would be upgrading the 20.

Can I get better torque with upgrades with my RB 20?

[toddlls]

To each their own, I was gonna do the motor swap thing-may still do it if mine goes bang & it will be with a 26 if I do.

I have just got my lil RB20 to nearly 300rwhp & holy shit its a lot of fun. Am gonna push her up to 350rwhp very soon & put a lightened flywheel in the mix too so I will get back to yah as to whether it will kick it with the big boys for around town driving.

I have been very lucky to have driven them all-nearly(havent had a fang in a 33gtrVspec yet) & those with different motors in em too. Although the R32 RB25 upgrade is pretty impressive & goes nice & hard when done right A R32Gtst with a RB26 single turbo is awesome-for me & I just cant justify goin the RB25 route. Same amount of f'n around to put em in. More power with the RB26-plain & simple.

As to RB20 not kicking it with the RB25's & RB26's at the track is just B.S. Mine has no problems taking some of them to school-all who have more power, better go-fast bits, some with track rubber too.

In the end do what YOU want to do. Dont worry what every 1 else thinks. Just look for the tutorials on how to do what it is you decide to do & let us know how you've gone & what issues you came up against-how you resolved em too

Here it is so you can see whats been done

http://www.skylinesaustralia.com/forums/To...st-t327323.html

[Roy]

Can I get better torque with upgrades with my RB 20?

A few questions. Are you doing the mods yourself, or paying somebody? Are you planning on upgrading the gearbox to an RB25 box anytime soon?

And rather then saying increased torque, you really need to specify where you want more grunt. Of course you can increase the torque of an RB20 by giving it better exhaust, intercooler, a better tune. Basically making it a better, more effecient air pump. Throw on a GT-SS which is a tad bigger then a std turbo but steel wheeled so you can jam 18psi into the engine and you will make a nice and punchy 200-210rwkws with great midrange from 4,00-5,500rpm with peak power somewhere in the 62,00rpm range. It will probably run out of puff at about std rev limit of 7,000rpm...so no point reving it much harder.

But being a small bore, short stroke 6 cylinder, even with the smallest turbo in the world and all the band aids you can bolt on, it is never going to have good reserves of torque from 2,500rpm to 4,000rpm. If that is where you want to start pulling at...then best grab the bigger displacement motor sooner rather then later as the bolt ons are different between the engines

[Harey]

So thats my best attempt at a balanced argument based on facts and experience... and actually while i am at it. Here is Russman in his HKS 2530 powered RB20 GTSt at Winton ...

And here he is being chased by an R33 GTR with R34 engine and N1 turbos making 280awkws ..

You are clearly a much better driver than the owner of the R33 GTR though! Still impressive nonetheless.

[Roy]

They are both good drivers. The GTR is doing about the same lap times as every other R33 GTR does on semis with the same mods. Perhaps 0.5second off the generall pace of R33 GTRs running suspension and breathing mods with about that power. They were both on worn semis so that would account for the very small difference in outright pace

[335]

A few questions. Are you doing the mods yourself, or paying somebody? Are you planning on upgrading the gearbox to an RB25 box anytime soon?

And rather then saying increased torque, you really need to specify where you want more grunt. Of course you can increase the torque of an RB20 by giving it better exhaust, intercooler, a better tune. Basically making it a better, more effecient air pump. Throw on a GT-SS which is a tad bigger then a std turbo but steel wheeled so you can jam 18psi into the engine and you will make a nice and punchy 200-210rwkws with great midrange from 4,00-5,500rpm with peak power somewhere in the 62,00rpm range. It will probably run out of puff at about std rev limit of 7,000rpm...so no point reving it much harder.

But being a small bore, short stroke 6 cylinder, even with the smallest turbo in the world and all the band aids you can bolt on, it is never going to have good reserves of torque from 2,500rpm to 4,000rpm. If that is where you want to start pulling at...then best grab the bigger displacement motor sooner rather then later as the bolt ons are different between the engines

Hello

I will do some myself and get someone to do other and tune.

What if I put Poncams in? What if I buy the Tomei 2.2 liter upgrade kit?

Edited August 19, 2010 by 335

[Bunta]

What does an R32 GTST weight with the R33s engine gearbox and brakes ?

Just curious , cheers A .

my R32 GTST with a RB25, 25 gearbox and R33 GTR Brembos weighed in at 1330kg on a weigh bridge down at the dump. it did have a GTR Bonnet and that would have saved some weight and it was a non abs model

[Rolls]

Rb25 definitely.

[istdercollen]

You say you live in Japan. You do realize that if you swap to an engine other than an RB20 you will not be able to JCI the car? It will fail inspection in 3 seconds, as the first thing they do is open your hood and look at the stamp on the engine block.

[335]

You say you live in Japan. You do realize that if you swap to an engine other than an RB20 you will not be able to JCI the car? It will fail inspection in 3 seconds, as the first thing they do is open your hood and look at the stamp on the engine block.

Thats not true, I have already contacted the proper government people and the only thing I have to do is fill out paper work with the changes and pay a higher road tax fee.

People due engine swaps a lot in Japan.

[istdercollen]

well doing the paperwork and inspections is another story. insurance goes up, JCI doubles, and so on. anyway, I would just take the RB20 to the edge of reality. It would be a screamer.

[335]

well doing the paperwork and inspections is another story. insurance goes up, JCI doubles, and so on. anyway, I would just take the RB20 to the edge of reality. It would be a screamer.

I will try that but it is not as expensive as you think. The most expensive part will be having someone tune the engine. JCI would be same price as if I had a vehicle which engine is over 2000cc, so even if I had a mini van or large size sedan such as a Mark 2 or R33 or anything, the JCI is the same price. Insurance yes but not by a lot, so yes I will try to mod the 20 but if I come across a 25 or 26 which is in good working order for cheap or someone gives me one, I will change engines.

My previous 32 had a RB25 turbo on it, no tuned computer, but it would boost before 3000 RPM. I want to have good driving in the 3000-4000 RPM range.

Which turbo would　good for this? 2530? 2830? I do not know the names of all of the different turbos I can put on the 20.

[Rolls]

Which turbo would　good for this? 2530? 2830? I do not know the names of all of the different turbos I can put on the 20.

You can make basically any turbo in the world fit if you want, but the 2530 would be about as big as you want to go on the 20 without sacrificing too much low down power.