Sensible power target for RB20 project

[browny]

Hey guys,

I was wanting some thoughts on a power target for my RB20DET project.

Say you were given the task of putting together an RB20 engine/gearbox package for a 1200kg car, What sort of sensible rWkW would you aim for and how would you do it?

This sounds a bit open ended so consider the following limitations:

* The car will be an every day driver, it has to be good to drive in traffic and reliable. If its a pig to drive its useless.

* I don't expect any wider than about 205 rubber will ever get put on the back

* There is a 99.999% chance that it will never get run down the 1/4 mile or raced in any way

* I want to run stock internals

As for budget, I don't really have anything in mind at the moment 'cos I am trying to get some ideas. I expect the limitations above will stop things getting too out of hand cost wise but you never know.

Comments suggesting that I get an RB25/30 won't be appreciated.....

[adam 32]

i think you should aim for the 220rwkw mark if you want it as a daily driver, and not have to sacrfice big lag and driveability

[rev210]

Well you can have a large turbo that comes on boost at 4500rpm and I'd still consider that traffic drivable because the torque of the 2l six will punt you around quite well without boost. It also eliminates some of the traction issues a smaller turbo has due to it hitting boost at only 2500rpm.

I'd say 260-280HP at the motor would otherwise be an excellent power level for a daily driver with your sort of needs. Forget the rear wheel figures, they are not worth troubling yourself over as no-one manufactures any part rated in rwkw or rwhp its always rated at the motor.

[meggala]

adam is right 220rwk is a good goal

200 would be plenty on 205's as well

read this to get an idea how

http://www.meggala.com/modys.htm

meggala

[adam 32]

ive owned an RB20 with a big turbo which spools at 4500rpm and its not traffic friendly at all. in fact after 6 months of driving it i got so sick of it im now in the process of chanigng it. so speaking from experience and not just theory, it isnt a good idea.

there is a point in calculating hp at the wheels because thats the amount of power that is getting to the ground. 260 flywheel hp will only see 200 at the wheels which is fairly pathetic for a modified car.

[Sydneykid]

Hi Browny, my suggestions follow;

*aim for approx 200 rwkw (around 340 bhp)

*hi flow standard turbo

*3" exhaust, turbo back (inc hi flow cat)

*adj cam pulleys

*R32/33 GTR standard intercooler

*aluminium pipework

*dyno tune and re chip std computer

*pod in a box

Should cost around $5K to $6K depending on how much you do yourself and pick up second hand.

Hope that helps

[rev210]

Originally posted by adam 32

there is a point in calculating hp at the wheels because thats the amount of power that is getting to the ground. 260 flywheel hp will only see 200 at the wheels which is fairly pathetic for a modified car.

Rear wheel readings are helpfull for 'tuning' on the spot. Only that particular dyno operator will be able to make sense of the figures, performance comparison wise, between cars they have previously tuned.And not between thier dyno and the bloke on the other side of the country/world.

They are not standardised form one dyno to another (need I mention myaree dyno?).

260HP or so at the motor is quite alot for a light car like the R32. It would see a nice mid 13 1/4 on street tyres. Just shows you how much bulldust people swallow and how much crapping on there is about dyno figures, particularly peak rearwheel power.

[browny]

Cool a few replies....

A couple of things:

Its not skyline - the significance of this is that the engine will be getting a pod and a 3" exhaust (the air box wont fit and I need a new exhaust anyway)

Meggala - I have read your site, several times

Sydneykid - I am doing all the work myself. Fair bit of work in this project. Pretty sure a GTR 'cooler wont fit. ATM I have a VR4 cooler 'cos its about the biggest I reckon I can get in the front without going custom made.

As for the rwkw vs fwkw thing. I know its dyno dependant but I only specified rwkw to try and keep all the replies referenced to the same point.

[rev210]

Browny,

Problem is the same point isn't the same point mate when you talk about rwkw/hp.

Ahhh...1200kgs.

Well 260hp will probably be plenty then. What is it a little datsun 1600 or something?

Leave the engine pretty stock and just up the boost a bit.

[browny]

Forgive my aweful ignorance about dyno's but how is engine hp measured and why is it more accurate than rwkw?

The car is one of the generals finest.

[Sydneykid]

"The car is one of the generals finest"

Can't say as I've ever seen one of those.

[browny]

I like it anyway

[red17]

My target is about 250ish rwhp. Im hoping to achieve this from:

3 inch exhaust from turbo back with dump.

R33 standard turbo (slightly larger than the stock RB20 one and allows you to put 14 pound through it with less stress than when its on the 2.5 litre. Theres also plenty of R33 owners trying to sell them off after upgrading.)

Nice front mount... possibly an ARE. You could also consider options such as GTR coolers or Supra cores. You could go japanese brand but most seem to be HUGE and flow mega-hp.

Adjustable cam gear.

14psi of boost

Remap ECU.

Dyno tune

Ive hit 220 rwhp as it is on 14psi with a stock dump, stock turbo and stock intercooler and massive fuelling issues (relating to aftermarket ECU more than supply). So im thinking the above mods should hopefully get me around the 250 mark... maybe im being unrealistic.

Red17

PS: One of the generals finest? The piazza?

[Clint32]

My RB20 makes 234rwkw on the stock injectors with a stock engine ( cams, cam gears, manifolds ect). So 220-230 is easy with all the mods mentioned previously.

Now to make the power im using a to4e turbo, this is a old design and not ball bearing but cheap. i make full boost by 4500rpm and while this is a lot higher than stock or 33 turbo it is by no means a pig to drive. You can drive around all day (i do 400kms a week) and keep up and beat traffic changing at 3000rpm and when you want to go you just put your foot down and hang on. Just a point that a car with a big turbo will still be a good daily driver, it may not be the best for drift or a thrash in the street but if you drive hard it dosent matter.

If your never going to race it or dont have a power figure in mind and you are running 205 tyres, stick with a stock type turbo (r33, vg30) and do a good job of the rest and make about 200, this is a easy reliable power up without the hassles of going the next step.

[Roy]

dyno tune and re chip std computer

Who in Sydney does this, and does it well???

SAS have quoted me about $1000, which suggests it definitely wont be cheaper, perhaps another say $100 on top. That is for tuning, removing the speed limiter, boost cut, fuel cut etc, and leaving the redline as per factory.

Considering they would have base settings from numerous different cars, i find this a little $$$$. Say 5 hours work, (i hope not 5 hour of dyno runs) that equates to $200 an hour. Even allowing for some dyno costs it is still expensive.

At this price id rather fork out the $2500 for installed and tuned Autronic. Or find someone other then a rotor shop that has a clue with Wold ECUs

[R32 Zilla]

If you are only going to have 205 wide tyres than i suggest you keep the power down to below 180rwkw. I have 196 rwkw and when i put 205s on the back there is a huge amount of wheel spin in 2nd gear when boost hits. Great fun but i dont think this is how you want your car to drive all the time. You would have even more wheel spin as your car is about 100kg's lighter.

Tim.

[meggala]

Red 17 I have that exact set up @ .9 bar boost I ran 14 flat @ 100 mph with another .2 of a second to gain in the 60' time it is the best value mods you can do.

meggala

read my site for more detail

[meggala]

roy we are doing chips and have some great results 190 rwkw on injectors

plenty of others there is no boost cut btw also can seet for z32 afm and working on injectors.

pm ne for more the price is very reasonable

[red17]

Meggala,

Yeah ive read your site a few times and was set on the VG30 turbo until you stated it seemed to shift the power alot further up the rev range. Which is exactly what i DONT want to do considering the RB20's lack of bottom end get up and go.

So the R33 turbo is probably a nice comprimise considering the target ive set out for. Just need to find one thats not been molested by its previous owner.

Red17

[browny]

My preference atm is to stick with OEM parts 'cos they are generally more readily available 2nd hand (albeit used)

Can anyone add anything to Meggalas web site discussion of the RB25 vs the VG30?

What is the potential of the RB25 turbo on an RB20?