Is The Rb20 Det 2.4 Liter Upgrade Worth It?

[yoshiii335]

Hello

I have been talking to different tuners here in Japan and one of them suggested a 2.4 litre upgrade kit for my RB20 Det.

Are these worth it or is it better to build up my 20 with the normal 2 litre? My goal is 400 hp for the street.

I am not going RB25 because of the costs of registering the car, paying the extra to the government for the engine change and the doubling of the yearly road tax fees here which is expensive.

[Matvei27]

400hp for the street is impossible on a RB20DET. It will be a lag fest.

Since you are in Japan I am assuming you can read Japanese? Go pick up an issue of Hyper-rev regarding the GTS-t, it will say the exact same thing I am about to tell you.

You have three options:

1. 350hp, responsive for street

2. 400hp, lag monster

3. increase displacement

The only real problem I see is that most of the 2.4 litre upgrade kits are no longer available (HKS, Tomei). What exactly was he suggesting you use?

Edited March 28, 2015 by Matvei27

[1400r]

should be able to make 400hp easy without going built motor and being in Japan when it goes bang it'll still be cheap to replace

[Matvei27]

should be able to make 400hp easy without going built motor and being in Japan when it goes bang it'll still be cheap to replace

He can do it but it won't be fun to drive on the street, and he said he wanted it for the street...so probably not a great idea.

If he doesn't want to pay for a 3 number plate, which the RB25 would require, the RB24 is really the best option he can get.

The problem is availability since the majority of these kits are discontinued.

Edited March 28, 2015 by Matvei27

[yoshiii335]

There is a state side company that sells kits for it. Here there are still the parts needed for the conversion available.

[Ben C34]

How does the higher registration fees compare to building a stroker?

Give me some numbers....

[Matvei27]

There is a state side company that sells kits for it. Here there are still the parts needed for the conversion available.

Which, specifically? The Tomei kit is discontinued, the HKS kit is discontinued...Testarossa still does RB23 and RB24 in Japan but the quality is a bit sketchy from what I have heard.

How does the higher registration fees compare to building a stroker?

Give me some numbers....

This isn't Australia. The RB22 and RB24 were popular in Japan for a very good reason.

[Missileman]

I asked this question to a relative who's been living in Japan for 15 years, he said there wasn't that much difference in cost between 2.0 and 2.5L vehicles.

[yoshiii335]

Don't have the prices in front of me right now. If I remember correctly:

To have a shop put it in is about 500-1000 dollars ( quality of work and shop varies) Most good shops here are expensive. Have to find a decent RB25 and make sure it works. About 800-1000 dollars. Price of whatever after market turbos, etc. Price? Registration between 500-1000 dollars(unless I was told wrong.) Yearly road tax, about 200 dollars a year. We have to pay a reregistration fee every two years also which will go up in price with the bigger engine. Its 800 dollars for me with the rb20.

[yoshiii335]

Yahoo action has it and I went to Tomei about three weeks ago and they still sell the parts, pistons, rods, head gasket, etc. Not sure of the brand in the states. Sold by a company called Raw Brokerage.

[Matvei27]

Are you 100 percent sure Tomei still sells the pistons? Because their website says 生産終了

http://www.tomei-p.co.jp/_2003web-catalogue/053_RB20_piston.html

If they actually still make them I'll go buy a 2.2 kit right now...

Edited March 28, 2015 by Matvei27

[yoshiii335]

Are you 100 percent sure Tomei still sells the pistons? Because their website says 生産終了

http://www.tomei-p.co.jp/_2003web-catalogue/053_RB20_piston.html

If they actually still make them I'll go buy a 2.2 kit right now...

Unless I was lied to, they still have it.

Yahoo action Japan carries it also.

[Matvei27]

Unless I was lied to, they still have it.

Yahoo action Japan carries it also.

The listings on Yahoo don't mean anything, if you read them they say to confirm stock with the manufacturer, and often times they are outdated listings.

Unless Tomei specifically told you they have them (despite the website saying they don't make them anymore), then they probably don't.

I'll call them on Monday.

Edited March 28, 2015 by Matvei27

[wolverine]

Don't have the prices in front of me right now. If I remember correctly:

To have a shop put it in is about 500-1000 dollars ( quality of work and shop varies) Most good shops here are expensive. Have to find a decent RB25 and make sure it works. About 800-1000 dollars. Price of whatever after market turbos, etc. Price? Registration between 500-1000 dollars(unless I was told wrong.) Yearly road tax, about 200 dollars a year. We have to pay a reregistration fee every two years also which will go up in price with the bigger engine. Its 800 dollars for me with the rb20.

A good RB25DET neo would be cheaper than building a stroker...which leaves room for paying extra at renewal time and you get the extra torque from day one.

[GTSBoy]

Building a RB20 stroker has never been "worth it" since the RB25 became available 2nd hand. They were only "worth it" when they were the only choice to put more capacity into a small RB. That was 20 years ago.

[discopotato03]

Can you buy a 2.5L R32 and put the turbo gear in that ? Or just buy a GTS25T.

The biggest problem for an RB20 block is the bore size , this limits the chamber diameter and that limits the valve size . RB20 valve sizes are inadequate for 2.3-2.4 litres and there is nothing economically viable you can do about it . Painted into a corner you can't get out of , this is literally why a big bore (86mm) RB24 or RB25 will always make better power than a stroked RB20 . BTW there was actually a big bore RB24 which I think had the RB20 stroke crank with slightly longer rods . It may have been a pov pak third world carby option .

A .

[Ben C34]

Then it willl be heaps better with an rb25 and vct but cost 200 bucks a year more for rego in Japan. Which is his main concern

[blind_elk]

Frankly, if its for the street, why on earth do you need 400hp?

[yoshiii335]

I will take it to the track about once a month.

[yoshiii335]

Frankly, if its for the street, why on earth do you need 400hp?

To be able to keep up with or pass Evo's, STI's, cars with 1JZ's in them.