power vs Dollars

[karay240]

RB20 vs SR20

Longer stroke = more torque = believe it or not, the SR has more low-end torque than the RB20.

 

What I can say in RB20's behalf is that, IF you can find parts for it, you can bore it and stroke it to 2.4 (using aftermarket pistons, rods, and a factory RB26 crank) for a fairly inexpensive price *cough cough*

 

If you're just wanting bolt-on performance, the SR20 would be the way to go, unless you're just absolutely in love w/ the idea of a I-6.

 

Kenny

http://www.rbmotoring.com

[getoffmyinternet]

I've always thought that in terms of philosophy it was like this

 

go big or go home = rb26dett

embarrass a corvette on a budget = rb25dett

don't overdo it on power or your wallet = sr20det

 

Why use an rb20 when you can decide between an rb25 or an sr20? It's not about the number of cylinders, it's about raw power. The sr20 is a great match and has plenty of budget, easy to find potential--an overall balance. The rb25 has even more potential on a slightly bigger and more long term budget. If you're really good with the knowhow, I would think you'd probably either go for the rb25 or the sr20 because either of their potential depend a lot on the mechanic--in a way, the possibilities are endless.The possibilities of an rb25 end about at the point where you discover you should have gone with a stronger block to keep it from destroying itself with all your upgrades, and the possibilities of an rb20 end much sooner than that.

 

Unfortunately for me, I'm bound by my go big or go home mentality. I just started my project, so I figure I have to just plan on being single for quite a while.

 

So the question is, which philosophy do you abide by?

[Careless]

not to mention that the weight savings of an SR20 and the fact that you could throw it way further back in the engine bay allow the balancing of the car to be more adjustable to your liking.

 

And the SR20 has far more after-market support anywhere in the world than the RB20, it makes more torque and can handle 500+ rwhp on the stock bottom end. For an aluminum 4 cylinder, I'd say that's pretty darn good.

 

SR20's are pretty cheap now anyways. I'm sure buying one would save you money on parts because of the aftermarket... which would leave you with parts for the rest of the car.

 

But since you live down under, i'd consider an RB30DET using an RB25 head. Find a blown RB25 that had a rod thrown or something, and grab it for low cost, and get everything you can off it. After all is said and done and you're at the cost of your RB25, you will have a torque monster capable of quite a bit more power/torque than an RB26 at lower RPM, which is alway good. RB30 blocks cost us about 1000 here, and cost you guys about 100 there. If the crank is in good order, you just saved yourself about 1400 bucks.

 

you can use the stock RB25 pistons, or some ACL Race version ones. Use some Spool rods for about 800 bucks, some ACL or King bearings for about 200 a set, and some fine machining and balancing and just other regular maintenance items that you SHOULD be replacing after any swap anyways, and you got yourself a bigger, badder RB engine for about the same price as the RB26 engine alone, not including any work to get it in.

 

Check it: http://gdz1la.kol.co.nz/

[kiwi303]

Ok, this is pretty much the best thread I could find searching and so old I need not fear hijacking it since it's long since died.

 

I've been planning on a SR20DET engine swap since I like the SR20 platform. however I have the option of picking up a RB20E for piss cheap. However it's a Single cam rather than a RB20DET twin cam turbo. However I will then have the option of later when the budget allows, of finding a RB26DETT or RB25DET head off a motor that threw a rod through the block or something plus some turbo pistons.

 

I was speaking with a mechanic mate and he said a twin cam head will fit a single cam block with no further alterations than retrofitting the timing pulleys from the twin block over to the single block.

 

So what I want to know, is what is the maximum power the stock non-turbo RB20 crank and rods will manage to produce? I would like to just swap heads and pistons.

 

If I can fit the cheap RB20E for now, and upgrade it later, I'll be able to have my new Z on the road that much sooner

[getoffmyinternet]

Are rb20s cheaper over there and have more aftermarket support? Again the situation over here is that the sr20 makes loads more sense because it actually produces more torque and can rev higher. The only thing the rb20 is probably better at is long term potential, but that's thousands of usd away anyhow. That is unless of course they are a dime a dozen in nz... Careless' idea makes more sense, find an rb30 block in the same condition and do just like you said, forget salvaging an rb20 block.

[kiwi303]

well, RB30E and RB20E, while not a dime a dozen are still very cheap these days, it's usually possible to buy a late 80's shagged out VL commodore with either 2 or 3 litre RB single cam motors for less than the cost of a bare SR20DET motor.

 

Usually around $300 or so for a RB20E and $500 for a RB30E working motor and loom/ecu.

In this case tho I can get the RB20E a lot cheaper. the other cheapie I'm eyeing is an L20E on trademe.co.nz for $150

[getoffmyinternet]

Wow. I should have taken a trip to NZ. Yeah, don't know about that l20 though... It the aftermarket parts follow the same trend, the RB30 is definitely worth the extra $200, or you'll regret it later.

[Gritz]

Are rb20s cheaper over there and have more aftermarket support? Again the situation over here is that the sr20 makes loads more sense because it actually produces more torque and can rev higher. The only thing the rb20 is probably better at is long term potential, but that's thousands of usd away anyhow. That is unless of course they are a dime a dozen in nz... Careless' idea makes more sense, find an rb30 block in the same condition and do just like you said, forget salvaging an rb20 block.

 

Can rev higher? from everything i have ever read.. the rb20 is the rev king..8000 rpm out the box...the sr20 needs head and valve train mods to do the same...right?

[getoffmyinternet]

I thought it was just further weight and balance adjustments. I could be wrong. Still though...

[Careless]

Can rev higher? from everything i have ever read.. the rb20 is the rev king..8000 rpm out the box...the sr20 needs head and valve train mods to do the same...right?

 

i'd say the CA18 is the rev king if you want to compare like-motors.

 

being an RB25 with a casting block removed to shorten length and remove two pistons, I'd say the less rotational mass would allow it to rev higher, and it does.

 

so what if you have to do a bit of valve train work to the SR20.

it's still a rock solid platform. I would do that over the RB20.

 

but either way, the RB20 price is a phenominal performance package when you get down to it. it leaves a lot of room for 300 or so rwhp in upgrades out of a tiny iron block 2 litre, and they're pretty stoutly casted.

 

price point is quite good, and comparable to the SR20.

 

but that said, i'd take lighter weight over higher horsepower any day, unless it was a really really REALLY windy day. LOL

[PanzerAce]

 

but that said, i'd take lighter weight over higher horsepower any day, unless it was a really really REALLY windy day. LOL

 

 

you laugh, but I've actually noticed significant gains/losses in mileage because of wind. Course, by wind I mean gusting to 50mph

 

 

But here is another aspect for the thread reviver to consider: Torque/streetability. I don't know what specifically you are building the car for, but if you want to be able to drive it on the street alot and have fun, you need to make sure that you don't have to rev into the stratosphere before you start making power. I don't know the wtq figures for the SR20 vs. RB20, but I think you should look at that as well.

[Careless]

The reason I mentioned that was because I was tossed across 3 lanes on Ontario's busiest highway in my fathers Corolla. Not fun!!!! especially when the person behind you thinks it's some drunk crazy dude in a Corolla!

 

And ditto on the torque/streetability.

 

A friend of mine was telling me not to get a lightweight flywheel for my car @ 11lbs... said I would have to spin it fast enough to go back in time if I wanted to make driving easy.... BUT OH WELLZ.

 

Judging by the torque the standard 7.8:1 compression Z31 makes at 2000 rpm compared to all the other cars I've driven in a comparable power range, I'd say a 3.0 Litre RB with a light flywheel and 11.5:1 can leave on it's own if I'm not careful.

 

Either way, lightweight first, add power second. =)

[PanzerAce]

Either way, lightweight first, add power second. =)

 

Less weight is like having more power, except better

[m4xwellmurd3r]

Less weight is like having more power, except better

 

Invisible horse power

you can have a car that power wise on the engine looks quite meek, but still have it kill another car with way more power just because it's light weight.

it's actually the reason i REALLY like VW's for drag racing. my dad's NA 2332 bug ran a best of 11.96 at 107mph and only has about 250hp (wheel or crank on a vw doesn't matter too much haha)

[Xander]

Less weight is like having more power, except better

 

Lotus exige S comes to mind

 

[PanzerAce]

Lotus exige S comes to mind

 

 

That's cheating though, it's like strapping a hamster to an Aim-9 sidewinder

[Xander]

That's cheating though, it's like strapping a hamster to an Aim-9 sidewinder

 

LOL. one cool looking hamster though. I raced one of these wasps to about 130 mph on the freeway here in Holland. We were almost exactly matched in acceleration and speed. I had a decent running l28 turbo with about 15 PSI of boost at the time. He was surprised that I could stick with him. He told me later that He would out run the new BMW M5. We stopped at a traffic light to turn right. when the light turned green he floored it and before he exited the corner he was doing at least 60 mph. He was running track tires on the street and that combined with the low weight made that thing corner like a F1 car. His car was about 10 times more expensive than mine though .

[getoffmyinternet]

I've always been curious how long track tires would actually last on the street with mostly nondestructive driving, ex. burnouts in front of in-n-out... Soft tires are kinda like invisible horsepower too, and both good tires and lighter chasis add all kinds of fringe benefits. Who wants to help me make a carbon fiber/titanium 240?

 

The one thing I hate is when ricers completely gut the car to outrun people. Now THAT's cheating. Having a lightweight spaceage unibody is sweet, taking a 1985 POS with a 1.6L and removing everything down to the mirrors and antenna is just bootleg. A car without a passenger seat isn't exactly what I call streetable. ...But is a car with drag meats in the back and dimes in the front technically streetable? Hmm, where to draw the line...