Ultimate Na Rb20

[zebra]

i'd be more inclined to say more around the figure of 100hp more than what a worked rb20 would make. i think that even getting to 200hp in a rb20 would take a fair bit. not saying it couldn't be done, but it would be a fair bit of work (and money) getting there judging by how much it takes to get a rb25 there.

and look i'm all for doing something different, but when it comes to building an engine to go into a race car, why bother building something when there are other options out there that will do the job better? going something like a sr20ve would give you 20 to 30% more power, and a less weight. we aren't just talking about building something to be different to show off to people with. we are talking about something to win races with, so why not give yourself a good platform to start with, especially when you are talking about a motor that is putting out nearly 40kw more in stock form.

The 36mm restrictor only allows around 300hp on any engine no matter how big the turbo.

There is an IPRA corolla with a 3S-GTE in it that runs a GT30 turbo, without a wastegate!, so it runs about 22-23PSI through the mid range but then tapers off to about 14psi at redline due to the restrictor and makes around 290hp on race gas.

[iseekool]

The OP mention he is not allowed a turbo, and I imagine he may need to keep the same "original engine". As good as the SR20VE maybe - it may not meet regulations.

Maybe we have to take a step back from the "max amount of power I can get" mentality and possibly more towards reliability and engine response side of things (nothing wrong with more power - maybe look at it from a different angle - is what I'm trying to say).

Since you will be revving the engine quite hard constantly - engine balance, oiling systems and cooling would be the first things to look at.

As with any race engine build - reliabilty should be right up there with performance, no point having all these KW and having the engine break down on you...

[zebra]

If it is improved production than he can turbo it...it will just be in the Over 2L category.

Engine also needs to have the same amount of cylinders as per factory.

So while we have all said sr20 is the best bet....if its a skyline you want to race than you cant do it.

But..

a 32 chassis will be 300kgs heavier than the honda's so even if you could get 300hp NA outta the 20 it wont be enough to be at the pointy end.

Best bet would be to start with a S series chassis imo

[mad082]

If it is improved production than he can turbo it...it will just be in the Over 2L category.

Engine also needs to have the same amount of cylinders as per factory.

So while we have all said sr20 is the best bet....if its a skyline you want to race than you cant do it.

But..

a 32 chassis will be 300kgs heavier than the honda's so even if you could get 300hp NA outta the 20 it wont be enough to be at the pointy end.

Best bet would be to start with a S series chassis imo

r32 did have a 4 cylinder option (ca18)

iseekool, what you said about response, having a built rb20 is going to mean having all the power at very high revs (as you are going to need a high reving engine to actually get the power). that isn't always a good thing. makes it slower off the line as you will either have to slip the clutch to keep the revs up high until you really get going, or you will have to just fry the tyres. that would be a similar problem as to what the hondas would have though, but since they are in a much lighter car and would probably be putting out similar sorts of power to what a rb20 could, it wouldn't be so much of an issue.

[iseekool]

r32 did have a 4 cylinder option (ca18)

iseekool, what you said about response, having a built rb20 is going to mean having all the power at very high revs (as you are going to need a high reving engine to actually get the power). that isn't always a good thing. makes it slower off the line as you will either have to slip the clutch to keep the revs up high until you really get going, or you will have to just fry the tyres. that would be a similar problem as to what the hondas would have though, but since they are in a much lighter car and would probably be putting out similar sorts of power to what a rb20 could, it wouldn't be so much of an issue.

Your right there Marc - maybe a work around would to have slightly lower geared diff to compensate - only problem would be on wide open tracks with long straights...

[SKiT_R31]

Your all negative nancy's. I'd be aiming to make peak power at about 8000rpm, you want the most rediculous cams you can find, adjustible gears for fine tuning power, matched length inlet runners (doesnt have to be ITB's, at the cost of responce you could get a better tune with a large single) and exhaust pipes (for that RPM) decent headwork and oversized std valves (not titanium), lightweight pistons, aim for a compression ratio in the mid 12's, but do it properly (with the pistons coming out past the deck, as far as the thickness of the headgasket) then get really good management and get a good tuner to tune it properly.

You want the tuner to monitor EGT's, to run the optimal fuel mixture (between 12.5-13.2) and the maximum ignition timing without creating too much heat or causing detonation.

General lightweight gear (flywheel to wheels) and 4.4 diff gears, it wont be slow, easy >200hp then just ring its neck. It doesnt take rediculous amounts of power to go fast, it really depends what its for.

If you get all the supporting mods sorted (oil pump, lifters, balencing - from balancer to clutch and everything in between) it will be a beast, and the power it makes could suprise you, providing you do your math right and ensure everything is 100% matched for a peak torque and power at the same spot. You need to talk to a really good professional engine builder, dont go to an RB specialist, go to somone who can get 200hp out of an oldschool pinto, and they'll work wonders .

[Chris-06R]

Good to see there's plenty of opinions, thanks for the replies all.

Some good points have been raised, here's a few things to clarify.

Improved production rules state that the engine block must have the same number of cylinders as was available in the original car, and must be from the same manufacturer. So for those who have mentioned it, you could run an SR powered Skyline if you want to.

This also means you could put this fantasy 200hp NA Rb20 into a light(er) R30 or R31 chassis - but that said, you should be able to strip an r32 down to a similar weight and make use of the updated suspension components.

And to be a front runner, well if we use the Civics as a benchmark, they are using engines which put out around 150kw from the factory, so you'd have to assume in race trim they would be up around 180kw??? (at the engine). They are also in a chassis which weighs around 1150kg from the factory.

But then again, you don't necessarily have to run at the front of the field to have fun (and besides, did anyone even listen to this thing?

[zebra]

I know you want to run in the U2L catagory, but why not run in the over 2L with a twin cam RB30 or a 25.

There isnt much weight to be taken out of a 32 in IPRA because you has to run factory panels and glass.

I dont want to sound like a negative nancy, but there are reasons that there are next to zero skylines in IPRA, because they are so restricted by the rules.

[Rowdy]

just do it!

[Dearlove]

well revs will be your friend

how bout using an rb25 and destroking it?? custom crank and rods (not as expensive as you'd think)

plus some one mention the power stroke on an 8 cyl is 45, sorry its actually 90 like the 4 pot, hence why any engine with cylinder's of multiple's of 3's are the smothest, not a v8

[iseekool]

well revs will be your friend

how bout using an rb25 and destroking it?? custom crank and rods (not as expensive as you'd think)

plus some one mention the power stroke on an 8 cyl is 45, sorry its actually 90 like the 4 pot, hence why any engine with cylinder's of multiple's of 3's are the smothest, not a v8

Actually I think we are both wrong.

I just did some research (because I was curious)

I4 fires every 180 degrees

I6 fires every 120 degrees

V8 fires every 90 degrees or 180 degrees - depending on engine design.

Anyways here is a good read ---> http://www.autozine.org/technical_school/engine/smooth1.htm

It talks about engine designs.

[GTS4WD]

In short,

SRDE/T = S13 because of less weight

Sr16/20VE = N15/N14/N13 because of less weight.

Fj = Dr30, again less weight.

In all honesty, If you want to race in IPRA, id go a turbo car. Chance are, your not going be highly ranked in the over 2L/turbo class, but you will be involved in the middle of the field mixing it up with competitors and thats what you want if your in IRPA, to be involved with other racers in a race environment.

My best best - Rb25DET in a 32, basic engine mods and attention spend on brakes/rubber/suspension.

[Gerg_R31]

im pretty sure the rb20's have the same size hydrualic lifters as the rb25, and ive done a few rb25 solid lifter conversions at work

plus camtech has on their website rb20/rb25 so quite possibly you could run with the rb25 cams in your 20 head, bit of porting, port match the intake manifold, can the injector part off the manifold weld a plate onto it and drill holes to suit the rb26 ITB

my curent rb30de build is expecting to pass $15k easy (almost built just waiting for full license in november)

[XRATED]

I'd start with a cheap throw away motor to trial on:

I'd get a cheap 20de, machine the crank down to minimum weight then ballanced, open up all the oil galleries etc... GTR tb's are 45mm each- thats alot of blade area for a 2lt engine, but they're cheap and relativly easy to fitt. Machine the block/head down to a good comp ratio and invest in some crazy cams/lifters. Good exh manifold...

Re-tune the stock ecu and see how it goes...

All up it shouldn't cost tooo much if its a flop. If you see good gains, then throw al the good gear into a race engine with short skirt forgies, better manifold/runners and ecu.

I say dooo iiittt!!!

Or if it really sucks- throw 300hp worth of nitrous at it on methanol!!!

[Chris-06R]

Good to see a few people with enthusiasm for the project

For those who wanted to use a SR20ve... Have you seen any examples of people mounting them longitudinally (such as using them to replace a SR20de or RB?) From what I can tell, this is going to be much more expensive and difficult than building up a fancy rb20, but by all means prove me wrong.

As for expense.... it does build up quickly. Browsing through some of the gear, prices like $400 for valve springs, $1200+ for rods etc certainly make me stop and think. Maybe using a $100 wrecker motor bottom end is the way to go while developing the head.

[screamin']

I'd go SR20 for track use. Way more off the shelf stuff and easier N/A hp.

Only reason I'm running an RB20 is because that's what the car came with and it costs me nothing to spend hours fluffing around with it.

Also, I reakon the sound better, and that's half the fun!

http://www.youtube.com/user/jasestu#p/a/u/0/jpoqHb4CkAg

[zebra]

Good to see a few people with enthusiasm for the project

For those who wanted to use a SR20ve... Have you seen any examples of people mounting them longitudinally (such as using them to replace a SR20de or RB?) From what I can tell, this is going to be much more expensive and difficult than building up a fancy rb20, but by all means prove me wrong.

As for expense.... it does build up quickly. Browsing through some of the gear, prices like $400 for valve springs, $1200+ for rods etc certainly make me stop and think. Maybe using a $100 wrecker motor bottom end is the way to go while developing the head.

The silva guys are going nuts with VE heads...maybe have a look on nissansilvia.com

have you thought about a VQ20? would be quite different, but not much off the shelf for them.

[iseekool]

The silva guys are going nuts with VE heads...maybe have a look on nissansilvia.com

have you thought about a VQ20? would be quite different, but not much off the shelf for them.

If budget and requirements are met. Why not go a VQ35 - torquey engine and lots of N/A aftermarket support.

[SKiT_R31]

wtf people his chosen his engine.

[mad082]

that doesn't mean it's the right/best choice, LOL