How to build an NA engine...

[gianttomato]

Agree 100%. I just had a small problem with generalisation.

No doubt with cams, head and the bottom end to survive the 9000 rpm excursions, I'll be seeing much bigger numbers.

Hp/$ ratios aren't a consideration, otherwise we'd all be doing turbos. Big hp NA motors are expensive creatures - full stop.

[ed]

erol's engine for example...
heres the engine assembly as tested in BOTH dyno tunes below (engine dyno)




dyno on STOCK long block/heads from japan. with everything otherwise set up as above

307 BHP @ 6500rpm, 271 lb/ft @ 5000rpm.



dyno on radically customised long block/heads, otherwise exact same setup above

534 BHP @ 8400rpm, 338 lb/ft @ 7800rpm

[Fish]

Hp/$ ratios aren't a consideration, otherwise we'd all be doing turbos. Big hp NA motors that last are expensive creatures - full stop.

Fixed.


Good topic too ed_jza80

[jfallen]

Great post, and well worth the read in mainly the Qualitative sence. Piston speed limits are always interesting. If anyone wants to download a calculator let me know, I'll email you one. What you've said rings very true, NA power = $$ especially on small displacement engines.

I'm almost to the stage of strapping my 4AG toghether (Twin solex's with trumpets, Extractors, balanced bottom end, 12:1 forged pistons, ignition only computer, metal HG.)

Unfortunatly while the bigport 4AG head is rather over engineered (as far as port sizes are concerned) I've had to leave the stock cams and springs in at this time (which sucks.) As soon as cash allows I'll be swapping in some larger cams, stiff springs and adjustable gears to complete the package. Because as you say the engine is a system, and everyting needs to work together.

The RT40 should really boggy
Jordan

[Mos]

i do want to clarify - im not talking about twaeks and fiddling to improve performance ~10%. im talking about building an NA engine that makes numbers

<snip>find me someone who has spent considerable money on 'stage 2 cams' and all the associated labour and costs (new timing belt, reshimming, assembly lube and new engine oil etc) who 6 months later isnt a bit *meh* about the whole thing... <snip>

anything significant and markedly effective for an NA engine IS uber expensive or time consuming (or both)

I would consider headers and an ECU to be "markedly effective" on a 1UZ, but I wouldn't consider it to be uber expensive - expensive yes, but not uber expensive.
It's hard to judge what the stock engine would make with factory exhaust and factory management, however it cannot be ignored that they make a difference and I doubt that difference is as low as 10%.

The only other thing I would like to add, is that my headers were made (more or less) to suit the factory engine - Peewee's were made to suit the earlier 1UZ (they use smaller diameter pipes than mine) and your engine will have larger diameter pipes again - in this case I agree that bolting on *your* headers to a stock engine won't have the effect that they will on your engine and thus would make little sense.

Bang for buck modifying atmo engines is usually plainly illogical

I'm with GT and the small problem with generalisation

yes, but ill make you use my injectors

Why, you reckon it will have the headflow to use them?

Mos.

[ed]

no, i just want the more customised map

generalisation = appreciation by a wider audience

[takai]

Good read Ed, just reminds me yet again what sort of pain im in for next year...... I thought last year i had had enough of Ansys Workbench.

[Sciflyer]

( a 5 litre V16 just can't quite make the same power as a 5 litre V8)

Theoretically maybe...

[JustCallMeOrlando]

I would consider headers and an ECU to be "markedly effective" on a 1UZ, but I wouldn't consider it to be uber expensive - expensive yes, but not uber expensive.
It's hard to judge what the stock engine would make with factory exhaust and factory management, however it cannot be ignored that they make a difference and I doubt that difference is as low as 10%.

Headers aren't always super effective, it depends which model UZ it was. The LS400(?) ones flow pretty damn well, whereas some of the others are terrible.

[gianttomato]

Theoretically maybe...

You plan to get around the frictional losses and extra mass how?

http://www.youtube.com/watch?v=oWorVoeZd3A

I stand by my argument that everything can be related back to The Simpsons.

[Mos]

Headers aren't always super effective, it depends which model UZ it was. The LS400(?) ones flow pretty damn well, whereas some of the others are terrible.

Mine were LS400, cast, larger diameter than the early ones, and much much better for flow (possibly an upgrade for the earlier 1UZs?), but I still doubt the engine would make much more than 160rwkw with them (I'd love to be proven wrong).

BTW, the stainless LS400 ones, while better than the crown logs, are still crap - I have a set, can supply photos (in another thread) if required

Mos.

[Nim]

Good post, and I totally agree with your statement that single bolt on mods don't work very well for an N/A engine.

As you said, there are tweaks you can make to get rid of some restrictions placed on an engine for emissions, or cheapness of production purposes, but beyond that you sort of have to replace everything.

I've noticed this with my DC2 Integra with the B18C2. A lot of people have modified their Integra with a cat back exhaust or full exhaust with extractors, pod filter or a proper CAI etc. And they find that their car's aren't as quick as my bog stock standard Integra. And if you look at some of the professional advice for modifying a Type R B18C5 or C7 and it seems to follow the line that everything else should be done first, like brakes, suspension, flywheel and clutch before you go anywhere near the engine. Then when you do touch the engine, do everything at once, from extractors to cams, to head work, to valve springs, ECU etc.

You plan to get around the frictional losses and extra mass how?

http://www.youtube.com/watch?v=oWorVoeZd3A

I stand by my argument that everything can be related back to The Simpsons.

Thermal efficiency of a smaller combustion chamber, shorter stroke and higher revs?

[Norbie]

Nice essay Ed, I'd rep you but apparently I've been loving you too much.

then they quit NA and go turbo or SC as its cheaper and requires less thinking?

That's me! Now where's my screwdriver, I could use an extra 50hp today.

[jezza323]

good post mate, should get some of those honda boys to read it....some of them seem to think they can rev their VTEC's to 12,000 rpm just by pulling it apart and balancing it....they also think this will give them most awesome powah!

on the subject of rod:stroke ratios, if you had a choice of a 1.5L with a 1:1.5 rod/stroke or a 1.33L with a 1:1.525 ratio....which would you choose? (yes both are not good ratios, but thems the options)

[ed]

no replacemet for displacement