N/A 818 Build

[EvilJack]

I realize there is another thread, but I wanted to discuss building a N/A 818, with no plans to turbo later, without hi-jacking his thread.

To keep this post short and to the point, I plan to do a full tear down and rebuild of the engine and transmission. While 200 whp would be nice it's not a neccesity. I am more concerned about building a durable and smooth running drive train.

I have been reading about transmission breakage I high HP engines. Is this still a big factor if running 200 whp or less?

Other then that I guess my basic question is what kind of parts and upgrades should I look into?

[shinn497]

NASIOC is your friend. (http://forums.nasioc.com/forums/showthread.php?t=1022154). Don't know too much about N/A subbie power but it doesn't seem like you can get much more than 15-20 hp without a lot of money or picking apart your engine. Compared to the 60hp gain from just a stock turbo and much more with bolt ons this is paltry. But n/a builds aren't really about power IMHO.

in a nutshell, the recomended upgrades are exhaust, intake, header, and then camshaft. Also lightweight flywheel and weight reduction ( if that is even possible

Read some of the other threads in particular phyrra's. They detail how older models are still compatible (possibly). It will still be a performance car probably comparable to an S2000 or BRZ in terms of power/weight and eclipsing them in handling. '

As for the tranny. Anything can break if used improperly, but the chances are much lower with this power to weight. I don't think it will be an issue and it we've had lots of debates on this, so it is hard to actually know.

[EvilJack]

Yeah I am not building this car for HP gains, but if there is any thing I can do while the engine is apart that will help I might as well look into it. Of course I don't want to go crazy spending money building up a N/A motor. Not sure what can really be done about the exhaust. That will probably end up being a custom set up as it is.

Also I think I read somewhere in the transmission debate that lightweight flywheels aren't a good idea on the subie.

[apexanimal]

getting to 200hp n/a is going to be tough... the basic n/a mods on an rs/2.5i are:

elh
good 2.25" exhaust
smooth intake after the airbox/before the tb
coolant tb bypass
some way of insulating the intake mani
lightened crank pulley
lightened flywheel (anything under 14lbs will likely throw a cel, and will affect stop and go driveability)

[Xusia]

This came from another thread, but here is some excellent, detailed information on building a AN engine: http://forums.nasioc.com/forums/showthread.php?t=1022154

It appears to me to be fairly easy to get close to 200hp. Given how much you'll save on the donor, you could spend some of that on performance.

[riptide motorsport]

what about a small shot of nitrous on these cars?

[Gary in NJ]

The items mentioned above are typical of "bolt-on" performance parts. To get you above the crowd you would need machine work on the heads and block including:

1) porting and polish the intake and exhaust ports
2) deck/shave the heads
3) overbore the cylinders

I prefer n/a power over forced induction as well. I'll be looking for a high mileage (read: cheap) donor, so a rebuild of the engine will be in its future. While the engine is apart is the right time to perform the upgrades noted above.

[305mouse]

If you bore it out, go with forged internals, get the compression higher, get the heads ported so they flow nicely and so on, I think you would have a nice build. It's going to be apart anyways, might was well upgrade all the internals. I think the head work and cams are going to make the biggest improvement.

[Oppenheimer]

It will still be a performance car probably comparable to an S2000 or BRZ in terms of power/weight and eclipsing them in handling.

The power/weight ratio will be much better than BRZ, and slightly better p/w but much more torque than S2000. I think a N/A 818 will still be a shockingly fast car (when compared to stock production sport oriented cars). Not to mention crazy fun to drive.

BTW, I am eager to see how the BRZ stacks up against the S2000. Car mags always want to compare currently available production cars against each other, but to my mind, BRZ vs used S2000 is the comparison I'm interested in knowing about.

[EvilJack]

Yeah I figure it would be good to do more then bolt-on's while I have it apart. If I do overbore is that going to increase fuel consption greatly? I realize just about any performance increase tends to do this especially if your heavy footed. I don't want there to be a huge decrease though.

Also, if I choose to shave the head, and not overbore, should I still use forged internals since I will still be increasing compression?
I have thought about adding nitrous since I have a kit sitting around, but I thInk I prefer not to.

[PhyrraM]

IMHO, any 2.2 or larger N/A donor will be a great choice. There is nothing wrong with N/A builds, and only get a bad name because when factory turbo cars/parts are available the dollar per horsepower needle swings far and fast to the turbo builds. $500 spent on a factory turbo motor will likely net 3x the power than spent on a N/A motor. However, 3x the power does not neccisarily = 3x the fun.

As far as the converting a normally aspirated engine to turbo, the same thing applies. It's all well and good when talking about Hondas and Toyotas that have no factory turbo parts, but for some reason doing the same thing to a Subaru is insane? Hogwash. At low boost, a stock N/A Subaru motor will handle it just as well as doing the same thing to a Civic or old Corolla. You just have to be as careful and keep your expectations reasonable.

How's this for a 'doable' low buck build:

'89-99 phase 1 (early phase 2), DUAL exhaust port (important, some are single) 2.2 liter SOHC motor. These early SOHC heads are small enough for a discarded OEM WRX exhaust header/upipe to fit (hence the dual port requirment). (The later SOHC heads are too big for cheap OEM headers to fit). Cheap discarded WRX turbo. Fabricated oil and water lines to the turbo. Fabricated piping to throttlebody - intercooler if desired. Old school rising rate FPR and a old school used eBay SAFC. Wastegate boost (~6psi). An upgrade that also fits a OEM WRX exhaust setup is the phase 1 DOHC heads - they will run on the same ECUs as the SOHC.

Why? Little known fact...ALL the phase 1 motors (EJ18, EJ20, EJ20turbo, EJ22, EJ22turbo) used the same crank and rods. The same oil pump. The same bearing clearances. Yes, lowly 110HP 1.8 liter motors had rods designed to support 250HP+. All had cast pistons, later turbos had HyperU type - but still cast. Forged pistons were only in STIs and even then not all. Open deck blocks are still good enough for at least 350HP. This leave the weak link on a early N/A 2.2s as the pistons. Keep it sane, don't get greedy. Keep it withing your chosen style of EM. I don't see the problem.

[NonProfit]

If I do overbore is that going to increase fuel consption greatly? I realize just about any performance increase tends to do this especially if your heavy footed.
As you increase displacement, fuel consumption will increase as well. However, the increased displacement caused by rebuilding will pale in comparison to fuel used during fast acceleration. With this lighter chassis and increased efficiency of a rebuilt motor, if you're careful, you'll likely see MPG improvements (as compared to the stock donor) regardless of the drivetrain you pick.

[Oppenheimer]

IMHO, any 2.2 or larger N/A donor will be a great choice. There is nothing wrong with N/A builds, and only get a bad name because when factory turbo cars/parts are available the dollar per horsepower needle swings far and fast to the turbo builds. $500 spent on a factory turbo motor will likely net 3x the power than spent on a N/A motor. However, 3x the power does not neccisarily = 3x the fun.

As far as the converting a normally aspirated engine to turbo, the same thing applies. It's all well and good when talking about Hondas and Toyotas that have no factory turbo parts, but for some reason doing the same thing to a Subaru is insane? Hogwash. At low boost, a stock N/A Subaru motor will handle it just as well as doing the same thing to a Civic or old Corolla. You just have to be as careful and keep your expectations reasonable.

Yeah, but a similar rule applies, $500 spent trying to put a Turbo on a N/A motor that already had a factory Turbo option is not cost effective (and probably requires more than $500). Why not just put that same effort into getting a WRX motor instead of trying to add Turbo to 2.5 RS. You'll end up with a better result for less $. Yes, it may not be any more effort or risk to add Turbo to 2.5 RS than add Turbo to Civic whatever, but just getting a WRX donor = so much easier & cheaper in the end.

[PhyrraM]

Yeah, but a similar rule applies, $500 spent trying to put a Turbo on a N/A motor that already had a factory Turbo option is not cost effective (and probably requires more than $500). Why not just put that same effort into getting a WRX motor instead of trying to add Turbo to 2.5 RS. You'll end up with a better result for less $. Yes, it may not be any more effort or risk to add Turbo to 2.5 RS than add Turbo to Civic whatever, but just getting a WRX donor = so much easier & cheaper in the end.

Completely agree. Just trying to clarify a few things and add options so folks can make informed descions. Statements like "Don't turbo an RS, it's a waste." are too vague and peeve me bit.

For example:
IF you already have a N/A build
AND IF you hate wiring and harness
AND IF you are looking for more power then a header and intake can give you
BUT not so much as to justify a built motor
THEN, maybe a low boost N/A build is fair to consider. (or maybe not, but it's not MY descion)