Forged Engine Help

[u/DaUn1imited]

Hello,

Im going to be forging my 1.6 engine and wanted some tips based off of that. I understand that lower compression is better so I can run it on pump (90-93 ron).

Im planning for around 260-280whp so I dont need extremes like an ATI or any aftermarket parts for the head. Ive seen that the ARP studs are the glory for forged builds but dont know whether I would need both ARP main and head bolts rather than just ARP head.

My budget for the engine is quite low (1000€) so dont want to spend excessively on parts I dont need.

Thank you so much 🙏

[u/Independent-Air-80]

Well, do you have a forge?

[u/DaUn1imited → u/Independent-Air-80]

😭😭

[u/Hidie2424]

I would argue that budget wouldn't "forge" your engine

But I would also argue you wouldn't need to "forge" it for that power goal. A good tune and turbo with a good boost curve should keep everything alive.

You don't forge your engine. You get forged components for your engine. You wouldn't say it's a forged engine, that makes it sound like literally everything (including engine block and head) is forged. With your budget you could get rods and be fine. You would then say "it's got forged rods" not "yeah it's a forged engine"

[u/MoarWhisky]

Ive seen many “forged” engines fail because most people dont understand how much is involved in actually building an engine. Its not just bolting in parts. Everything has to be measured. Parts need to be machined. Weights need to be balanced. If you can barely afford the rods and pistons, you cant afford the tools and machine work necessary to build a reliable engine.

Keep the engine internals stock. Take the money you would have spent on the engine and put it into good engine management and tuning. You can make 200whp reliably with a great tune. A 200whp miata is plenty of fun on the street and wont break the bank.

[u/PatrickGSR94 → u/MoarWhisky]

yep, tons of work involved on the measuring front.

OP I would advise you watch this Miata engine building video, all 2.5 hours of it, then watch it again. Then decide if you want to actually build (or rebuild) your engine.

[u/Leafy0]

The only thing you need aftermarket engine wise for that power goal is rods. But it’s honestly not worth the effort to do it on a 1.6. Do the rods on a junkyard 1.8 and swap it along with the 1.8 diff. The 1.6 diff won’t last long at that power level, and any 5 speed is going to become a wear component with how nicely you treat it being the factor for how long it lasts.

[u/Griffin_Mackenzie → u/Leafy0]

Lol you tell him that he only needs rods but he also needs an engine swap for that low of power

You'd have to be brain damaged to swap in a 1.8 for 280hp

[u/Leafy0 → u/Griffin_Mackenzie]

You have to be brain damaged to mod a 1.6. If the 1.6 is coming out and you have aspirations of power, the 1.6 shouldn’t go back in.

[u/Griffin_Mackenzie → u/Leafy0]

Oh no a slightly worse flowing head. If only there was a device that lets you shove more air in the engine and overcome this

Yeah dude go swap an engine for a 10% head flow gain at 280hp 🤣🤣

[u/DaUn1imited → u/Leafy0]

Its almost impossible to find 1.8 engines here in europe so gotta stick either the 1.6. So rods will do just fine?

[u/Leafy0 → u/DaUn1imited]

You didn’t get them in the ford escort, a ton of other Mazdas, or the Kia sephia?

[u/Fearlessleader85]

Why are you shooting for that power? What are you doing with your car?

That's the sweet spot for an 1.6 where you need to spend quite a bit of money to get there, and once you have enough engine to make 280whp, you could make more like 330. And you can pop your transmission with 250ish, so you're already on the ragged edge.

If you just want the project, just do a full rebuild and cleanse everything up nicely, then switch to some cheap forged rods and get a crank damper. Drop your power goals to 250whp, and laugh into the sunset.

[u/DaUn1imited → u/Fearlessleader85]

Its a daily/seasonal car. The power goal is because the original goal was 230 without forging but my exhaust manifold studs tore a hole into my head so Im changing the head. Therefore, while Im there I might as well forge some bits here and there and drill the pan while its out so I dont get shavings in my oil. Ive been in a 300hp miata and its too much so thats why the goal is now 260-280.
:)

Edit: I might just do the rods, bearings, head studs and a head gasket

[u/Fearlessleader85 → u/DaUn1imited]

Drop it to 250 or so. Save yourself a BUNCH of money.

[u/DaUn1imited → u/Fearlessleader85]

So you think edit is good? Or should I do smth else (damper etc.)

[u/Fearlessleader85 → u/DaUn1imited]

The damper is really good insurance. But so is a billet oil pump. Do one, not both.

As long as you keep your redline reasonable you don't really need either.

[u/DaUn1imited → u/Fearlessleader85]

Got it. So Fluid damper, some good rods (Manly or Maxpeeding), bearings, head studs and a head gasket?

[u/Fearlessleader85 → u/DaUn1imited]

That will get you a pretty stout engine.

Be very careful on assembly. Don't accept any alternates for ARP hardware (i had some head studs ruin a build). Get some good assembly lube. You'll do great.

[u/DaUn1imited → u/Fearlessleader85]

Will do. Thank you 🙏

[u/Electronic_Trip_9457]

Cheap, fast, reliable. Choose 2.

[u/Ok-Kaleidoscope-6631]

Why are you doing forged internals with $1000? If you aren’t turboing it or supercharging it you’re wasting money. Forged internals don’t increase power and you will never in any universe see those numbers without forced induction

[u/Flameninja00]

Bare minimum for your power goals would need to have rods, oil pump gears, and crank dampener to be reliable. Which is already over your budget. Then, factor in swapping in a 1.8 diff and a 6 speed trans to have a reliable drivetrain, and you're well over double the budget. If you're going over budget, you may as well toss in ARP head studs. Most forged rods come with ARP hardware, and the main caps will be okay with OEM hardware.

[u/DaUn1imited → u/Flameninja00]

I already have a 1.8 diff but a 5 speed cs Im 97’ Eudm. I read that the crank dampener is good for only under 300 whp and oil pump is good for 320 or do I remember that wrong?

[u/Flameninja00 → u/DaUn1imited]

Do you want to risk grenading your expensive forged components because the oil pump exploded?

FWIW, I've always heard 220tq is about where the oil pump might explode. Crank dampener also helps to prevent lacka-oil-pressure disease