1.8L budget turbo build for dummies

I've never built an engine (though I know the basics). I have (3) 1.8L Miata engines sitting on the floor, and I'm ready to get started.

The car will be a $20XX Challenger, but I want to do better. I've got the money in my budget for a basic engine build, and figured I ought to try to do it right (well, as right as you can on a Challenge budget).

The goal is a Megasquirted T3/T4 turbo with 250 hp on E85, as reliably as I can. Lots of boost, no nitrous.

What's your basic recipe? Tips/ tricks? Resources? Caveats?

Planning on doing any porting? Cleaning up the combustion chamber to remove any potential hot spots might help detonation. Also the more it flows the lower boost needed to achieve your power goal. Plus it's budget free.

eBay h beam rods, taken to machine shop to be resized if needed.

I don't have any tips, but please do a build thread, I'd love to see the collective wisdom you gather

icaneat50eggs wrote: I don't have any tips, but please do a build thread, I'd love to see the collective wisdom you gather

Yep! Here we are! Build thread- Voila!

Plenty of fuel. Intercool.

Surely there are more folks here that know something about building a Miata engine, aren't there?

So far, the collective wisdom of this thread has H-beam rods. There's gotta be more...

I'd be spending all of my time on the head, exhaust and tuning. At 250 hp, you don't need H beams. You don't even need to pull the valve cover.

In reply to Keith Tanner:

What if he really wanted 300+ whp for a few drag runs?

In reply to Keith Tanner:

You don't need them but he did say he wanted 250hp reliably. You can make 250hp unopened as you said but how long will it hold?

Start by 'free building' it. Dunno much about miatas but I read this a while back and it was a good article.

http://www.motoiq.com/MagazineArticles/ID/1347/FrankenMiata-Part-I--Freebuilding-the-Engine.aspx

Geez, you guys are rough!

I want to do 250 hp reliably, and will push it past 300 for a few drag runs.

In reply to Keith Tanner:

OK, let me word it differently.

How much power can I reasonably achieve in short bursts for the Challenge, and later maintain reliably in a track-use car IF I am willing to put the effort in to do a budget build of a 1.8L big turbo E85 car?

What recipe would you recommend?

Let's say I am willing to put $500- 800 into engine internal parts and/or machining.

Robbie wrote: Start by 'free building' it. Dunno much about miatas but I read this a while back and it was a good article. http://www.motoiq.com/MagazineArticles/ID/1347/FrankenMiata-Part-I--Freebuilding-the-Engine.aspx

That's a really good article, and I love the way he writes- Thanks!

MrJoshua wrote: In reply to Keith Tanner: What if he really wanted 300+ whp for a few drag runs?

Make a 250hp engine, and turn it up to 15 for the drags. It's the last moving event- if it fails, no biggie.

That was our logic to push 8000 rpm on our engine.

chiodos wrote: In reply to Keith Tanner: You don't need them but he did say he wanted 250hp reliably. You can make 250hp unopened as you said but how long will it hold?

Decades. Seriously. We've got a customer who's gone past 400,000 miles on his. The clutch pedal broke in half at 300,000. We run stock engines at that power level all the time and we haven't catastrophically damaged one since some time in the early 90's. We've worn out a few, but that's what happens when you start with a junkyard engine and run it on track for a few years.

SVreX wrote: In reply to Keith Tanner: OK, let me word it differently. How much power can I reasonably achieve in short bursts for the Challenge, and later maintain reliably in a track-use car IF I am willing to put the effort in to do a budget build of a 1.8L big turbo E85 car? What recipe would you recommend? Let's say I am willing to put $500- 800 into engine internal parts and/or machining.

So now you're changing the rules. You don't want 250 anymore, you want 300. And if you get that, you'll want 350. I get this all the time in phone calls from kids who read too many forum posts.

$500-800 into parts and machining - I'm going to stick with my original plan. Work on the head. Maybe throw some new rings in there so you have good combustion chamber sealing. Start with the required parts for an engine rebuild such as bearings, gaskets and seals. This is assuming an engine that's intended to live longer than the Challenge, otherwise I'd reuse as much as possible to fit the budget.

Figure out what machining you'll need to pay for - I'm assuming that you're willing to lap your own valves and do your own dremel work. With your remaining budget, figure how much you can actually spend on parts like pistons and rods - remembering that you'll probably have to get the block bored if you go for pistons. And are you willing to gamble that those cheap pistons and rods are actually any better than the proven stock parts? If you've only got a budget for pistons OR rods, I'd go with rods for this build. I'd rather see a good set of rods than a cheap set of rods and pistons, especially with E85.

Keep in mind that E85 is going to require fuel upgrades all the way down the line. You're going to need to move a lot more of it, and all your new parts will need to be E85 compatible. If you're on a Challenge budget, that might be a better place to spend your money.

In reply to Keith Tanner:

You're right. I changed the rules.

But you changed them first by answering my "How to do a budget build" question with "Don't build it- run it stock"!

I appreciate your well-reasoned answers- that's why I asked.

Not trying to be a starry-eyed kid reading too much on the internet, but you've got to admit, the Challenge will do that to people!

I am trying to approach the Challenge a little differently this year. I want to put the time and effort into a car that will have value after the event, not just all the cheap crap parts I can throw at it to see what it takes to blow it on the drags.

This setup sounds familiar

Spend your effort on the manifold and fueling (big ass injectors & tuning). A healthy 1.8 will be plenty strong for a short amount of time at least. Stock fuel system is fine with E85, or at least that was the case for us.

I'm not sure how much power we (Texas A&M) were making at the drags, but the engine wasn't holding us back. We would have cranked the boost higher than 18psi if we had traction, and I bet the 5-speed would have gone first.

The exhaust ports need some work to get a quicker spool, and the intake ports really need to be cleaned up and wet-flow balanced to ensure that you don't get a lean-running cylinder. The 1.8 heads have notoriously inconsistent intake ports, to the point that serious Spec Miata engine builders will reject 3 or 4 heads before finding one with all four intake ports equal enough to make front runner power levels.

SVreX wrote: In reply to Keith Tanner: You're right. I changed the rules. But you changed them first by answering my "How to do a budget build" question with "Don't build it- run it stock"!

You gave a goal, I gave my opinion on how to reach it! As we say when troubleshooting at work, what's the REAL question?

We've done some testing on various rubber parts and fuel components with E85. They don't all fare well. If you're planning on long-term use, you'll want to address that. Short term, you can probably get away with it.

Why e85 out of curiosity? Just doesn't seem worth the hassle to me.

daeman wrote: Why e85 out of curiosity? Just doesn't seem worth the hassle to me.

Much higher octane will help with boosting, and not lowering the compression- that's the big carrot for this build.

Cooling the intake charge is a secondary carrot.

And having a richer LBT that makes power is a third carrot.

http://www.enginebasics.com/EFI%20Tuning/E85%20vs%20Meth%20Injection.html

http://www.turbomirage.com/water.html

Rmon wrote: This setup sounds familiar

It should.

Since imitation is the greatest form of flattery, you should be tickled that I flat out stole it from you.

...although I would add that our plan was always to do it. Just didn't pull it off last year, and watching what you did convinced me I was right.