NA leading to FI
 

So my first train-wreck soliciting advice (https://www.miataturbo.net/diy-turbo-discussion-14/weakest-links-chain-89763/ ) sent me off with my tail between my legs.
Subsequently, I have followed Braineack’s advice from the sticky-ed uber-thread and read what I can find of Maximum Boost. This is all the answers to all of my questions, though I’m sure I’ll have more once I understand more fully.
Since I’m much more comfortable with the workings of a traditional NA engine, I’m thinking that a foray into NA tuning might be advisable before attempting FI. However, I still want to boost eventually. With that in mind, I hope you guys could advise me whether I’ve reasoned correctly on the following: I have laid out a plan for a decent induction set-up; head mill, gas-flow, port match; oversized valves; overbore; bigger injectors; stroker kit with high compression pistons; Tomei cams; ECU; decent header.
My reckoning is: the induction kit can possibly be cannibalised when turbo-ing, the engine work surely benefits a FI engine as much – if not proportionately more – as a NA engine, I have seen Tomei cams discussed in both NA and FI builds, and on the 949 racing site it vaguely and briefly mentions that they can be useful to either set-up. Therefore, as long as I get the cylinders over-bored to a size which I can get low compression ratio pistons as well as high, the only losses I would suffer moving up to FI would be for a new set of pistons, whatever I lose buying first-hand selling second-hand, or buying second-hand and selling third-hand header, and the cost of retuning ignition and cam timings etc. (but I would need to pay for rolling-road time anyway adding FI obviously). I haven’t included cost of additional FI related gubbins.

Can you guys tell me if my logic is sound or not?
By the time all that is done, hopefully I will have mastered all the nuances of turbocharging and have pored over flow maps and know exactly what turbo I want and how I’m going to support it.
TIA

It is a stupid idea. Well most of it. If you want to make any NA power at a reasonable budget you do the follow.

1. MS3X and wideband.
2. VVT motor,
3. Flat Top manifold
4. Racing Beat Header and exhaust.
5. Custom intake approximately 21" long.

Then when you are ready to go FI you sell the header and exhaust for most of what you paid for it. Add the turbo and IC and be set. Also drill and tap the oil line while the motor is out. Run an oil feed line for the eventual turbo. It is much easier to install the TSE oil adapter with the motor out of the car. You can then cap the fitting on the adapter.

Thanks.

Budget wasn't my first concern (not that I have loads to throw) but building something tangibly more powerful. Other than the ridiculous money/effort:gain ratio, is there anything fundamentally wrong with the logic?

Not that I can't be persuaded to less drastic measures, just for clarity.

Please read this thread over of Quinn's (GarageQuinnMotors) 185 whp N/A NB engine (My 185 whp N/A Engine. Stock Bottom End. - ClubRoadster.net).

Take a good hard look at how much time, effort, and cash was spent getting the engine to perform at that level. Then factor in reduced drivability and vastly reduce reliability over a FI engine making similar numbers.

It's certainly badass and all, but he even admits the engine has sacrificed significant longevity to perform at that level.

With a lot less money and time, superior reliability and drivability, you can build something much more powerful with FI. If you are looking for NA power, the BP is the wrong engine to be looking at. You have lots of options these days for NA power. Honda VQ V6, Honda k20/k24, LS, Ecotec, 13B, etc.

I'm well aware of the limits of NA tuning with these engines. I have spent a long time talking to a fella here in the UK who has a 200hp NA. Ridiculous details. Shim underbuckets the lot. Oil change every 2000 miles.

I'm not trying to build some extreme NA. I'm asking, will the modifications I listed be beneficial to a FI build or not?

You are going to be above 10k dollars in the hole in just power mods before you know it with how you are talking, and I don't think you realize that. Then the costs of all the other mods to make the rest of the car up to par with the power. Expect to easily be 15k into your build by the end.

To answer your question, we'll have to know what kind of power goals you have in mind. While Miata heads flow like shit compared to other engines, you don't really need to upgrade/ modify the head in FI applications unless you're thinking about making serious power, or you want to rev to the moon just to say you can. 400WHP is easily attainable with nothing but a turbo and forged bottom end. Even those who topped out at 400WHP found their next restriction to be the NB1 intake manifold. Will a bunch of :burncash: headwork :burncash: be beneficial in a FI application? Yeah, duh, more flow is more flow. However, it's stupid to waste the money unless you're making dumb power. Changing pistons when FI time comes is just another :burncash:.
Most definitely not sound logic.

What makes you think I don't realise that? Though I'm impressed with your maths because that's pretty much where I got to (in English money) but that included machine work and dyno time too.

If you love wasting money, this is a great idea, and you should do it

:likecat:

I'm not sure why everything seems to get reduced to whp. I actually thought that with the headwork and little extra displacement it would be possible to get early spool out of a turbo that suits the mx5, but normally has lag problems. I don't know what turbos are out there - that's why I'm researching them. But I'll get as many whp as I can out of a turbo I can get going from 3000rpm. Yes, I am aware that things need replacing from 250hp+.

I'm not asking if this is a sensible or cost-effective form of modification; I know it is not. Thank you for your reply.

That doesn't answer my question. I didn't ask is this a cost-effective way to modify an mx5; I asked would performing these modifications inhibit adding FI in the future? No one has tried to tear me a new one over the modifications, just my budget choices, so I'm going to take the answer as no.

The high compression may limit you later depending on what fuel you have available

It has been worded every way imaginable, by multiple users on this forum, in both of your threads, and there is still a disconnect apparently. I will try, but only because I like doing this sometimes to keep my logic skills in check:

Take this plan and remove everything but an ECU and the bigger injectors. (I am going out on a limb, assuming you mean a MS3/Haltech/full standalone/etc. when you say "ECU"). The 30-40 HP gain you would get from an NA build of that cost/scale is a waste of money. Take all the money you saved by not buying anything but an MS3 and injectors, and you would be damned near the cost of building up your turbo kit.

The power gain from boosting an already built motor of the spec you posted, is a whole other level entirely. It would be tons of power, potentially, that's great! but guess what? 5 speeds (or even 6 speeds) won't take it, tire/wheel packages increase in cost/size, brakes as well.. It is not just an engine/turbo build at that point. Once you dive that deep, the whole car is going that deep. Did I say, deep, enough?

To add, the cam's would not be beneficial at all to a turbo set-up. Sure you can sell them and the header for near what you paid.. But is all that hassle worth it? When if you had simply allocated the money/build in the best direction from the get go, you would be where you wanted to get to, faster?

Thanks you, this is a reasonable and reasoned response. I am well aware that I will potentially be into transmission and differential upgrade territory - if I'm willing to drop 10 grand on 40-50hp when I can get a full turbo installation for 4 grand, why assume that I'm not prepared for this eventuality? I'm not after a budget build: I'm looking to have fun and build something unique.

Yes by ECU I meant stand-alone: MS3 (or ME221 or the like).

I'm grateful for the observation re the cams - I'll have to do more reading, but I've seen them used in turbo builds; I'll have to question builders themselves if they reply to see if they are any use. I'm assuming overlap is greatly reduced in FI applications. This is the type of response I was hoping for; I certainly would reconsider the cams (and pulleys and belts etc) if they have no FI value.

Thank you.

I have access to 'premium' unleaded.

I'm curious, do you think the increased compression ratio provided by the overbore etc will be a problem once the pistons are swapped out for low ratio ones?

overbore doesn't increase compression. milling head does. higher dish pistons does.
premium unleaded means nothing. actual verified octane does.
if you swap in low comp pistons later then obviously you won't have high comp and obv won't be a problem.

Take note, that I did not make any of those recommendations based on money, and that is not a coincidence. The only time I mentioned money was to show the equal value of a built up DIY quality turbo kit and NA build parts. There is no money saved there, just re-allocating.

Be unique, more "power" to you (see what I did there?). To be honest, as sad as it sounds, doing it the most logical method, is becoming unique, but that is a whole other can of worms.

If you are okay with the build not being the most efficient with your time, infact terribly inefficient with your time, then carry on. Just don't under estimate the time involved with DIYing a turbo kit. Take the time you planned for it to take, and double it.

Start a build thread!

No you are correct - you are increasing BOTH parts of the stroke by the same proportion, so the ratio will stay the same. School-boy error.

'Premium' over here refers universally to 97-99 RON.

Since I put in the post that I was going to swap out the high-comp pistons when adding FI, I didn't know if you were meaning the compression ratio would still be a problem, or whether you hadn't seen that. Thank you though.

Thanks!

While I want to select components myself, I'm going to get professionals to fit it, and obviously adapt with systems and parts they are accustomed to. All this is recon so that when I approach a builder-tuner I know exactly what I want and what I'm talking about. Hell, I wouldn't put 200 quid into something I bolted together, let alone 20k. Once I'm going I will start a thread. Will be a while yet, as you can probably gather from the levels of my progress.

I really do appreciate the input.

Seriously if you just want to spend money willy-nilly then call savington@TSE. Tell him you want a built bottom end with one of Emilio's CnC heads.

Also putting in high compression pistons now to then swap to low compression pistons later is just fucking stupid.