Miata 1.6 - interesting N/A build - buying advice needed.

Hey Guys, I'm looking at an engine built with the following specs:

NA6 1.6 long block

-Paeco 7800 cams

-Supertech dual valve springs

-Eagle rods

-All new bearings and seals

-Stock pistons

-Billet oil pump

-New water pump

-Adjustable cam gears

According to my google-fu Emillio prefers the built N/A blocks for longevity:

"If I had a buck for everytime I have seen this happen, I'd buy everyone reading this a nice lunch. We race N/A cars for one reason: They cost way less to build and maintain that a turbo car. This is not conjecture, but direct personal experience. There is no free lunch when it comes to power adders if you are going to hammer on the car once it's built. Rock solid reliability on track, for an expert driver is far cheaper N/A than turbo."

I'm a bit worried on how aggressive the cams are in the particular build. He's looking for 800 out of it and has a set of 12:1 1.6 pistons for sale also. I'm not looking for all out power, I'm looking for a spunky engine for a 1500lb car that needs to be as reliable as a track motor can be. Do you guys think this fits the bill?

Per the Paeco website (which is awful to look at, but I digress);

MA-7800: This is a very torquey racing camshaft that will provide great acceleration coming out of the corners. Best power range is 3000-7800 and it will rev to 8200 RPM. INTAKE: 45/77 EXHAUST: 75/47 DURATION: 302 LIFT: .398"

Necessary mods: 12-13:1 compression, modified cylinder head, PAECO valve train, exhaust header, racing ignition, Webers, copper head gasket, chrome-moly or titanium con rods.

Based on the information from the cam vendor above, it sounds like a bad combination. I do find it odd that they tell you which carbs and head gasket to buy.

Yeah, they looked... Mildly aggressive. For the work put into it seemed worth swapping the cams down or the pistons up to the 12:1.

Their website is hilarious.

Emilio also raced naturally aspirated cars because they fit much better into the classing scheme he ran. He's not wrong - racing a 250 hp car is more expensive and difficult than racing a 150 hp car, regardless of how you make that power. And a 400 hp car adds a bunch of new potential failure points.

I don't know the cams. My own Locost runs a 1.6 with the following, and it's a rock solid little beast.

• Webcam 505 cams
• Carrillo rods
• Wiseco 11:1 pistons
• Supertech single valve springs and Ti retainers
• adjustable cam gears

With some mild headwork, a good header and ITBs, it's running 148 rwhp. I could probably do better with a modern ECU. I've had one failure on track, and that was the stock valve springs after sustained 8000 rpm running. No need for dual springs, just a good single spring. The cams give it a great nature above 4000 rpm, but it's pretty dead below that. On a track car, that shouldn't be an issue.

On "your" engine, I'd throw an Ati damper on there. I need to add one to my own engine. It's a smarter choice than a billet pump, as it addresses the problem instead of trying to dodge the symptoms.

Just run solid lifters with excessive lash to lighten things up. I'm sure it'll be fine. (this is a joke don't do this)

Unless you have, or are willing to aquire, a Mega Squirt stand-alone PCM, and going with a bigger throttlebody and bigger MAF sensor (the two main power bottlenecks for the 1.6) and possibly bigger injectors (not sure how much headroom the stock 1.6 injectors have); there is no point going with those cams. The stock PCM is not flashable during a dyno tuning session (an absolute must with this setup) and cannot tune that much air nor get a usable spark curve, and the stock 1.6 throttlebody and MAF will not allow enough airflow in any case. The 12:1 pistons, however, will make those cams REALLY work well, especially with the adjustable cam gears tuned on a dyno. In short, this engine combo is NOT a drop-in that can be used with stock engine controls. Go with a dyno-tunable ECM, 1.8 NB2 throttlebody and MAF, Racing Beat header and free-flow exhaust, and it will be a blast after it gets tuned to run on premium octane pump gas.

IIRC, the stock 1.6 throttle body is the same size as the 1.8 unit.

Stock 1.6 injectors are big enough for about 160 rwhp.

I'm surprised Paeco is still around. they had a baad reputation in the spridget dept years ago. I'd be wary...

hijack: Keith - are those 11:1 pistons a custom or off the shelf product?

@Wild - I picked up a MS pnp2 yesterday as well.

@Keith - Thanks! I'll never understand how you reply so quickly and pragmatically. The Ati damper looks amazing, it's going on my to buy list since I'm most concerned about making something that doesn't mind being beaten on day in and out. Sadly out of stock right now.

@pres589 - lol

Sounds like I should buy and make some changes to it? Pricing it out raw makes it a good enough deal even with needing to swap some parts out that I should "come out ahead(hah! that's what I'll tell my wife)."

I have a stock 1.6 to put in the exocet right now, but it's got 200k miles on it and probably needs a bit of love. The plan is currently to drop everything in stock and then iterate from there and this looks like a reasonable point to iterate from.

The ATi is indeed in stock at FM right now. Looks like the website is a little bit out of date.

At $800 for a freshly built 1.6, it sounds like a decent deal. You could always drop your stock cams into it!

As for the pistons, they're a special order item at FM.
https://www.flyinmiata.com/wiseco-forged-1-6-normally-aspirated-pistons.html

In reply to WildScotsRacing:

Ah, must just be the MAF that's the bottleneck, then.

The flapper-door AFM is a problem for sure.

Also, the TPS attached to the side of that 1.6 throttle body is basically just an idle and a WOT switch, so you lose the TPS as a sensor for driveability. The latter is why you often see guys change the throttle body when they do a 1.8 swap, to get the improved TPS.

Yep, I've got a BMW VPTS and the wiring to get rid of the AFM for my build when I get to that point.

Keith Tanner wrote: The flapper-door AFM is a problem for sure. Also, the TPS attached to the side of that 1.6 throttle body is basically just an idle and a WOT switch, so you lose the TPS as a sensor for driveability. The latter is why you often see guys change the throttle body when they do a 1.8 swap, to get the improved TPS.

If he goes to the MS then he can just use a different, variable TPS. There are guys on miataturbo.net that mod various BMW variable TPS with a connector that fits so you can just swap that and not the throttle body.

Edit: Posted before I saw the above.

Or you can use a TPS from a 1.6 automatic. But the easy route is to use the throttle body that's already bolted to the 1.8 when you're doing a swap

My comments were in reference to a swap and why the throttle bodies were often changed at the same time. Take that out of the equation and there's obviously more information that can be shared.