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Solo_S14

NA8 Stock WHP?

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Rather than get a bunch of opinions on the internet, I'll come here to get a bunch of opinions on the internet 😂

My personal experience - put my stock motor NA8 on the dyno with basically no mods and made 108whp.

I was under the impression that was kinda low, partially based on the (TT6?) guys all running ~128whp with apparently stock internals.

However, talking to a few guys in passing, they seem to have had similar ~110whp results. (Dyno Jet).

So for those of you that have been into TT / SM recently.....what's a reasonable number for a stock motor NA8 on say the 14deg timing trick and stock ECU?

Cheers,

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If you're using the NA8 head I left with Sam that's my old ~65k orig miles head, made 125whp on it with intake, header, exhaust and MS3. It makes garbage power compared to your typical SM head (ex. xfactor).  With cams could probably hit mid 130s without too much fuss. On stock intake/header/ecu all you can do is static timing bump and adjustable AFR, but wouldn't expect more than 115whp or so without a good head.

 

*124

 

FB_IMG_1597049253103.jpg

 

And here's current motor (BP4W) on same intake, header, exhaust, MS3 with BP5A intake cam.

 

FB_IMG_1597049374088.jpg

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Thanks man.  There was a head kicking around somewhere along the way, but it had a valve seat broken out of the casting of the head so it was junked.

The 108 was on the engine that came in my red car, unknown swap basically, stock intake, header, ecu.  So the ~115whp limit sounds like the answer / bridge I was looking for, for a healthier stock motor without ECU and supporting bolt ons.

This is a capture from a video since they never actually sent me the file, and we didn't really care just wanted a baseline:

IMG_6418.thumb.jpg.6134fcaa83ec18f6ca69af096b8396f5.jpg

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1 hour ago, Solo_S14 said:

Thanks man.  There was a head kicking around somewhere along the way, but it had a valve seat broken out of the casting of the head so it was junked.

That was the Ed Gilfus head that lived in the car during its life in SM.

 

I actually have Cobb's head in the garage still, I think. Or maybe it's a BP4W head. I don't know. I'll check.

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2 hours ago, Solo_S14 said:

Thanks man.  There was a head kicking around somewhere along the way, but it had a valve seat broken out of the casting of the head so it was junked.

The 108 was on the engine that came in my red car, unknown swap basically, stock intake, header, ecu.  So the ~115whp limit sounds like the answer / bridge I was looking for, for a healthier stock motor without ECU and supporting bolt ons.

This is a capture from a video since they never actually sent me the file, and we didn't really care just wanted a baseline:

 

You can see part of the problem on the AFR readout. 12 is low boost turbo territory. Timing bump and 12.5-8ish would unlock some power right off the rip. Stock ECU runs pretty lean until ~4.5k and then too rich.

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1 hour ago, Hollywood said:

 

I actually have Cobb's head in the garage still, I think. Or maybe it's a BP4W head. I don't know. I'll check.

Probably mine if you still have one laying around. Won't make crap for power, but I imagine it's got a lot of track hours left on it if he wants a free head 😛

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I'm at 123hp and a little on my junkyard engine NA8 Spec Miata.. with only a FPR, a SM exhaust and some adjustement by Jim at MSR

 

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Edited by Dennis
added dyno sheet

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that is officially the highest junkyard number I've ever seen. was this east street's junkyard?

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41 minutes ago, Hollywood said:

that is officially the highest junkyard number I've ever seen. was this east street's junkyard?

Can’t afford that junkyard.. just random 500 $ automatic, pulled motor and sold the car.. 100$ Plus some fresh seals invested.. 
 

First engine in the car did 1.5 hp more, with a ESR head on a junkyard bottom, but that one didn’t survive..

 

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Automatic is half point less compression 8.5 vs 9.0, so that makes even less sense.

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1 hour ago, cabowabo said:

Automatic is half point less compression 8.5 vs 9.0, so that makes even less sense.

Thought that was only for the 1.6's? 

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19 hours ago, Dennis said:

Thought that was only for the 1.6's? 

I thought it was NA8, too, but maybe not.

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We decided to do a headgasket on that 108whp/102tq engine before the ChampCar race at H2R in September.  Cyl #2 was pushing water out the open rad cap (slightly) on a cold motor during a leakdown.

Prior to the race, on a hero Amazon compression test gauge that reads higher than my other one, the compression looked like this:

Pre Race - Cold / Dry Compression

Cyl #1 - 155psi

Cyl #2 - 150psi

Cyl #3 - 165psi

Cyl #4 - 170psi

On the Saturday, we placed 3rd overall in A-class, behind two well sorted NB1 and NB2 VVT swapped Miatas (Josh is on here actually), with our best lap times in the 1:31's.

Sunday, we had a mechanical in the morning - causing us to run the race in 4th gear only 😂.  Pace dropped into the 1:35's.......but looks like that's because we had more than just transmission issues on the weekend:

Post Race - Cold / Dry Compression

Cyl #1 - 157psi

Cyl #2 - 150psi

Cyl #3 - 162psi

Cyl #4 - 52psi (💀)

Dropped a cap full of oil into each cylinder, and ran the CT in reverse order with a charger on the battery.  Pretty well confirmed things:

Post Race - Cold / WET Compression

Cyl #1 - 195psi  (+38psi)

Cyl #2 - 202psi  (+52psi)

Cyl #3 - 210psi  (+48psi)

Cyl #4 - 130psi  (+78psi)

 

So, now we look for the "easy button":

1. Teardown our (2x) NA8 engines, hone, deck, refresh.  Hope for ~115-120whp?

2. Go for an NB1 engine (fits rules), largely a "bolt-in affair" with an RPM switch?  Go for ~125whp without too much fuss?

3. Pull up the boot straps, go for a MegaSquirt, pursue the VVT Glory, chase the cool kids, hope for ~135whp?  Maybe have a down car for several months?

What would TJ's do?

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2 is the easy button if you don't feel like installing aftermarket ECU and dyno tuning. I thought that car already had a RPM switch for VICS in it? Check on passenger side firewall (engine bay side). Could have sworn we (well, not we, but Clint) installed it with NB1 motor and it made 132whp or so.

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There is definitely an MSD RPM switch sitting on the top of my toolbox yup 

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9 minutes ago, Solo_S14 said:

There is definitely an MSD RPM switch sitting on the top of my toolbox yup 

Yep, that's easy button, technically. I don't know how available NB1 junkyard motors are these days, guessing not very. If you go that route it is easy though as you just need to bolt it in, get FPR set correctly for safe AFR's, and send it. The NB1 swap is cake, just a few things to mix n' match between the motors. Racecar, so delete the EGR pipe (won't line up from NA header to NB1 egr), you have to flip the FPR or something, and  a few other things. It's well documented. 

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