dan91

I finally completed a VVT swap into my 1991. The new engine is as follows:

-84mm pistons, Supertech 9:1, although actual compression is closer to 8.6:1 when I measure it
-FM Super-A Beam Carillo Rods
-New bearings and studs and all that
-Crank scraper, modified to probable uselessness
-Homemade oil pan baffle
-CNC head with +1mm intake and +2mm exhaust valves. Intake valves back cut
-Entire combustion chamber ceramic coated (valves, head, and pistons)
-Shim under bucket conversion with Supertech heavy double springs
-Custom cams from Mike Keegan
-8000 rpm redline, but the tach is a fat liar that reads 800 rpm high, so the dyno runs ended early
-Flat top intake, port matched to head and throttle body
-Skunk2 TB
-Intake made up of 2003 crossover tube, 1991 stock air box with AFM removed
-NA8 exhaust headers connecting to original 1.6 cat and exhaust
-10.3 lb flywheel with FM Happy Meal kit

The 1.6 baseline dyno run was 100 HP on a Dynojet, which seems high for an engine with 150k miles that sometimes makes coolant disappear but maybe a light flywheel accounts for that. Using the same dyno 3 years later with the 1.8 (1.9?), the best run was 128 HP uncorrected, 124 corrected



. I would have been pleased with this had I not watched videos of stock 1.8s making the exact same power. I'm consoling myself with the knowledge that stock 1.8s have much higher compression and I have turbo parts sitting in my garage. This setup has not been tuned at all, so there is a lot left on the table, but I'm going to save tuning money for when there is boost. Runs 1 and 2 were with VVT disconnected, run 3 is connected.

The RPM pickup on the spark plug wire was useless and just got noise, so the dyno chart is vs ground speed (mph). I got soft copies of the files, downloaded the Dynojet software, exported the curves as points, and made useful curves in Excel vs RPM.

Anyone want a 100 horsepower 1.6?

18psi

iTrader: (76)

You're not gonna make much power on low comp n/a and not spinning it high. So this is pretty normal.
Boost is always the answer.

dan91

The answer is in the works. I have a few other projects before installing the EFR6258 on the shelf, but I'm really looking forward to it

andyfloyd

Not that it really matters but whats up with that giant torque dip at 3500. Is this a BRZ? Numbers seem solid though

18psi

iTrader: (76)

Pretty normal for an n/a BP.

andyfloyd

It is? Dang I guess since I've been turbo for so long I've never realized it lol.

dan91

I think that dip is common on Miata engines, but the VVT run really exacerbated it. I think tuning the VVT could help a lot with that