VVT Anti-Bolt Ons Dyno
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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 https://cimg6.ibsrv.net/gimg/www.mia...e92e8f19d3.jpg https://cimg8.ibsrv.net/gimg/www.mia...78009edeae.jpg . 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? |
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. |
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
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Not that it really matters but whats up with that giant torque dip at 3500. Is this a BRZ? Numbers seem solid though
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Pretty normal for an n/a BP.
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Originally Posted by 18psi
(Post 1586079)
Pretty normal for an n/a BP.
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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
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