First, a little background on the car and motor.
The car is a 1996 Geo Metro 1.0L 5 speed.
The head is a competely built head by SuprFly(Mr. Cove). Here are the specs on it.............
Performance head package, 89-up 3cyl.
In the performance head package, you get a completely rebuilt, ported and polished head, machined for high compression. It includes a high performance cam of your choice. During rebuild, valve guides, and seals are not checked, they are automatically replaced. The valve seats are ground to 45 degrees, and the valves are ground on three angles, and polished for increased flow. The valve grind is an excellent compromise of performance and longevity. All valves are hand lapped during final assembly. The head mating surface is machined for high compression, 9.5-1 to 10.5-1, or higher by special request.
Intake and exhaust ports, and bowls are ported, with the greater emphasis being on the exhaust side, for increased exhaust flow.
The hydraulic lifters are removed, disassembled, inspected, cleaned, and re-assembled. Any defective/worn lifters are replaced.
With the head package, you get a proven 3tech performance cam of your choice.
The cam that is currently being used is his 218 duration/.350" lift profile.
Overall, I'm EXTREMELY pleased with this setup. The car pulls MUCH better than what I thought it would. On perfectly level ground with no wind, the old top speed was 77 mph in 5th gear. With the new head in place, I've gotten the car up to 93 mph and it was still pulling! Both of these speeds were shown on a Scan Gauge(OBD2 diagnostic tool) and are more accurate than the stock speedometer. The car also has no trouble with cruising at 70-75 mph now!!
The only downfall to this setup soo far is that the car currently runs rich at idle. I'm in the process of trying a couple of differant tricks to get around this. Soo far, I've adjusted the TPS so that it now reads 20 out of 100 on the Scan Gauge(approximately 1 volt) at idle. Orginally it read 10 at idle(0.5 volt). This certainly reduced the raw gas smell coming out of the exhaust, but now the car won't idle on it's own(tries to idle at 500 rpm) so I've got to bump up the idle adjustment to idle it back up to 800 rpm.
I also played around with the timing a bit. I went from full retard(-5 degrees at idle) to full advanced(+2 degrees at idle). Full advanced gave the best power, off ide response, and the car managed to idle at 500 rpm(barely). At redline, timing advance is reading 31 degrees total with no audible knock or ping(please note that I've been running 93 octane gas for the last about 10 tanks of gas).
My next step is going to be idling the car up a bit(back to the stock 800 rpm point) and to get another O2 bung welded to the exhaust so I can install a borrowed wide band O2 sensor in to monitor air/fuel ratios.
This modification is definately the best $350 I've spent on any car! It definately gets a HUGE bang for the buck award in my book!
2010 Nissan Frontier SE Quad Cab 4.0L V-6
Someday I will get another Metro, but this time it will be all out built 1.3L!!!