bikesandcars
True Classic
I"ll post pictures of the curves shortly, I don't have them here with me.
We testing the lemons x at a dyno last Friday
Because thursday and friday were so busy I barely had time to throw the new cam in and get the car running. After some hiccups friday morning we basically threw the car on the trailer, raided the shop for tools, and headed out.
Our first dyno run netted us about 65 hp (at the wheel). This was very dissapointing, but the good news is that it was mainly due to poor ignition timing. After adjusting the timing we got the power over 70. From there we started playing with the fuel pressure, advancing the valve timing, fine tuning the ignition timing, and tuning the exhaust gas pressure. Our final run netted us about 83 HP at the wheels (about 100 at the crank), with peak torque of 80 lbf at 4500 rpm and about 80 hp from 4500 to 7000 rpm (falling after 7,000). The engine is nice and torquey, and should pull out of corners well.
Dyno tuning was a real eye-opening experience, seeing how changes effect the car taught me a lot about the car and how to tune it moving forward. We also discovered that the Tach we had was 900 rpm off at 7,000 rpm. As a simple solution I bought a new tach from advance auto that will serve as our primary, while we keep the old tach for the shift light and water temp.
The car is ready to go to capitol offense this weekend besides some very minor details. We finished nut and bolt / final prep Sunday.
I learned a couple things (even the dyno guy did).
When it comes to fine tuning I really recommend getting a super-trapp disk set. Just tuning the exhaust alone gave us 5 HP from 4K to 5000rpm with no peak loss.
The weber is sensitive to fuel pressure, and when dead-headed needs to see low fuel pressure (2psi most) to run right.
The cam from elgin does exactly what I asked it to do, not very peaky but has a nice broad torque curve. Advancing the cam a few degrees netted us 5HP through the whole range.
When thinking about carb tuning...get the rest of the system running first. Optimizing the valve / ignition timing and fuel pressure has a huge effect on air/fuel ratio (we used a wide band tester). When we started the carb was way too rich. We thought we needed new jetting. As it turns out, with the fuel pressure right and the valve / ignition timing optimized the fuel came right in-line. If we would have gone right to the carb we would have messed ourselves up.
All in all I was expecting a few more HP, but with the torque curve how it is the power seems about right (on a pump gas motor). We're in the range of 9.5 to 10:1 compression.
Thanks to Dave at KDR Performance, I highly recommend a trip to his Dyno, they were awesome. He's west of Allentown PA about 1/2 hour.
We testing the lemons x at a dyno last Friday
Because thursday and friday were so busy I barely had time to throw the new cam in and get the car running. After some hiccups friday morning we basically threw the car on the trailer, raided the shop for tools, and headed out.
Our first dyno run netted us about 65 hp (at the wheel). This was very dissapointing, but the good news is that it was mainly due to poor ignition timing. After adjusting the timing we got the power over 70. From there we started playing with the fuel pressure, advancing the valve timing, fine tuning the ignition timing, and tuning the exhaust gas pressure. Our final run netted us about 83 HP at the wheels (about 100 at the crank), with peak torque of 80 lbf at 4500 rpm and about 80 hp from 4500 to 7000 rpm (falling after 7,000). The engine is nice and torquey, and should pull out of corners well.
Dyno tuning was a real eye-opening experience, seeing how changes effect the car taught me a lot about the car and how to tune it moving forward. We also discovered that the Tach we had was 900 rpm off at 7,000 rpm. As a simple solution I bought a new tach from advance auto that will serve as our primary, while we keep the old tach for the shift light and water temp.
The car is ready to go to capitol offense this weekend besides some very minor details. We finished nut and bolt / final prep Sunday.
I learned a couple things (even the dyno guy did).
When it comes to fine tuning I really recommend getting a super-trapp disk set. Just tuning the exhaust alone gave us 5 HP from 4K to 5000rpm with no peak loss.
The weber is sensitive to fuel pressure, and when dead-headed needs to see low fuel pressure (2psi most) to run right.
The cam from elgin does exactly what I asked it to do, not very peaky but has a nice broad torque curve. Advancing the cam a few degrees netted us 5HP through the whole range.
When thinking about carb tuning...get the rest of the system running first. Optimizing the valve / ignition timing and fuel pressure has a huge effect on air/fuel ratio (we used a wide band tester). When we started the carb was way too rich. We thought we needed new jetting. As it turns out, with the fuel pressure right and the valve / ignition timing optimized the fuel came right in-line. If we would have gone right to the carb we would have messed ourselves up.
All in all I was expecting a few more HP, but with the torque curve how it is the power seems about right (on a pump gas motor). We're in the range of 9.5 to 10:1 compression.
Thanks to Dave at KDR Performance, I highly recommend a trip to his Dyno, they were awesome. He's west of Allentown PA about 1/2 hour.
