I am nearing the point in my 7A project where I need to order my finishing kit and to do that I must decide on the engine configuration. For the last six months I have been leaning strongly toward an IO-360 with horizontal induction. No scoop on the cowl and 5-7 more HP sounds good compared to the IO-360 with vertical induction. But lately I have been reconsidering the tradeoff. Specifically, I think I have identified some other important factors. I need someone to tell me if I have this correct or if I am wrong or missing something important.
With the choice of horizontal induction comes the following:
1. I have to spend about $1000 more for the horizontal intake sump compared to the vertical induction sump
2. I have to spend a lot more time integrating the Vans snorkel and intake filter that does not fit very well and probably requires significant modifications to work
3. The Vetterman exhaust system cost is slightly higher for a horizontal induction
4. I have to figure out numerous custom modifications to the firewall forward installation for things like throttle cable routing
Do I have these facts correct? I would really appreciate feedback from those who have done either the horizontal or vertical setup for an IO-360, especially in a 7A because the nose gear structure may also be a factor I don?t fully understand. I used to care about the scoop on the front of the cowl but that is not really important to me anymore. Do you love your horizontal setup? Is the extra cost and time involved really worth the extra power? Does the extra power come at the expense of increased fuel consumption? What about the vertical camp? Would you do it again and why? I don?t want to start a war. I just need help from those with some first hand experience.
John Harrell
RV7A
Empennage done
Wings done
Fuselage coming along nicely
www.johnsrv7a.wordpress.com
With the choice of horizontal induction comes the following:
1. I have to spend about $1000 more for the horizontal intake sump compared to the vertical induction sump
2. I have to spend a lot more time integrating the Vans snorkel and intake filter that does not fit very well and probably requires significant modifications to work
3. The Vetterman exhaust system cost is slightly higher for a horizontal induction
4. I have to figure out numerous custom modifications to the firewall forward installation for things like throttle cable routing
Do I have these facts correct? I would really appreciate feedback from those who have done either the horizontal or vertical setup for an IO-360, especially in a 7A because the nose gear structure may also be a factor I don?t fully understand. I used to care about the scoop on the front of the cowl but that is not really important to me anymore. Do you love your horizontal setup? Is the extra cost and time involved really worth the extra power? Does the extra power come at the expense of increased fuel consumption? What about the vertical camp? Would you do it again and why? I don?t want to start a war. I just need help from those with some first hand experience.
John Harrell
RV7A
Empennage done
Wings done
Fuselage coming along nicely
www.johnsrv7a.wordpress.com