grantcarruthers
Well Known Member
So I'm thinking about the Peterson STC for my bought RV-4 so I can run Mogas at least part of the time. I have an O-320 D1A that Peterson says can run on premium (91) only. No problem so far. They make several suggestions on the experimental aircraft page that brings me here to the -4 builders forum with questions.
They recommend heat shielding on fuel lines under the cowl to help prevent vapor lock, no problem, I'll address it with the annual in April which is when I'll have the $240 decals 'installed' to make it mogas compatible if I go ahead with this.
They suggest fuel pumps at the tank to pressure feed fuel up to the hot cowl, again to prevent vapor lock issues. Not much I can do here. The -4 either has them or doesn't. So what is a typical -4 install with a carb. I'm guessing a single fuel pump under the cowl rather than 2 out at the tanks??? Anyone have an issue with the -4 on mogas and a single fuel pump under the cowl. So far my -4 seems to run cool but oil and cht's running low'ish doesn't mean the undercowl area is cool from a vapor lock standpoint.
Anyone out there with -4 experience and or mogas in an RV experience have any USEFUL thoughts on the issue. From what little I know about mogas it seems fine for the O-320 even at 160hp on premium. But what you don't know you don't know is what can kill you most often.
With the limited availability of mogas away from home I'll likely end up burning a 50:50 mix of mogas/100ll in the tanks from a practical standpoint anyway. But at some point a full tank of mogas is probably gonna happen so it's gotta be able to run it all the time if its going to run it some time.
Thanks in advance. In short I'm looking for reasons not to run mogas in a -4 from a design aspect specifically and what should be done to run it correctly if it can.
Grant
They recommend heat shielding on fuel lines under the cowl to help prevent vapor lock, no problem, I'll address it with the annual in April which is when I'll have the $240 decals 'installed' to make it mogas compatible if I go ahead with this.
They suggest fuel pumps at the tank to pressure feed fuel up to the hot cowl, again to prevent vapor lock issues. Not much I can do here. The -4 either has them or doesn't. So what is a typical -4 install with a carb. I'm guessing a single fuel pump under the cowl rather than 2 out at the tanks??? Anyone have an issue with the -4 on mogas and a single fuel pump under the cowl. So far my -4 seems to run cool but oil and cht's running low'ish doesn't mean the undercowl area is cool from a vapor lock standpoint.
Anyone out there with -4 experience and or mogas in an RV experience have any USEFUL thoughts on the issue. From what little I know about mogas it seems fine for the O-320 even at 160hp on premium. But what you don't know you don't know is what can kill you most often.
With the limited availability of mogas away from home I'll likely end up burning a 50:50 mix of mogas/100ll in the tanks from a practical standpoint anyway. But at some point a full tank of mogas is probably gonna happen so it's gotta be able to run it all the time if its going to run it some time.
Thanks in advance. In short I'm looking for reasons not to run mogas in a -4 from a design aspect specifically and what should be done to run it correctly if it can.
Grant