Forum » Understanding AFR » E85 max power lambda value copare gas pump fuel

E85 max power lambda value copare gas pump fuel

Understanding AFR

Discussion and questions related to the course Understand AFR

= Resolved threads

Page 1

Dear all,

i will use modelled fuel from ECU g4+ from my Mitsubishi lancer evo9, id1300cc, turbo pressure 1.65b, flex fuel e85

I search some information and experience from you about lambda value (max power lambda value) for pump gas and e85 for turbo engine

For pump gas Stoich ratio is 14.7 / lambda 1. For cruising i will use lambda 1 and for full boost 1.65b i will use 0.73 lambda

For e85 Stoich ratio is 9.8 / lambda 1, for cruising i will use lambda 1 and for full boost 1.65b i dont know yet may be around 0.8 lambda

do you have some test what is the best lambda value for e85 in full bosst for the max power?

Thanks in adavnce

dyno will tell you, yet generally similar lambda as 98, unless there was it was excessively rich on 98 to combat knock then it will be a bit leaner on e85

Scott is spot on - The ideal lambda value is not fixed and will vary from engine to engine. That being said, E85 tends to respond well at the same lambda targets as pump gas under high load. You can actually run leaner on E85 many times because you won't be relying on the cooling aspect of an overly rich mixture in order to prevent knock.

In general on E85 I'll be in the vicinity of 0.80-0.82 and on pump gas I might be more likely to be in the region of 0.78-0.80. While you're running reasonably high boost on pump gas with 1.65 bar, I'd be surprised if you aren't giving away some power running at 0.73 lambda. The dyno will be the true answer to your question though.

any reason power starts to drop off if we run a mixture that's to rich?

Depends on the fuel, but petrol/gasoline and E85 will burn slower and cooler if over-rich - both reduce potential power.