Why Am I Getting Such Terrrible MPG?

[Byron510]

Sell that useless motor! I'll buy it as a spare! Name your price!

I was kinda thinking the same thing Dave

But honestly, it is a pretty big cam. However if you find it drivable enough, stay with it. You should see no less that 18 MPG with that cam on the street. I know Paul does a great job on carbs, so I'm sure it runs well.

My 2.2LZ motor in the rally car did once see 12 MPG, I think that is the lowest number I ever calculated in any 510 I've owned. That was a particularly rough set of stages, lots of 2nd gear it was so tight. And it was a hell of a climb on a really loose surface. Even in ice racing, I averaged over 16 in those events.

However I did recently pull a similarly spec'd cam outr of the Bronze, and I haven't looked back. I certainly lost power past 5K, but I gained so much more at 2 to 4K - a worth wile trade off for what the car is being used for. And I did a track day last fall out at Mission, and still had plenty of fun.

Keep us posted on what you find out.

Byron

[okayfine]

Loving all the replies for my troubles. Thank you all.

How come you went stealth and never answered any of the questions?

[30something]

I haven't gone stealth. Cant do much till all the snow goes away. My car is rust free and I want it to stay that way. Once the weather starts to get better it will be my first priority because I am excited about my car again. Big plans for this year. Next thing I want to figure out is to get out to some local 510 events so I can meet more people into these cars and know some information to share. Anyone know what events are coming up soon? Cheers.

[finn]

There's lots of troubleshooting steps you can knock out in your garage. Pull apart the carb and inspect/rebuild. Check your timing. Install an air/fuel ratio gauge. Seems like you asked a question but don't care to follow up with. Remember Peter and the wolf? Same thing here....

[okayfine]

You could also pull plugs. You could also answer how exactly you calculated your fuel mileage and all the other questions surrounding your actual methods. But, hey, wait until spring when we can do this all over again.

[bigjim5551212]

I know this is old, but if you have more than 3.5 psi fuel pressure, you will have flooding and poor economy

[icehouse]

Paul knows his carbs, are you sure on your numbers????
On our Specialty race car, set up for road racing, we got 12 MPG and that was at race speed.
At that low of an MPG, I am amazed that it runs.

as Mike suggests..check all those things.

In my turbo motor, L20+ at full on 300 HP mode, I get about 5 Mpg, at take it to the moon RPM.

maybe a trip to Specialty Engineering would be in order on this one.

Our race car with the NA SR20DE which makes 122 WHP is 9.5 MPG at Seattle which must be due to the long straigtway because at ORP the best track I've ever been to we get 13.6 mpg it doesn't really have a straightaway.