what gas grade (octane) is suggested for these motors been running 87 but not sure if i should go to 89? any help would be appreciated!

 

Designed for 87 octane. You might see a bit of a performance boost, and maybe a point or so better fuel economy running 89, but, probably not enough to justify the additional cost.

 

87 on mine for years.The only time I run 91 is when I drain the MX bikes and dump about 4-5 gallons in it.You'll be fine with low grade.

 

The only time I ever used 91 was when my plenum was blown thinking the higher octane would quiet the pinging...didn't really help.

 

89 cus it's cheaper than 87 or 91.

 

87 is what their made to run with, going to a higher octane makes a slight difference in my truck but some report no change, it really depends on the individual motor and if it likes a higher octane

 

Only reasons to run anything higher than 87...

1. Cheaper (example: 89 octane out hear is 10% ethanol, tax breaks end up making it cheaper)
2. Hide a blown plenum gasket or similar problem (reduce ping)
3. You have a programmer/tune that allows you to take advantage of the higher octane

On a stock tune, except for reason 1 or 2, almost no reason whatsoever to run anything other than 87. It doesn't help your engine, it doesn't give you any performance increase (since the PCM doesn't take advantage of it with stock tune).

 

great info guys thanks i really appreciate it!

 

I use 91 octane, but only because the B&G program on my PCM requires it or I will ping under load (lot of timing advance). I can get away with mid grade though most of the time. As far as performance goes, there really isn't any performance gain to be had from changing to a higher octane with a stock motor. Now if you run 100% gas, then you will notice a difference. Most pump gas is 10% ethanol. Ethanol is not as efficient as gas, so the more ethanol you get, the less power you have. I notice a huge difference whenever I fill up with 100% gas, no ethanol. My mileage is better too. Here's a website to help you find a gas station that sells 100% gas in your area. They are getting fewer and fewer. Give it a try though, you'll be happy you did.

http://pure-gas.org/

 

I can't even get gas that doesn't have at least 10% ethanol in it here. Unless I go to the airport, and pay north of 4 bucks a gallon for 101 octane AVGas.... Not gonna do that.