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-   -   More gas, same premix? (https://www.rx7club.com/general-rotary-tech-support-11/more-gas-same-premix-1137341/)

JLS 89 T2 07-08-19 05:29 PM

More gas, same premix?
 
Probably a dumb question, but hey, if you never ask... Once I’m using more gas, does my premix remain the same?

Getting close to what I consider my vanilla build. Engine management, fuel system upgrade, bigger injectors, hybrid or new turbo.
I have a working OMP, but still premix a little, half ounce to a gallon.

So, once my boost and gas are upped, will I be delivering plug fouling levels of oil? I suspect not, but figured i’d ask. I have searched, but can’t find the answer, sorry if this has been covered.

Oh, I don’t have cats now and plan on trading up the current exhaust for a nicer one, looking at the REV II from Racing Beat.

Copeland 07-09-19 09:52 AM

The premix ratio remains the same regardless of the gas usage in the car.

If you make significantly more power or plan to track the car, you should consider a stronger premix ratio at that time. I have heard of anywhere between 250:1 and 20:1 ratios being used with no plug fouling.

JLS 89 T2 07-09-19 11:52 AM

Thanks Copeland

psyaddict 07-13-19 04:43 PM

i use 1:125 ratio

peejay 07-14-19 07:38 AM


Originally Posted by JLS 89 T2 (Post 12357616)
Probably a dumb question, but hey, if you never ask... Once I’m using more gas, does my premix remain the same?

Getting close to what I consider my vanilla build. Engine management, fuel system upgrade, bigger injectors, hybrid or new turbo.
I have a working OMP, but still premix a little, half ounce to a gallon.

So, once my boost and gas are upped, will I be delivering plug fouling levels of oil? I suspect not, but figured i’d ask. I have searched, but can’t find the answer, sorry if this has been covered.

Oh, I don’t have cats now and plan on trading up the current exhaust for a nicer one, looking at the REV II from Racing Beat.

You should probably be using more premix because apex seal loadings go up out of porportion with fuel increase. After all the factory oil dribblers are at like 400:1 at idle and 120:1 at max power... and they apply the oil directly to the surface, whereas most of the oil that you premix goes in and out of the engine without even touching metal.

Racing Beat was premixing something like 6 ounces per gallon (can't be bothered to look it up) on a high powered 2 rotor. I have found power gains up to 50:1 on a naturally aspirated engine, which will have much lower apex seal loadings than anything with a turbo.

peejay 07-14-19 07:39 AM


Originally Posted by Copeland (Post 12357753)
The premix ratio remains the same regardless of the gas usage in the car.

That's good advice if you like losing power and wrecking rotor housings.

Copeland 07-14-19 06:42 PM


Originally Posted by peejay (Post 12358746)
That's good advice if you like losing power and wrecking rotor housings.

Please enlighten me.

My post simply meant that the ratio is static if premixed in the tank. The OMP can be changed based on load. If you quoted the whole post, you’d see I recommend more premix with more power.


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