~3 gallons. So, filled the rest of the way with 93. I then turned off the Profec B and will just ride around at 7 pounds until I run all the gas out of the tank. No biggie.

But it did make me curious...

Anybody ever run the car for extended periods (with all else working properly) at 7 pounds of boost? Did you notice any performance/engine/mileage/etc... differences other than slightly lower power output?

 

I DD my FD and run 7-8 psi everyday..When I first purchased my FD I knew absolutely nothing about it,so for the first 2 times I filled up,I filled up on 87 octance..Little did I know how dumb that was,but performance wise and mileage wise I don't notice much of a difference...

 

I had a buddy who used 87 octane for years until I told him to use 93...

 

I wouldnt think you would notice all that much unless you boosted it up more.
However as he said ^ use 93...

 

i ran my fd on 87 octane for a few months with no trouble, but i used 8.5 CR rotors in my engine and a haltech e8. max boost was 11psi on a t66.

 

I hate driving through NJ because on more than one occasion when I stop for gas and tell them to put in 93 I check the receipt and they actually put in 87. Sucks not being able to pump your own gas there. Now I watch them like a hawk to make sure they don't screw it up.

 

Up here in Alberta we only have 91octane at the majority of gas stations. Is 91 octane good enough?

 

in japan they run 99oct in ireland we get 95 oct..i met this other guy over here and he said you have to change the management system and id have to go to england to get it done or wreck the engine.. i thought he was talkin ****, after readin these posts, its confurmed his stupitity

 

An Fd at stock boost is perfectly fine with 87 octane. I've driven mine that way for the last 6 months with over 100k on the original engine. Increasing the boost is where you will start to have problems since the fuel burns faster.


Some of you guys need to understand what's going on inside your engines. All this paranoia when if comes to 87 is unneccessary. Our engines have 9.0 compression which is low. For the most part turbo charged engines are NA the majority of the time while your driving it. Really it's a waste to run a slower buring fuel when your just cruising/normal driving. The slower burning fuel will carbon up faster. Idealy you want the fastest buring fuel for your driving condition. That's why 87 is perfect for highway driving.

 

94 fd-12 years with 87 octane - I splurge on 93 for some fun... Car runs fine just not as spirited with the lower octane...but it is mostly stock but a DP. I ran my FC only on 87 as it hated the higher octane.

 

Thanks for all the responses...

But what I was asking was, does anyone notice anything about running the car on lower boost. As in:

If you have a aftermarket ECU, can you notice the engine running any cooler, with any noticeable inprovement of mileage, any less cooling requirements, etc. I imagine not, but I was curious.

 

This post doesn't make sense.

Why would the car run less spirited with lower octane? It's not like our cars have wonderful knock sensors that retard the timing- If his engine is knocking enough for that to happen, it's as good as blown, correct?

1 gallon of 87 octane gas actually has more energy than 1 gallon of 93 octane gas, so if it's not knocking, the parent post makes no sense.

 

You guys running 87 are just silly.....the minimum recommended octane is 91. I guess if you drive around like grandma, it's ok.

 

All we can get in these parts anymore is 91 octane, which I always use. If I could get 93 (which was available until just a year or so ago) I would use it. Hell, just for grins on occasion I'll put in a gallon or two of 100 octane race fuel when I want to really be 'safe' whilst getting on it in cool air conditions.
The problem with running 87 octane is that one 'oops' and you are done. There is no way the stock knock sensor is fast enough to retard the timing to keep detonation at bay.
I have on occasion run 87 octane in my twin-turbo Volvo S80 T6 and I notice a difference in performance. The ECU in that car is a work of art and monitors a lot more things more accurately than what the ECU in the FD can be expected to do, given the difference in years.

 

this post makes no sense.

they have the same energy. 93 can handle more compression before it auto ignites.

 

been running my car for a few years now with around 90 RON....NOT RON+MON/2. To be honest its difficult to say what the octane rating in my country is, it might be even lower.
I drive my 7 only on the weekends. AND I DRIVE LIKE A GRANNY......boost limited at 7psi. I believe what Tyler said is right-if you have the octane available why on earth would someone want to run their car on 87?? I'm unlucky in a lot of way, since i dont even know how a 7 feels at 12psi let alone anything higher. I will never sell it though......rotors are now in my blood.

 

You guys talking about the compression are only considering the static compression of the motor. When looking at a turbo motor, under boost you need to consider dynamic compression, which is total compression including boost pressure, which can be very high. I might have overly simplified it but you should get the point.

I think you would be crazy to run 87 octane on a turbocharged motor. Sure you may get away with it, but why risk a several thousand dollar motor to save a few bucks at the pump. No logic in that.

 

I agree with those that state that you should use only premium 92 or 93 octane only. I have on occasion used 87 and it wasn't too long after when my engine blew. When it blew it was on premium. I don't know just how sensitive the anti knock system is on this engine. I doubt whether it is fast enough to protect the engine from detonation. Just my thoughts.

 

My FD runs fine on 87 octane - it runs better on 93 octane - thus it is "less spirited" on the lower 87 octane - the difference is noticealbe but it does not make the car inoperable. THat was my only point. It has never nocked or had a fuel issue. If your car is stock it can run fine on 87 octane and as stated that is all I ever put in my FC with no failures. Energy in gas and Octane ratings aside most cars will perfom better with higher octane - that does not mean they can not run on lower octane without issue. If the post still does not make sense to you so be it.

 

Just wondering how many mods on the engine? I would agree- run premium if it were more than a few.

 

I only use 94 octane up here in Vancouver BC. First I insert the pump nozzle in my ***, then in the car, then I know I'm getting screwed by the gas company. Chevron Gasoline is the best for my car, then Petro Canada, and last Mohawk - Mohawk has an ethanol blend which the car likes for freakin flooring it but, it starts to act weird after a 2 tanks, don't ask why, it just starts to stumble more. Also runs hotter? The lowest I've run is 92 octane and that is when I was completely stock. I would never run lower than 91 octane, even when not boosting I notice 92 octane. Ethanol is bad, stay away, I'll explain later but I'm drunk right now.

 

Hmm weird. I have the same set-up but mine felt faster with 87.

 

Do you think it's still silly that our engines have lasted longer than yours? His 12 yrs of experience says it's safe regardless what the recommended rating is.

 

ooohhh mode ED


but eh fsm recommends 91 FTW

and im fsm's bitch. i do what it tells me to

 

LOL yougster I've been driving rotaries since you were 3. FSM also says not to use sythetics but many of the rotary experts do. There's always an exception to the rule if you know what the hell your doing nubie.