HunkyDory

Hey guys, I bought myself a 1980 RX-7 a few weeks back and one of the details of the car the guy was talking about is that the engine (Holley carb'd 13B transplant) was "supersealed," and from my research, I'm guessing it means it was rebuilt with RA Super Seals. I was told the car can only run 93 octane because of them. Do the seals themselves really necessitate feeding the car premium petrol?

Thanks in advance, y'all.

misterstyx69

iTrader: (142)

Have you tried the difference between regular and 93?
maybe it is just the price?..
But then again,I have seen "quirky Engines" that will run better on Hi test than regular.
Seals have nothing to do with what the car would use for gasoline.
The Carb may be a factor here too.
I'm an EFI Guy now,so I haven't dabbled in Carbs since my old 350 engine.

diabolical1

iTrader: (3)

if no form of forced induction is involved, then what he said is utter rubbish.

misterstyx69

iTrader: (142)

"Utter Rubbish"..???
quit eating Fish and chips and watching Coronation Street Jason!!..it's effecting you Immensely Ol' chap!..lol!

Ghooble

iTrader: (1)

What if it had higher comp rotors?

diabolical1

iTrader: (3)

if you're running the correct timing, it shouldn't matter. I use 87 in my Rx-8 and it runs just as good as when I used to run 93. for the record, I have been informed that some Rx-8s do knock, but I've never experienced it with mine. older 13Bs with 9.4s and 9.7s will take 87 octane just fine.

diabolical1

iTrader: (3)

what can I say? culture-wise, I have a fairly colourful ... er ... I mean colorful family. besides ... absolutely nothing wrong with fish-n-chips.

HunkyDory

Thanks for all the replies everyone.

I haven't tried using a lower grade gas yet for fear of detonation. (More info The car has some weird MSD ignition with the distributor not having vacuum advance lines (the diaphragms are still hanging off of the distributor though). Fuel cut-off is set to 10K.

The engine was originally built by a rotary specialty shop here in central FL with the purpose of drag racing. My thoughts were the same, where the engine should just be running good 'ol stock compression, so regular grade would be okay to run, but who knows, maybe there is some other black magic going on that I don't know about. Then I had the same idea that it may be that I have high comp rotors, but that seems to have been debunked as well. I'd rather not risk blowing the car up so for now I'll stick to premium until I can talk to the shop where the shortblock was supposedly built. If I can't get any answers from them, I'll start weaning the car off premium little by little with a 50:50 premium/midgrade tank and see how she handles it.

At least now I know the seals aren't the culprit, or high-comp rotors if I have those as well. Good knowledge for the future. Thanks again.

diabolical1

iTrader: (3)

1. does the engine have any kind of radical porting?
2. what size Holley?
3. where is the timing at idle? at 5000 RPM?
4. do you have reason to believe it was knocking with the previous owner?

misterstyx69

iTrader: (142)

You don't need a "tankful" to test the LO or HI test sitauation.
when the car gets near 1/8 or so,add your "weening mixture" and see what happens.
That way if it starts acting up then Fill UP..and then you that will pretty well take you back to normal.
If you have a half tank of HI and add a Half tank of Regular and it doesn't work then you have a WHOLE tank of gas that you can't use.
This way at least you can get back to the HI Test level,or close to it if you do Not do a half and half tank trial run.

..Diabolical wants to know if you prefer Tartar sauce or Ketchup on your Fish!.(had to ..heh..Good mood today!)

Aaron Cake

iTrader: (1)

Unless something ridiculous has been done with timing (ie. fixed 40 degrees of advance) then there is no reason to run premium.

HunkyDory

1. The engine has been streetported.

2. You got me stumped. Pictures are below. Maybe someone can guestimate a size?

3. I'll see if I can borrow my friend's timing light tomorrow and check that out.

4. Not at all. Previous owner says he only ever ran premium, and never had problems. Bought the car directly from the specialty shop owner, who built it. He probably recommended premium, so that's what the owner before me ran. I really do need to speak with the shop owner to get truly reliable details.

5. No tartare, no ketchup. Mustard please!

Carb Pics:

diabolical1

iTrader: (3)

streetport is okay. I only asked because you mentioned the ignition cutoff being set to 10k and also because I figured it would be more likely for someone to screw up the timing on a bridge or semi-pp. so I just wanted to see if you were leaving something out.

I'm no use to you with ID-ing your Holley from a photo, so hopefully someone that can, will see this and respond. however, if you're not experiencing any obvious fuel issues, then it's likely to be sized right (or at least tuned right) for your 13B. I only asked about it, again, to flesh out any potential reasons why someone may have been fixated on fuel octane.

timing is your real issue though. check it and confirm. however, if it's okay, then as others (and myself) have stated previously, you're okay to use 87 and be just fine.

it can't hurt to get a more accurate history on your car and engine, but I don't expect you to find a valid reason for 93.

oh ... and cat's nuts, um, catsup yeah ... I mean ketchup.

Ulburner

Your carb should be stamped on the air horn that should tell you the model number. You can go to http://www.holley.com/data/TechServi...%20Listing.pdf and figure out what CFM it is.