Edelbrock EP4B intake - what's the truth ?.

Damn, am I going to have problems running 93 octane in my 59?

starchief_59 wrote:

Damn, am I going to have problems running 93 octane in my 59?

BIG TIME!!

9.5-1 is about all you can get away with these days on pump gas. If you zero deck the block, you may get away with 10-1......maybe.

Robert.....maybe, maybe not. I've been running Sunoco 93 in my numbers matching 1967 Firebird 400 for the last five years with no problems. The original compression ratio is 10.75-1. Of coarse I don't beat it to death, but I've been known to hammer it through the gears once in a while! My 1959 has been bored .030 over and the heads have been shaved enough to straighten them, so the compression is likely a little more than 10.5-1. What you need to do is to listen for pinging, especially when running it hard or putting a load on it. The solution to a problem could be to retard the timing a little, but this will cut back on performance some. Some of my friends that have numbers matching performance cars, add two or three gallons of Cam2 to their tanks before they fill up if they notice a problem......John

Damn that sucks. I'm running a fairly large cam which I was told will help to bleed off some compression. But shit, 10.5:1....

I wish we could get 100 octane at the pump. That would be awesome

What is Cam2?

I always get the problem when i pull the caravan - under heavy load it starts to detonate unless i run Shell V-power 99 oct. Also i think it cleans the engine, cause i can get away with a tank or two of 95 before the problem gets worse again. Only the high octane eliminates the problem completly.
You can run an additive though - i run a lead replacement anyway, so you could get a leadreplacement with boost such as Castrol.

What octane would I need to run a 10.5:1? like 100?

Man that sucks, haha Maybe I'll buy a barrel of some kind of race gas and add some to every tank. Or I could just make it a regular thing to go to the track every few weeks and fill it up with some 105 or something haha

Don't you have commercial octane booster available at the stations ?. Also addition of ethylalcohol (if available) - maybe 5 or 10 % - will improve things. I have not tried this, since it is not available here, but if you use rubber hoses that are alcohol resistant you should be able to use this trick. Milage will decrease a little, as alcohol has a lower energy density. Remember it has to be water free alcohol - otherwise water is going to seperate on the buttom of your tank, and eventually drown your engine

In theory our engines should run fine on pure ethyl alcohol, but you would need to use 30 % bigger jets in the carb(s) - as long as the rubber can tolerate it. Good to know when we run out of old dino's

Pure alcohol should tolerate at least 15:1 cr by the way.

We have octane boosters here but I'm not sure if any are actually worth a shit.

The alcohol trick sounds like a lot of work. I guess I'll just have to see how it runs when I get it on the road

Robert.....Cam2 is a brand of racing gasoline sold up here in the Northeast. I think it is about 105 octane. Don't know if it's sold Nationally, but there are many brands out there. Usually it is sold at drag strips, and gas stations near drag strips. Next time you go to the races, take 2 or 3 5 gallon cans with you, and fill up. Sometimes their pumps have 110 and 115 also. As I mentioned above, 4 or 5 gallons in our size tanks and the rest 93 octane should get you to 100 easily. That's what the guys with the muscle machines do around here if they have a problem......John

Just be thankful you don't live in Cali. You can pretty much forget about getting any high octane fuel from this stupid state.

One recommendation I have is setting up a water injection system. Water injection significantly reduced ping, increases power, and even increases efficiency. However, if you decide to beat on this motor, you need a "forced" system since engine vacuum driven units (the most basic, simple and reliable method) wont be very effective when you have the loud pedal to the floor and engine vacuum is at "0"

I do plan on taking this to the track so I guess that's what I'll do. No big deal, the track is only about 30 minutes away. How long is gas "good" if I do keep some in gas cans?

I've heard of the water/meth injection on diesels and other turbo vehicles. I didn't know people did it on NA motors.

I'm very glad I don't like in Cali. I'm pretty happy here in Texas. Our laws seem pretty laid back...as long as you don't kill someone

Thanks guys

starchief_59 wrote:

I've heard of the water/meth injection on diesels and other turbo vehicles. I didn't know people did it on NA motors.

It was initially used in NA motors for piston engine aircrafts prior to World War II

http://en.wikipedia.org/wiki/Water_injection_(engines)

That's cool. I did not know that

We have Sunoco up here that sells 110 octane. As far as how long gas will last, 1-2 years at the most without stabilizer in it, and even then I don't know what happens to octane rating, efficiency, etc.

Your best option is to decrease the compression. We just went through this with a guy over on HCP. There's no cheap fix to high compression, fix it right or trash your engine. $0.02

Well to get it down enough to be able to run it on the street probably means putting dished pistons in it. Fuck that. I'd rather run 4-5 gallons of race gas per tank. I've also been told that compression ratios were different back then and a 10.5:1 is more like 10.2 or maybe even a little bit lower. No one has been able to tell me why but apparently compression ratios back then weren't quite as high as they were rated.

Must be nice to be able to get 110

Never use it. Just a piss ass waste of money to run $4.50/gallon gas. You're going to end up wrecking shit if you don't fix it and try to bandaid the problem with higher octane.

Shit that is cheap - we currently have to pay at least 10 kr/l for normal premium fuel. thats about 42 kr/gallon or about 8 $. .
Add to that some of the highest taxes on new cars in the world :
First 80000 kr (12000 $) of car value : 100 % tax
the rest : 180 % tax
+ 25 % sales tax (VAT) on top of it all.
No wonder we drive old cars here .

Compression isn't the problem. The gas we have nowadays is the problem. Running higher octane is the solution. That's what higher octane gas is for, it's not a bandaid. It's not like high octane gas is some unproven "trick." For certain compression ratios you have to run certain gas. Like 14:1 compression cars usually run alcohol. And more compression you run nitro. 26:1 Diesels run diesel. My truck is 9.6:1 and Chrysler only recommends 89 octane. It's not like dodge made a mistake and the 89 octane is a band aid. They wanted to bump up the compression to gain a little more hp. So I don't believe that 105 octane is a bandaid if you need it. Now if you try to run 105 octane in a stock honda I can see some problems resulting but if you match your compression with your octane you won't have problems.

Lots of cars from the late 50-early 70s were 10:1+ compression and ran fine on pump gas back then. We can't do it now because our gas is shit. They didn't have problems back then with their high compression cars. If they did they wouldn't have made them. That's performance went to shit in the mid 70s. Shitty gas, more emissions, less compression, less horsepower.

Now I wish I would have got some dished pistons instead of the flat tops but I'm not going to tear my motor apart and rebuild it just to get it down to 9.5:1. I told the guy who built it that I had to run it on 93 octane and he said it would be fine. I have doubts now but the motors already built. Oh well

I guess some thicker head gaskets would help a little also. I don't know, I think 20$ in high octane gas every couple of weeks isn't that big of a deal. I mean just one year ago we were paying $4.50 for 87 octane and we had to live with it. I can live with a $60 gas bill every 2 weeks or about every 200 miles and have the extra power from the higher compression and save the money on a new rebuild.

What would it cost to get my motor redone with new pistons? Few hundred bucks for new pistons plus a few hundred bucks in labor? Fuck that

Do the work yourself man. Why have someone else build your engine? If you don't know how or don't have the tools, it's about time to step up and learn, go buy the tools and Git 'R Dun!

As far as the gas, compression BS. You keep telling yourself that it's not a bandaid and let us know how well your car runs when the engine takes a shit and you have to rebuild t he whole thing. Didn't you learn anything from that dumbass over on HCP? Gas back then also had lead, sulfur,etc. in it. It ran different then because it was different. You're comparing apples to ornage just to justify your careless engine building.

In the end it's your engine but being lazy and all that hard work is going to be worth nothing and you'll be right back in the position you are in now.

And if you do decide to run high octane, you're giong to have to run high octane. Not mix the shit to try and save a few bucks.

Here's a link to the thread at HCP I mentioned.

http://hardcorepontiacs.com/forum/6307-cam-c-r-question-any-guesses.html

Well, i guess there is no harm in trying. Ultimatly you will immidiatly notice if detonation occures - i know i hear it load and clear - and i reduce the load immidiatly. It's not like the engine blows up without any warning. If it turns out to be a problem change the pistons or use higher octane, but why not wait and see how bad it is. As far as the modern engines go they have more sofisticated chamber design that allows higher compression on lower rated gas. Higher compression yields better economy and more power, as long as you can avoid detonation. I mean the engine is already put together as you said - so why pull it apart without even trying.

Exactly, I've been waiting almost 4 years to drive this thing. I'm not going to tear apart my whole motor because a few guys on another forum say it can't be done. The guy who built my motor said it would be fine, everyone else has said it will probably be ok. We'll find out soon.

So 100+ octane has no use and people that build cars 9.5:1 and up will blow up their motors no matter what? I'm going to strongly disagree with that. If people can beat on 12:1 race motors all day long season after season on 115 octane how am I going to blow up my motor by running 4 gallons of 105 octane? What exactly is it going to hurt?

I'm also going to partially disagree with the cam not affecting compression. I don't know that it actually affects the compression but you can run a higher compression motor on pump gas if you have a big cam. It bleeds off the pressure I guess. I have been told this by many people.

And no, I didn't learn anything from that HCP thread.

I had someone else build my engine because I've never built an engine before. Obviously it's not that simple of a task. The guy who built my motor builds race motors all day long. I thought he knew what he was doing.

Like I said before. It's your engine.

And actually, yes. Building engines is a simple task. I've had no schooling on building engines. Just decided I wanted to learn. With some reading and some questions I have successfully rebuilt 3 engines since I started this hobby.

You just keep on self justifying yourself speedy.

Here's another reference for high compression engines...

http://www.jalopyjournal.com/forum/showthread.php?t=398505&highlight=high+compression