Cranking compression results are in

[ClassAct]

Meanwhile, back on topic…

Back on topic...I run 12:1 on pump gas with iron heads. A

ll things claimed to be wrong. There is a process to follow doing higher than "orthodox" compression ratios on pump gas. You absolutely MUST use a timing CURVE. You also need to control coolant temps. I know that thermodynamically that's a bad policy but it's my OPINION that what power I lost with the cooler temps (if in fact cooler temps make less power but I digress) I more than gained back with what I consider "standard" timing.

Also, I have struggle with some people who think that reducing timing is bad. It's not. If I can run more compression and I have to reduce timing who cares??? You are reducing pumping loss. That's a good thing.


Running more compression is like adding a power adder. The combustion chamber is packed tighter so it NEEDS LESS timing, yet people talk like you just dropped 50 HP by taking 2 degrees of timing out.

I don't build for luck. I science it out. That's why you can't do it. Welcome to 2024, same as 1984 unless you keep learning.

It's great to have an opinion but what's bad is repeating error over and over and over and over like it's fact.


IMO, building a street/strip with less than 11:1 is leaving power and drivability on the table.

But, if you believe the orthodoxy you end up building than you can tune for and then they claim it can't be done.

And BTW I'm not saying you as in YOU but in general terms.

I have done jsut this also. Ran 12.65:1 on pump gas with retarded spark timing (27deg).
Kept off the throttle if when temps over 180F. Reduced power output.
When ran on 110 Octane unleaded and correct WOT timing (36F) The engine is MUCH happier.
MORE more horsepower and torque and throttle response.

On the street in the real world driving conditions you cannot hold the (Air inlet and Water temps) temps under that tight control.

Your luck will run out. Water-methanol injection is a viable method alternative to high octane gas.

[Stan Weiss]

There are current production engines, in street cars running 13:1 on 87, at WOT...so a lot has changed. Those same engines do pick up power on 93. But if you are expecting old stuff to run more compression on 93 than we did 25 years ago, your setup won't be the same as it was 25 years ago. But not only is it possible, it's common place and these days and is being done while under warranty....with coolant Temps between 210-220*. No water meth injection. The world is no longer flat.

So are you running a carb or EFI and a computer controlled engine tune-up?

Stan

[cab0154]

There are current production engines, in street cars running 13:1 on 87, at WOT...so a lot has changed. Those same engines do pick up power on 93. But if you are expecting old stuff to run more compression on 93 than we did 25 years ago, your setup won't be the same as it was 25 years ago. But not only is it possible, it's common place and these days and is being done while under warranty....with coolant Temps between 210-220*. No water meth injection. The world is no longer flat.

So are you running a carb or EFI and a computer controlled engine tune-up?

Stan

My wifes 13:1 2021 toyota is EFI. Most of the Suzukis we build at the shop that are 13:1 and run on 93, are efi. Some are carb. My coyote truck is efi. Some of tbe other coyote stuff we mess with is efi. The sbf in my mustang that is 12:1 is an AED 4150.

[BobbyB]

There are current production engines, in street cars running 13:1 on 87, at WOT...so a lot has changed. Those same engines do pick up power on 93. But if you are expecting old stuff to run more compression on 93 than we did 25 years ago, your setup won't be the same as it was 25 years ago. But not only is it possible, it's common place and these days and is being done while under warranty....with coolant Temps between 210-220*. No water meth injection. The world is no longer flat.

So are you running a carb or EFI and a computer controlled engine tune-up?

Stan

My wifes 13:1 2021 toyota is EFI. Most of the Suzukis we build at the shop that are 13:1 and run on 93, are efi. Some are carb. My coyote truck is efi. Some of tbe other coyote stuff we mess with is efi. The sbf in my mustang that is 12:1 is an AED 4150.

Is your 12:1 sbf driven on the street? If so, please give us the particulars.

[cab0154]

So are you running a carb or EFI and a computer controlled engine tune-up?

Stan

My wifes 13:1 2021 toyota is EFI. Most of the Suzukis we build at the shop that are 13:1 and run on 93, are efi. Some are carb. My coyote truck is efi. Some of tbe other coyote stuff we mess with is efi. The sbf in my mustang that is 12:1 is an AED 4150.

Is your 12:1 sbf driven on the street? If so, please give us the particulars.

Sometimes. I really didnt build it to run on 93, but it does just fine. I would characterize it as a street/strip car. i have the AED gas carb for it as well as a c&s methanol carb. just depends on what I want to use. its a 418, profiler heads, super victor intake, street roller. 7al3 for ignition. pretty basic. this thread has me thinking maybe i need to hookup the wideband and see what i can get away with on some quality 93. i just put fresh gas ported rings in it, fresh hone, advanced the cam, coated the piston crowns and skirts, went to electric wp and a vacuum pump. so its going back on the dyno pretty soon. i might play around with pump gas with it if the guy whose dyno i will be using wont mind. it makes more more power than the little stuska we use for the sportbike engines will hold.

FWIW, a lot of what i see in terms of octane tolerance from a mechanical standpoint, seems to be a combination of overlap flow (valve placement/chamber design) and managing the IVC event. the more overlap flow a head has, seems that it needs less help from the cam in terms of valve overlap and IVC. just a common denominator I have noticced.

[Tartilla]

My Glen-L Thunderbolt v-drive lake boat built in the '70s has an LT1 short block with 292 heads. Solid cam. 11:1 with a Joe Hunt Vertex Mag.Timing is a prob around 34° all in in by 3000 ish.

6000 RPM max at max speed.

Cam is the 370hp LT1 cam. 316/336 adv. Something like that.

Pump gas. Never had any issues, or indications of detonation. Raw water cooled...running temps about 270°f.

Just my experience.

[Tartilla]

Was trying to find an editor...but it evaded me there is one.

316/336 solid FT cam specs include the lash of 0.024"in.

Obviously my running temps are 170°f.

[Bill Chase]

Have you noticed $tupid $hit is never constipated?

Yes it is. So backed up it comes out the mouth instead of the rear end where it's supposed to.

[F-BIRD'88]

You will never maintain 170 deg F water temp on a street driven car that you actually drive.
Reality.

[Warp Speed]

Bla Bla Bla

[ClassAct]

You will never maintain 170 deg F water temp on a street driven car that you actually drive.
Reality.

You sure about that? I live in a high desert valley. In the summer we are over a hundred degrees a lot. I run my engine at 160. I can run it cooler than that but the defrost becomes ineffective and since its a STREET car and I drive it year round I need a defrost. Out here in the high desert valley we get down below zero. If it's dry I drive the car.

Once again, because you can't do something doesn't mean anything other than YOU can't do it. Maybe a long look in the mirror considering why people tell you the truth and you can't accept it.

[cab0154]

You will never maintain 170 deg F water temp on a street driven car that you actually drive.
Reality.

interesting. i managed to do it over 25 years ago with iron heads and a 60mm turbo under a stock hood with a hood blanket and the a/c on, during the summer in texas. if you couldnt manage that in canada I dont know what to tell you; since i spent my very early years in N. Idaho and know for a fact it is MUCH easier to keep an engine cool up there, than it is down here in TX.

[hoffman900]

Bla Bla Bla

This thread is a real dumpster fire, eh?

[F-BIRD'88]

You will never maintain 170 deg F water temp on a street driven car that you actually drive.
Reality.

You sure about that? I live in a high desert valley. In the summer we are over a hundred degrees a lot. I run my engine at 160. I can run it cooler than that but the defrost becomes ineffective and since its a STREET car and I drive it year round I need a defrost. Out here in the high desert valley we get down below zero. If it's dry I drive the car.

Once again, because you can't do something doesn't mean anything other than YOU can't do it. Maybe a long look in the mirror considering why people tell you the truth and you can't accept it.

You won't maintsin 170F on a 100F day. Stop dreaming.

[F-BIRD'88]

I call BS on you guy claiming to maintain 170F on a hot day in traffic . In a rfeal world driving situation. Stop dreaming
Stop misleading this guy with his LT1. If your outside temp is 100F so is your engine inlet temp .(Or higher.)
Stop it.