Yep.....and you've seen them all .....

KW

 

No, but in 12 years of messing with them and while being on three or four different forums I have seen a lot more then most .

 

12 years?
That's cute.

KW

 

For LT1s specifically? Yes. In a good mood so I'll take the bait...show me a 13:1 LT1 that runs well on pump gas .

Only ones I can recall at 13:1 or higher are E85 or race gas setups.

Of course at that point you need to pay attention to piston design, cylinder heads, and cam as well...can't just say xx:1 compression is fine with xx octane gas.

 

OK, I agree though I often rebuild engines with 12:1 C.R., my 60-2 accurate DIS, including the high output coil IGN-GEN-IV. (120mj).
One example of MY work : A 67 Camaro, my 65mm ITB's, a 4" x 4.1" LS-427, my Redline ECU-882C is such a case.
A "tight" +.008" deck with 1041's is the Squish Value, using a "flat top" RacTec piston.
A camshaft 236/242 @ 116 C/L was installed.
The head is ALSO of concern, a LS-2 "high swirl" head was fitted.

I have pictures, Road Dyno tested, customer's home is in Lake Mathews @ 2000'.

ONE reason this works well is the R/L @ Rod length of 6.125 Divided by the Stroke, 4.10" !
Another case : The second MOST FAMOUS, second oldest, race in the world begins at 9000' feet then ends at 14,000'.
That race engine, a LS-482 RHS, had a 18:1 CR race gas engine, assembled for Jeff McPherson.
MY Redline ECU-882C AND MY 280mj IGN-1A coils were fitted.

I wonder who here has had his equipment in THAT race ?

What is your Altitude ?
What is your choice of ignition/fuel injection ?
What is the tooth count on your Crankshaft Target Wheel ?

Lance

 

Show me the ones that don't.

BTW.....12.5:1 (solid roller) LT4 that I drive often on the street.....to and from work.....in 100+ degree rush-hour traffic.....on pump gas....with no issues. I know it can be done because I have, and am, doing it.

In light of what I've experienced with my car, I see no reason why a properly spec'ed LT1/4 can't do "a hair shy of 13:1" (your words ) with a properly matched cam and proper quench.

Suffice to say that we have a difference of opinion....and that neither one of us knows for sure.

KW

 

Hey KW Baraka, when you drive your setup on pump gas, are you tuned the same as when you race at the track? What rpm do you take your setup to?

 

Okay, in this season of "Peace on Earth and Good Will Towards Men" let's just say that the LT1 engine "envelope" is now being ..... expanded!

Here is a link to a 396 LT1 going into a "B" body running 13:1 SCR on 93 octane pump gas making 509 RWHP:

http://www.superchevy.com/how-to/eng...g-into-b-body/

(Quoting from the above article "Running on mere 93-octane pump gas, the 13:1-compression LT1 made 509 rwhp at peak and 475 lb-ft of torque.")

Things are changing all the time and let's just say that you can't stretch the envelope .... without pushing up against it.

Again, thanks to all who have responded!

 

Same tune.....but I add 4 to gallons of race fuel to 1/2 tank of premium on my way to the track.

I shift at 6500 RPMs because my opti- gets a bit crazy around 6800-6900 RPMs.

Once I go with the 24x conversion, we'll see how high it pulls power and will adjust shift points accordingly.

KW

 

Have you raced it on pump gas or went WOT under drag race load? I am guessing the 4 gallon mix is for insurance. I am sure you are missing some power shifting at only 6500 with the solid roller. My setup just starts feeling good at 6500..lol.

I have run mine on pump gas just fine at 12.15-1 compression with a 259 267 @.050 108lsa 6.5x cam but it was only cruising under 3200 rpms and not under a lot of load. The car seemed to be fine with no detonation but I am not sure I would be willing to try it with pump gas at WOT down the race track.

I still need to fine tune the fuel tables on my setup down the track then see the minimum timing I need to make max power down the track before venturing into mixing pump/race gas and or trying a pump gas tune. I hate running $9/gallon race fuel. I specked this combo out in 08 for a borderline pump gas setup so I am hoping to at least get away with a mix to go further.


Thanks for the reply,
Matt

 

Why not replace it?

 

He bought the Torqhead setup a week ago or so.

 

The plan was to go 24x. Since it's car #3, I can't justify installing another opti just to pull it after a couple of months.

Haven't raced it on just pump but I have it WOT with just pump.

Yeah......leaving a lot on the table shifting at 6500 RPMs......but that'll soon be remedied.

KW

 

Read about that motor when they were building it maybe 2-3 years ago, it was posted somewhere in here. Cool that its not only still running, but being worked on. I was very interested at the time since it has a similar head to my current build and I was curious of its performance.

I do remember them specifically stating it was an E85/race gas build, which was one of my gripes with it since mine is for pump gas...along with using stud mount rockers and no girdle on a pretty healthy solid roller, and the plain Vic E instead of a Supervic for an SR 396.

Big difference between 12.5:1 and 13:1. Your build mixes in 1/3 race gas already and its a full half point from what was mentioned. At 13:1 it wouldn't just be "insurance", it would be necessary.

 

OK KW, my question is to you, In Good Faith.

There is time/work involved to "switch" to a 24xe TW, your stated future choice.
The same work/costs accure when a 58x (60-2) Target Wheel is fitted.
The 24 tooth wheel has a TWO degree accuracy range.
The 58 (59) tooth wheel has a 1/4 degree accuracy range.

Thus I ask you which one is better ?

Lance

 

Just to clarify, you are aware this is a Gen 2 LT1 sub forum, correct?

 

I choose to add race fuel because temps are often still in the 90's when I race. When I drive on the street, I have no issues with 92 octane regardless of what the temps are.

If my engine were 12:1, I'd still add the race fuel.


To me, it's irrelevant if there is no 58x kit available for the LT1/4, for about the same cost of the 24x kit. And no way am I in the mode of piecing together a 58x setup.

That said, I'm sure a 58x setup would be 'better'..

KW

 

OK, for "no mercy", my guess is that I have been installing MY 60-2 (GM-58x) BEFORE you were BORN on GM SBC/BBC engines, INCLUDING MY OWN Lola 332 F-5000 in 1984.

I created a 60-2, 36-1, 24-2 TW for use on BBC, SBC engines BEFORE EFI was selling that art.
The "art" of an under front cover TW with sensor.

The largest user is CPS in Paris, Texas for use on their 25K hour engines.

The TW's I make, for under front cover use, sell for the same price.

I post this to be of help, just place an order.

Lance

 

You would be correct on that aspect.

However, in my wasted years with an LT1 car, I have never stumbled across your system being offered for an LT1. (This is more user error on my parts, I assume you advertise for a SBC rather than specific LT1?) If you have pics or any details on your system on an LT1, please post up. I am curious.

On my motor I have a 24x reluctor wheel.

 

Hi, thanks for the interest.
I do have a site "panteraefi.com", major updates starting Jan-1.
The EMS is there, I have the manuals and will E-Mail them if asked.
I have created "opti-spark" 24xe, 24-2, 36-1/2, 48-2 (gear down TW), and 60-2 units. (proto tested)

The OEM style 360 Absolute Encoder production unit can be site seen #99891.032.

Would there be some here that could use a 58x "opti" with 4x CAS ?
Would there be some here that could use a 58x "opti" with 1x CAS ?
The choice of a Flat Cap for the OptiSpark, both, could be included ?
Would you like to have "multy" TWs included ?

You state "24x", NO such GM OEM'd item.
There are OEM 24 tooth, 24-1 and 24-2 TW's.
My question to you, "What does your "x" state ?
I only support the three above.

The KW "post" about Piecing.

I LIKE the owner of EFI-24x, a great engineer.
He too sells/manufactures my 60-2 (GM58x) for use with his product like.

What we learned : The 58x can be fitted for the SAME costs.

NOT many good answers were provided for the OP's "quench" question.
The term Quench puts out a fire, the term Squish makes the fire burn more correctly.

Lance