found my ignition problem

[jordan]

My stroker RB motor has been giving me ignition/detonation issues ever since I started it up a few years ago.  They seem to be random.  I get pinging when the weather changes, or when I put a passenger in the car.  On top of that, I have had an ignition fail, and a coil fail at other random times.  So I turned down the timing and started driving mellow.  And I hate that.  I am an adrenalin junkie, and I am leaving more power on the table with the timing turned down.  So, being sick of driving a car that doesn't run strong all the time, I sucked it up and took it to a shop for help.  I took it to Kilpatrick Engine in Waukesha Wi.  Bigs stomping grounds.  Their shop is awesome!  They had a bunch of cars in for nitrous kits, pro-touring set ups, FI conversions, and they are doing a 70 cuda with XV motorsports level 2 suspension and a twin turbo Hemi!!!  They have a machine shop and specialize in hemi builds and only try to build mopar motors.  These guys looked at my set up and couldn't find anything wrong with my ignition system.  Then they asked me about my pistons.  I have flat top pistons and 440 source heads on a stroker.   They took my engine build list, and re crunched the numbers and came up with 11.9:1 compression!!!!  Recommend that I start using 110 octane gas at $8/gal.  My quick math says it won't take long to cost me more money than a set of pistons cost.  So, it looks like I will be pulling my motor at some point and putting in dished pistons so I can actually drive this thing like I want too.  All this time thinking I was screwing something up, but it was built wrong all along.  I emphasized to my builder 100 times, that I want a pump gas, street motor, 11:1 max.  Now I will be calling him to line up the piston exchange.  I hope he will fit me in yet this summer, even though it is race season for him.  Total drag.  I have a lot of work to do now instead of play.   

[Cuda Cody]

   11.9 to 1    Even 11 to 1 will be a little rough with pump gas.  I like lower then that for street driving and easy starts. 

[jordan]

Kilpatrick recommended closer to 10:1 even with the aluminum heads for street driving pump gas.  I suppose I will loose a lot of horsepower too. 

[Chryco Psycho]

If you maintain the quench you will be ok into the high 10;1 range even close to 11'1 will work if the quench is there using Alum heads of course
12;1 is impossible on any pump gas

[jordan]

I now realize why I could never get it consistent.  So this quandary leads me to fuel.  Will any of the fuel additives and octane boosters help me out until I can get it pulled apart and put back in?  "Race Gas" in a can has been advertised a lot lately.  Anybody use it?  Or is there any other product that will boost my octane?  Will it keep me driving for a while?  Or am I just putting the hurt on everything else in my motor every time it pings and I am better off not running it as it is without race fuel or different pistons?

[Chryco Psycho]

nothing I have found really helps , if you have a local airport buy 110 ll but you have to buy it in gerry cans & put it in the car somewhere else
boosters will bring you up a point or 2 but not ten that you need

[1 Wild R/T]

So what are the specifics of your build? 

Flat Tops with valve notches?       4cc
Stealth heads                              80cc
Piston how deep in the hole?
Head Gasket Bore?
Head Gasket Thickness?

For Dynamic C/R
What Cam & What's it degreed to?

[RUNCHARGER]

Yikes: You have obviously been right on the edge of detonation if your car is that susceptible to weight/weather. Most people don't realize that dropping compression a bit has far less influence on performance/efficiency than dropping timing does.

[Cuda Cody]

I like HP as much as the next guy, but I hate not having an engine run good.  I've found it's much easier to get an engine to be street driving and easy starting when I start under 10 to 1.  I like them in the mid to low 9's to 1.  I do not make as much HP that way, but my engines runs great and start right up.  I drive them and have no worries.  Anything over 11 to 1 and it's not going to be easy to make it street friendly.  Not saying it can't be done.  The only solution now at the compression you are at is to run race fuel.  Really race fuel.   

What is your goal with the car?

[Marc70challenger]

I now realize why I could never get it consistent.  So this quandary leads me to fuel.  Will any of the fuel additives and octane boosters help me out until I can get it pulled apart and put back in?  "Race Gas" in a can has been advertised a lot lately.  Anybody use it?  Or is there any other product that will boost my octane?  Will it keep me driving for a while?  Or am I just putting the hurt on everything else in my motor every time it pings and I am better off not running it as it is without race fuel or different pistons?

http://race-gas.com

Works for me

Like Chrcho said other crap brings it up 10ths. 

[MoparLeo]

It sounds to me like you need another car. One to drive when you are doing normal stuff, and one for when you need that adrenaline. BNo such thing as a dual purpose car really. Race cars make crappy street cars, and street cars are street cars.

[Chryco Psycho]

I seem to have found a balance with making great power & keeping it pump gas friendly but you have to be on your game , Quench is Key
I agree that backing off the timing hurts more then dropping compression .
I generally agree about the street / race car as well , but Computers & Multiport EFI can do so much more than we could in the past , Just look at the Hellcat 700 hp & you can drive it anywhere , using similar technology on older engines you can have the best of both worlds  , I have done it 
Did a 68 RR 440 not stroked , 720 gross HP approx 450 at the tires & more tq than the Hellcat ,Victor heads , 680 lift solid roller cam BUT it never loped as every cylinder fired every time it would idle in traffic never over heat & run mid 11s on street tires @ 4000' altitude on premium 92 octane !
I wonder what it would have made as a 512 build 

[1 Wild R/T]

I wonder what it would have made as a 512 build 

It would have made the crankshaft leave the block.....

Then again more cubes means more power at lower RPM's so it might have been fine...

[Chryco Psycho]

Only if it was a Chevy
the RB will hold onto the crank just fine 

[1 Wild R/T]

I've seen enough split main webs to know the weakness...