Jeep Strokers

I think Flash did i great job of explaining it in the "compression ratio" faq located in the faq section. I've quoted it below

Thanks Mgardiner1! I do appreciate it.

Nice, obviously I didn't see that post. He even covered the elevation issue. Thanks for that quick and simplified reply.

I spent a lot of time on that one, trying to cover all the base...... for just this kind of thread.

I don't know who made that statement but it's a load of old bollocks! My stroker runs happily on 91 octane at sea level in 110*F Dubai mid-summer heat, and it has a stock cam with a 9.25:1 CR and a quench of 0.088". I'm even running the hottest plugs available (Champion RC12LYC)

hmd100100, I'm kind late on my replay, Sorry about that.
First off Dr Dyno, AKA Cheromaniac is a vary wiz man, and had done his research well...........How ever I DO NOT retract my statement because he think....... "it's a load of old bollocks!".........Dyno, I would Challenge you to build another stroker, and install it in a U.S.A. certified XJ and then run it in 110*F at sea level........Yes i know you could do it!!!! But it would take a lot more attention to detail then you have done with this one.(Not that you didn't put a lot of attention to detail in you present on)
When you set your adj map sensor, there is No close loop program in the computer to affect that setting.
Most people building there first stroker(some of them, there vary first, eng build!!!!!) will not under stand hot spots, what they are or how to eliminate then.
If they believe I'm full of it!!!!!!! they MAY,......... End up with a stroker that requires 91+ octane all the rest of its life!!!!..................If my so called "Bollocks" will cause them to thing about it a little bit more, and my....I say My, cause them to change there stroker plan before they start, and my, cause them to enjoy there stroker a little bit better When its built.
Then my Time spent explaining it, was well worth the trouble and effort of typing it, and have it put in the fax section.


Flash

Welcome back Flash

I have a 9.6 SCR, 8.25, and .057 quench DCR stroker. I have only had an opportunity to run 93 octane in mine as i wanted to start high, and step it down. However, with only 150 miles on my engine in the past month (thanks to my cheap D35 axle, x2!!), i cannot vouch how 8.25 DCR at SEA level works with other grades of fuel, and my specs. My house is 80 feet above see level, and Sea level is just down the road

Flash is pointing out that his computer is a export model and is controlling the motor quite differently than the domestic models. Good to see Flash back using the virtual ink !
John

I'm at sea level.

Thanks guys, Glad to be back.

I just had to leave here, long enough, so John could catch up with my post count

Flash

That's me, old and slow
John

Flash wrote:First off Dr Dyno, AKA Cheromaniac is a vary wiz man, and had done his research well...........How ever I DO NOT retract my statement because he think....... "it's a load of old bollocks!".........Dyno, I would Challenge you to build another stroker, and install it in a U.S.A. certified XJ and then run it in 110*F at sea level........Yes i know you could do it!!!! But it would take a lot more attention to detail then you have done with this one.(Not that you didn't put a lot of attention to detail in you present on)
When you set your adj map sensor, there is No close loop program in the computer to affect that setting.
Most people building there first stroker (some of them, there vary first, eng build!!!!!) will not under stand hot spots, what they are or how to eliminate then.

You're right about my computer 'cause mine's an export model that doesn't have closed loop O2 sensor feedback control, but that shouldn't make any difference 'cause I removed my MAP adjuster anyway (the stock 5.05v MAP voltage works fine).
Secondly, I did sand the piston dishes smooth and removed rough spots from the combustion chambers to reduce the risk of pre-ignition, hence I can still run stock plugs in scorching hot weather despite the 0.088" quench.
Static CR is 9.25:1 and dynamic CR with the stock cam is 8.63:1 at sea level. Changing from the Crane 753905 cam to the stock cam made it easier to run lower octane fuel due to the lower DCR (stock cam closes intake valves 9.5 degrees later than the Crane). When I had the Crane I couldn't run lower than 91 octane fuel (DCR was 8.90:1).

Cheromaniac wrote:

Flash wrote:First off Dr Dyno, AKA Cheromaniac is a vary wiz man, and had done his research well...........How ever I DO NOT retract my statement because he think....... "it's a load of old bollocks!".........Dyno, I would Challenge you to build another stroker, and install it in a U.S.A. certified XJ and then run it in 110*F at sea level........Yes i know you could do it!!!! But it would take a lot more attention to detail then you have done with this one.(Not that you didn't put a lot of attention to detail in you present on)
When you set your adj map sensor, there is No close loop program in the computer to affect that setting.
Most people building there first stroker (some of them, there vary first, eng build!!!!!) will not under stand hot spots, what they are or how to eliminate then.

You're right about my computer 'cause mine's an export model that doesn't have closed loop O2 sensor feedback control, but that shouldn't make any difference 'cause I removed my MAP adjuster anyway (the stock 5.05v MAP voltage works fine).
Secondly, I did sand the piston dishes smooth and removed rough spots from the combustion chambers to reduce the risk of pre-ignition, hence I can still run stock plugs in scorching hot weather despite the 0.088" quench.
Static CR is 9.25:1 and dynamic CR with the stock cam is 8.63:1 at sea level. Changing from the Crane 753905 cam to the stock cam made it easier to run lower octane fuel due to the lower DCR (stock cam closes intake valves 9.5 degrees later than the Crane). When I had the Crane I couldn't run lower than 91 octane fuel (DCR was 8.90:1).

Yup, thats what shocked me, when i was playing around with all of the IVC spec from many cams and found that the stock cam had a better DCR(lower) then the bigger Crane cam........Just the opposite, of most larger then stock cams.


Flash