CA 91 Pump Gas and M8 Compression

[838]

What is the max static, corrected and/or ccp you all would consider going on an M8 124-128" kit
to run on CA 91 pump fuel?  Would those numbers change if Zero-decked, .030 head gasket, ported heads?  It will be properly dyno tuned.

Thanks

[Don D]

230 psi

[838]

230 psi

Would you go to 12:1 if ccp were 230?

[Don D]

Yes and have done several that way.

[cheech]

Would you go to 12:1 if ccp were 230?

Before Don chimes in again. If you aren't aware and have not seen this was recently posted in the Dyno section. Click
I believe owner assembled, but as thread states cylinders and heads done by Don.
No cranking pressure stated but says set for 12.1:1.
Edit: LOL he and I were typing at same time.

[838]

That 482 looks great. Had not seen it listed. Lot Lower lift than the other cams with this type duration.

Would you go to 12:1 if ccp were 230?

Before Don chimes in again. If you aren't aware and have not seen this was recently posted in the Dyno section. Click
I believe owner assembled, but as thread states cylinders and heads done by Don.
No cranking pressure stated but says set for 12.1:1.
Edit: LOL he and I were typing at same time.

[FLSTFIDave]

I had done set my compression for 12.1 to 1 to run the CR-482 cam.  Cam provided a real big jump in number with the added compression.  Was surprised it was so Hi.

CCP is right at 229

I have just over 1500 miles on the build.  Brandon said it was very easy to tune.  I have heard no detention at all, but its not been over 75 degrees out side yet.  Runs very well, very smooth and easy to ride.

There is also a 126 build on a 2017 FLTRXS in the dyno section running 12.1 to 1 with no issues yet and over 2K miles on his build

[Hillside Motorcycle]

What is the max static, corrected and/or ccp you all would consider going on an M8 124-128" kit
to run on CA 91 pump fuel?  Would those numbers change if Zero-decked, .030 head gasket, ported heads?  It will be properly dyno tuned.

Thanks

The M8 engine doesn't mind those ccp's, and for a couple reasons.
We 0 deck the S&S 124", and 128"s, and use, as a rule, the S&S .550.
0 tuning issues whatsoever on 91 pump gas.

[838]

What is the max static, corrected and/or ccp you all would consider going on an M8 124-128" kit
to run on CA 91 pump fuel?  Would those numbers change if Zero-decked, .030 head gasket, ported heads?  It will be properly dyno tuned.

Thanks

The M8 engine doesn't mind those ccp's, and for a couple reasons.
We 0 deck the S&S 124", and 128"s, and use, as a rule, the S&S .550.
0 tuning issues whatsoever on 91 pump gas.

Hillside: Curious what numbers you've seen and at what compression with this setup.

[JW113]

Question: Doesn't the M8 have knock detection as part of the ignition system?

-JW

[cheech]

Question: Doesn't the M8 have knock detection as part of the ignition system?

-JW

You thinking of the Ion sense as the twin cams had?
The M8 has actual bolt on knock sensors. Mark 12 in Pic
[attach=0,msg1341513]

[JW113]

No, was hoping they'd put actual knock sensors in their latest generation 21st century and two decade marvel. Like autos have been using since the 70s!  'Bout time.

Thanks, glad to know this. I think I'd worry a bit less about spark knock with the M8 and 91 octane gas.

-JW

[HD/Wrench]

so with the TC we added a fair amount % wise in CCP over stock the 4 valve head is easy going for timing so why is there a 230 rule ?? they pump 235 ish stock .

240 is a walk in the park CCP wise .  With a skilled tuner , now a shop using auto tune as there main method of tuning is the wrong shop .