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motomwo
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Joined: February 10, 2017
Posts: 263
Location: Oregon
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 Posted: Tue Aug 16, 2022 10:07 am Post subject: 2276 with fk10 cam compression ratio recommendation. |
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Looking for people's opinion on compression ratio to use on my current build. I am getting ready to order some wedge ports trying to decide on the compression ratio to have them cut for. I will be running 91 octane pump gas. This is in a 61 bug street driven weekend only toy. I am thinking 10:1. I want to be able to run as much compression possible safely using 91 octane pump gas. My elevation here is 2700 ft.
The motor:
82 x 94
cb cnc wedge ports 44 x 37.5
fk10 engle cam
cb 1.4 rocker arms
deck height is .041"
rods are Scat 5.394"
cb lightened fly wheel
stage 1 kennedy clutch
carbs will be either 45 DRLA's or Weber 48idf's
msd distributor with 6AL box
Merged header will be either 1 5/8" or 1 3/4"
_________________
1961 Bug, 2276 cb wedge ports 44x37 11.1 comp fk10 1.5 rockers 48idf's 1 3/4" header Rancho pro street trans SAW axles Airkewld 4# narrowed beam, Koni shocks, Airkewld dis brake all around. 5.5/4.5 BRMs
1966 Bug, 2127, panchito heads, fk8, 1.3 rockers, dual 44idfs, 1 5/8 merge header, Rancho pro strt flyer, empi axles, Airkewld's 4" beam and discs all around and adjustable shocks. 4.5 & 5.5 BRMs
Last edited by motomwo on Tue Aug 16, 2022 10:43 am; edited 1 time in total |
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k@rlos
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Joined: October 04, 2012
Posts: 485
Location: Suffolk, England
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| Posted: Tue Aug 16, 2022 10:19 am Post subject: Re: 2276 with fk10 cam compression ratio recommendation. |
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| I have a 2276 with an FK10 in my baywindow bus. CB 044 heads, 42x37.5, IDA’s and a 1” 5/8 A1 sidewinder. Just shy of 10:1 if memory serves. I run it on U.K. 99 octane (same as US 95) runs & drives lovely. Goes like stink too! |
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motomwo
Samba Member
Joined: February 10, 2017
Posts: 263
Location: Oregon
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| Posted: Tue Aug 16, 2022 10:24 am Post subject: Re: 2276 with fk10 cam compression ratio recommendation. |
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| k@rlos wrote: |
| I have a 2276 with an FK10 in my baywindow bus. CB 044 heads, 42x37.5, IDA’s and a 1” 5/8 A1 sidewinder. Just shy of 10:1 if memory serves. I run it on U.K. 99 octane (same as US 95) runs & drives lovely. Goes like stink too! |
Unfortunately I cannot get 95 octane around here.
_________________
1961 Bug, 2276 cb wedge ports 44x37 11.1 comp fk10 1.5 rockers 48idf's 1 3/4" header Rancho pro street trans SAW axles Airkewld 4# narrowed beam, Koni shocks, Airkewld dis brake all around. 5.5/4.5 BRMs
1966 Bug, 2127, panchito heads, fk8, 1.3 rockers, dual 44idfs, 1 5/8 merge header, Rancho pro strt flyer, empi axles, Airkewld's 4" beam and discs all around and adjustable shocks. 4.5 & 5.5 BRMs |
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vwracerdave
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Joined: November 11, 2004
Posts: 15309
Location: Deep in the 405
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| Posted: Tue Aug 16, 2022 10:37 am Post subject: Re: 2276 with fk10 cam compression ratio recommendation. |
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Lots of folks will disagree with me but that's OK. It's your engine and your choice.
With 91 octane pump gas I wouldn't go over 9.5:1 I'd run a 1 3/4" exhaust.
_________________
2017 Street Comp Champion - Thunder Valley Raceway Park - Noble, OK
2010 Sportsman ET Champion - Mid-America Dragway - Arkansas City, KS
1997 Sportsman ET Champion - Thunder Valley Raceway Park - Noble ,OK |
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Brian_e
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Joined: July 28, 2009
Posts: 3293
Location: Rapid City, SD
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| Posted: Tue Aug 16, 2022 10:37 am Post subject: Re: 2276 with fk10 cam compression ratio recommendation. |
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I think you will be fine at 10:1. Just make sure you build it to have .040-.045" deck.
I think your rod length on your list must have been a mistake. 
A 1 5/8" to 1 3/4" step header would be ideal.
All else looks really good.
Brian
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motomwo
Samba Member
Joined: February 10, 2017
Posts: 263
Location: Oregon
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| Posted: Tue Aug 16, 2022 10:48 am Post subject: Re: 2276 with fk10 cam compression ratio recommendation. |
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| Brian_e wrote: |
I think you will be fine at 10:1. Just make sure you build it to have .040-.045" deck.
I think your rod length on your list must have been a mistake.
A 1 5/8" to 1 3/4" step header would be ideal.
All else looks really good.
Brian |
Thanks Brian, Good catch. I edited the Rod length. I have the deck height set at .041". Stepped headers would be great if I can get them.
_________________
1961 Bug, 2276 cb wedge ports 44x37 11.1 comp fk10 1.5 rockers 48idf's 1 3/4" header Rancho pro street trans SAW axles Airkewld 4# narrowed beam, Koni shocks, Airkewld dis brake all around. 5.5/4.5 BRMs
1966 Bug, 2127, panchito heads, fk8, 1.3 rockers, dual 44idfs, 1 5/8 merge header, Rancho pro strt flyer, empi axles, Airkewld's 4" beam and discs all around and adjustable shocks. 4.5 & 5.5 BRMs |
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UK Luke 72
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Joined: September 07, 2011
Posts: 2867
Location: Little Britain
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sled
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Joined: February 16, 2005
Posts: 6179
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| Posted: Tue Aug 16, 2022 4:00 pm Post subject: Re: 2276 with fk10 cam compression ratio recommendation. |
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how often do you think you'll drive down to sea level, if ever? being at 2700 feet (or higher) allows for higher compression.
10:1 and make sure you tune it WELL. Order your header with an O2 bung (or add one later) and tune with a Wideband.
you can order a stepped header from A1
sounds like a fun engine!!
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drive your split. |
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motomwo
Samba Member
Joined: February 10, 2017
Posts: 263
Location: Oregon
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| Posted: Tue Aug 16, 2022 4:42 pm Post subject: Re: 2276 with fk10 cam compression ratio recommendation. |
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| sled wrote: |
how often do you think you'll drive down to sea level, if ever? being at 2700 feet (or higher) allows for higher compression.
10:1 and make sure you tune it WELL. Order your header with an O2 bung (or add one later) and tune with a Wideband.
you can order a stepped header from A1
sounds like a fun engine!! |
Yep absolutely I will use a wide band to tune with. I did that with my 2127 motor in my 66 bug and made jetting sooo easy. You can see when you got it right or wrong.
I don't know personally but I have heard it is up to 6 month wait on A1 getting headers done. I hope not.
Marty
_________________
1961 Bug, 2276 cb wedge ports 44x37 11.1 comp fk10 1.5 rockers 48idf's 1 3/4" header Rancho pro street trans SAW axles Airkewld 4# narrowed beam, Koni shocks, Airkewld dis brake all around. 5.5/4.5 BRMs
1966 Bug, 2127, panchito heads, fk8, 1.3 rockers, dual 44idfs, 1 5/8 merge header, Rancho pro strt flyer, empi axles, Airkewld's 4" beam and discs all around and adjustable shocks. 4.5 & 5.5 BRMs
Last edited by motomwo on Thu Aug 25, 2022 1:19 pm; edited 1 time in total |
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Brian_e
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Joined: July 28, 2009
Posts: 3293
Location: Rapid City, SD
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jpaull
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Joined: February 22, 2005
Posts: 3466
Location: Paradise, Ca
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| Posted: Tue Aug 16, 2022 4:57 pm Post subject: Re: 2276 with fk10 cam compression ratio recommendation. |
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I would not go under 10.5:1 with that cam or its gonna be a dog at 2700 ft. You need that psi desperatly.
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[email protected] MPH 1/4 Mile & 8.1 @ 83.7MPH in 1/8 Mile with Mild Type 1 VW Mag Case 2234cc commuter engine in stock weight bug w/only .491 total lift(CB2292 Cam), 42x37 heads, 48idf's, Street tires, Belt on, Mufflers, Pump gas, video of the run here: https://youtu.be/M3SPqMOKAOg
Transmission by MCMScott:
Rhino case, Klinkenberg 4.12, Superdiff, 002 mainshaft with 091 first idler. Weddle 1.48 Third & 1.14 Fourth. |
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motomwo
Samba Member
Joined: February 10, 2017
Posts: 263
Location: Oregon
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| Posted: Tue Aug 16, 2022 5:48 pm Post subject: Re: 2276 with fk10 cam compression ratio recommendation. |
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| jpaull wrote: |
| I would not go under 10.5:1 with that cam or its gonna be a dog at 2700 ft. You need that psi desperatly. |
Jeff,
I used the Wallace Racing calculator plugging in the 10.5:1 compression and this is what it shows for my motor and my elevation.
Static compression ratio of 10.5:1.
Effective stroke is 2.19 inches.
Your dynamic compression ratio is 7.45:1 .
Your dynamic cranking pressure is 134.82 PSI.
What do you think?
Marty
_________________
1961 Bug, 2276 cb wedge ports 44x37 11.1 comp fk10 1.5 rockers 48idf's 1 3/4" header Rancho pro street trans SAW axles Airkewld 4# narrowed beam, Koni shocks, Airkewld dis brake all around. 5.5/4.5 BRMs
1966 Bug, 2127, panchito heads, fk8, 1.3 rockers, dual 44idfs, 1 5/8 merge header, Rancho pro strt flyer, empi axles, Airkewld's 4" beam and discs all around and adjustable shocks. 4.5 & 5.5 BRMs |
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[email protected]
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Joined: May 17, 2003
Posts: 4863
Location: Harmony, PA
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| Posted: Tue Aug 16, 2022 8:15 pm Post subject: Re: 2276 with fk10 cam compression ratio recommendation. |
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| What are the valve timing events on your card? I’ve seen an Fk-10 that has the intake closing at 56 degrees, and one closing at 63. The later closing will bleed off more cylinder pressure, and be able to support 3/4 to 1 point more static compression. I have the earlier closing 56 degree version in a 2276, and it was set at 9.6:1 for 93 premium fuel around 700-1200 ft. elevation. The calculator that was used is from United Engine, but I don’t think they have any variance for elevation. |
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67rustavenger 
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Joined: February 24, 2015
Posts: 9772
Location: Oregon
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| Posted: Tue Aug 16, 2022 8:34 pm Post subject: Re: 2276 with fk10 cam compression ratio recommendation. |
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| [email protected] wrote: |
| What are the valve timing events on your card? I’ve seen an Fk-10 that has the intake closing at 56 degrees, and one closing at 63. The later closing will bleed off more cylinder pressure, and be able to support 3/4 to 1 point more static compression. I have the earlier closing 56 degree version in a 2276, and it was set at 9.6:1 for 93 premium fuel around 700-1200 ft. elevation. The calculator that was used is from United Engine, but I don’t think they have any variance for elevation. |
FWIW.
I have a newly purchased FK-10 camshaft.
The timing card indicates the intake valve closes at 63°.
Haven't measured it yet.
_________________
I have learned over the years.
Cheap parts are gonna disappoint you.
Buy Once, Cry Once!
There's never enough time to do it right the first time. But there's always enough time to do it thrice.
GFY's Xevin and VW_Jimbo! |
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k@rlos
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Joined: October 04, 2012
Posts: 485
Location: Suffolk, England
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| Posted: Wed Aug 17, 2022 2:01 am Post subject: Re: 2276 with fk10 cam compression ratio recommendation. |
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| UK Luke 72 wrote: |
I'm running 11:1 on mine
But Dave will tell you its only got a 100 mile lifespan.
I agree on the header suggestion from Brian. |
😂 |
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UK Luke 72
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Joined: September 07, 2011
Posts: 2867
Location: Little Britain
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| Posted: Wed Aug 17, 2022 2:14 am Post subject: Re: 2276 with fk10 cam compression ratio recommendation. |
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| 67rustavenger wrote: |
| [email protected] wrote: |
| What are the valve timing events on your card? I’ve seen an Fk-10 that has the intake closing at 56 degrees, and one closing at 63. The later closing will bleed off more cylinder pressure, and be able to support 3/4 to 1 point more static compression. I have the earlier closing 56 degree version in a 2276, and it was set at 9.6:1 for 93 premium fuel around 700-1200 ft. elevation. The calculator that was used is from United Engine, but I don’t think they have any variance for elevation. |
FWIW.
I have a newly purchased FK-10 camshaft.
The timing card indicates the intake valve closes at 63°.
Haven't measured it yet. |
My card said 63° but it measured 59°
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madmike
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Joined: July 11, 2005
Posts: 5292
Location: Atlanta,Michigan
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| Posted: Wed Aug 17, 2022 3:43 am Post subject: Re: 2276 with fk10 cam compression ratio recommendation. |
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My card said 56* on the FK 10 in my 2180cc , I have 8.5 to 1 cr, although it's turboed ,,most of my driving is in n/a,,, it's really n/a until boost, it has good Power/torque when in n/a Vacume mode ,,get the picture? 
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76 Drag/Street bug 2180cc 'Turbo' 11:85 @113 mph"If I go any faster I'll burn up the Hamster" ,gets 28 mpg. also 10/09/22 11.90 @115 mph
"If I'm ever on Life Support,UNPLUG Me, Then Plug me back In see if that Works" |
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motomwo
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Joined: February 10, 2017
Posts: 263
Location: Oregon
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| Posted: Wed Aug 17, 2022 6:50 am Post subject: Re: 2276 with fk10 cam compression ratio recommendation. |
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| [email protected] wrote: |
| What are the valve timing events on your card? I’ve seen an Fk-10 that has the intake closing at 56 degrees, and one closing at 63. The later closing will bleed off more cylinder pressure, and be able to support 3/4 to 1 point more static compression. I have the earlier closing 56 degree version in a 2276, and it was set at 9.6:1 for 93 premium fuel around 700-1200 ft. elevation. The calculator that was used is from United Engine, but I don’t think they have any variance for elevation. |
My fk10 cam card shows intake closing at 63 deg.
Marty
_________________
1961 Bug, 2276 cb wedge ports 44x37 11.1 comp fk10 1.5 rockers 48idf's 1 3/4" header Rancho pro street trans SAW axles Airkewld 4# narrowed beam, Koni shocks, Airkewld dis brake all around. 5.5/4.5 BRMs
1966 Bug, 2127, panchito heads, fk8, 1.3 rockers, dual 44idfs, 1 5/8 merge header, Rancho pro strt flyer, empi axles, Airkewld's 4" beam and discs all around and adjustable shocks. 4.5 & 5.5 BRMs |
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Alstrup
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Location: Videbaek Denmark
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| Posted: Wed Aug 17, 2022 7:22 am Post subject: Re: 2276 with fk10 cam compression ratio recommendation. |
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According to the cam card it sounds to be ground straight up. don´t let that fool ya. They can be anywhere from that to +4 degrees advanced IRL. some times even retarded. But mostly advanced. The FK 10 is an "rpm" cam. not really much morte power than the FK8, but about 500 rpm more powerband upwards. If it is for a super street car I would set it up 2 max 3 degrees advanced. That will help the engine make a little more usable power in the lower rpms.
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motomwo
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Joined: February 10, 2017
Posts: 263
Location: Oregon
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| Posted: Wed Aug 17, 2022 7:42 am Post subject: Re: 2276 with fk10 cam compression ratio recommendation. |
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| Alstrup wrote: |
| According to the cam card it sounds to be ground straight up. don´t let that fool ya. They can be anywhere from that to +4 degrees advanced IRL. some times even retarded. But mostly advanced. The FK 10 is an "rpm" cam. not really much morte power than the FK8, but about 500 rpm more powerband upwards. If it is for a super street car I would set it up 2 max 3 degrees advanced. That will help the engine make a little more usable power in the lower rpms. |
Thank you,
I haven't got to the stage of the build to degree the cam in.
Marty
_________________
1961 Bug, 2276 cb wedge ports 44x37 11.1 comp fk10 1.5 rockers 48idf's 1 3/4" header Rancho pro street trans SAW axles Airkewld 4# narrowed beam, Koni shocks, Airkewld dis brake all around. 5.5/4.5 BRMs
1966 Bug, 2127, panchito heads, fk8, 1.3 rockers, dual 44idfs, 1 5/8 merge header, Rancho pro strt flyer, empi axles, Airkewld's 4" beam and discs all around and adjustable shocks. 4.5 & 5.5 BRMs |
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