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kdnguyen61 Samba Member
Joined: June 14, 2019 Posts: 109 Location: Houston, Texas
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Posted: Fri Sep 17, 2021 6:11 am Post subject: EMPI 44 HPMX Performance with 2276cc |
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Dear Members,
My friend and I just completed a 2276cc engine with Engle cam FK8 and 40X35.5 heads. I decided to go with EMPI 44 HPMX since they don't have 48 size and I can't afford the Weber 48. It came with 0.135 main jets, 0.055 idle jets, 0.200 air jets, 0.055 exhaust pump jets, and 0.050 accelerated pump jets. The engine choked at 50mph and ran very poor performance above that. So we decided to change the main jets to 0.160 and idle jets to 0.70. The engine runs great after that with timing about 10 before TDC at idle and around 30 full advance 3500rpm. It seems to us that the engine is running a little rich as we can see sometime black smoke comes from exhaust. We are wondering should I lower the main jets to like from 0.160 to 0.155 or down more to 0.150 and the same with idle jets from 0.070to 0.065 or down to 0.060?? The car can peel tires on first gear and runs pretty good to me. Appreciate any comments you may have. Thank you. |
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kdnguyen61 Samba Member
Joined: June 14, 2019 Posts: 109 Location: Houston, Texas
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Posted: Fri Sep 17, 2021 6:13 am Post subject: Re: EMPI 44 HPMX Performance with 2276cc |
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Sorry, the setup is a dual carbs. |
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Dale M. Samba Member
Joined: April 12, 2006 Posts: 20378 Location: Just a tiny bit west of Yosemite Valley
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Posted: Fri Sep 17, 2021 6:34 am Post subject: Re: EMPI 44 HPMX Performance with 2276cc |
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Sounds like you went from to small jetting to to big.... Think you change in jetting size was to radical...
Idle jets might be to big.... Go back to your .055's and see if it helps.... Most idle jetting stays in the .055 to .060 range... Idle jets only give good fuel mixture below 3000 or so RPM.... Above that carbs pretty much run on mains... With to big of idle jets you are dumping a lot of fuel into engine you probably don't need... _________________ Fear The Government That Wants To Take Your Guns" - Thomas Jefferson.
"Kellison Sand Piper Roadster" For Street & Show.
"Joe Pody Sandrover" Buggy with 2180 for Autocross (Sold)
============================================================
All suggestions and advice are purely my own opinion. You are free to ignore them if you wish ... |
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Lingwendil Samba Member
Joined: February 25, 2009 Posts: 3988 Location: Antioch, California, a block from the hood
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74 Thing Samba Member
Joined: September 02, 2004 Posts: 7390
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Posted: Fri Sep 17, 2021 8:45 am Post subject: Re: EMPI 44 HPMX Performance with 2276cc |
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What size venturis?
Yes, you are now way too rich in both the idle and mains. |
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kdnguyen61 Samba Member
Joined: June 14, 2019 Posts: 109 Location: Houston, Texas
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Posted: Fri Sep 17, 2021 10:10 am Post subject: Re: EMPI 44 HPMX Performance with 2276cc |
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I have 32mm venturis. I will go back to .055 idle jets and retest it. Thank you all for great comments. |
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74 Thing Samba Member
Joined: September 02, 2004 Posts: 7390
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[email protected] Samba Member
Joined: August 15, 2002 Posts: 4394 Location: Brew City
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Alstrup Samba Member
Joined: July 12, 2007 Posts: 7212 Location: Videbaek Denmark
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Posted: Fri Sep 17, 2021 4:07 pm Post subject: Re: EMPI 44 HPMX Performance with 2276cc |
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I donīt think I have ever seen an ACVW with 44īs that needed 60 idle jets unless the engine was very low compression, like 8-1 with an FK8 or something like that.
But, it is very float height dependant. Set float heght to 12 mm for starters.
Reinstall the 55 idles, keep the 155īs (which are probably too small, especially if thereīs some grunt in the engine, Increase main air to 220 and see what happens. Its not unusual to be in the 165-175 main and 210-220 main air range on nippy 2275īs. (For me at least)
Sometimes you need to go down in main air again to control the AFR @ wot, but 220 is a good starting point.
Wrt main jet sizes. Remember, there are two reasons to why an engine with IDFīs needs/wants large jets. 1, if it is low compression and/or inefficient for whatever reason. And 2, if it really makes power. _________________ https://www.thesamba.com/vw/forum/viewtopic.php?t=435993 |
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kdnguyen61 Samba Member
Joined: June 14, 2019 Posts: 109 Location: Houston, Texas
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Posted: Wed Jul 06, 2022 4:11 pm Post subject: Re: EMPI 44 HPMX Performance with 2276cc |
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Dear Members,
I am back in the same scenario again. The current setup carbs is .160 main jets, .200 air jets, and .55 idle jets. Sometime the engine choke when I hit the gas lightly. If I hit the gas pedal hard then there is no problem. There is a little of black smoke in the tail pipes (may be running a little rich?). Below is a chart that I found and I think the main jets and air there are too low. Appreciate any comments.
I saw a segment on TV for Iron Resurrection and they had a Ghia on it with 1915cc engine and dual carbs. Man, that car ran like madness. I would love to have that. One thing, they reset the float even they bought it brand new carbs. Should I reset my float? And how?
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67rustavenger Samba Member
Joined: February 24, 2015 Posts: 9756 Location: Oregon
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Posted: Wed Jul 06, 2022 7:40 pm Post subject: Re: EMPI 44 HPMX Performance with 2276cc |
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I always clean and set the floats on a new/new to me set of carbs.
Remove the top of the carb and stand it vertically, with the float hanging from the pivot shaft.
Measure the distance from the top to the float. Make sure that the gasket is in place when you measure.
There is a little metal tab on the float that contacts the fuel shutoff valve in the carb top.
When adjusting your float level. Bend the tab closer to the valve to lower the float level.
If you need more float height bend the tab away from the valve.
I usually set my Weber (or whatever clone IDF) at 10.4mm. I have a cheap 3/8" extension that works as a tool for setting the float level.
Just slip the tool between the float and carb top. If the float blocks the tool from slipping between the float and the top, make an adjustment as described above.
Ideally you want the float to just touch the measuring tool when the float height is set correctly.
That's the way I set them. Others will have their own method of setting the floats.
YMMV! _________________ 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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Slow 1200 Samba Member
Joined: July 02, 2004 Posts: 2105
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Posted: Thu Jul 07, 2022 5:20 am Post subject: Re: EMPI 44 HPMX Performance with 2276cc |
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kdnguyen61 wrote: |
I have 32mm venturis. I will go back to .055 idle jets and retest it. Thank you all for great comments. |
you need 36s in there at least |
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Alstrup Samba Member
Joined: July 12, 2007 Posts: 7212 Location: Videbaek Denmark
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Posted: Thu Jul 07, 2022 11:38 am Post subject: Re: EMPI 44 HPMX Performance with 2276cc |
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Slow 1200 wrote: |
kdnguyen61 wrote: |
I have 32mm venturis. I will go back to .055 idle jets and retest it. Thank you all for great comments. |
you need 36s in there at least |
I agree. But 36 is plenty. the engine wohnt pull more than about just shy of 160 anyway, unless the heads are really good. _________________ https://www.thesamba.com/vw/forum/viewtopic.php?t=435993 |
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kdnguyen61 Samba Member
Joined: June 14, 2019 Posts: 109 Location: Houston, Texas
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Posted: Mon Jul 11, 2022 8:40 am Post subject: Re: EMPI 44 HPMX Performance with 2276cc |
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Path forward for me I am thinking is:
1) Reset float
2) Change out to 36mm venturis
3) Change out main jets to .150 or should I change to .140? Engine compression is 9.5:1. Heads have 40X35.5 heavy duty springs
4) Keep air and idle jets the same.
Is that sounds good? |
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vwracerdave Samba Member
Joined: November 11, 2004 Posts: 15303 Location: Deep in the 405
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Posted: Mon Jul 11, 2022 9:29 am Post subject: Re: EMPI 44 HPMX Performance with 2276cc |
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Please tell us more details about the engine. Exactly which 40X35 heads. What exhaust system. What ratio rockers. Maybe a few pics. _________________ 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
Featured in Dec. 2001 HOT VW's Magazine page 63
Watch my racing video's http://www.youtube.com/user/okvwracer/videos |
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kdnguyen61 Samba Member
Joined: June 14, 2019 Posts: 109 Location: Houston, Texas
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Posted: Wed Jul 13, 2022 2:15 pm Post subject: Re: EMPI 44 HPMX Performance with 2276cc |
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It is a 2276cc engine with Engle cam FK8. It also has:
82mm chromoly stroker crank
9.5 compression ratio
31mm HP lifters
The heads are:
GTV-2 Dual Port Air-cooled VW Cylinder Head 94mm Bore
Intake Valve 40mm Stainless Steel
Exhaust Valve 35.5mm Stainless Steel
Combustion Chamber 56cc
Cylinder Head Material: Aluminum Alloy
Spark Plug Hole: 12mm 3/4" Reach
Dual Hi-Rev Valve Springs
Chromoly Retainers
Hardened Valve Stem Keepers |
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kdnguyen61 Samba Member
Joined: June 14, 2019 Posts: 109 Location: Houston, Texas
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Posted: Wed Jul 13, 2022 2:18 pm Post subject: Re: EMPI 44 HPMX Performance with 2276cc |
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It also has performance super Hi-Ratio Rocker Arm Shaft Kits 1.25 ratio and running with EMPI 4 tips Monza exhaust system. |
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Rome Samba Member
Joined: June 02, 2004 Posts: 9641 Location: Pearl River, NY
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Posted: Wed Jul 13, 2022 5:17 pm Post subject: Re: EMPI 44 HPMX Performance with 2276cc |
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The engine choked at 50mph and ran very poor performance above that. |
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running with EMPI 4 tips Monza exhaust system. |
Oh my... You're blowing so much combustion exhaust volume out the larger exhaust valves at mid-range rpms and higher; but the gas volume is being significantly restricted by the small pipe diameter of that exhaust... You should ideally have a real header that uses 1.5" diameter pipes. Are you also using stock-type heater boxes? If so, that's another restriction in the exhaust flow. |
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madmike Samba Member
Joined: July 11, 2005 Posts: 5292 Location: Atlanta,Michigan
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Posted: Wed Jul 13, 2022 5:32 pm Post subject: Re: EMPI 44 HPMX Performance with 2276cc |
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FK 8 requires a 1:4 ratio Rocker _________________ 'Black Ice'Drag Buggy 'Turbo'
Rail Buggy 1915 turbo
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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vwracerdave Samba Member
Joined: November 11, 2004 Posts: 15303 Location: Deep in the 405
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Posted: Wed Jul 13, 2022 7:37 pm Post subject: Re: EMPI 44 HPMX Performance with 2276cc |
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Rome wrote: |
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The engine choked at 50mph and ran very poor performance above that. |
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running with EMPI 4 tips Monza exhaust system. |
Oh my... You're blowing so much combustion exhaust volume out the larger exhaust valves at mid-range rpms and higher; but the gas volume is being significantly restricted by the small pipe diameter of that exhaust... You should ideally have a real header that uses 1.5" diameter pipes. Are you also using stock-type heater boxes? If so, that's another restriction in the exhaust flow. |
That was my thought and why I ask him what exhaust.
I'd suggest 1 5/8" exhaust.
36mm venturies
55 idle - 150main - 200 air - F-11 emulsion tubes as a starting point. _________________ 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
Featured in Dec. 2001 HOT VW's Magazine page 63
Watch my racing video's http://www.youtube.com/user/okvwracer/videos |
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