carb intake test

[grumpyvette]

in the sept 2008 chevy high performance magazine they did an intake/cam test,on a sbc 383 with 10.5:1 cpr and brodix IK200cc heads and a couple of comp cams solid roller cams and a 750cfm holley carb, keep in mind the single plane intakes used a more radical cam than the dual planes were tested with, and the engine combo they used is unlikely to match your so the results on your combo are sure to differ, but its still rather interesting to see the differences an intake makes
, BTW they DID test the EDELBROCK DUAL PLANE intake with the larger cam, that the single planes were tested with and and the EDELBROCK single plane with the smaller cam the dual planes were tested with
Chevy high performance mags sbc intake test
1969 3932472 302 4 al Holley Z-28, F, Hirise
1967-68 3917610 302 4 al Holley Z-28, F, hirise
be aware that matching your exhaust system header scavenging and cam timing , and reducing your exhaust system flow restriction,has a great deal to do with how well your intake manifold potentially flows, at its most efficient rpm band, gains of 50-60 ft lbs of torque,(or in some cases much more) over what the stock engine made have frequently been seen when properly matched cam timing, header scavenging and intake design are well matched
Id also point out that cam timing matched to the exhaust scavenging has a huge effect on potential intake flow rates




BTW READ THIS ALSO
yeah! I know youll want to ignore the sub links, but theres a ton of charts and related info you need so ignoring the data is not helping you

http://www.popularhotrodding.com/engine ... index.html

https://www.youtube.com/watch?v=Bmj48i_v6-8

https://www.youtube.com/watch?v=i2DvnoHWagk

http://www.hotrod.com/how-to/engine/130 ... mparisons/

https://www.youtube.com/watch?v=i2DvnoHWagk

http://www.racingheadservice.com/rhs/in ... -chevyhtml

viewtopic.php?f=55&t=5518&p=16612#p16612

viewtopic.php?f=55&t=8961&p=31945&hilit=duct+hood+cool#p31945

Dual planes
BRAND...............¦Torque.........rpm........hp..........rpm
Brodix-hv101........471...............3900......437.........5500
Dart.42811000......482...............3900.......43...........5400
Edelbrock
Rpm air gap..7501..485..............3900.......441.........5600
BIG CAM test.........494......4200..........509.......6200
Professional prod
Crosswind.............482...........3800........430........5500
Summit-226010.......487...........3800........430.........5800
Weiand 8501.........489...........3800.........433.........5600
Chevy z28
/327/365hp intake..468............3800........¦417........5600

Single planes
BRAND.............Torque.............rpm......hp...........rpm
Brodix hv1011..472...................5100......492..........6200
Dart..42411000..479..................5100.......512...........6400
Edelbrock
vic jr..2975.......477.................5100........500.........6100
EDELBROCK
SMALL CAM....466...................3800..........448..........5600
edelbrock
super vic.....476...................4900............507.........6400
GM performance
10051102.......484..................5200...........515...........6300
HOLLEY KD
300-110..........478.................5100...........509...........6300
Pro..prod
Hurricane.......478................4900...........509............6200
Weiand
team.............478................5200..............507...........6100
world prod.....483................5000.............512............6300

NOTICE HOW THE LARGE CAM DUAL PLANE, COMBO DID VERY WELL

you might want to watch these videos

http://www.youtube.com/watch?v=N_ART4SBmdg

viewtopic.php?f=55&t=4362&p=11449#p11449

RPM vs RPM Air Gap:

http://www.youtube.com/watch?v=k9Klp0ze_ps

Weiand vs. Edelbrock

http://www.youtube.com/watch?v=lqqtK0lPjrA

the basic rule is a dual plane intake will almost always be the better choice over a single plane intake if the cam duration is under about 235-240 degrees@.050 lift
http://www.chevyhiperformance.com/techa ... 0_cfm.html
if you read thru the link above, very carefully youll find the 750cfm -to 830cfm carbs made the best average power, on that 383 sbc, so if we average the results lets say an 800cfm might have been near ideal.
now you might think.... ok,
800cfm/383 cubic inches =2.09 cfm per cubic inch of displacement,
so logically a 454 big block x 2.09=948cfm.....,
or a 327 x 2.09= 683 cfm,
but the truth here is that a skilled and experienced engine tuner can get a 950cfm or a 750cfm carb to work remarkably well on either the 383 0r 454 engine.
that 2.09 cfm per cubic inch of engine displacement will get you "in the ball park" but its your ability to tune the carburetor to match the application , far more than the rated carb size thats much more critical to matching the carb to the engine.


READ THIS AND ITS SUB LINKED INFO
viewtopic.php?f=55&t=8485&p=29767#p29767

viewtopic.php?f=55&t=10073&p=39779#p39779

http://www.airflowresearch.com/articles ... 5/A-P1.htm

viewtopic.php?f=69&t=7028&p=41780&hilit=dart+882#p41780

viewtopic.php?f=52&t=266&p=35948&hilit=dart+882#p35948

viewtopic.php?f=52&t=6012&p=18608&hilit=dart+882#p18608

viewtopic.php?f=52&t=5364&p=16066&hilit=dart+882#p16066

[grumpyvette]

READ THRU THE LINKS
viewtopic.php?f=55&t=1038

viewtopic.php?f=55&t=2857

http://victorylibrary.com/mopar/intake-tech-c.htm#new

http://www.circletrack.com/techarticles ... index.html

http://www.popularhotrodding.com/engine ... index.html

viewtopic.php?f=55&t=2739&p=7119#p7119

viewtopic.php?f=55&t=5510&p=16567#p16567

http://www.youtube.com/watch?v=Bmj48i_v ... re=related

http://www.youtube.com/watch?v=i2DvnoHW ... re=related

http://www.circletrack.com/techarticles ... index.html

http://www.circletrack.com/enginetech/c ... index.html

http://www.circletrack.com/techarticles ... index.html

[Indycars]

in the sept 2008 chevy high performance magazine they did an intake/cam test,on a sbc 383 with 10.5:1 cpr and brodix IK200cc heads and a couple of comp cams solid roller cams and a 750cfm holley carb, keep in mind the single plane intakes used a more radical cam than the dual planes were tested with, and the engine combo they used is unlikely to match your so the results on your combo are sure to differ, but its still rather interesting to see the differances an intake makes
, BTW they DID test the EDELBROCK DUAL PLANE intake with the larger cam, that the single planes were tested with and and the EDELBROCK single plane with the smaller cam the dual planes were tested with
Chevy high performance mags sbc intake test

BTW READ THIS ALSO
http://www.popularhotrodding.com/engine ... index.html

Dual planes
BRAND...............¦Torque.........rpm........hp..........rpm
Brodix-hv101........471...............3900......437.........5500
Dart.42811000......482...............3900.......43...........5400
Edelbrock
Rpm air gap..7501..485..............3900.......441.........5600
BIG CAM test.........494......4200..........509.......6200
Professional prod
Crosswind.............482...........3800........430........5500
Summit-226010.......487...........3800........430.........5800
Weiand 8501.........489...........3800.........433.........5600
Chevy z28
/327/365hp intake..468............3800........¦417........5600

Single planes
BRAND.............Torque.............rpm......hp...........rpm
Brodix hv1011..472...................5100......492..........6200
Dart..42411000..479..................5100.......512...........6400
Edelbrock
vic jr..2975.......477.................5100........500.........6100
EDELBROCK
SMALL CAM....466...................3800..........448..........5600
edelbrock
super vic.....476...................4900............507.........6400
GM performance
10051102.......484..................5200...........515...........6300
HOLLEY KD
300-110..........478.................5100...........509...........6300
Pro..prod
Hurricane.......478................4900...........509............6200
Weiand
team.............478................5200..............507...........6100
world prod.....483................5000.............512............6300

I wanted to see these numbers in a graph to make better sense of the data. I also left out data for the "Big Cam Test"
and "Small Cam Test", so that it would NOT effect the Average Results. Do you remember where the numbers came from,
I don't find them in the article on Popular Hotrodding ???

The graphs don't tell you at what RPM, but within a single or dual plane manifold they only vary a few hundred RPM.

SinglePlaneManifoldComparison.JPG

DualPlaneManifoldComparison.JPG

[grumpyvette]

the test was posted in the sept 2008 chevy high performance magazine which it seems is no longer easily accessed
after testing dozens of the commonly available SBC intakes on many dozens Of cars I generally just select either the edelbrock dual plane air gap or weiand air strike dual plane intakes if Im going to run a dual plane intake or a WEIAND 300-110 or EDELBROCK super vic if Im going to use a single plane.
with the edelbrock dual plane and the wieand single plane as the two real favorites.
because I rarely if ever see much gains over those choices on sbc applications UNLESS you get into something more exotic than a single 4 barrel carb application
once youve got one of those four intakes mounted on decent cylinder heads and matched to a good cam and tuned headers,and a decent 750cfm holley -850cfm holley thats well tuned you can basically say the inductions covered
AS a GENERAL RULE YOU'LL USUALLY FIND A Dual PLANE INTAKE SUPERIOR ON ANY ENGINE HAVING ANY CAM WITH LESS THAN ABOUT A 235 DEGREE DURATION (@.050 lift) AND A 10:1 CPR or less, SIMPLY BECAUSE OF THE SINGLE PLANE INTAKE DESIGN THAT FAVORS THE UPPER RPM RANGE, where youll need more compression and cam duration to take full advantage of the increased potential flow rates, the better single planes provide, yet up to about 6000rpm the better dual planes usually still remain a valid option,obviously displacement head flow and cam timing effect results but I generally see the dual planes produce better average results unless your engine spends a significant percentage of its time producing power at well over 5000rpm

http://www.summitracing.com/parts/HLY-300-110/

http://www.summitracing.com/parts/EDL-2925/?rtype=10

[grumpyvette]

heres a big block oval port intake test result on a basically mild 502 crate engine

[mtrhead]

How do you think the Edelbrock STR10 crossram (or equivalent) would compare on equal engines? Assuming the ports matched and the carbs where of the same vintage as the tests above? Because of the age of the crossrams I've never read a real dyno comparison or any form of testing with data.

I have a STR10 that I have welded/ported to match the 1206 gasket size and currently working on the DP's (carbs) to put it on after driving the existing welded/ported AirGap 830DP setup

[grumpyvette]

Ive done several engine builds using the OFFENHAUSER and EDELBROCK SMOKEY RAM cross ram intakes , keep in mind a cross ram intake was designed to be used an a serious race combo , and the cross ram dual quad intake was a 1960s design before they had effective test procedures, before they had larger carbs that flowed well it was an effort to allow the twin carbs to ffed a larger plenum and longer runners engineers knew would be required to maximize the engines volumetric efficincy at the much higher average rpm and power band that racing requires. and while its certainly able to allow you to make 450-550 hp in a well matched combo is essentially a high rpm only intake, design,like a tunnel ram intake where low rpm torque is not being considered a major requirement and low rpm drive-ability is of little concern. frequently a 302-406 SBC with a cross ram will be set up similar to a tunnel ram intake but without the need for the increased over the engine clearance required, a cross ram essentially is a tunnel ram designed for better hood clearance. having a cam like a CRANE 110921, or ISKY Z-30 solid lifter flat tappet cams, 11.5:1 compression,open headers and a manual transmission to be used where the engine seldom operates below 4000rpm and frequently sees 6500rpm, under those conditions fuel distributions fairly consistent with two 600cfm holley carbs that are set up correctly , one of the most common mistakes I see is guys running tunnel ram or cross ram intakes without having heads that flow at least 250cfm at .500 lift or expecting anything but open headers and a manual trans being driven like you just stole the car, to work correctly, thats not likely to work because those intakes function best in that 4500rpm-7000rpm power band





related threads you should read
viewtopic.php?f=55&t=3431&p=9088&hilit=crossram#p9088

viewtopic.php?f=44&t=623&p=834&hilit=+crossram#p834

[grumpyvette]

http://www.superchevy.com/technical/eng ... sc_airgap/



DARKER LINES ARE AIR GAP INTAKE lighter lines extensively ported single plane ,race intake

[grumpyvette]

CRISS COBB POSTED THIS INFO
We currently have a customer's 380 SBC Dirt Modified Engine in the shop and decided to do some manifold testing. The engine had an Edelbrock 2925 Super Victor that had some plenum modifications and port matched to a Fel-Pro 1206 gasket. We have a Speier Racing Edelbrock 2925 Plenum Mill modification in house for development work, so we wanted to try it on this motor. We have had several questions if this modifcation had been tested on smaller cubic inch engines and up until this point we had not had the opportunity.

Listed below are some details about the engine.
380 cid SBC
Bore: 4.155"
Stroke: 3.500"
Rod Length: 6.000"
Compression: 13.5
Piston: JE Dome
Ring Pack: 1/16, 1/16, 3/16
Oil Pan: Dirt Modified Kick-out Steel Pan
Cam: Lunati Solid Roller 262/272 .670"/.670" 101.5 ICL / 106 LSA
Heads: Brodix Weld Tech Track 1
Rocker Arms: TD Shaft Rockers 1.6 / 1.55
Intake: Edelbrock 2925
Carb: 950 Ultra HP Holley (830 cfm - 1.375" Venturi - 1.75" Throttle Bore)
Headers: 1 3/4"

Dyno Info - Power Peaks & Averages - Comparison of Manifolds








Stock 2925 flow:

#7- 312
#5- 305
#3- 289
#1- 308

Milled & ported runner flow:

#7- 376
#5- 360
#3- 364
#1- 376


the only problem I have with the data is that its arrived at flowing the runners in the reverse direction from designed which can alter the results, intakes are commonly flow tested this way simply because its far easier to do it that way, and keep in mind that the combined flow rate of the runner and cylinder head is USUALLY lower that the flow rates of either tested separately, example if your intake runner flows 360cfm and your cylinder head flows 358cfm on the flow bench you can,t reasonably assume that when bolted together they still flow 358cfm

http://www.summitracing.com/parts/HLY-300-110/




while theres zero doubt that careful porting of any intake can usually increase its runners flow rates and as a result hp, the best out of the box results Ive seen in a standard base size single plane small block intake is from the keith darton design, single plane intake, but thats not the same thing as saying thats the best intake, to use on every combo, a ported dual plane the the edelbrock air gap will produce better average torque on many SBC builds and theres a couple non-traditional single 4 barrel intakes that will out perform these two in a few specific builds designed to maximize those rather unique intakes flow characteristics of those designs.
remember that the engines displacement, its compression ,your drive trains gearing,your cylinder head design, cam timing,exhaust tuning and several other factors effect the results youll get and make intake selection critical to making the best combo.
REMEMBER what goes in thru the intake runners gets heated, expands and needs to exit, so a well tuned exhaust header and a low restriction exhaust , and properly matched cam timing, can make a huge improvement in intake flow rates, a properly set up cam and tuned exhaust can do a great deal to draw in the next intake charge as the previous exhaust charge exits, greatly reducing resistance to intake flow, entering the cylinder

viewtopic.php?f=56&t=1503&p=3419#p3419
SMOKEYRAM (SY1)BELOW





EDELBROCKS SBC CROSS RAM

[grumpyvette]

HERES A FEW GOOD PICTURES OF SINGLE PLANE SBC INTAKES CHAD "Speier Racing Heads"POSTED







Sizes. Measure in middle of opening and lengths in middle of runner.


Holley 300-110
inner runner: 2.94 CSA, 4.625 long
outer runner: 3.36 CSA, 5.50 long

Edelbrock 2925
inner runner: 2.89 CSA, 5.58 long
outer runner: 2.85 CSA, 6.56 long

Edelbrock 2970
inner runner: 3.26 CSA, 5.525 long
outer runner: 3.29 CSA, 6.54 long

Edelbrock 2892
inner runner: 3.58 CSA, 5.42 long
outer runner: 3.66 CSA, 6.30 long

Hurricane (Bowtie)
inner runner: 3.34 CSA, 5.54 long
outer runner: 3.70 CSA, 6.42 long

Holley 300-25
inner runner: 3.34 CSA, 4.38 long
outer runner: 3.45 CSA, 5.025 long

[grumpyvette]

http://www.carcraft.com/techarticles/13 ... mparisons/

HERE IS AN INTERESTING INTAKE MANIFOLD TEST on a sbc engine similar to what many guys will build,






heres the test engine specs



COMMON SBC INTAKE PORTS
felpro # 1204=Port Size: 1.23" x 1.99"=2.448 sq inches

felpro # 1205=Port Size: 1.28" x 2.09"=2.67 sq inches

felpro # 1206=Port Size: 1.34" x 2.21"=2.96 sq inches

felpro # 1207=Port Size: 1.38" x 2.28"=3.146 sq inches

felpro # 1209=Port Size: 1.38" x 2.38"=3.28 sq inches

felpro # 1255 VORTEC=Port Size: 1.08" x 2.16"-2.33 sq inches

felpro # 1263=Port Size: 1.31" x 2.02"=2.65 sq inches

felpro # 1266=Port Size: 1.34" x 2.21"=2.96 sq inches

felpro # 1284 LT1=Port Size: 1.25 x 2.04''=2.55 sq inches

felpro # 1289 FASTBURN=Port Size: 1.30" x 2.31" 3.00 sq inches

USE THE CALCULATORS, YOULL, QUICKLY FIND THE LIMITATIONS
http://www.rbracing-rsr.com/runnertorquecalc.html
http://www.wallaceracing.com/chokepoint.php
http://www.wallaceracing.com/header_length.php

the valve curtain area, cam duration and lift controlling that curtain area,or port cross sectional area will pose a restriction to air flow at some point,in the engines rpm band, but you can extend the effective air flow duration and efficiency with carefully timed exhaust scavenging, that helps draw in the intake runner inertia load of air/fuel,charge much more effectively if the peak negative pressure wave is correctly timed

the port flow on any 1.94 intake valve max,s out at near .485 valve lift ,or 2.96 sq inches of area, a 2.02" valve max,s out at near .505 lift,or in theory about 3.2 sq inches but the valve seat/throat diameter is smaller and the valve guide,stem and valve itself restricts flow this is the point where increasing the port cross sectional area, or runner cross sectional area increase, doesn,t help nearly as much as extending the cams duration and lift cams with larger lift and duration allow the port to flow for a longer time frame on each intake stroke but not more flow air at max draw, what can be done is to increase efficiency by carefully timing exhaust scavenging to effectively increase the duration of the flow during the overlap period.


A CORRECTLY TUNED SET OF HEADERS , MATCHED TO A CORRECTLY DESIGNED CAM TIMING HAS A SIGNIFICANT EFFECT ON INTAKE FLOW AND CYLINDER SCAVENGING EFFICIENCY, EXHAUST SCAVENGING CAN BE 5 TIMES STRONGER THAN THE PISTON, MOVEMENT INDUCED NEGATIVE PRESSURE (VACUUM) IN THE INTAKE RUNNERS




you will need to match both the port cross sectional area and length to the cam timing , while taking into consideration the engine displacement and intended operational power band to select the correct intake manifold design.


USE THE CALCULATORS, YOULL, QUICKLY FIND THE LIMITATIONS
http://www.rbracing-rsr.com/runnertorquecalc.html
http://www.wallaceracing.com/chokepoint.php
http://www.wallaceracing.com/header_length.php

but keep in mind the port flow rate is restricted by both the intake cross sectional area and the duration , or time the valves off its seat WHILE theres a significant pressure differential between the intake port and the cylinder, the intake runner can be designed to induce inertial pressure in a set rpm band, but its the exhaust flow that's far more influential at helping to drag in the next intake charge into the cylinder as its fast moving gasses exit the exhaust, thus the overlap period is vitally important to maximizing cylinder fill efficiency, once you reach the rpm range where there's a significant inertial energy level in both the intake and exhaust to draw in and cause the exiting gases to be drawn out of the cylinder.
if you do some research you quickly find that the engines power curve very closely relates to its cylinder fill efficiency,

you also find that the intake port cross sectional area and valve size plus the cam duration ,lift and overlap have a huge effect on the engines ability to operate efficiently art any rpm range, because of either flow restriction if the port cross sectional area or cam timing are restricting flow or low port gas velocity levels, if the compression ratio,exhaust scavenging ,engine displacement or cam timing are not maximizing the flow rates in the ports
longer stroke to bore ratios need a tighter cam LSA to allow more effective cylinder scavenging




tighter LSA tend to increase the OVERLAP but thats not always the case





DURATION AND LSA are NOT necessarily related








AS you change intake runner length changes, and to some extent cam timing changes it can be used to tune the torque peaks, but cross sectional area of the runners and head ports will dictate a great deal of the air flow speed and where the RPM BAND the restriction to flow occurs, and limits the engines ability to make more power

[grumpyvette]

BTW if your looking for intake manifold height info there some available at least for edelbrock intakes

http://www.edelbrock.com/automotive_new/mc/manifolds/race_ref_dimensions.shtml

viewtopic.php?f=55&t=431&p=828&hilit=holley+stealth+porting#p828



if your willing to do some fabrication there's a great many more options available as many single and multi carb intakes that can be machined and welded to allow installation of injectors and a fuel rail, so that adding a throttle body cam basically convert the carb intake to a efi intake design.

http://www.proweldperformanceparts.com/id23.html

viewtopic.php?f=55&t=431&p=828&hilit=holley+stealth+porting#p828

http://www.hrpartsandstuff.com/products ... rbungs.htm

http://www.atfspeed.com/store/index.php ... cts_id=533

http://www.atfspeed.com/store/index.php ... cts_id=100

http://www.holley.com/data/Products/Tec ... 072rev.pdf







ABOVE AND BELOW YOU SEE WHERE THE TUNNEL RAM INTAKE WAS CONVERTED TO USE INJECTORS CONVERTING IT INTO MPFI

[grumpyvette]

btw if you have an edelbrock intake on your car and your debating if you can swap to a different intake due to concerns over hood clearance, issues the first step you need to take is to purchase some oil base modeling clay , place a couple 1.5" tall 1" cubes on each of the four corner's of your current air cleaner and close the hood and carefully note the contact points (IF ANY) the hood made on the clay on the current air cleaner indicating limited hood clearance issues , and measure the compressed thickness of the clay to get an idea as to the height limitations a new intake might have in your particular application BEFORE you purchase THE NEW INTAKE AND AFTER NOTING THE DIFFERENCE IN STATED CARB HEIGHT LISTED!

[grumpyvette]

DUAL PLANE INTAKES

http://www.carcraft.com/techarticles/13 ... mparisons/






SINGLE PLANE INTAKES
http://www.carcraft.com/techarticles/13 ... akes_test/

[grumpyvette]

https://www.youtube.com/watch?v=Bmj48i_v6-8

https://www.youtube.com/watch?v=i2DvnoHWagk

IF you watched these two similar video links youll see that theres a measurable difference in the results they got while testing several intake designs, and while thats rather useful info ID point out that a great deal of the result you see is strongly effected by a combination of factors and things like the cylinder heads selected,the intakes used on, the port runner and plenum work on the intake, it self and the cam timing, lca, DISPLACEMENT AND COMPRESSION all POTENTIALLY EFFECT THE RESULTS AND OVER THE YEARS I'VE LEARNED TO TAKE THESE TESTS RESULTS WITH A BIG BIT OS SKEPTICISM , now I/nm not saying the results are not valid at all, only that a bit of intake port and prep work or careful selection of the matching components that is hardly obvious could and will skew the dyno results you see in any dyno test.
did you notice that made a point out of NOT TUNING the carb or changing the timing to match each individual intakes requirements, its almost a sure thing that a bit of dyno testing will result in finding each intake will require a bit different jetting or ignition curve advance to maximize that intakes potential and
you can be damn sure if EDELBROCK, TRICKFLOW,OFFANHAUSER or WEIAND is paying for the DYNO TEST results, And that particular vendor waving the stack of fresh $100 bills under the dyno operators nose, you can be reasonably sure the dyno operator will mysteriously find their intake design shows just a few horse power advantage over the likely competitor.(or hes unlikely to get the repeat business he depends on.) or the magazine that's promoting the test won,t get thousands of dollars in advertizing budgets
ALL the SHARPER dyno operator has to do is tune the carb to maximize the potential of the intake he prefers to give it a potential performance edge, then run the identical setting in the test with all the carbed intakes.
you might be amazed at what results from an hours careful work with a high speed die grinder and carbide burr and use of some port work on the intake plenum with a mill, its hardly rare to pick up 12-17 hp thru minor tweaks and port clean-up work, so don,t think that one particular intake has it s competitors left in the dust, you could easily find a bit of port work or, swapping to a different ratio roller rocker on either the intake or exhaust or both, a different jetting or a different cam LCA makes a huge difference in the dyno results.
yes theres some real trash and some darn good intake designs and yes you tend to find the more expensive intakes do produce better power
(someone always pays for the research and development time)
but just be aware that a good tuner and experienced porter can make a significant difference in the results and dyno tests in magazines are not always truly honest assessments of all the competition,
matching the headers design to the cam timing the engine responds too the best, alone has been repeatedly shown to be worth over 30-35 hp with the same intake being used, once the tuning was correctly matched to maximize the combos potential. porting a plenum and runners can easily get you an additional 15 plus hp.


RELATED INFO
viewtopic.php?f=87&t=1817&p=4698#p4698

viewtopic.php?f=55&t=4362&p=11449&hilit=plenum+port+spacer#p11449

[Indycars]

Is that reversion pulses that I see at 3:18 minutes on the first video? I noticed an
uneven flow of fuel briefly while the engine is running at near idle speed.