# TECH: OEM Intake manifold dyno ~ MKIII vs MKIV



## tdogg74 (Mar 1, 2002)

Special thanks to *Prof315* for his dedication to dyno test these for us and *ny_fam* for providing the test subjects. 
Purpose of this thread: To show the hp/tq differences between:
Stock MKIII intake manifold
Ported MKIII intake manifold
Stock MKIV intake manifold
Ported MKIV intake manifold
*Motor information: (none of this will change during the testing)*
95 OBD1 ABA block, stock bore, stock rods and pistons, fresh rings and bearings, ABA windage tray style oil pan gasket and 16V oil pump and dizzy blockoff
95 OBD1 German casting cylinder head, milled .025", street port and good 3 angle valve job, new valve seals, TT heavy duty dual springs, TT272 hydro cam.
All components checked for spec and engine cc'd at 10.29 to 1.
MS2 v3.57 ECU running extra firmware v2.10.
GM waste spark copilpacks for ignition directly controlled by the MS.
New Ford motorsport 24lb/hr blue top injectors
AMK stainless 4 into 2 into 1 header, 2.25" pipe with a dynomax bullet as a resonator and a stainless round muffler.
Stock OBDI throttle body.
*Intake manifold info:
ABA OBDII Intake Manifold*
Lower runner length is 6.2" long
Port inside diameter 32.5mm (head side)
Port inside diameter 34.5mm (opening connecting to upper manifold)
Single runner volume 150cc
Upper manifold section
Port inside diameter 34.25mm (opening connecting to lower manifold)
Runner length 3.875"
Plenum Volume 1.8L
MK3 upper manifold backside 








*AEG Intake Manifold*
(MK4 with same intakes AEG, AVH, AZG, BEV and BBW )
Lower runner length is 6.0" long
Port inside diameter 32.8mm (head side)
Port inside diameter 40.0mm (opening connecting to upper manifold)
Single runner volume 150cc
Upper manifold section
Port inside diameter 39.8mm (opening connecting to lower manifold)
Runner length 8"
Plenum Volume About 1.8 -2.0L (internal brace was in the way)
MK4 upper manifold backside








*Flow Tests
Stock MK4*
Upper and Lower sections tested together. Each runner tested individually, with all vacuum ports plugged. Air was pushed in through the TB opening. Flow is measured in inches of water, Lower numbers indicate better flow. Low numbers are good.
*OEM MKIV*
Runner #1 - 13.5"
Runner #2 - 10"
Runner #3 - 10"
Runner #4 - 10.25"
*Stage-1 Ported MKIV*
Flow is measured in inches of water, Lower numbers indicate better flow. Low numbers are good.
Runner #1 - 9.5"
Runner #2 - 9.5"
Runner #3 - 9.5"
Runner #4 - 9.5"
*Stage III Ported MKIV*
Flow is measured in inches of water, Lower numbers indicate better flow. Low numbers are good.
Runner #1 - 9.0"
Runner #2 - 9.0"
Runner #3 - 9.0"
Runner #4 - 9.0"
Ported MK4 lower picture








Flow tests are done with a Manometer.
About the manifolds:
It wouldn't be easy to bolt a mk3 upper manifold to a lower mk4 manifold. The bolt patterns don't match, and the ports don't align properly.








The lower sections of the mk3 and mk4 manifold are where the flow restrictions are. Note the mk3 manifold and mk4 have the same size port openings to the head.
MK3 top/ MK4 bottom of picture








*WHP / WTQ results*
Nonported MKIII - 107.58whp / 114.03 wtq
Ported MKIII - 107.18whp / 113.62 wtq
Nonported MKIV - 110.85whp - 119.76wtq
Ported MKIV - 112.29whp / 119.62wtq
*DYNO RESULTS*
MKIII unported - BLUE
MKIII ported - GREEN
MKIV unported - ORANGE
MKIV ported - RED
*OEM vs PORTED MKIII*








Bigger - http://farm3.static.flickr.com...o.jpg
*OEM vs PORTED MKIV*








Bigger - http://farm3.static.flickr.com...o.jpg
*ALL MANIFOLDS*








Bigger - http://farm3.static.flickr.com...o.jpg

_**NOTE*
During the MKIII dyno tests, it was determined that there was a throttle cable issue and that that might have scewed the numbers. Once the throttle cable issue was corrected and re-dynoed, the results were more or less the same. The original MKIII dyno results were used in this thread.*_








_Modified by tdogg74 at 11:38 AM 12-15-2009_


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## Prof315 (Jan 5, 2009)

*Re: TECH: OEM Intake manifold dyno ~ MKIII vs MKIV (tdogg74)*

And a big thanks to tdogg74 as well for putting all of this info together.
As the results show, the ported mk4 intake made the best numbers. It also feels the best in my car which shouldn't be all that suprising as the average power #s went up quite a bit. Regardless it looks to me as if a mk4 intake (ported or not ) is a better manifold.


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## 75injectedSB (Feb 6, 2006)

*Re: TECH: OEM Intake manifold dyno ~ MKIII vs MKIV (Prof315)*

Good work guys, thanks for putting this together and making it available to all. Its good to see all the speculation put to bed and good hard numbers put up. http://****************.com/smile/emthup.gif http://****************.com/smile/emthup.gif


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## tdogg74 (Mar 1, 2002)

*FV-QR*

Now we need to do an SRI manifold......
_dun dun duuuuuunnnnn_


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## indianred2.0 (Aug 11, 2007)

Excellent work guys. This needs to be added to the DIY/FAQ section.


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## tdogg74 (Mar 1, 2002)

*FV-QR*

Here is a comparison most people would be interested in: Stock MKIII vs stock MKIV.
Just keep in mind that your results will be different depending on which software you run and the cam profile you choose. Also, keep in mind that any head work seriously alters the torque curve as well.








Bigger - http://farm3.static.flickr.com...o.jpg


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## MecE2.0 (Dec 20, 2005)

*Re: FV-QR (tdogg74)*

very nice guys http://****************.com/smile/emthup.gif 
not too surprised with the ported mk3 results, but i am surprised at how well the ported mk4 ran (just didn't think it would net anything at all). i'm interested to see some SRI runs as well.


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## jerrymic (Apr 19, 2007)

*Re: TECH: OEM Intake manifold dyno ~ MKIII vs MKIV (tdogg74)*

thanks for your time and effort http://****************.com/smile/emthup.gif


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## metalb (Mar 13, 2007)

*Re: TECH: OEM Intake manifold dyno ~ MKIII vs MKIV (jerrymic)*

Awesome!
This is exactly what we need in the tech forums.
Glad people still experiment, only way to learn. http://****************.com/smile/emthup.gif


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## ny_fam (Apr 3, 2004)

*Re: TECH: OEM Intake manifold dyno ~ MKIII vs MKIV (metalb)*

Thanks Prof315 for working on this project with me, and tdogg74 for making the results easy to read.
Find the two manifold designs and how the power output changes very interesting. From looking at the results you wouldn't think they were from intakes with different runners lengths or plenum volumes, as the power peeks are in the same places.
cheers
ny_fam


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## Prof315 (Jan 5, 2009)

*Re: TECH: OEM Intake manifold dyno ~ MKIII vs MKIV (ny_fam)*


_Quote, originally posted by *ny_fam* »_Thanks Prof315 for working on this project with me, and tdogg74 for making the results easy to read.
Find the two manifold designs and how the power output changes very interesting. From looking at the results you wouldn't think they were from intakes with different runners lengths or plenum volumes, as the power peeks are in the same places.
cheers
ny_fam


I suspect the difference in runner diameter is responsible for that.


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## MecE2.0 (Dec 20, 2005)

*Re: TECH: OEM Intake manifold dyno ~ MKIII vs MKIV (Prof315)*

x2, its all about harmonic tuning.


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## The_Elusive_Pickle (Nov 7, 2014)

I know this is an old, old thread but I was wondering something. It appears that this motor, with all its mods, was making about the same power as it supposedly did when it was new? Is that right? Just curious.
Thanks


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## redzone98 (Jun 10, 2004)

im confused by your question...


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## ps2375 (Aug 13, 2003)

The_Elusive_Pickle said:


> I know this is an old, old thread but I was wondering something. It appears that this motor, with all its mods, was making about the same power as it supposedly did when it was new? Is that right? Just curious.
> Thanks


power at the wheels is different than power at the crank.
BTW, I have a ported mkIV manifold swap for sale. Check the classifieds.


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