[powerwheels]

An Analytical Approach to the Honda Intake Manifold

Honda offers 3 different intake manifolds for the City/ Civic engines, one is which comes in the City engine, the second is the one that comes in the D16Z6 engine which most people are familiar with & the third is the odd shaped plenum manifold which comes in the 96-2000 D16Y8 engine.

Of the 3, the best performing one is the D16Y8 manifold which is difficult to obtain, while the one that comes on the D16Z6 is marginally better than the OE one that comes on the city engine. Over the several years that we have been involved in tuning we have had the opportunity to carefully evaluate the benefits of each of them. to classify them is simply thus:- the OE manifold is good for mid-range, the Z6 for high mid-range power & the D16Y8 manifold for high mid/ top end power.



The manifold on the left is the D16Z6 manifold and the one on the right is from the D16Y8.

From the economics perspective we did some interesting mods & found that the OE manifold is not as bad as we first thought it to be. In fact it performs better than expected for street use with a little bit of intelligent engineering, which nullifies the need of changing to a Z6 manifold. However if one gets the D16Y8 manifold it would definitely the one to use as there is a noticeable difference over the others.

An interesting combination of our special 4-2-1 exhaust system coupled to a very trick cold air intake system along with a 30mm spacer block placed below the OE throttle body on the OE intake manifold & changing the final drive TO 4.25from the 1.3 gearbox actually changed the complete feel of the engine, & a few run ups were done against other so called highly modded street Hondas which had the exhaust systems, the D 16 Intakes, head work & modified ECU. We ran head to head with no virtual difference at all Cost wise we had no headwork, no ECU, no special intake manifold .Economics wise we had a simple effective setup. Further this concept actually we found to work well on both the VTEC & non VTEC 1.5 engines. The only limiting factor was the engine rev limit remained unchanged as the ECU was standard. For the money spent we still had a winner on the street.

To further improve engine output the stock cam from the D16Y8 was employed which further helped the upper mid range power while still maintaining the stock ECU. The stock D16Y8 cam is a shade better cam than the one that comes as OE on the normal D15 VTEC. Added to this is the fact that the later Honda City engines after 2000 came with bigger valves (30mm intake & 26mm exhaust) while the earlier ones came with 29mm Intake & 25mm exhaust valves . With the bigger valves already in place we saw no real need to do any head work for street use as the normal OE head has ample flow for use up to 7500rpm. This entire combination was very effective to compete against any of the other more modded Hondas that prowl the streets of Bangalore.

One gauge which we have found to be an absolute asset is the wide band air/ fuel gauge thru which we monitor the entire ECU setup. We recommend this to everyone who wants to do serious modifications to any petrol engine.
In our highly modified D15 Honda drag engines where we regularly do 12 seconds in the quarter mile & also in the super saloon Motor Rev Honda City which we were primarily responsible for putting together for 2011, the Edelbrock intake manifold part #4756 does work remarkably well along with the 65mm Edelbrock throttle body #4791. In spite of us having various ITB combinations to choose from, we still find this to be an excellent intake both for forced Induction & n/a applications. It has a power band upto 8000rpm which means in race trim you shift at close to 9000rpm along with the correct high lift cam, & gear box/ final ratios & exhaust system. One key link to make the Edelbrock manifold work so effectively is to induce high velocity thru the air intake system which we learnt thru our drag development program.



Edelbrock has also available a dedicated D15B/D16Z6 Intake manifold under part # 4754( one is available with us) which is very similar in appearance & layout to # 4756 However the plenum &intake runner frequency dynamics are different from the part # 4756 . Either one works well depending how you address your power curve needs. So, you really have a choice of very good intake manifolds.

If one wishes to custom make their own intake manifold they can be sourced from a company by name Velocity Motorsports (ph # 016 2794 903, Malaysia, address is Jalan PJS 11/3, Bandar Sunway, 46150 Petaling Jaya,Selangor DE, Malaysia) who are located behind Kaki Motors on Sunway Bhandar .Sunway Bhandar is the famous street in Selangor where all the hot car performance parts are available. Here you will find a tremendous amount of race cars & race shops & is a very enlightening experience for those interested in car performance parts. Kaki motors is the main distributor for Velocity Motorsports& has a huge range of different manifolds on display. Velocity manifolds is run by Mr. Samson & Mr. Suraj Nirmmal where all the custom fabrication is done for any engine. See below the picture of one such intake manifold done by them for us for an experimental high output turbo application for a Honda City.







The price is around RM 1000/- (Malaysian Ringet) per manifold & slightly more if you want to have it anodised in any color. They also offer the feature of engraving your name on the manifold if you so desire .All the work is custom so give yourself enough lead time for any manifold to get done.

Since all engines operate using the principles of harmonic cycles one should keep in mind that the genera l operating range of any manifold is in the range of 4000-4500rpm window for the Honda City / Civic engines There are some who make irrational claims of a power range from 2000-9500rpm. It is obviously aimed to either impress the gullible customer or that they lack the proper understanding of the principles of manifold design. No matter what engineering ideas are employed there are limitations to the range of operation to any manifold. The laws of physics, thermodynamics have to be respected.

The Honda engine in itself is an excellent engine with a lot of reliability &in stock form itself is capable of sustaining much abuse .Attention to detail & patience, accuracy & proper installation of components is the key to extracting power from these engines. All our test measurements are based on distance markers, & time differential instruments. This has been our form of analysis of measurement over many years using proper vehicle dynamics engineering principles to evaluate what we do whether it’s a street car or a drag car. It has been a yardstick of measurement for us which we find very effective in our analysis of components. Dynos are a good source of measurement but can be conveniently (often are) rigged in their calibrations if required to produce various results to impress customers or to psyche the competition. In the end cars race, dynos don’t. Vehicle performance on the road matters which takes into account all friction losses, tire sizes, gearing etc. it’s the sum total that eventually has to be displayed.

That is the real world dyno.—actual vehicle performance.

Happy tuning,

Raj Hingorani

[Catalyst_delhi]

Wow! this was simply mind blowing,Never thought the intake plays such a big part!

[_raviShankar_]

That's a lot of information in a single post.
Welcome to the forum. I believe your active participation in this forum will enlighten us all.

[Jaggu]

Welcome to the forum and thanks for sharing the info.

The price quoted it pretty reasonable and the workmanship seems to be quite good also. Instead of casting i notice that they have done fabrication using welding and all. Is there any disadvantage coz of this? Or is it because of the custom orders?

[AlphaKilo]

can you post some pressure, temperature graphs (comparing old vs. the custom) ones?

Thanks.

[powerwheels]

@jaggu The welding is because of the custom work needed for the manifold. The welds are on the outside and do not affect the performance in anyway. Most custom manifolds feature welds like this.

[headers]

Wonderful message Sir - Welcome to the forum.

Could you share some details about the wideband airfuel gauge? Is there a similar one for Diesel engines?

Cheers

[kayne]

Hey Raj welcome its about time you made your presence felt here , i still have the zen and runs like a treat on steroids , i hope all is well with you .

[chethan25]

Hey Raj Sir, that was great info there !! thank you for sharing this, looking forward for more such info. As the saying, if one has the basics right we can bank on it for further driving in efficiency and streamlining.

Originally Posted by powerwheels

An interesting combination of our special 4-2-1 exhaust system coupled to a very trick cold air intake system along with a 30mm spacer block placed below the OE throttle body on the OE intake manifold

I didnt understand the spacer part here can you may be explain it a little elaborately please

[baddy]

^ Iam assuming he has increased the intake flow length by 30mm after installing the spacer. Intake efficiency is also dependant on the flow length.
Interesting thread i would be watching this for more info

[vinayvtec]

WoW 7,913 Views... this is awesome information, so now everyone knows how the so called custom intakes takes birth and its not a magic.

Liked a lot "The end cars race, dynos don’t"

[powerwheels]

Mod team note: Back to back posts, please use Multi Quote (Quote +) instead. Thanks

For wide band AFR gauges, you could check out AEMElectronics.com or InnovateMotorsports.com. Those are the two sites where you could source the gauges. We don't deal with diesel engines so we don't really have any information for them.

Originally Posted by kayne

Hey Raj welcome its about time you made your presence felt here , i still have the zen and runs like a treat on steroids , i hope all is well with you .

Hey Kayne,its great to know your little cart is still active. please be on the look out for more funny tuning stories. And say hi to the rest of the group.

Originally Posted by baddy

^ Iam assuming he has increased the intake flow length by 30mm after installing the spacer. Intake efficiency is also dependant on the flow length.
Interesting thread i would be watching this for more info

You are right. It also increases the volume below the throttle body. Which benefits the upper mid range for the OE Vtec manifold.

[motorpsycho]

Thanks for the post, Awesome read.

The custom made from Velocity the intake tubes mouth looks like bell mouth intake system, if it is would it still work with a Ram air type of intake where the plenum is running a slightly higher pressure.
Also how does the length and width of the manifold effect the engine characteristics?

[Sn1p3r]

Thanks for the informative post.

Has anyone done mods for the current city ivtec L15A7 engine or to other parts?

[GauravLadwal]

Originally Posted by Sn1p3r

Thanks for the informative post.

Has anyone done mods for the current city ivtec L15A7 engine or to other parts?

Yep my honda has a k&n, de-catted exhaust, unichip ecu and tein coilovers. looking for more mods. any idea?