Hi everyone,

here is the sit rep on my engine.. F20B2 (almost identical to the F22B2 in the US)..

It is currently in great mechanical condition, AEM SRI, DC 4-2-1 header, APEXi WS2 exahaust, soon to be installed bisimoto custom level 1.5 cam, will be tuned using a VAFC (have no other choice)....
I am considering porting the head soon as well, because the machine shop will guarantee me a 20% flow improvement (proven by use of flow bench)...

The question I have is, what is the most restrictive part of the intake system on these engines? Is it the throttle body or intake manifold?

What is the stock throttle body size on these F22's? Is it 60mm? Considering this, what is the benefit to going to a larger one or possibly porting it out? Will it remove the restriction point or will I still be limited by the plenum? What size or how much porting is reasonable on the F series throttle body?

Also, if I was to change the throttle body to something bigger, will I have trouble fitting my intake, considering it is sized to match with my stock motor? What do people do to get around this problem..

Thanks

 

If the F20B2 is anything like the F22B2. The restriction is the head itself. The throttle body is 54mm at the plate. That is not a restriction. Upgrading to an H23 throttle body that is 60mm @ the plate will change the characteristics of the throttle response, if it is to large the throttle will bog down. That's why bigger is not always better.

If you want to feel the full gains of a larger throttle body you should go with an F23 intake manifold and H23 throttle body. You should see some good gains with a port matched TB and IM. In conjunction with the upgraded cam and a good head porting. It should give you noticeable gains in throttle response and it will free up some Hp as well. Your 2.5" exhaust should be good enough for those mods, you may want to upgrade to a set of OBD1 H22 injectors as well. Always help to have a bit more room to move if you need it while tuning.

With the cam upgrade and a good tune the above parts will give you a nice responsive engine. Not saying it will give you 50whp or anything. However, the performance will be noticeable. Not so sure about the tune with a VAFC though, no OBD1 ECU tuners down there?

 

Well, the reason I'm going with the VAFC is two reasons really.. Firstly I got it free and secondly the car is automatic.. Not my choice really but it will stay that way for the near future because I don't really see the sense in paying for the swap when the trans is still in such good condition..
Basically, making the car faster in the meantime is no harm because I can always handle the manual swap later on..

Concerning the injectors, I can always upgrade those after we get the accordian on the dyno to tune.. I will only do that if I know that I am close to max duty cycle on therm.

Concerning the IM, how much of an upgrade is the F23 over the F22? Enough to justify having to import an IM? Its pretty hard work getting parts like that down there...
If what your saying is true (and i'm sure it is considering the extensive headwork you have one on the F22) then the porting should show significant flow gains...

Of course the porting is not particularly cheap if I want it done right, probably around $400-$550 depending on options. One of these options is the multi-angle valve job for an additional $60 or so.. Will this make a significant difference?

TB to IM matching and IM to head matching (with gasket modifications) are available for about $50 each.. Something worth looking into.
But is the stock TB a different size from the stock IM plenum to justify matching?

Also, how does matching the IM to the head work exactly.. I was planning on putting on one of the Bisimoto heat shielding gaskets, so its possible that it can be modified along with the ports for less restrictive airflow?

I am sorry to assault you with questions like this but I am new to the porting scene and wanted to get as much information as I can before making a decision..

Thanks

 

Dang, you beat me to it!

As far as info on the F23 IM differences:

http://www.accordinglydone.com/forum...ghlight=F23+IM

Which came from this thread (which should look familiar to Ghost):

https://honda-tech.com/forums/honda-accord-1990-2002-2/f23-intake-manifold-f22b1-head-2275394/

I wish the pictures still worked, but this is the best I've seen as far as any comparisons being made.

As far as the TB size, Ghost summed that up nicely as usual.

Also keeping the TB a factory part (compared to aftermarket) is always nice considering most aftermarket TB's I've had experience with and read about just don't work as well.

EDIT: Found a link with working pictures for the F23 IM (AND it's a DIY install!):

http://cb7tuner.com/vbb/showthread.php?p=2541622

 

I agree that a factory TB is always a better option..
As usual, I'm over in the US right now so I don't have access to my car to see if the TB is the same size as the IM ...
If not, i'll definitely have it portmatched and see what comes of it...

Concerning the heat being the restriction, the porting process should definitely rectify this I am assuming? The biggest problem with the porting problem is not the price for me, its having to have the car down for almost 2 weeks..I have spare vehicles but it is troublesome to have to pay my mechanic to take the head off, drop it to the machine shop, and then bring it back and have the mech remount it..

The machine shop says they will expect (proven with flow bench results) flow increases of 20% post-porting.. That equates to about 25-30cfm with roughly 1HP per 2.5 cfm.. So a gain of 8-10hp is not that significant, but the more mods I do subsequently, even turboing will benefit from the headwork..

 

that last link dident work

 

This one works; http://cb7tuner.com/vbb/showthread.php?p=2541622

 

That's wierd, it still works just fine for me.

Thanks for the other one Ghost, though it looks exactly the same.

 

It is

 

do these f23 manis have enough meat to be port matched to a 70mm tb?

 

I literally just put an H23A1 TB on my F22B1 IM the other day and I LOVE IT. My motor is an F22B1 as well.


I cant wait to get the F23 intake manifold on there.

 

.

 

Balwin,
Did you port the F22B1 IM to match the larger H23 throttle opening?


SQ is the SQUAD,
I'm not 100% on the F23 IM port size, however I do know that the F22B* IM cannot be bored out to 70mm without blocking off the IACV port on the manifold. The F23 IM is already larger than the F22B so that's a start. I wouldn't go 70mm unless you plan on doing some bottom end internal work. 58-60mm should be more than big enough for a stock bottom end.

 

Thanks Ghost, I myself am not looking to go bigger than 58-60mm at any point in time..

How hard will it be to port the IM and throttle of the F22B2 to achieve this? I am assuming that a small increase such as this can only benefit me after doing the cam swap/head work?

 

It's actually relatively easy to port the IM a bit larger. A drill and carbide bit would do the job. just be careful of the IACV port. Porting the throttle body is a different matter. It would be best to send your throttle body to Maxbore and have him machine it to 64mm if that is what you want. Or you could buy an H23 throttle body (58-60mm) and go that route.

Where your ride is an automatic you will need to find and H23 from an automatic.

 

I have read in a magazine that porting a Honda cylinder head is not necessary. It will actually hurt performance, unless you have a full race turbo car. But a 3 angle valve job is very good at enhancing flow. I would also consider doing a 5 speed transmission. An automatic sucks up too much power, and will cause idle issues with the lack of tuning available.

 

Well I would love to send my TB to maxbore but the car is located in the caribbean so that really rules it out as an option..
All my porting will be done at a local machine shop and flow tested after...
I am thinking if possible to shave maybe 2mm off the internal diameter of the throttle, maybe 3mm and then portmatch the IM?
How much mm can reasonably be gained by porting the mm and tb?

 

It really depends on what type of setup you are running (F.I., nitrous, N/A, etc.).

Each likes a certain method of porting, and if you just go in and start opening up everything you may very well lose some power or not achieve optimal gains. That's just a basic overview though, you can look it up for more detail.


Also, he already is well aware of the tuning downfalls and here is why he is sticking with the auto:

 

You realize that if you port the throttle body out 2-3mm you will also require a larger throttle plate to match. Or are you talking about only porting the back side of the throttle body behind the throttle plate? If that is what you are looking to do it really won't increase the flow. The throttle plate will still only be 54mm with a 56-57mm port opening.

To answer your question the largest opening that you can go on a stock F22 IM would be 64/65mm. Not 100% if the F20B2 is the exact same or not.

uberEFtuner,

I don't think he is talking about hogging out the ports. A cleanup of casting flaws and blending in the valve seats won't hurt the flow. However, I do agree that the magic is all in the valve seat angles used when doing the valve job.

 

Yes, I have no intention of opening it up for opening sake...
Everything I do with the porting will be measured to offer increased flow (both in volume while maintaining velocity)..
I am not planning to go anything ridiculous, but I feel like a 20% increase in head flow is a reasonable gain... Especially when you consider that I do not have any real intake or exhaust restriction..



Ghost, I'm fairly certain that the IM, head and exhaust of the F20B2 and F22B2 are identical.. I know as a fact that the block is slightly different though:

F20B2
Displacement 1997cc
Max.power (Net), kw(PS)/rpm 135 ps (99.29 kw) / 5700 rpm
Max.torque(Net), N*m(kg*m)/rpm 18.5 kg*m (181.42 N*m) / 4500 rpm
Compression ratio 9:1
Bore, mm 85
Stroke, mm 88

F22B2
Displacement: 2156 cc
Bore 85mm
Stroke 95mm
Compression ratio: 8.8:1
Max power: 130 hp (97 kW) @ 5300 rpm
Max torque: 139 ft·lbf (188 N m) @ 4200 rpm