Honda B16A2 engine - possible modifications

[Walezy]

Hello Guy,
Did you ever get a chance to work on Honda Civic VTi engine? The engine code is B16A2 and it is 1,6l engine with 16v and Vtec system. The engine has 160HP in standard at some about 8000revs. It withstands easily 9000-9500rpm on stock bottom end. My friend owns such car and he uses it for rally. Right now I am preparing with him the car(fully sandblasted body, seam wleded, uniball links, 4,92 main ratio , LSD diff etc.) the car will for sure be quite fast but I would like to know if there is a chance to make it even faster while still keeping it in group A regulations(stock throttle so I cannot use separate throttles). What would you suggest to modify? If the engine has 100HP per litre then I think that not too much will be possible to be done to the head or I am wrong.

[Acki]

Good head prep and cams, buy a Vtec controller ;)

[Guy Croft]

is it this head?

[Walezy]

Yes it is.

[Guy Croft]

OK, thanks,

see photos - I did some bare port flow testing last year, it is a truly high flow head, around 160 cfm 'out of the box' and might well flow more with inlet manifold fitted (like the Peugeot S16 featured in GC V/W, + 6cfm with manifold). I don't know what it's like with valves fitted but i suspect very good indeed and I think there would be some extra flow potential from smoothing the port and short side radius, reshaping the splitter too and doing a nice valve-seat job.

Vauxhall XE 2 liter engines make 270bhp with a full spec GC head, just over 150 cfm at 10" at 11-12mm valve lift with race 33/29mm valves, so I should think a Honda 1600 with this head fully developed and the right cam profiles ought to be capable of 190bhp plus - even on your existing throttle setup, and way over that on throttle bodies. I imagine the compression ratio is over 10/1 on your motor anyway, that's what I'd want if going to more powerful cams, most modern FI engines run that CR or higher still - for fuel economy. If cams are out of your price range or simply not available (quite possible given the 'newness' of the motor - not many people tuning it - yet) then go for head mods and recalibrate the fuel system to give more fuel for the higher airflow. I would just say though, that a head of that capability really needs to be done in conjunction with flowbench testing, get it wrong (especially round the short side radius) and you could make it worse.

These are a new generation of head by the way.
Cavernous (VERY roomy) intake port (conventional theory would say - 'ports are way too big - there will be no intake velocity at any speed') the same 'Peugeot style' deep-drop from the horizontal sidedraft port to valve region.
Same setup on Suzuki, Toyota heads too. Not a downdraft angle in site (see GC V/W - 'all the power is in the head') . I must admit I don't yet understand why they work so well, even with variable valve timing, and I certainly know how that works.

GC

[Walezy]

thank you for your kind help. What I am going to do is to leave the engine standard for now. We will be putting the engine into the car in near future(the car has been totally stripped and now we put it all together) to test it on dyno before making any modifications. After I check if the engine makes that claimed 160HP I will start to make it better. As for the cams there are some available on the market and not that expensive. The cams have such description:

Type: Stage I
Part Number: 10117
Lift/Duration: IN. 0456, 252; EX. 0.426, 249
Notes: Valvetrain upgrade recommended

Type: Stage II
Part Number: 10115
Lift/Duration: IN. 0485, 266; EX. 0.466, 262
Notes: Valvetrain upgrade required

Type: Stage III
Part Number: 10116
Lift/Duration: IN. 0504, 270; EX. 0.465, 279
Notes: Valvetrain upgrade required

This is what the seller says about those 3 types of cams. As for the duration i think that it says about the performance lobes.
Is this any good?
We have two such engines at the moment but none of them has been stripped yet although the previous owner claims that one of the engines was prepared in Belgium(I believe for group N) and has some mods done(for sure he said about performance valve springs) so maybe I will be able to use them when I make the mods.
I will post pictures and description of mods later (it might take some time as we are preparing at the same time also my Fiat 131 Abarth(replica)). but for sure I will post dyno tests before and after mods.

[Guy Croft]

I was talking to an important contact yesterday about dyno test on that 1600 Honda engine. Using an 1800 head (I don't know the difference) with competition cams and standard throttle they did get 196bhp, I am told the engine had very poor torque below 5000 though; almost 'none at all' to use race engine parlance. We did not talk that much, I hope I hae portrayed the results right.

Cams for this engine - as a rule - please avoid reference to price and especially to an internet auction site (they do quite enough of their own advertising), I'd like to know the name of the manufacturer (maker, not just seller).

GC

[Walezy]

The manufacturer of the cams is OBX although the same cams are available from Skunk2 for a bit higher price. OBX is just a copy of Skunk2. I would like to get about 200HP from that engine.
As I have one spare engine maybe I will get forged pistons(ross pistons or JE pistons) with 12,5CR and forged conrods(easily available at reasonable costs) then I could try to get more power but will I be able to get it from standard throttle? This is a plan for next winter as we will test the engine on standard bottom end in few rallies this season.

[mandic]

Dont want to redirect You from GC forum, but You can make a peek here:

http://www.honda-tech.com/zeromain

thank you

Ziga