wrightcomputing

I built an Autocross car from scratch called Scrap Metal. It currently has a 2.2 F22C1 from an 05 S2000. Here is the car in action.
If I drop to the 2.0 (NA) I can run in the light class and take 330lbs off the car. I have purchased and F20C however it is not in great shape and there are scratches on the cylinder walls. It does however have a good crank, connecting rods, cams etc. Pistons look trashed.

My plan is to rebuild the 2.2L with the 2.0 crank. I am looking for advice to get a little more power from the engine on a reasonable budget ($1-2K) Hopefully to retain the power of the 2.2L or even gain a little. I have some questions and would love feedback

• I have heard that mixing the cams can be beneficial eg AP2 intake AP1 exhaust
• I'm thinking about increasing compression Maybe to 12.5:1 and running E85 any idea on power gains?
• I would like to run lighter connecting rods and pistons and also lighten and balance the crank any recommendations
• As mentions running E85 what size injectors, any injectors from another car you can add such as an STI or EVO and add their fuel rail to the S2K or similar (I can fabricate).
• Any other recommendations to add some power.

JUSTINTHECOASTIE

what power range do you have in mind? A oem rebuild, with bolt ons and ems will only net 215-240whp.

bgoetz

i don't think you can do what you want on your budget. I have heard of slightly larger pistons, similar to the JDM motor to pick up 10 more whp

wrightcomputing

I am not looking to gain huge power but would like to retain the power of the 2.2L engine when I drop to the 2.0 if possible (I reread and edited my first post as it is a bit misleading to power goals). With the car being about 330lbs lighter (From 1750lbs to 1420lbs with driver) I will be gaining about 25% power to weight ratio anyway. I already have an AEM EMS V2.

Reliability and functionality is more important to me then extra power, however I am taking the engine apart to change the crank anyway so there are minimal labor costs involved to change other parts such as cams, pistons and connecting rods, head gasket etc.

If I use all the parts I have (AP1 and early AP2 engine) the rebuild will basically cost me nothing. I expect to lose about 7-10% of the torque, due to reduced displacement. Some peak HP would be retained due to higher redline.

For CAMs I can choose any variation of mix and match AP1/AP2 which will cost nothing. I will do some testing on the dyno to confirm numbers as there are easy enough to swap but would like to hear feedback to point me in the right direction. Not looking to do aftermarket at the moment as it is an easy addition later.

I can bump compression by about ~0.3 by removing the center layer of the OEM head gasket, same as the spoon head gasket. Anyone know of reliability issues here? When I look at a compression calculator though this would only gain ~0.5whp which does not seem worth it, but it is a no cost mod so I will probably do it.

Going with higher compression pistons to 12.5:1 or similar on a compression calculator only nets 2-3whp. Lighter would also have some benefits such as faster revving. Connecting rods would just save weight. Any weight saving of pistons and rods would be doubled as I will also remove it from the crank. I'm not sure $1000+ investment is worth it when you factor in reduced reliability over OEM. Any recommendations for reliable part here from people have actually used the parts.

E85 is something that I can run later so not a huge issue at the moment. However if I go to 12.5 compression I really have to convert to E85 and don't have the flex fuel option. (I know it is possible to run 12.5 on pump gas but it seems like an unnecessary risk as it right at the limit). Running E85 in my car will only be the cost of the injectors and maybe a fuel pump which would be ~$500. Then I have the hassle of getting E85 all the time and using/carrying twice as much fuel which also makes the car heavier.

The reason I ask is after I do things like this someone at the track says, didn't you change the "favorite part here" everyone knows thats the hot setup and will gain "inflated power gain here".

Spartarus

This is everything I've gathered thus far... Hope it helps.

AP1 cams, or aftermarket. No AP2 cams.

Specs. IN/EX VTEC, IN/EX non-vtec, lift VT / Non VT in, then mm... Here:

USDM F20C (S2000 '00-'03) Stock 300°/298° 226°/222° .498"/.459" 12.65/11.66
USDM F22C (S2000 '04-up) Stock 296°/296° 224°/222° .487"/.475" 12.37/12.06

E85 will make more power regardless, but you'll go through a lot more gas.

Acura RDX injectors can be used, not sure the years. They're a little bigger... 410cc.

Thermal gasket for the Intake manifold (Hondata or equivalent) has been shown to significantly reduce IAT's, lower IAT = More power.

You won't lose as much torque as you expect. You will not lose any power up top.

AP1 Valve springs are better.

Messing with the head gasket thickness affects timing chain tension.

slowd16

Any reason you cant put ITB's on the car?

wrightcomputing

Great info. I will start with the AP1 CAM when I dyno and switch them around and see what happens. The profiles look a lot better, to be honest the Non VTec does not really matter. When I dyno'd the car we ended up setting the VTech at around 3000rpm and when autocrossing the car never really goes below that. The Non VTech can is only used for rolling around the pits and idle.

Good point with the gasket I had not thought about the timing chain issue.

I already have the Hondata thermal intake gasket, I had a Blox's but it melted :-0 the Hondata seems to be holding up better. I've also bypassed all the coolant from the IAC and throttle body. I tried a couple of different throttle bodies but they kept sticking so I went back to the OEM one as it just became frustrating.

I can upgrade to independent throttle bodies and probably will in the future. However currently I want to keep the cost down but get the engine internals sorted as I am replacing the crank anyway. Other typical bolt ons such as aftermarket CAMs can come later. I would like to add a drysump as I pull up to 1.8G (2G in a slide) but I have not been able find a reasonably priced kit. The problem is these upgrades are thousands of dollars and I have lots of other areas to make the car faster that are much cheaper.

slowd16

I understand the want to not spend tons of money but everything your talking about inside the motor isn't cheap. The ITB's will give you better gains in TQ and response. Going higher compression pistons pretty much means you need to sleeve the block because there are very few FRM options in pistons. How severe is the cylinder wall scoring?

Cheap ITB option:
https://www.s2ki.com/forums/s2000-na...setup-1111428/

Quinn

I did a build on my 125k mile F20C after the valve seals wore out and were smoking.

- I took .015" off of the head to bump compression and run a Spoon headgasket on top of that. This bumps compression to about 11.7:1. The stock tensioner can handle the slack no problem.
- You can port the stock intake manifold opening for free and mate it to a 70mm throttle body which can be had for around 100.00.
- I changed the valvetrain out for all Supertech and run a set of BC Stage 2 cams.
- J's header, full 70mm exhaust.
- Haltech Platinum
- The setup made 232 whp and 148 lb/ft on a DynoJet, STD correction factor.

I still think there is more power to be had with a better intake manifold and adjustable cam gears. This is something I am going to explore in the near future.

I am documenting this build on my YouTube channel going forward. Here is the overview for it:

JUSTINTHECOASTIE

If I were you, I'd look into the k20/k24 swap. Broader aftermarket and great NA reliable potential and cheap engine to purchase. I had similar hopes as you did for the F20c.