Hello to everyone,

After reading a lot of various forum communities I found that honda-tech.com is the most friendly and result orientated, so I would like to ask for people who build and who tune engines to give some advice on my build and how to get most reliable power out of my setup (b20 with b16 head). The car is used for circuit racing and hill climb, so some 30min runs max. usually short runs of bout 6-10 minutes.

Last year I built b20 block with RS machine pistons and H beam forged rods, which gave me some extra CR I needed for my built head. And this unleashed some more power.

Head: skunk2 pro 2 cams, s2 springs, s2 retainers, s2 pro inlet manifold and 69mm throttle body, hytech style try y header with 2,5" exhaust.

Fuel: walbro 255lph with 340cc prelude injectors.

ECU: Hondata s300

With stock b20z bottom end (just modified pistons to accept higher lift) and built head I had 239bhp and 200nm with rev limiter set at 8600rpm. CR was about 10:1 on 98 fuel.

With RS machine type r style pistons and some cam gear changes we got 269bhp and 233nm. CR I believe was 12:1 or 12,3:1 on 98 fuel and 8500rpm rev limit.

It is worth mentioning that the changes in cam gears gave me extra 14bhp, so i think that my cams are still not degreed correctly, so I would like to get some advice. I haven't checked p2v or v2v clearances, so this must be taken into account that the settings must be on the safe side.

The problem is that i got a cracked sleeve after season and I am pretty sure it happened because of bad map (fueling or timing).

So now I am thinking what to do with my bottom end. To replace b20 block and to change injectors to evo IX 560cc ones and go with e85 fuel instead of 98? People say that it is much more reliable.

Another idea is to go with b16a2 engine and just some higher cr pistons to have thicker sleeves = more reliable setup.

So I have some questions:
1. Is it possible to fine tune such setup to be reliable?
2. Will I gain something with larger throttle body, larger exhaust?
3. What are the best and still safe cam gear settings for skunk2 pro2 cams? I am using tuner series skunk2 gears.
4. Go with larger injctors? EVO IX 560cc ones?

Another thing is that my timing tables were very messed, because my tuner was not able to set idle for these cams. But after some personal search in hondata help files I was able to use IACV corrections to keep my idle stable, so with some reading i done some correction to idle timing tables. Can I found some person in this forum who can have a look at my hondata file and say something about it?

I think it is enough for my first post in this section.

Thank you very much.

 

Sorry I dont have a lot of Input on your setup but are you certain that a bad tune cracked your sleeve? B20 sleeves are pretty weak compared to b18 sleeves, so were there indications that the engine was knocking when you pulled it apart?

Larger throttle body wont gice you any more power. What itll do is reduce your throttle control. Instead of theoretically hitting wot at 80% throttle, youll hit it at say, 60% (numbers just thrown in as an example)
A good way to see if your throttle body is sized properly is to check for vacuum. The point at which your engine sees atmospheric is wot. You dont want to hit it too soon or too late. Someone said 80% is a decent number to shoot for.

Exhaust sizing depends on your engine. I think a decent 2.5in exhaust would be optimal

 

I believe it was short time/momental detonation, so this was enough for the sleeve to crack. As i was running the car much stronger before with no issues and the sleeve cracked on my practice where i wasn't even revving high, but I noticed few times my AFR was on the lean side, so maybe this caused the sleeve to crack. Also few times ecu was cutting fuelling, so maybe these things caused the result

 

you have access to 98 octane and only running 12:1 CR


would this 98 be pump gas?


If it is, Id say the 98 is a little more reliable then E85 where not all E85 is the same.

 

You are wrong because E85 is more reliable than 98, because e85 octane is about 105.

 

^^
I am aware of the octane differences but you have alot to learn about E85 and quality control.

Have you researched the E85 in your country?

Like I said, Not ALL E85 is the same.


But since your not boosted, Id stick with 98. 12:1 compression is fine with 91-93 so 98 is no problem.

 

e85 is great depending where you live like esotericimage said. Id rather have 98 though, less hassle and wear on your fuel components

 

B20 vtec with internals and e85 I'd advise 550-720vx injectors. On my built b20 vtec I maxed out rdx 410's on low cam(89%) and over 100% on high cam. Too small of injector = bad furl curve which equals bad torque curve. B20 vtec is as reliable as you make it btw, keep it from overheating and use good quality oil.

 

1:they're as reliable as you build them ACL rod/main bearings used also arp rod/main bolts used ? i know not having them doesn't make a sleeve crack just wondering. Nice number tho 260+/170+ 2:the whole deal with a larger tb causing you to loose throttle control is true to a degree if the intake plenum is lets say 66mm and you're running a 70/74mm yes you do reach WOT faster. But if you have a 74mm plenum and 74mm TB then you're on track and would would see a gain matching the two of them up, i'd reccomend a 3'' with a setup like you're talkinf about. 3:Let somone who knows what they're doing degree the cams and set the gears i never touched mine. 4:i'd reccomend injector dynamics 550CC's i have 440CC grams in my set up kinda close to yours 85mm 12:5:1 pro 1's etc.

 

Pro 1's are a small and mild cam man, not big at all(not for 2.0).

 

^^this is true, you need a bigger cam