Hi all,

I need some help regarding my setup on my b18cr. I got power dip when trying to set the VTEC on 5.5k rpm or lower. Currently have to set 6k rpm and but still got minor power dip. My car wont go until 6k++ rpm. Somebody say because of low compression ratio. I am planning to change new piston, any suggestion? It is B16B piston suitable for my pro3? Thank in advance

• Skunk2 Custom Header
• Skunk2 Pro 3 Cams
• Skunk2 Intake Manifold Ported
• S2 Springs & S2 Retainers
• Hondata ECU
• Skunk2 Throttle Body 68mm
• Stock Piston

 

Just sounds overcammed to me. 10.8:1 CR on a 81mm block is not giving you the displacement you need to make those cams work correctly and efficiently. You will want at least 12:1 compression with your current setup to make those cams respond the way they are supposed to.

 

That cam is going to want a fairly high vtec crossover with your compression and displacement.

 

If I change to B16B piston, will this problem solve? I think stock b16b piston have high CR compared to B18CR. Correct me if I'm wrong.

 

There are much better choices compared to these pistons. P30's or JDM P73's will both put compression in the mid 11's. There is a thread in the forum that been a big topic involving CTR's and 1.8's. read through that. its title ATTN: PEOPLE REBUILDING GSR's

 

I do read it... a lot information there. Don't want to take risk blow up my engine. P30's maybe a good choice but P73?? that my stock piston P73-00 .

From http://www.c-speedracing.com/howto/c...c/compcalc.php calculation , if I'm using P30 for my setup is 11.96:1. I worried if CR still not enough. As per Skunk2 support site http://www.skunk2.com/cgi-bin/kb.cgi...id=139&lang=en

 

You need a lot of compression in a 1.8 for pro3 cams. Im at about 13.2:1 compression and when I talked to skunk they said I was borderline on using the pro3 and said the pro2 would be a better choice. Basicly the amount of compression you will need will make the car unrealistic for a daily driver as you wont be able to run pump gas.

 

You will have a tough time with valve to piston clearances with any OEM cast piston. The valve pockets in the P30, P72 or P anything will have very shallow, narrow valve pockets as they are designed for use with OEM camshafts. In order to run a set of aggressive camshafts such as Pro 3's you will need to look into a forged aftermarket piston. These pistons have very deep and wide valve pockets as they are designed for use with large aftermarket camshafts. We typically only recommend Pro Stage 3 camshafts for heavily modified 2.0L (preferably 2.1 or bigger) engines.

If you have more questions the guys on HT tend to be pretty spot on with their replies.

You can also email me at BrianN@Skunk2.com and I will be happy to discuss your build.

 

How about Wiseco K593M82? Do you think this forged piston will do their job? But I worried P2V clearance since the dome for this piston (8.25cc) a bit closer with CTR piston (8.63cc). The CR is 12.5 - 13.2 as advertised on their website.

Currently my car make 205 hp on dynojet and running on 97 octane gas. I occasionally enter the drag test and this car is my daily driven car.

wiseco catalog - http://www.wiseco.com/Catalogs/Sport...AcuraHonda.pdf

 

As always brian is top notch @ responding.

 

The best advice you will ever get is to sell those Pro3's and buy a set of Skunk tuner 2 cams. You will make more power everywhere as these cams are better suited for your build. Don't change the pistons...change the cams.

 

Gonna go to work now. I will joined back another 12 days, hopefully got good input when I came back. Offshore life no internet, work work work...

 

thank brian, i will email you as soon as I arrived at platform.

 

Pro1's would probably be a better choice.. i had s2s2's in my itr, i liked them, then i had pro1's.. more power overall everywhere.

 

Happy to help right AllM0t0r? Educating the Honda world one thread at a time!

@ OP you do have kind of a mismatch right now. You can either match the engine to your camshafts, or try to get camshafts that will match your engine.

Hands down the least expensive route would be to remove the Pro 3's and get some Tuner 2 or Pro 1 camshafts. I like the Pro camshafts myself but we all have our own opinions.

It is my opinion that with 1.8L of displacement even a dramatic increase in compression would not be enough to make those Pro 3's the ideal choice. Email and we can go over all the different options.

 

yea pro3s are way to big for that engine..just sell them

 

I run those pistons in my build with Pro 3's. No worries about p2v. Just make sure you check them though. I did get away with it but very minimal.

 

I run the same pistons in my build only mine are 81.5mm with pro3s so far so good but compression is very well needed using pro3s...and good head work