Curious on what people opinions are with my set up. I bought my car with a b16b swap. It was built with eagle rods, arp head studs, and nippon high compression pistons. After the original owner did this he sold it to the guy I bought it from and that guy started to turbo it. I bought it mid process and just finished the turbo set up on it. My question is how good will the high compression pistons be with a turbo? I only plan on running like 7 or 8lbs and hope to be around 300-325 hp. But I’m worried that the b16b is already high compression and now it has even higher compression pistons.....

 

what compression ratio is the motor now? Anything 10.1 and under will be fine running 93 pump gas, while anything above that I would recommend running e85 or using a very good tuner

 

What compression is the engine at? I *hope* you took the time to find that info out. Lol!

 

OP, are you sure about some of those engine specs ? I don't remember Eagle offering a B16B connecting rod... and they do not show one in their catalog now.

 

I noticed the same thing. They never have had that offering for a B16B. So, unless there were some changes like the crankshaft, there's further information to be investigated. "High" compression doesn't get that high until you're getting into the 11.0:1 territory and you're using lower-knock resistant fuel.

Even at 10.4:1, you're fine as long as the tuning is solid (but I would say that regardless of the static compression ratio of the engine).

So, More information from the OP, please. And do your research to be sure you know what you're giving out.

 

I’m not sure what the compression ratio is. That’s my problem. And what I posted is what I was told it had done to it. Whether it’s true or not I really don’t know. I found out who the original owner was who did the b16b swap and he said that’s what was done. I believe they were in The motor because you can see some etc gasket maker coming out in some spots. The motor seems to be very healthy and run nicely. As far as idle and small revs. I haven’t driven it yet. So is there no easy way to find out the compression ratio? I’m a paint and body guy so I don’t know it all when it comes to the mechanicals. I’m ok with most stuff just not the technical engine side if things. That’s why I’m here asking for help and opinions.

 

This is what I found is that the motor is already 10:8:1 so if the previous owner did have nippon high compression pistons in it then I don’t know what it would be at now

 

This was the info on the original add when I bought the car

This is the message I got from the guy who built it.

 

So what you're saying, basically, is somebody sold the dude you bought the car from and he said they said that it had (fill in the blank) done? Ok. Full disclosure, you need to treat it as stock at this point. The B16B is a good engine; stock compression close to 11:1, high revving bugger. If they claimed to have added "high compression" pistons, chances are they put **** in that actually, and probably, lowered it. Lol! Most marketed "high compression" pistons are usually 10.5-11:1.

 

Thanks for the reply and I actually talked to the guy who built it on the phone and he said he built it like a year ago and put about 12k miles on it while he had it. Then sold it to who I bought it from and that guy never drove it. He just started to turbo it and only got halfway done with installing the kit. I now have it and am trying to figure out how to finish it correctly. I bought hondata s300 for it and installed some gauges like boost, oil pressure, fuel pressure, water temp, and a wideband. I bought bigger injectors for it and built an exhaust. I still need to upgrade the map sensor and fuel pump.

 

pictures are always helpful so we see what is there and potentially where you may improve.

 

Thes me aren’t the best pics but I can take some more current ones later

 

My guess (and that's all it is...take it for what it's worth) is that they rebuilt the engine with what Nippon is calling their high compression piston. From my 5 minutes of research, Nippon modeled this piston after the B16B pistons, made some small tweaks, and offered them in the 81+mm range as well as the 84+mm range to fit B18 blocks. These pistons would be considered high compression in a B18 block, however in the B16B, the would be equivalent to OEM compression specifications. Obviously other factors play into the compression ratio of your specific engine like what thickness head gasket was used, how much have the head and block deck been milled, rod length, etc. I would think think if a normal HG was used, not a lot of milling was performed, and B16B rods (142.3mm length) were used, you will be around 10.9:1 - 11.0:1 CR. I'm making a LOT of assumptions to come up with these numbers...assumptions I may not be comfortable making were this my own personal engine that was about to get a turbo slapped on it.

Now, to your question about how the (assumed) compression ratio will behave with the turbo. I'm not a wizzard and have not had a turbocharged Honda with that high of compression, but from what I understand that is about as high as you would want to run compression on a turbo setup. Make sure you have a good tuner - your timing curves can make or break your setup. What fuel will you be running? Higher compression will be much more responsive out of boost and make more power with less boost, but your are closer to the detonation threshold.

 

I’ve searched a little about the nippon pistons but never came across that info. I honestly hope that is the case and they are just stock compression. I could always put a thicker head gasket on it if I have to. And I found a tuner that feels very confident about being able to tune it right. I’m going to be running 93 octane but I was also only planning on running like 5 to 7 lbs of boost on a t3/t4 .63 turbo. Hoping with that amount of boost I can get around 280 horse without pushing the motor too hard. I just want a fun conservative tune and I’ve always wanted a turbo civic so I’ll be happy enough with that. I don’t need an all out race car. I don’t need to be the fastest car in town either lol

 

You’ll be alright with that low of boost/horsepower goals even if it is 11.0:1 compression ratio with a good tune. Meaning retard the timing at least half of a degree to one degree per pound of boost. Might as well retard the timing about 3 degrees overall. Make sure you listen for predetonation of the air/fuel mix. You could get an exhaust gas temperature gauge to monitor for too high of exhaust temperatures. I’m not sure the temperatures you are looking for, you need to look that up. But even if they put 12:1 compression pistons in it, which they might have meant to stay all motor at first, but then I’m not sure why the second guy would start a turbo kit if it was an all motor build...you could still safely turbo the car with 12:1 and get to the 280 hp goal. Just retard the timing, go with 11.0 or 11.5:1 air fuel ratio, and monitor the exhaust gas temps for unusually high temperatures. If you see high exhaust temperatures, then stop the tune, and install a thicker head gasket, then go back to tune it later with a lower compression ratio.
There is no way to find out your compression ratio without knowing what parts are in it. However, you could compression test each of your cylinders, and usually higher compression engines have more compression on a compression test. I’d guess your compression is around 195-200 psi in a compression test, but that’s just a guess. And you can look up typical compression for a b16b, or a b18c5, and you could base that against your results.

 

Find someone with cylinder camera and take some photos of the pistons before you do anything over 5 psi.

 

Ok thanks! I am planning on getting an exhaust temp gauge next. I just hooked up boost, oil pressure, water temp and a wideband. I’ve heard that the exhaust temp is pretty good to know too. I tried to do a compression test this last weekend but I was getting a slow crank and low numbers on it. Like 95 across the board... I Just put a new starter in it today and am going to clean up some grounds and try the compression test again soon on it.

 

That depends upon what wheels are in the turbocharger. What you've just stated were simply housing sizes and nothing to do with the compressor/exhaust wheel airflow conversion capabilities, so stating a boost pressure threshold doesn't mean much.

You really need to know what you're installing. Get those housing apart and start measuring wheels, in millimeters..

 

You'll never convert us! Merica!

 

And we're wondering why International Trade deals never go in our favor when it comes to manufacturing. 'Murica-thinkin' keeps people from workin'.! :-(

 

We won our independence from England and just look what we've done with it.. lol

 

Yeah......

 

As an engineer, I absolutely love the metric system and can't believe we're still dealing in fractions in this country. The resistance to change in this sense is mind boggling.

 

I like the metric system as well. I work in a chemical plant that is German owned and we use metric units for our instruments.

 

I completely concur