I am running a gsr block b16 head. I rebuilt the bottom end and installed ctr pistons. i have driven it about 150 miles. I got on it once and it felt considerably slower then before. (stock bottom end with worn rings). i havent done a compression test yet but will the motor slowly get stronger through the break in process?

I raced my buddies si before the rebuild and beat him by a car and a half after the rebuild he beat me by 2 cars!!! WTF!!!!

 

is the car tuned or still running off the gsr map ?

 

check the timing

 

it is a chipped ecu with a Type r basemap.

i know it isnt tuned but my buddy had the smae setup awhile ago and his car would run really well. Will the timing really affect it that much?

 

Are you serious?

Check the timing with a timing light or take it to some one that has a timing light and knows what they are doing with a honda.

If you can't get the timing in sync by moving the dizzy then chances are your cam timing is not in sync. And this will cause the car to run rather horribly.

Oh.. btw get the car tuned if everything else checks out. Who knows what is actually on the "type R" basemap.

 

You do realize what those Type R pistons did to your compression, right? With the B16 head on the car your looking at 12.7:1. Thats assuming no milling/decking. I don't think there are many "basemaps" that are going to run correctly with those levels. Your probably detonating and the knock sensor is pulling so much timing its pointless. Why the hell would you put those pistons in that engine?

 

^cause there hype R, DUHHHH

 

the cr is not that high. check your sources.....

 

People told me that my compresion is in the 12.1s. I have a b18c1 block, gsr crank, gsr rods with usdm itr pistons. Stock unmolested gsr head. So what is the real compresion.
I want to know once and for all.

Sorry if i kinda interupted but i am currious to find out myself.

 

The only way to know your actual compression ratio is to measure it with a burette.

 

I will go and google what that stands for.
Done
A burette (also buret) is a vertical cylindrical piece of laboratory glassware with a volumetric graduation on its full length and a precision tap, or stopcock, on the bottom. It is used to dispense known amounts of a liquid reagent in experiments for which such precision is necessary, such as a titration experiment. Burettes are extremely accurate - a 50 cm3 burette has a tolerance of 0.1 cm3 (class B) or 0.06 cm3 (class A).

Burettes measure from the top since they are used to measure liquids dispensed out the bottom. The difference between starting and final volume is the amount dispensed

 

Yes, if you do not actually measure the compression ratio, you are just guessing. I remember 20 years ago every meathead building American V8's had their engine CC'ed (compression ratio measured with a burette). Why is it that nobody does this anymore?

 

Because theres alot of compresion calculators online today. Just punch in a couple numbers and bwala. U get ure compresion ratio. I have no idea on how to use those calculators.

 

But a calculator does not measure anything. There is too much variation between parts for those to be any accurate. Has anyone ever used the calculator *and* measured their exact compression ratio? What was the result?

 

i guess some ppl became comfy with round about numbers rather then exact numbers these days

 

hahahah gsr block b16 head and ctr's depending on headgasket and head milling it will be between 12.7 and 13:1

stock head no milling with ctr pistons its 12.7:1

if its milled 10k its 13.15:1

if hes running on a type r map, that motor is running like **** i guarantee it

to the other guy who is running itr pistons, your compression is below 12.1

depending on usdm or jdm itr's your between 11.1 and 11.7 also depending on if your head has been milled or not


haha i still laugh gsr with b16 head on pct's with itr tune :shakes head: go get that **** tuned asap before you fukin blow it up

 

In my GSR I also have USDM ITR pistons. The head has been milled and the block decked. Combustion chambers CC's. I am between 11.5:1 and 11.6:1.
Calculators can get you close you will need to measure to get it right.

 

QFT x 2.

 

Oh really? You know im a little more educated then you must think. First of all, I will advise you that the compression height on a CTR piston is NOT THE SAME as it is for the stock GSR pistons. With this in mind, YOU can now go "check your sources".. Once you figure out the correct data to use, come back and tell me I am wrong once again.

Online compression calculators are only as good as the information you put into them. I made this same mistake a long long time ago and had to learn things the hard way.

 

are you stupid?

12.7 isn't high?

Considering 12.5 is pushing the limits of pump gas, unless your tuned, your really in another world..

I run 12.8CR on mine, but my car, is tuned, very well, at full and partial throttle..

one lean spot, could melt a piston specially CTR's which are garbage in the first place.
Why would you rebuild?? With ctrs.. that piston is entirely too heavy, and no tot mention it distorts the flame front and it doesn't allow for proper combustion..
i wish people would read, ctr pistons aren't good.

 

Does everyone still think that cr is what makes power? I see these threads all the time and im still amazed that they still pop up all the time.

I just finished a gsr with 10:1 cr, Brian Crower stage 3 cams, ported head and a skunk2 manifold and its making 230 whp after the tune. It brakes 200 whp by 7000 rpm and 150 wtq by 4500 rpm.

Same cams in a motor with ctr pistons made less than 200 whp on the same dyno.

Tuning is more than just a/f. Timing, vtec crossover, cam gears can affect the power band.

I really get tired of seeing this posts. Thats why alot of good builders and tuners stop posting.

 

umm you should re read that

he said its not that high . as in the compression ratio is not that high with ctr piston

 

I think I would agree on this but more along the lines of "why is it so important that you know your compression ratio if you don't even know why the compression ratio is important?". Your static compression ratio is just one part of a million different things that all come together to make power. Compression ratio is definitely one of those things where more is not always better.

 

Did anyone else realize he knows his car is running like crap, has less than 150 miles on a rebuild, and doesn't know what the issue is yet; but still he's raced his buddy already....?

"I got on it once" ........ "He beat me by two cars!!! WTF!!"

WTF is right! This is why I do not post on here that much...



Typically the engine does get stronger as the break-in process is finished. But if you blow it up before you finish breaking it in you become another ricer statistic. GL

 

to the other guy who is running itr pistons, your compression is below 12.1

depending on usdm or jdm itr's your between 11.1 and 11.7 also depending on if your head has been milled or not

Ok so its for shure 11.1. My head is stock unmolested head. Thge reason why i want to know so bad what my CR is. So i can get the right cams later on.
Thanks