01-0720

everybody always says turbo r motor are a waste the compression is to high , bahh its barely higher than a gsr usdm itr motors are like 10-5-1 or somthin an the gsr is 10-2-1 or some crap now if one was to have a r motor an put a drag kit some 440s hondata 2b and other little things that be a good motor correct

SlowB16

I wouldnt do it because the R motor is meant for the road. A track car. I think people value that motor a little more than the others as well, after all it is the baddest of the VTEC engines. Plus, the compression is higher, and the higher the compression, the more you want to stay away from boost. But if I had one....Id do it!!

2K_TEG

The type R was built to be a high compression engine. Once you take that away you basically have a b18c1 with a nicer head. The money spent to get the c5 could better be spent on some sleeves, forged internals for a c1. If I had unlimited funds I would turbo a type R, but in the real world it is just cheaper to use a gsr motor. If i had a type r though, I wouldn't swap out the motor, I would get some forged internals though.

Also, there are a lot more Lses, Gsrs so of course there will be more of these with turbo.

intekragsr

well wouldnt boosting a higher comp motor make more power? It just takes ***** and mad tuning to get it running safe.

rioninja

Well, i have a second gen JDM B16a in my car right now, and i'm boosting to 5psi currently with NO INTERCOOLER as of yet. The 2nd gen B16as have 10.5:1 compression, similar to the typer. Its all about supplying enough fuel. Go to:http://www.smokemup.com/utilities/calc.cfm
Mostly domestic, but a great resource of info/calculations. Check out the portion on effective compression ratio.
I'm using the vafc mod, and have not had so much as a hint of detonation so far.
I know i already said it, but ITS ALL ABOUT SUPPLYING ENOUGH FUEL.
10 psi on a 10:1 compression motor will yield a much higher 'effective compression ratio' than 10 psi on a 9:1 motor.
Some people will say "10 psi is safer on the lower compression motor". This is only partly true, there is nothing unsafe about fairly high boost on a high compression motor, your just gonna need more fuel.
Of course there gets a point when pump gas isn't gonna cut it anymore, once a high enough ECR is reached.

dustin

You can only "tune" so far until you reach fuel octane limits. If we all could run around on C16 all day ..

dustin

Well, honestly, for serious boost situations... you want a lower compression ratio... and here's why.

You make power by burning fuel. So lets pick a magic dynamic compression ratio say 20:1 or whatever.

Now with raised static compression (your 10.5:1 or whatever) and X amount of boost, you achive this 20:1 dynamic compression ratio. In a motor with reduced static compression ratio, obviously the dynamic compression will be lower than 20:1 at the same boost level. You can compensate for this by raising the boost to the point where dynamic compression is equal. However, when you add boost, YOU ADD FUEL. Burning more fuel = more bhp.

Note that 20:1 is just an example, and you would need some insanely high octane fuel to pull this off (like C16)... heh.

I was going to run 10.0:1 comp. JE pistons in my GSR, but after researching the serious limits of california 91 octane, I just won't be able to get to my hp goals without lower static compression. These pistons are going in my daily driver LS and I'm either getting 9.0:1 or 9.5:1 pistons for my B18C.

Dustin

dustin

Also realize that that "Effective compression ratio" thing is pretty bogus. All it does is:

static compression ratio * ((boost in psi / 14.7) + 1)

or

static compression ratio + ((boost in psi * static compression ratio) / 14.7)

Heh.

Dustin

Reid

Second gen B16s have a compression ratio of 10.4:1, close to an ITR's but not quite. JDM B18C GSR engines have 10.6:1 compression ratios.

intekragsr

ok dustin, i would understand you 100 percent if i knew the difference between static compression and dynamic compression. Thanks

dustin

Hmm static compression is the difference in combustion chamber volume from when the piston is at BDC to when it is at TDC.

Dynamic compression (in the sense we are using it) takes atmospheric issues/pressure into account. If you force twice the mixture into the same space, you have double the "dynamic compression". Of course there are many more factors that influence dynamic compression (cam overlap, temperature, etc) so this is an oversimplification.

Dustin

rioninja

Your right, but close enough

and to dustin for the info. Your 100% correct, all i was trying to get across is that its not absolutly unsafe to boost a higher compression motor like most people will tell you.

dustin

I agree. for low boost levels, by all means use decent compression for the sake of daily driving.

Brian_92GSR

With a 9:1 compression ratio, what are the limits boost wise of 93 octane gas? I'm asking in regard to a fully built GSR motor. With proper tuning (hondata), what's the general area for max psi?

espanol

doesn't lisa kubo use high compression pistons in a b16a...? i don't know..just something i heard>

intekragsr

Ok got ya. I just ordered my drag 3 and hondata 2b and other little fuel goodies. So since it has been said that my gsr compression is too high, should I simply get an inline pro head gasket to lower it? Or since I am getting it tuned, it wont be necessary? I am also under the impression that I need adjustable cam gears to fit the headgasket. Please correct me if I am wrong in any of my statements.

Oh yea, I will be getting a built block from importbuilders.com in about 4 months.


[Modified by intekragsr, 8:02 AM 4/12/2002]

SIK IN DA HED

am i the only one who doesnt know what the hell dustin is talkin about? hehe i think ive corrupted my brain with too much knowledge from this forum.

bigTom

the reason the motor is a "waste" is simply because the itr motor is basically a 5k motor... considering ull be building it... y not start off with a gsr motor for around 3k? in the end u will swap out all the internals so all that extra money for the itr motor is a "waste" when u'll throw it all away anyway! i guess some people like it for the ooooooo aaaaaah factor that its a b18c5.... BFD!