PhatBoy5015

If the compression on a GSR motor was lowered to 8.5 and boosted, would it still be able to rev to 8100 safely?

anony95ex

That depends on many variables...

Heylookits shawn

yes


- assuming all correct parts were used

PhatBoy5015

Variable such as...? If the entire motor was completely stock but it was boosted and the compression was dropped, would it be able to then?

Jay_Sensing

Redline is in no way based on compression of the motor man.

It is based on valve train. If your springs don't have enough seat pressure, you will get valve float which causes valves to meet pistons. The other portion is RPM range for the cams. If you have a fully built valvetrain but stock cams, you are making no more power revving higher becuase you are out of the range of the cams and just making noise so in effect, no.

EGmikeH22

okay smarty pants, if the entire motor is completely stock, how is the compression changed and how is it boosted.

sometimes i think people say stock when it says honda on the title....

Luserkid

If the motor was built correctly then you should be fine at 8100. Although you could probably go higher if its built. But only thing to tell you that is a dyno and a tuner.

PhatBoy5015

when i said stock, i meant it had stock head and block but a thicker head gasket. (therefore the compression is lower) But the motor being still completely stock. OK smarty pants.

EGmikeH22

okay a turbo honda engine with lowered compression is not stock man.. but i know what you mean..

there should be some kind of a term for "stock shortblock and valvetrain", i'd use "not built" or something, but stock is something you'd see in a showroom, not a turbo GSR in a civic with head studs and lower compression.

come on....

but to answer the question, the valvetrain and cam profile are what decide a good place to shift. A higher shift point doesn't really matter, its just whose engine makes power where, and how good are they at getting there and staying there while racing, **** if my engine got the most power at 1200 RPM i'd be the first ****** out there with 33s on my civic.

revving ultra high is pointless...

shamoo

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by PhatBoy5015 &raquo;</TD></TR><TR><TD CLASS="quote">when i said stock, i meant it had stock head and block but a thicker head gasket. (therefore the compression is lower) But the motor being still completely stock. OK smarty pants.</TD></TR></TABLE>

Anytime there is a change in static compression due to a thicker head gasket, lower compression pistons, etc, combustion characteristics will change. Honda engineers have modified the ECU to have as much a perfect (as much as they can with technology today) combustion as possible given the stock compression numbers, spark delivery, fuel delivery, etc.

Any time you change that, and the combustion specs will be different. This may or may not have an effect on performance depending on how you handle these changes. If you're boosting, you should be especially aware how important tuning is. Tuning will take away most of the negative side effects of modifying the engine out of OEM Honda specs, but it will NEVER be exactly the same.

Once you handle these changes accordingly, then the reliability won't be affected. Thus redline can be the same (or even higher, depending on what the application is).