B20 Vtec power.

**Terrano08** · 14-10-2009 01:01 PM

hey ive got a dc2 vtir with a stock engine conversion to B20B8 block and vtir head. The engine revs out to 7200 and no work has been done at all. no cold air intake, no tune, NOTHING. anyone know what kind of power this should be making and ide also like to know what revs to shift at or would anyone by any chance have a dyno sheet for this ??

**Bludger** · 14-10-2009 05:57 PM

that thing wouldn't run.

**mocchi** · 14-10-2009 06:47 PM

Originally Posted by Bludger

that thing wouldn't run.

bahahaha!!! taht thing wont runnnnnnnnnnnn vroooom!!!

**eg5civic** · 14-10-2009 06:53 PM

Originally Posted by Terrano08

by any chance have a dyno sheet for this ??

get it dyno'd?

**Chr1s** · 14-10-2009 07:01 PM

You should be sitting around the 120kw mark.

I think you mean no ECU as in, no tune? I am very worried you're running on a B18 tune, the b20 obviously needs more fuel. 7200 is pretty premature also, but keeping in mind you havn't got any decent rod bolts holding the rods together. I'd get a decent build before you regret it.

**Terrano08** · 15-10-2009 01:38 AM

Originally Posted by Chr1s

You should be sitting around the 120kw mark.

I think you mean no ECU as in, no tune? I am very worried you're running on a B18 tune, the b20 obviously needs more fuel. 7200 is pretty premature also, but keeping in mind you havn't got any decent rod bolts holding the rods together. I'd get a decent build before you regret it.

yeah i meant its not tuned. in what way would i regret it ?? it actually goes pretty good for a minimal budget build. just cant afford internals so i gotta work on little things like, CAI, tune, and how to drive it properly..

should i shift every gear at redline or somewhere else??

**Chr1s** · 15-10-2009 12:48 PM

The small rod bolts of the standard b20 were not designed to see extended RPM the combination makes. They will fail, just give it time and it won't be an easy fix if it does.

You're short shifting the motor, I guarantee you that your power curve will continue to peak past 7200rpm yet you can't take advantage of it as the bottom end is not strong enough.

I'm not saying you can't spin it harder, or the moment you do a rod will decide to have a go at the bore, but it can happen.

**string** · 15-10-2009 02:06 PM

Originally Posted by Chr1s

The small rod bolts of the standard b20 were not designed to see extended RPM and power the combination makes.

Why would increased power contribute to rod bolt failure? Extra downwards force on the piston doesn't make the bolts work harder to hold the cap on - the force is in the wrong direction.

**GSi_PSi** · 15-10-2009 02:42 PM

7200 is pretty gay lol.. if it is indeed stock bottom end (ie stock rod bolts), be very very carefull, otherwise thrash it and rebuild cause if your planning on revving out this motor its not going to last long.

**Chr1s** · 16-10-2009 10:52 AM

Originally Posted by string

Why would increased power contribute to rod bolt failure? Extra downwards force on the piston doesn't make the bolts work harder to hold the cap on - the force is in the wrong direction.

Nicely noticed. Either way, I wouldn't skimp on replacing them.

**e240** · 16-10-2009 11:05 AM

Originally Posted by string

Why would increased power contribute to rod bolt failure? Extra downwards force on the piston doesn't make the bolts work harder to hold the cap on - the force is in the wrong direction.

I don't think that thats the correct way of looking at this though because it isn't just a push pull force but also a rotational force as the rod moves with the crankshaft. The top of the rod supports the piston, "added weight", the rod (and ultimately the bolts) are supporting this load whether the piston is going up or down - and there's never a "straight down" force applied except when the piston is TDC right? The rods are almost always at an angle.

**tinkerbell** · 16-10-2009 12:24 PM

Originally Posted by string

Why would increased power contribute to rod bolt failure? Extra downwards force on the piston doesn't make the bolts work harder to hold the cap on - the force is in the wrong direction.

the force never changes direction does it?

or the caps and bolts are weightless and don't have inertia?

now i have heard everything!