I'm not really that impressed. The increase is good, but the overall power sucks.
I have a b20Z with a P8R head (33mm intake valves), Crower 403's and upgraded valvetrain, Comptech header, Thermal 2.25 exhaust, AEM CAI, Skunk2 IM

The redline was raised to 7500

Here are some pics:





What do you guys think?

 

I don't see how the hell a B20 can only have 109 torque What type of dyno is this on?

 

Mustang Dyno

 

torque seems way low

 

numbers from Mustang dyno's are hard to compare to DynaPack, Dyno Dynamics, or Dynojet numbers. Why not just pay for a base line on a different Dyno?

 

Was the p8r head already on the motor before or did you just add it?I have never seen a p8r head in person and don't know the chamber's cc size but I would think it's bigger them the regular ls heads that have an 81mm bore chamber vs your 84 mm bore chamber.You may have lowered the compression to the point it hurt power esp torque.

 

yah something isnt right with the setup because i made 105tq on a mustang dyno with a D16. i would think with that 2.0 block you would be seeing much better TQ numbers at least.

 

Torqur does seem low. However your power doesnt look bad for 403's and no raise in compression. Bump up the compression and you should see gains. Also 404's make way more power than 403's.

The P8R heads have a 47cc combustion chamber as to to the normal head is 45cc.

Seriously if you think about it you are at 8.8:1 CR right now, so if you bump it up to 11.0:1 + and add 404's you will see big gains! You have bigger Intake valves, take advantage of them.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by hybrid_vtec &raquo;</TD></TR><TR><TD CLASS="quote">Torqur does seem low. However your power doesnt look bad for 403's and no raise in compression. Bump up the compression and you should see gains. Also 404's make way more power than 403's.

The P8R heads have a 47cc combustion chamber as to to the normal head is 45cc.

Seriously if you think about it you are at 8.8:1 CR right now, so if you bump it up to 11.0:1 + and add 404's you will see big gains! You have bigger Intake valves, take advantage of them.</TD></TR></TABLE>


ONce again the nonvtec guru speaks.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by hybrid_vtec &raquo;</TD></TR><TR><TD CLASS="quote">The P8R heads have a 47cc combustion chamber as to to the normal head is 45cc.</TD></TR></TABLE>Ahh I see,thank you that rules my theory out.

 

so I took it to the track today and ran a 15.325 at 90.197 mph

compared to a 15.268 I ran before the new head, Crower 403s and tuning

------------

the only good news is that I am more consistently running 15.3s

The mph are a little higher than normal (which shows potential)

Bad news: I can't get my 60ft times any lower than 2.2, I think its just the camber problem

 

How do you expect those allmotor cams to make ANY kind of power with an 8:8 c/r? Bump the c/r and you will see NICE gains.

 

i agree you need more compression to see the gains you are looking for

 

I share the same sentiment, CR too low.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by hybrid_vtec &raquo;</TD></TR><TR><TD CLASS="quote">

Seriously if you think about it you are at 8.8:1 CR right now, so if you bump it up to 11.0:1 + and add 404's you will see big gains! You have bigger Intake valves, take advantage of them.</TD></TR></TABLE>

I thought the B20Z had higher comp that 8.8?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by hybrid_vtec &raquo;</TD></TR><TR><TD CLASS="quote">
The P8R heads have a 47cc combustion chamber as to to the normal head is 45cc.

Seriously if you think about it you are at 8.8:1 CR right now....</TD></TR></TABLE>

Bigger combustion chamber drops CR.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by RagingAngel &raquo;</TD></TR><TR><TD CLASS="quote">

Bigger combustion chamber drops CR.

</TD></TR></TABLE>

I am aware of this, but is 2cc that much of a comp drop?

 

you're right...

it should still be about 9.3:1 ish with the B20Z pistons and a OEM 3 layer gasket. vs. 9.6:1 on the 45cc chamber.

Irregardless, it's still pretty low for a performance cam.... it should at the very least be 10:1....

 

If you think about it, JDM B16'S are 10.2-10.4 depending on which generation were talking. And even with 10.4, your still not getting all the power you COULD get out of stage1 cams or even typeR cams.

I know were not talking about a vtec motor but the concept is the same. Aggressive cams need high compression to maximize performance gains.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Vtaaak y0 &raquo;</TD></TR><TR><TD CLASS="quote">

I thought the B20Z had higher comp that 8.8? </TD></TR></TABLE>

You're right, B20Z is 9.6:1. My bad!


<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Mag00n &raquo;</TD></TR><TR><TD CLASS="quote">If you think about it, JDM B16'S are 10.2-10.4 depending on which generation were talking. And even with 10.4, your still not getting all the power you COULD get out of stage1 cams or even typeR cams.

I know were not talking about a vtec motor but the concept is the same. Aggressive cams need high compression to maximize performance gains.</TD></TR></TABLE>

You can only go so high with compression until it begins to hurt your performance and gains become minimal. Also it will put tons of stress on the motor b/c it will be working against the compression and cause the motor to be less reliable.

If it is for the street, choose something reasonable that will match the cam. Calculate for Dynamic Compression Ratio rather than static. This way you will know your real CR for the setup you choose to run

 

before i put my 404s in i plan on raising the compression... you ran a 15.2? i ran a 15.1 with a stock B20Z in my hatch.. i hope my 404s ran better than that.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by hybrid_vtec &raquo;</TD></TR><TR><TD CLASS="quote">

You're right, B20Z is 9.6:1. My bad!


You can only go so high with compression until it begins to hurt your performance and gains become minimal. Also it will put tons of stress on the motor b/c it will be working against the compression and cause the motor to be less reliable.

If it is for the street, choose something reasonable that will match the cam. Calculate for Dynamic Compression Ratio rather than static. This way you will know your real CR for the setup you choose to run</TD></TR></TABLE>

How do you calculate for dynamic compression ratio? Yeah I searched, any links?

 

http://www.rbracing-rsr.com/comprAdvHD.htm

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by hybrid_vtec &raquo;</TD></TR><TR><TD CLASS="quote">

You can only go so high with compression until it begins to hurt your performance and gains become minimal. Also it will put tons of stress on the motor b/c it will be working against the compression and cause the motor to be less reliable.

If it is for the street, choose something reasonable that will match the cam. Calculate for Dynamic Compression Ratio rather than static. This way you will know your real CR for the setup you choose to run</TD></TR></TABLE>

Im aware of that, i never told him to go crazy, i told him that 8.8 or 9.3 or whatever the hell hes running is not enough to match his cam choice.....

Dont forget tuning too...

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Mag00n &raquo;</TD></TR><TR><TD CLASS="quote">

Im aware of that, i never told him to go crazy, i told him that 8.8 or 9.3 or whatever the hell hes running is not enough to match his cam choice.....

Dont forget tuning too...</TD></TR></TABLE>



I think 11.4:1 Pistons Endyne offers would be great for him.