Is there a difference between bt and st 20v head???

[slider4life]

Hi guys reason I ask this is I have a bt 20v and I want to do my own port and polish on my head but I can't afford to have my car off the road for a long period of time. I can find silvertop heads cheap enough but I can't find a bt one. So my question is if I port polish a st head can I bolt my cams out of my bt and fit the solver top to my motor????? And is a bt head better then an st head??? Thanks guys

[Sam-Q]

so you currently have a blacktop and want to chuck a silvertop head on? if so then no

anyway look here:



also while I am normaly encouraging of people doing their own work to do anything worthwhile on a silvertop head you need an extended series carbide burr to reach down there. That's worth over $100 otherwise you might just be going backwards.

[Vance]

in short

dont bother getiing a port and polished head for a 20v since you have a bt. bt heads are already ported very well.

difference between bt and st heads mainly is the porting. angles on bt are better for NA and angles for st are better for FI. so really unless youre going turbo dont bother with a st head

[Matt]

+1 on the don't bother porting a blacktop head.....

They flow well enough as it is.

[slider4life]

well ive been told that this is my next modification to do to gain more power, at the moment i have a bt 20v runnig 272deg cams still retain vvt, rsr extractors and 21/4 exhaust,trumpets a haltech e8 computer alloy pullys toda fly wheel and that about it. it currently makes 128hp or 96rwkw and i get about 300klm to a tank. i think this power figure is a little low, what do you guys think??? and what would your next mod be for a power increase, im aiming for the 150hp+ mark staying na, ive read nearly every square inch of billzilla and he says bigger cams and head work mainly and to go bigger cams means deleting vvt

[Frak]

Considering what you have done to the engine, I think 96rwkw's is a bit low, my daily is an AE111 with minor mods and pulls exactly 100rwkw on our mainline dyno. I get around 7.2/7.4ltr/100km which means around 675km to a tank

[Vance]

it definately sounds to me like you need someone else to tune it. you should be getting that much if not more power from a standard engine with minor mods with a good tune like frak said. 300km's a tank is rediculous if its tuned. you should be atleast 150hp where you are now.


get someone else to tune it and then ask yourself these questions:

are you happy with how it is performing? do you feel like it needs a little more power or shitloads more or no more?

[Frak]

It amazes me time and time again, when I get a car on the dyno(that has been tuned else where) how badly tuned nearly ALL of them are!!! rediculous a/f's in light load, seriously 12.0:1 in light load cruise!!! The other week I saw a car which had been tuned and the guy tuning it actually rev limited the engine 2000rpm below where it should of been, when asked I said "that engine really should make good power to 7000rpm and you've limited it to 5000rpm", he said he had done thousands(yes thousands!!) and that's how he tuned them, he didn't believe in dyno's and didn't use an a/f meter....he could feel it!!!

I said to the guy that owned the car "The reason he has limited it is this, if he has the a/f and timing wrong at high rpm, it won't last long, he's trying to keep it alive cos he has no idea"

Had a car in the other week running an EMS(which I quite like) tune was SOOOO bad, we were setting a/f's/timing live and the gains were phenomenal!!

The hard thing is finding a place you are happy with.


P.S. Here's a pic of the new control desk for our engine dyno

[takai]

Jamie... want to tune my car

[slider4life]

So were would you guys recommend for my setup I will travel to Sydney if I have to farm this is the third time it been tuned wrong I hate this shit