Hey all, we finally got the 540 burban tuned on the dyno with the ported / modified stock intake manifold and 80mm throttle body. 22hp/0ft-lbs was picked up at peak, but the power gained throughout the power band more than makes up for the minimal peak gains.

So we're as clear as possible, the "baseline" for the 540 is: K&N intake, stock throttle body, mild porting on stock iron heads, 203 camshaft, roller rockers, iron head spring kit, JBA "shorty" headers, cats, spintech 8000

The intake run has the ported / modified stock intake manifold and 80mm throttle body with all of the above modifications.



Thoughts, comments, demands for video (its coming soon) are appreciated!

 

Are those numbers rear wheel or crank as the dyno sheet shows? Any update on that new intake you guys are producing?

 

It's pretty amazing to me that even with head work and a cam this engine makes more torque at 2000 RPM than 4000 RPM

 

Those are crank numbers. Rear wheel was 335HP/470TRQ (stock rear wheel output on a factory 8.1L is 261HP/358TRQ according to Hypertech).

We're in the process of redesigning the new manifold. It produces great power on the top end, but low end power was lacking compared to the Cool Gap manifold with its longer runners. We're going to add more runner length and give it another go. On the upshot, the base plate (2 piece design) will make for a great template for hot rod style stack injection like the old HO750 used to have.



What you're seeing here is the stock heads restricting upper RPM power output. If you compare Truck stage 2 - which is basically what the 540 kit has (minus aluminum heads) you can see the extreme difference in power band between the iron heads and our aluminum heads. The stock iron heads flow about 288CFM intake / 180CFM exhaust at .530 lift whereas the aluminum heads are moving around 335CFM intake / 235CFM exhaust.

Also, keep in mind the extra 50 cubes that the 4.75 stroke kit adds will tend to make this engine a bit more torquey as well as make the 203 cam act a little bit more like the 202 high torque cam because of the extra cylinder volume. Based on how "boringly" stock-like driveable the suburban is, we figure that the BP-206 will be the hot street choice for the 540 kit and the 203/205 cams will serve more for torquey, low to mid-range applications.

 

When do you guys plan on putting the aluminum heads on it? Really interested to see the difference

 

We've got an extra set of aluminum cylinder heads at the shop but they probably won't go on the 540 till July or August. We're planning to put a BP205 cam in at the same time. The 205 is the same duration/lobe separation as 203 cam, but .600+ lift to take advantage of the head flow.

 

nice!!

 

IF i wasnt getting out of the army sooner then i expected would of already ordered a set of heads.

 

got any pictures of the "burban" ?

 

I vote Twins!!! :-)