Wow is all I can say 206hp NA

[nw_guy4_fun]

This is what I call pushing the envelope. 206hp NA no adders
I have sung the virtues of IR for a long time suggesting two front heads and leave it to these guys to get it on!
It works obviously.
http://www.starracing.com/photos.php
Look at the 145" Silver Dyna

[Nitram_b4]

Fine work in every aspect

[Totenkopf]

That's about 1.42hp/cu.in. This is about the same as TXChop's 117 hp/cu.in. by the way. Just about the limit for the street. Our NA race motors are up in the 1.6+hp/cu.in. range, unstreetable though due to heat buildup.

[nw_guy4_fun]

How true, I think the significant development over the last several years is these things are now streetable and the power levels, useable, are rising, finally. Plus all the stroke, piston speed rod length issues are there but still the power levels are very high. The constraint of course is cooling. I don't see all that much complexity (well at least in my minds eye bench racing) building a circuit to cool the heads by oil as done on the XR1200.

[Totenkopf]

Independent intake runners on these is a real advantage on being able to tune to the pulses without shared intake crosstalk.

Otto did a dual supercharger alcohol drag bike where the front and rear heads were swapped, allowing for intake independence and driving two roots blowers. A call to John Andrews, to get the cam adjusted and then off to the races. Overcoming throttle break was a problem though.

[bowtech40]

So would BC Gerolomy`s dual runner intake be an advantage over a regular TB then? I always wanted to try one, but they only make it for 06 and older unless you convert all kinds of wires.

[nw_guy4_fun]

Dewey used to use them on the all bore 107" when Grock was involved and it worked well but that said today I would pass. Difficult to integrate with the Delphi plus the TB is too small, our motors grew up and an IR setup needs a much more throttle area to equal the airflow of a shared runner setup. IME I found on the motors I built they needed 1:1 or higher TB size in mm per cu/in. I used up to 1.6 but that was a 8000 rpm motor (2 liter Ford SOHC Dual Weber 48DCOE)

Those guys at Star Racing did two front heads for a reason, real estate plus the ability to package better and not interfere with the rider in a street situation. Plus this configuration gives the ability to wave pulse tune by changing manifold lengths. What I don't understand why they didn't go rearward, air likes a straight path ya know, similar to the XR750 configuration.

[Totenkopf]

Originally Posted by nw_guy4_fun

<snip>

Those guys at Star Racing did two front heads for a reason, real estate plus the ability to package better and not interfere with the rider in a street situation. Plus this configuration gives the ability to wave pulse tune by changing manifold lengths. What I don't understand why they didn't go rearward, air likes a straight path ya know, similar to the XR750 configuration.

yeah, I would also like to have seen that too.

[Knighty-Knight]

According to George Bryce, the next iteration will use two rear heads.

[Troy L]

dyno sheet for 145

[Knighty-Knight]

Originally Posted by nw_guy4_fun

building a circuit to cool the heads by oil as done on the XR1200.

Hi Don, I haven't been able to find a picture of this cooling system, do you happen to have one kicking around?

[pwmorris]

Awsome motor-
-145's out of the box 170 HP give or take (with pretty much any fuel delivery/intake system).

-Sammy Bonner's similar 145" with the Star upgrade with a single "D" carb=206 HP.

I love the IR's for the cool effect and the direct injection. With FI they flat out work, delivering perfect AF ratio's and incredibly crisp throttle response; but they in and of themselves aren't what is making the big power on this beast.

Anyone want to guess the CR of this motor?

[No Cents]

15:1 ?
Just guessing.

No Cents

[Troy L]

it sure sounds thunderous ( we call it dynamite in the pipes out here in Vegas )
also guessing 14:1 or 15:1 ...

[hdrider82]

wow,,, way cool,,, by a nates a$$ i tip 100 hp. i can't imagine turning the handle on that one. is it streetable????? two front heads... 14/15:1. what do they run for fuel. dark beer??? lol