Harrop supercharger

[bolus]

You should leave the firewall off so you can hear the supercharger better and show it off at the same time:)

[silver]

if it was left off it would sure increase the airflow to the engine hmmmmmmmmmmmmmmmmm

[NormLarson]

Don't worry, I would personally block all off the air (I'm kind of a big guy)

[NormLarson]

What compression are those that have changed pistons running and why? If I remember correctly, the stock compression is fairly high for a supercharged engine.  My opportunity to specify a different ratio  is rapidly approaching.  Tom is busy in Oregon finishing bracketry and other stuff on my car.  When he is done with that he will pull the head off and extract the stock pistons and mic the wrist pins.  According to Chevy there are two sizes of wrist pins 20 and 23 mm.  We cannot order until we know.  Thoughts?

[Heywood-Yablowme]

I would do 10.5-1  and sleep just fine. Not sure about wrist pin size on the stock rods.Chevy should know...

[NormLarson]

Mark, do you know what the stock ratio is?

[Heywood-Yablowme]

9.5-1

[bolus]

Before going turbo, Darth went to 10.5:1 in his car.  I have 10:1 in my car.  with the right tune and cooling you should have no problems running the higher compression. 

[NormLarson]

I guess my thinking is old skool ... I am under the belief that you lower compression to add boost.  I do understand the points regarding the better cooling that is provided now and there is always the fact that the Harrop is supposed to be more efficient.  It is opposite of what we used to do.

[bolus]

Remember the hondas have 11:1

I am pushing my HP without even using water injection at this point.  Even my engine builder said I would explode without race fuel, methanol and supercooling.    it was fun to drive up and tell him and he just went "huh, how about that"

[Speedytec]

Finally some European tuners also start working with this better supercharger.
How about this power curve for a Harrop'd 2,2 Ecotec in a VX220/Speedster.  (=850kg rwd Lotus Elise clone.)
(standard 10:1 compression)
[img width=775 height=600]http://www.courtenaysport.co.uk/images/SpeedsterSC.jpg[/img]

See: http://www.vx220.org.uk/forums/index.ph ... opic=74322

[silver]

is this bhp or whp?

[bolus]

BHP,  305-310 WHP

[Heywood-Yablowme]

I would be very happy with that hp/tq curve in my car.  They only took it to 7k too! Hmm..

[silver]

why is it that some people try to reverse the math to show engine hp/tq....I'm sure this dyno was done on a chassis dyno, it would be much more "equal" to have the actual dyno numbers from the chassis

who knows the dyno guy could have started with 280hp, and just calculated a 20% loss instead of starting with 300hp and assuming 15% drivetrain loss.


To me if this is manipulated like that it's a worthless dyno chart