Sign in to follow this  
Followers 0

HKS 700E performance

29 posts in this topic

Posted (edited)

I'm putting an HKS with a 3.47 gearbox and a 71" Kiev prop in my Kitfox. There are a (very) few planes flying with that combination and reporting OK performance (SkyRanger, Avid, Super Koala). Frankly, I got the engine very cheap otherwise I wouldn't do it.

I'm going with short rear intakes (8" length *including* the carbs) and 30" exhaust pipes based on the experience of a trike flyer in S. Africa and some testing done by a few on the HKS forum. FWIW, those numbers also agree with what came out of calculator for motorcycle intake/exhaust design when I fed in all the numbers from the HKS.

That guy in S. Africa cast me a rough pair of intakes like the ones he had for $50. (I said thank you kindly). Took me a little while to machine them to fit. Won't be night and day difference but when starting with 60hp I'll take every bit available. Probably will lose some lower speed torque (nothing is free) but will trade it for improved climb performance.

So my KF won't be a great climber or go fast (darned I feel bad now) but will be good for cruising around. I found that the 582 did *not* like avgas and car gas isn't available if I'm tooling around very far from home. Plus that engine always needed some tinkering (hate Rotax part prices -> crazy).

Edited by napierm

Share this post


Link to post
Share on other sites

Posted

What specs do you need to plug numbers into your exhaust calculator? I need to come up with a good exhaust system for my 800 conversion I am workng on. Trying to cut twist and fit the stock pipe into the cowling is gonna be a beyatch do to the way the exhaust crosses over the top of the engine. Ahh the joys of experimentals! I figure I am going to loose a little power becasue I have to monkey with the exhaust, but I am starting at 140 HP so I think I can afford to loose a little bit, as long ans she still runs smooth!

:BC:

Share this post


Link to post
Share on other sites

Posted (edited)

What specs do you need to plug numbers into your exhaust calculator? I need to come up with a good exhaust system for my 800 conversion I am workng on. Trying to cut twist and fit the stock pipe into the cowling is gonna be a beyatch do to the way the exhaust crosses over the top of the engine. Ahh the joys of experimentals! I figure I am going to loose a little power becasue I have to monkey with the exhaust, but I am starting at 140 HP so I think I can afford to loose a little bit, as long ans she still runs smooth!

:BC:

Here's one:

http://www.mez.co.uk/mezporting/exhaust_length.html

There was another one but can't find it now. Wants CC of 1 cylinder, target RPM, and exhaust valve timing.

Found a picture of Paul's HKS on his trike. He sent me more detailed stuff a while back but I think I've lost it all now along with my last brain cell.

http://forums.bmaa.org/default.aspx?f=15&m=103195

Edited by napierm

Share this post


Link to post
Share on other sites

Posted

What specs do you need to plug numbers into your exhaust calculator? I need to come up with a good exhaust system for my 800 conversion I am workng on. Trying to cut twist and fit the stock pipe into the cowling is gonna be a beyatch do to the way the exhaust crosses over the top of the engine. Ahh the joys of experimentals! I figure I am going to loose a little power becasue I have to monkey with the exhaust, but I am starting at 140 HP so I think I can afford to loose a little bit, as long ans she still runs smooth!

:BC:

Leni, Are you planning to mount it upright or inverted? Might make fitting the expansion chamber in there a little easier.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now
Sign in to follow this  
Followers 0