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push the 70km/h top end?
Posted: Wed May 30, 2018 11:58 am
by audiocontr
Pedal down, on flat ground, i can consistently hit 70 km/h. Sometimes to 75 if the road surface is nice and smooth. What can i do to push this top end a bit without swapping tires? Any carb modifications to try?
(Removed the governor, oil bath, have 13" wheels and winter tires. Windshield is down)
Re: push the 70km/h top end?
Posted: Wed May 30, 2018 12:28 pm
by pinzi
I think you need to do a littel bit more than that , getting a higher compression would help or just wait until the wind turns so jou have it in the back
What gearing do you have as there are different ones on the portals.
Re: push the 70km/h top end?
Posted: Wed May 30, 2018 1:41 pm
by TechMOGogy
Your speedo could be off - have you verified speed via a GPS App?
Or... you may have the rare 75km hub gears as mentioned!
Here are repo's
Re: push the 70km/h top end?
Posted: Wed May 30, 2018 2:09 pm
by audiocontr
Any easy way to determine gearing?
Re: push the 70km/h top end?
Posted: Wed May 30, 2018 2:51 pm
by pinzi
Yes they should be a number on your whleelflange...think if its a 32 you have the 75km/u gearing
Re: push the 70km/h top end?
Posted: Wed May 30, 2018 2:59 pm
by pinzi
Correction...just checked mine, should be 31 on the wheelfange
Re: push the 70km/h top end?
Posted: Wed May 30, 2018 10:57 pm
by Garrycol
When tuned my Haflinger will do just over 90kph flat out - probably a little faster if the windscreen was folded down. I cruise at 70kph and 4000RPM.
It has VW barrels and modified 87mm VW pistons taking the engine out to 762cc. Not sure of the compression ratio but is a little more than standard. It has 75kph hub gears with 14" Fiat alloy wheels with 185R14 Mud and snow tyres which work out about 25.5" in diameter. While top speed is just over 90and 5000rpm it is just not worth pushing it so I cruise at 70kph and 4000rpm and I can do this all day up and down reasonable hills - bigger ones means going back to 4th and going slower.
I have had the piston profile more agressive in the past to deliver higher compression but engine reliability becomes and issue.
Carb is standard as is the exhaust - timing is standard but I am thinking about advancing it to the equivalent of 10 degrees BTDC. It has an Expedition Imports Pertonix ignition module.
Really to go faster in a Haflinger you need to get the engine to rev higher (not easy for a Haflinger engine) or get a higher reving different engine. Due to gearing there is not much else you can do.
At speed the Haflinger is quite stable but you do have to take the poor braking into consideration.
Garry