Mac
Member
So several weeks ago someone asked the question. How much material should we remove from the helix to achieve more overdrive shift. My reply was dead wrong. I said the primary would bottom before the secondary helix would bottom. My answer was that the trick never really worked for us. I turned on the lathe two helix's for our SRX's for a buddy and myself that we felt never worked when we tested. Anyway Turk knew it worked and replied .080 thousandths.
To confirm Myth-Busters style I drilled a small hole .062 in the helix face. I inserted a small piece solder and used crazy gel to hold in place. As you can see is the pics the solder was mashed completely. I would say confirmed. Wow its hard to be this wrong in front of so many.
To confirm Myth-Busters style I drilled a small hole .062 in the helix face. I inserted a small piece solder and used crazy gel to hold in place. As you can see is the pics the solder was mashed completely. I would say confirmed. Wow its hard to be this wrong in front of so many.
So, what kind of performance improvement did you get from this mod?
How much speed did you gain from doing this? did you try a stock helix for speed and then try the cut helix for speed?
where did you mill .080 off of? can you show pics of where you take the material off?
where did you mill .080 off of? can you show pics of where you take the material off?
Mac
Member
Sorry no performance or gain just yet. This test was with a Apex helix uncut. Couple of things. I didnt have my GPS so I don't have MPH. I'm gonna test with three passes 1200 feet exactly the same so the clutches are totally bottomed out. Add all three together and divide by 3 for an average. Then cut helix .080 and reinstall the solder. Then test again with three passes so I can report MPH increase. Also I want to see if the solder will bottom out again after .08 is removed.
madzx2
Member
where are you removing the material from?
Mac
Member
If you remove material from the surface hi-lighted in green your allowing overdrive. How far can you go? I will report next week cause I have no idea. Eventually the primary will bottom out and will be fully closed.
Testing Testing Testing.
Testing Testing Testing.
tofastSRX
New member
good deal but you must also machine the primary right?
extremelyfastmax4
New member
no u dont machine the primary that cut is for the secondary 2 allow it 2 go 2 full shift in other words allows the belt in ur secondary 2 go all the way 2 the bottom. if u buy the ajustable helix from shock wave it needs 2 be shaved allso the same way as it takes away about 10 miles an hour on ur sled AL
extremelyfastmax4
New member
u gain 10 miles an hour on ur shockwave helix with the cut. i was 3/16 of an inch on my shock wave helix.
mopar1rules
Active member
Very nice post mac. Great pics too. Guys, you can simply cut the highlighted area that mac pointed out in green, to be approx .030" above the helix bushing. On a OEM helix, this equals around .125-.150" taken off.
So to be clear, this machining process would only apply to certain OEM Yamaha helix's and just the shockwave helix? Bender, Hauck, etc. dont need this mod?
all need to be check
bluemonster1
LIFE MEMBER ONLY ONCE!!!
my bender allows belt to drop all the way down,the stock 47 does not even get there.
mopar1rules
Active member
modsrx said:
Correct. I've never had to machine a maxx perf or bender helix tho. Always OEM.
Mac
Member
Here is the question I have. We know the secondary bottomed and prevented further advance with my setup. Is the primary right behind it and will bottom with another say twenty thousandths. If this were true we might not see much improvement after I cut the helix?
mopar1rules
Active member
Mac said:
true, but at least the primary won't keep trying to upshift, when the secondary is bottomed out, causing the belt to want to stretch.
also, great idea w/the solder, to indicate a bottoming issue.
Mac said:
yes mac, the primary will bottom out, if you look at the sheaves theres a little raised portion on them from the rest of the sheave face right at the bottom near the spider shaft. You can machine the faces if you want to get into overdrive.
Mac
Member
I don't think I'm gonna go through all the trouble of disassembling and machining the primary to pursue overdrive. Don has pointed out that overdrive is a waste of effort anyway in previous threads. I am wondering how many MPH can be achieved with machining the helix only and its a real easy modification if it works.
I thought this mod was in the tech. I have been doing this in the drill press with a disk sander for years with the old style hauck helixes that were recut stockers. Also cut primary below the engagement line.
tofastSRX
New member
so the primary does also need to be machined ?? for overdrive?