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Discussion Starter #1
What is the stock mechanical compression ratio for a TLR?
 

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Discussion Starter #2
Found it. stock TLR is 11.7:1
shoot, here I thought these Wiseco 12:1 pistons were going to raise my ratio, this might help an 11.3:1 TLS but won't make a difference on a TLR.

then I find out N2Wheelies is running 14.5:1

What was I thinking??? Now I understand what Art was trying to tell me, I still have to do something to raise the compression more.
 

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Discussion Starter #3
Oh shoot shoot shoot. There goes my high-HP dreams.

SO, I have to send it out for mods in order to raise compression. Darn, I was hoping I only needed to drop in pistons. Thought the dome on those Wiseco's looked kinda flat. Now I feel really clueless. So if I have the cylinder base o-ringed to eliminate the base gasket completely, what's my squish going to be? Is it better/cheaper/more straightforward to mill some off the bottom of the cylinders? Then I will want the adjustable cam gears. And I'll have to use relatively mild cams. Suddenly my costs went way up and my target HP went way down.
 

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I think you'd have to assemble then measure the existing squish before you can say removing x mm = y squish as YMMV with production tolerances.
 

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I installed the Wisecos on my S 40k miles ago (over 80,000 now) and set the squish at 1.0mm which gave me about 12.3:1 static. Really, though, the dynamic compression is much more important than the static on BMEPs. IMHO milling the base of the cylinder is a much better way to go.
 

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But when you mill the cylinder or head you change (retard) the cam timing so to do it right you really need to time the cams.....
 

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Discussion Starter #8
Yeah. Adjustable gears are another $450. Yikes.

I found some with the Falicon name on 'em.
Web Cam has some.
Nothing cheaper yet.
 

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Discussion Starter #9
Sheesh that's one thing I dislike about doing an engine: take it apart, put it together, take it apart, put it together, take it apart, put it together. Split the rods, put it together with plastigage, open it, put it together with correct shims and if you do't trust them plastigage again put it together take it apart. Put it all together with gaskets, crank it thru with a ball of clay in the cyl, take it apart & measure the clay, machine it, put it all together and crank it thru with a ball of clay, take it apart & measure the clay, put it together. That's if you're lucky. I'd have thought that by now there'd be a drop-in 13:1 piston kit with mild cams and two base gaskets, and you'd test-assemble once and put it together to stay. I'm surprised Wiseco only offers one piston.

So if I'm having someone else mill the cyl base, is this something you measure once and mill once, or do you start with having them take off a few thou before you even test-assemble it for a measurement before the second milling? Do you ever end up reshaping any of the piston top if one area gets too close? Do you need more clearance fore and aft than on the sides to allow for piston rocking; last time I did this pistons were not this short and had a lot more skirt and rocking wasn't an issue.
 

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The stock static compression ratio will measure out to around 10 to 1 because the squish is around 1.4 to 1.6mm. Set it to a smaller number and then you get to 11.3 to 1 with the stock pistons and head. Check to see if the Wisco piston have a different deck hight.
 

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measure the squish at the front and rear of the piston,then find the mean.i did mine this year. it's easy to do. case of taking your time and not rushing.:) machinig the base of the cylinders is the best way to go....i'm using tlr cams. loosing 0.5 mm wont make a huge difference to your cam timing...i'd be very surprised if they're made 100% right by suzuki in the first place.:O
 

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Discussion Starter #13
I installed the Wisecos on my S 40k miles ago (over 80,000 now) and set the squish at 1.0mm which gave me about 12.3:1 static. Really, though, the dynamic compression is much more important than the static on BMEPs. IMHO milling the base of the cylinder is a much better way to go.
That sounds about like all I can hope for. SO, did you mill the cyl base? Ho w much did you end up taking off? Is there a handy online calculator applett somewhere to save me from doing the math? If you don't CC the chamber and the piston crown how can you really tell what your mechanical compression ratio is?

Yes, I understand about the dynamic effective compression. But I need an idea of the mechanical ratio before I select a cam, and I need a cam before I check clearances. So I need somewhere to start and a target goal.

How much clearance is there between the exhaust valves and the Wiseco piston? What cams are you running?
 
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