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YASVT (Yet Another Sixteen Valve Turbo) - now 16V Whiteblock (LS)

Took it to an autocross yesterday and it was such a mess on a tight twisty course that now I'm more motivated to do a few changes.

Rear axle. This has a junkyard G80 in it, unmodified. But it's always seemed a bit worn, never much torque transfer from a stop, and of course, locked out above 25 mph. On an autocross course you're always turning, and with the IPD sways front and rear it's unweighting the rear tire right away, so I was rarely able to put any power down at all. This is a bit of an issue on a road, but there's usually a little room between corners, put your foot down, the turbo LS eats up the straightaway. Just almost comical how little power I was able to use yesterday.

So I think I'm now more motivated to get off my butt about putting the Ford 8.8 I have in. I'm thinking about having it rebuilt with a Torsen diff. I just absolutely love the way the Torsen diff works in the Miata.

With it spinning the inside tire at the slightest whiff of power, certainly there wasn't any oversteer going on, but there was a bit of understeer. I think it might need a touch more camber than the stock strut mounts allow. Plus they're the stock rubber things, they look a bit stretched upward from the Bilstein's pushing on them for a decade and a half, and they're a bit cracked. Best to replace them before they let go and punch holes in the hood anyhow. Maybe some coilovers?
 
I'd swap the rear end before making any other changes. I bet that torsen changes the way the car drives out of corners a bunch.
 
Go back to a stock rear sway bar and install some spherical bearings. This will change the car a ton in autocross. Mine is pretty stuck in corners.
 
JohnMc said:
Won't a stock rear sway (softer) just increase the amount of understeer?
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No, you want to add bar to opposite of the driven wheels to increase oversteer. Adding front bar decreases body roll, while decreasing rear bar allows the axle to roll and maintain parallel with the ground.
 
I'm not talking about power oversteer, that's entirely different, and with a Torsen putting power to the outside wheel, I'm sure it will do that regardless of sways or spring rates.

But in terms of regular cornering, adding roll stiffness (either with spring rates (relative to the other axle) or sway bars (again, relative to the other axle) will reduce the overall grip on that axle. So if you soften the rear, this will increase understeer.

That was my general understanding, and some quick googling seems to back that up.

What you are saying would help to increase loading on the inside rear tire, so I could use some more throttle in turns, but I'm going to put a Torsen in the Ford 8.8, so that shouldn't be much of a concern. As it is, it doesn't power oversteer because it can't put any real power down.
 
JohnMc said:
I'm not talking about power oversteer, that's entirely different, and with a Torsen putting power to the outside wheel, I'm sure it will do that regardless of sways or spring rates.

But in terms of regular cornering, adding roll stiffness (either with spring rates (relative to the other axle) or sway bars (again, relative to the other axle) will reduce the overall grip on that axle. So if you soften the rear, this will increase understeer.

That was my general understanding, and some quick googling seems to back that up.

What you are saying would help to increase loading on the inside rear tire, so I could use some more throttle in turns, but I'm going to put a Torsen in the Ford 8.8, so that shouldn't be much of a concern. As it is, it doesn't power oversteer because it can't put any real power down.
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In a 240 with stiff springs, a stiff bar will induce lifting the inside wheel of the rear axle. It’s compounded when poly bushings are used on torque rods and trailing arms at the axle side.

A 16mm rear bar with sphericals or factory rubber will make the car feel neutral. Traction out of corners will improve noticeably.

This has a lot to to with the relatively steep roll axis inclination angle of a lowered 240.
 
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It's definitely lifting the inside rear wheel (well, maybe not lifting it, but unloading it pretty easily), but I would think that would tend to make it oversteer. I never got any hints of oversteer at all, just an inability to put down power in a corner (because the inside tire spun, certainly not oversteering). Leaving the main handling issue to be some understeer at the limit in most situations.

And I think a softer rear bar would just make understeer worse? It would help with the spinning inside rear tire, but I think I'll tackle that with a torsen in the Ford 8.8.

PS: It's on stock lower control arms and bushings still. And the upper control arms are those adjustable IPD bars with poly bushings, simply because it destroys stock bushings and ovalizes stock bars pretty quickly. I don't think those bars are adding any roll resistance. I mean, they probably *should* be, but they're adjustable, and every time I look at them, they've loosened the lock nut and are free to rotate on the threaded adjuster. They can't change length at all (it's just a single adjuster, not a pair of left/right threads), but it's certainly free to rotate as needed.


Oh yeah, and another slight issue was a fuel starvation (???) issue I got in some of the hardest corners. I had about 1/3rd of a tank, it certainly felt like fuel sloshed away from the pump, I'd go for a little throttle and the motor would bog. A split second later, no problem.

And it spit up a little oil from one of e breathers (either the turbo oil sump can breather or the passenger valve cover breather, not sure). I need to put a catch can on it. And figure out which one is burping up oil. You have to really be thrashing it for that to happen, I've only seen it happen twice. Yesterday and a month-ish ago at Mountain Meet after running the Tail o'the Dragon pretty hard.
 
Bump for hydro clutch question from pg 78 -- was the switch to the 5/8" a good change?

And did you have the 3/4" MC from the redblock days and how was it on that setup, any different?
 
Yes, it was a good change. The pedal effort went from really heavy to a somewhat more normal amount of slightly heavy. And the engagement zone went from very small to something more useable.

The 3/4" MC was a stock Volvo 262 hydraulic master. And Camaro T56 cars have 3/4" clutch masters. I thought it was going to be a great combo. But I didn't think about the pedal leverage, the Camaro pedal must have a higher ratio.

The redblock setup was using the original cable clutch, T5 trans.
 
Haven't touched this for a while. Lousy weather, etc.

Ordered a Truck Norris cam for it though. The LSA cam I stuck in there turns out to be entirely the wrong cam for a turbo 5.3 motor. I didn't do enough thinking before putting that in the first time around. I'd have been better leaving the factory LH8 cam in it. The LSA cam has (ironically) a HUGE lobe separation angle, which I thin k is making it feel lazy off boost, lazy off idle, and late(r) to spool. Which is all fine with a non-centrifugal supercharger cramming air into it even at low rpm, but far, far from ideal when you're waiting for the turbo to spool.

It's got pretty fresh lifters in new trays, so hope is I can change the cam without pulling the heads. And hopefully the cam can come out with the radiator/intercooler/grille out of the way. It would suck to need to pull the engine just to swap the cam. If I have to pull the engine it's going to get a light flywheel.
 
the truck norris cam is where its at. i have them in all my cars now. so much more low end torque.

Well is not "the" truck norris cam its a low buck truck cam from richard holdener, half the price same cam
 
JohnMc said:
Haven't touched this for a while. Lousy weather, etc.

Ordered a Truck Norris cam for it though. The LSA cam I stuck in there turns out to be entirely the wrong cam for a turbo 5.3 motor. I didn't do enough thinking before putting that in the first time around. I'd have been better leaving the factory LH8 cam in it. The LSA cam has (ironically) a HUGE lobe separation angle, which I thin k is making it feel lazy off boost, lazy off idle, and late(r) to spool. Which is all fine with a non-centrifugal supercharger cramming air into it even at low rpm, but far, far from ideal when you're waiting for the turbo to spool.

It's got pretty fresh lifters in new trays, so hope is I can change the cam without pulling the heads. And hopefully the cam can come out with the radiator/intercooler/grille out of the way. It would suck to need to pull the engine just to swap the cam. If I have to pull the engine it's going to get a light flywheel.
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I have the Madd Max Cam. Similar but a higher RPM cam. It's pretty awesome for my setup with the TKX 5 speed.
 
Belatedly moved this into the garage and started taking it apart. Now that we're to the part of the year where there are some half decent days here and there.

Good news is that eyeballing the cam position it certainly looks like it will come out the front of the car without pulling the engine. I'll just need to remove that center support in the radiator support. Drill the spot welds and bolt it back in afterward.

I'll certainly ponder long and hard about pulling the motor out anyhow, to put in a light flywheel, but somehow I'm not sure that juice is worth the squeeze. I might talk myself into skipping that for now. Light flywheels just perk up the driving experience so much, though...
 
Got the front of the engine down to spot a few issue making this a little bigger.

First was a small surprise. The huge bolt holding the front pulley on was finger tight. Certainly could have wiggled completely out if it wanted too. I just unscrewed it by hand. But no signs that the main pulley had moved even a millimeter. It still put up an appropriate enough amount of resistance to a puller before coming off. I'll call that one a close miss. I'd have to assume that the pulley could come loose eventually with no bolt on it.

And on a less positive note - when I pulled the timing cover off I saw a broken timing chain guide. The loose side has a fairly flimsy plastic guide that was snapped off somewhere down behind the oil pump. The left side of this:
12626407.jpg


Unfortunately, to replace that guide you need to remove the oil pump. The oil pump is attached to the block with 4 easily accessed forward facing bolts under the timing cover, easy peasy. Only... there's the pickup tube. Which is bolted to the underside of the oil pump. I looked long and hard and there's not much of a way around unbolting the oil pan and dropping it an inch for access.

So yeah, task got a little bigger. I was done for the day, I didn't even look at how access for all the oil pan bolts is. If it's enough of a hassle I'll jsut pull the engine/trans and use the opportunity to put a light flywheel on it.
 
JohnMc said:
Belatedly moved this into the garage and started taking it apart. Now that we're to the part of the year where there are some half decent days here and there.

Good news is that eyeballing the cam position it certainly looks like it will come out the front of the car without pulling the engine. I'll just need to remove that center support in the radiator support. Drill the spot welds and bolt it back in afterward.

I'll certainly ponder long and hard about pulling the motor out anyhow, to put in a light flywheel, but somehow I'm not sure that juice is worth the squeeze. I might talk myself into skipping that for now. Light flywheels just perk up the driving experience so much, though...
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I Put mine in jack stand to pull the trans last night, but I might just pull it all from the top. I'm not sure how feasible pulling the trans from the bottom will be.
 
cosbySweater said:
You can lower the oil pan and get the pickup tube off in car. I never put the tensioner back on. They aren’t needed
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I never even thought about just leaving it. Obviously, it was running fine with that tensioner broken. And it really isn't a tensioner, it barely puts any pressure on the chain. Googling around it does seem like it doesn't do much, isn't really needed. Earlier engines had nothing at all, some had these little plastic springy arms pushing on the slack side, some had just a plastic block sitting on the inside.

Leaving it as is would certainly save a whole of of extra work.
 
I do need to reshim my oil pump now, though. I unbolted it to see if the guide would come loose. The bolts almost miss the oil pump to begin with, but instead they screw almost all the way out before hitting the oil pump. So close that I though if the pump would move just a little they might come out, but nope.
 
Nice day yesterday so I rode my bike instead of working on this. I just need to whip the valve covers, rockers, and pushrods off, spin the cam, and insert the lifter holding rods and swap the cam. Not going to look at the 165K mile cam bearings. Unless one comes out with the cam I'm just going to slide the new cam in.

uO3ne4d.jpeg

Broken 'tensioner' bit in front.

FWIW it was still sitting in place next to the chain. Apparently the chain doesn't whip around enough to even knock it out of place.
 
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