A 3.4 DOHC Build then... F40 Turbo (Page 8/57)
Joseph Upson MAR 04, 05:58 AM
There is an aftermarket flywheel available in aluminum that supports the stock G6 clutch and pressure plate. I had the stock pressure plate checked and it produces 2000 lbs of clamping force so I highly doubt you need to place any focus on that given it is as high or higher in clamping force than most of your aftermarket performance pressure plates for the typical run of lesser trannies for the 60 degree motor. You should look into a disc better than stock though.

I use a Kevlar disc based on the stock G6 hub which I don't recommend now because of minimal damping ability. The picture below is of my options at the time I had it made and I went with the circular arrangement seen below over the puck. My flywheel is a modified unit from the F-body with a stock already HD pressure plate relative to the OE Fiero plate at the time it was produced, that was modified to produce about 2300 lbs of clamping force. Stock was somewhere around 1600 lbs of clamp force I believe.

[This message has been edited by Joseph Upson (edited 03-04-2013).]

Fierobsessed MAR 04, 07:08 AM
I have a 2.8/3.4 camaro flywheel. So I have a pretty good idea what I am going to do with that... I have a lathe too, and I am not afraid to use it!

Maybe I will have a custom clutch made. Ideally I would like to get the disc's weight down a bit. I hate heavy discs. Maybe that 4 puck is the trick I need

Edit: 240mm diameter, 23 spline X1", very light weight... $119. Could be as good as it gets? Might be a bit harsh though.

[This message has been edited by Fierobsessed (edited 03-04-2013).]

Slowbuild MAR 04, 11:48 AM
Really nice.

It's been mentined, and I don't know if you adressed it or not, but having your air filter so close to the manifold will probably destroy it. It gets HOT in there. Glowing hot.

The wastegate may survive so close to the hot side of the turbo, but it may also self destruct, or worse, start sticking. sticking closed would be bad. If you have room, I'd extend it away from the turbo, or use a turbo blanket/shield of some kind.

I can only wish my welds were that good!!!

EDIT:

I see that you are using a turbo blanket. Very good. I'm still concerned for your air filter though.

For my knowledge (I have a 3.4 DOHC sitting in a box in my basement), where do the F23 control cables hook in? For the Muncie 4speed, those cables are why I couldn't locate my turbo there..too much heat for the cables. Forgive me if this is a dumb question..I know nothing about the F23).


Chay

[This message has been edited by Slowbuild (edited 03-04-2013).]

Joseph Upson MAR 04, 11:58 AM

quote
Originally posted by Slowbuild:
The wastegate may survive so close to the hot side of the turbo, but it may also self destruct, or worse, start sticking. sticking closed would be bad. If you have room, I'd extend it away from the turbo, or use a turbo blanket/shield of some kind.

I can only wish my welds were that good!!!
Chay



That's the kind of thing you worry about with Ebay special wastegates, name brand shouldn't be a problem not to mention that a street driven vehicle is not likely to encounter the kind of extremes that cause that kind of threat to the wastegate. The one example I saw of an aftermarket wastegate sticking was in an unscientific, impractical unrealistic setting where it was heated to glowing hot temps and opened and closed continuously until it stuck which took several minutes and far longer than any street driven vehicle would come near matching.
Fierobsessed MAR 04, 10:45 PM

quote
Originally posted by Slowbuild:

Really nice.

It's been mentined, and I don't know if you adressed it or not, but having your air filter so close to the manifold will probably destroy it. It gets HOT in there. Glowing hot.

The wastegate may survive so close to the hot side of the turbo, but it may also self destruct, or worse, start sticking. sticking closed would be bad. If you have room, I'd extend it away from the turbo, or use a turbo blanket/shield of some kind.

I can only wish my welds were that good!!!

EDIT:

I see that you are using a turbo blanket. Very good. I'm still concerned for your air filter though.

For my knowledge (I have a 3.4 DOHC sitting in a box in my basement), where do the F23 control cables hook in? For the Muncie 4speed, those cables are why I couldn't locate my turbo there..too much heat for the cables. Forgive me if this is a dumb question..I know nothing about the F23).


Chay




The pipe will be covered and insulated. The crossover is not as close as it appears in one of the pics above. I will address all of that heat shielding and insulating towards the end of the build.

Thanks for the compliment on the welds, I am getting better at it all the time. A the end of the day it is A LOT of stainless welds!

What Joseph Upson said is absoutely true. A nameless or cheap knockoff wastegate might be questionable. But this is a TIAL, it is their latest and greatest model. the MV-S which they run all day long glowing red hot without issue in tests. It is even water cooled, which they said is not necessary for my application, but I'm going to hook it up anyway.

Anyway... Today's progress report.

I started this morning with a run to the Pic-a-part, looking for a factory oil cooler, and much to my surprise I found a 91-93 LQ1, with the oil cooler! I yanked all related items to convert my engine over.


Cleaned the parts up a bit.

The water feed actually comes from a brass fitting screwed into the coolant drain plug in the block.
The water neck has a few spots where the aluminum was completely rotted through. But I have to use this water neck it has the return from the oil cooler. The 94-97 engines don't have the port, maybe I can fix it with epoxy, or TIG it.



Next I began tackling the 3" part of the exhaust. I started with this 180, I cut it at 45 degrees to form the question mark shaped pipe that the Fiero's stock exhaust system has.



Tried a fit up, found I needed to add a 1.75" long straight to the sections to make it fit nicely.


Welded up


Then, I welded the V-band flanges to the catalytic converter, and started doing some more fitup.


At this point, I'm calling it a night, perhaps tomorrow morning I'll get the remainder of the exhaust from the downpipe to the cat finished. We'll see how that goes...
sleevePAPA MAR 04, 11:53 PM
there was a guy chasing me around trying to sell me a burrito when I was at the pic a part today LMAO
Will MAR 05, 11:23 AM

quote
Originally posted by Fierobsessed:
However, I don't like the idea of using an undampened clutch disc. They can beat a transmission, or drive line to death. Every engine crankshaft pulse needs to be absorbed at the clutch, using a dual mass flywheel works, or a dampened disc. I plan on making a custom flywheel, using a SPEC high clamp pressure plate. But what disc??? Anyone have any ideas?



Sprung hub clutch disks and dual mass flywheels ONLY reduce gear rattle in the transmission.
They are for noise reduction ONLY. End of discussion.
(Except in the case that the secondary mass of a dual mass flywheel actually slips from the torque, but that's not a normal mode of function).

Think about it... How stiff would those springs have to be to prevent engine torque from simply compressing them into coil bind and making a solid connection?
When my Northstar destroyed its first Centerforce and I sent the disk back, the tech who looked at it noted that the travel stops in the hub were beaten flat... So obviously the springs in that hub had nothing to do with cushioning engine torque.
Joseph Upson MAR 05, 12:09 PM

quote
Originally posted by Will:


Sprung hub clutch disks and dual mass flywheels ONLY reduce gear rattle in the transmission.
They are for noise reduction ONLY. End of discussion.
(Except in the case that the secondary mass of a dual mass flywheel actually slips from the torque, but that's not a normal mode of function).

Think about it... How stiff would those springs have to be to prevent engine torque from simply compressing them into coil bind and making a solid connection?
When my Northstar destroyed its first Centerforce and I sent the disk back, the tech who looked at it noted that the travel stops in the hub were beaten flat... So obviously the springs in that hub had nothing to do with cushioning engine torque.




I have to disagree for two reasons Will, first the dualmass flywheel for the F40 does not use springs, or springs only, as I tampered with one of the OE flywheels short of disassembling it and some type of grease came out of it. Second, within the design parameters of the stock dualmass application the flywheel may offer shock protection in the same manner that smooth clutch engagement as opposed to a clutch pedal slipping dump does. It definitely quiets the tranny down but I do not believe that is its sole purpose as it should be capable of damping the firing pulses in the same manner that the harmonic balancer does as long as it is not static which should be the case under most if not all conditions in the stock application. It is designed to slip also at its torque limit. Whatever the case, the over all mass of the flywheel may be the real protector as opposed to the limited independent movement of both parts.
Fierobsessed MAR 05, 01:15 PM
The torque needed to compress the springs till it hits the stops on the OEM F40 disc is roughly 1-2 lb/ft. Those springs don't do squat! I can only guess that their purpose is to allow the some give to shift if the meshing is close enough. For all intensive purposes, the F40 disc is a solid disk. Any torque at all hits the stops. The function of the springs is moved to the flywheel on a dual-mass which technically speaking, is a better place for it. Less inertia in the disc, longer synchro life, better shifting.

On my clutchnet disc, Its probably in the 100 lb-ft range to compress them fully. Let's just say it was extremely tough to check them out. The springs are VERY beefy. Im sure in any event that when you are accelerating heavily, no matter the clutch, that you are driving the wheels undampened, but with the higher RPM of hard acceleration, the weight of the flywheel smoothes the pulses out beautifully anyway. It's not like you spend a lot of time in this condition.

I agree Will that the springs, or the dual mass flywheel reduce noise. But I'm saying that in addition to that, it directly reduces spline fatigue and fretting. (at the clutch disc, at the dog rings, at the axles... ect.) Joseph Upson lost his 6 speed from what is believed was most likely caused by the fatigue of having ZERO give in the driveline, with the engine at low RPM's in 6th gear for an extended period of time, which is a normal mode of operation for 6th gear. The evidence supports it.

Either way, I'm going with a light weight design sprung disc and a solid normal weight flywheel. But I am stil trying to find a disc with that magic combination that gets me light weight, Torque capacity, drivability and durability for a reasonable price. Thats a real challenge! I've seen some very interesting discs out there.

[This message has been edited by Fierobsessed (edited 03-05-2013).]

Will MAR 06, 10:31 AM

quote
Originally posted by Joseph Upson:
damping the firing pulses in the same manner that the harmonic balancer does...



If you're basing your understanding on that, you need to do some more research into how a harmonic balancer works.

The harmonic damper absorbs the torsional "ringing" in the crankshaft but does absolutely nothing to reduce peak output torque from the engine.


quote
Originally posted by Joseph Upson:
Whatever the case, the over all mass of the flywheel may be the real protector as opposed to the limited independent movement of both parts.



I think it's pretty well established that increasing flywheel weight increases transient loading on shifts. The transient loading from decelerating the flywheel is far greater than the engine's actual output.

That's why first gen CTS-V's with stock flywheels tend to blow their diffs apart, while those with lightweight flywheels don't have that problem to the same extent.


quote
Originally posted by Fierobsessed:

The torque needed to compress the springs till it hits the stops on the OEM F40 disc is roughly 1-2 lb/ft. Those springs don't do squat! I can only guess that their purpose is to allow the some give to shift if the meshing is close enough.



It's noise reduction and only noise reduction, pure and simple.
Thank you for making the measurement and posting the numbers.


quote
Originally posted by Fierobsessed:
I agree Will that the springs, or the dual mass flywheel reduce noise. But I'm saying that in addition to that, it directly reduces spline fatigue and fretting. (at the clutch disc, at the dog rings, at the axles... ect.) Joseph Upson lost his 6 speed from what is believed was most likely caused by the fatigue of having ZERO give in the driveline, with the engine at low RPM's in 6th gear for an extended period of time, which is a normal mode of operation for 6th gear. The evidence supports it.



That doesn't pass my sniff test.

A car that *ACTUALLY* has a spline fretting problem is the BMW E30 325iX where the front driveshaft is driven by the transfer case. That ONLY happens when the incorrect lubricant is used in that spline interface. That driveline has THREE rubber flex disks in it AND a sprung hub clutch.