Anyone used a VH44 as a clutch booster?

[tawa 150]

The clutch in my e36 has been quite heavy ever since I did a manual conversion (NZAD lightweight flywheel in a g220 box). Recently heard about the VH44 units as an option to sort it out. The stroke length/engagement seems really good so I don't think it's just a matter of changing pedal ratio or master/slave cylinder diameter.

I'm thinking I'll get a VH44 to try, from what I can tell, the assist ration can be changed by changing out a spring, and from there it's just a matter of getting the plumbing all tidy and having good vac available and all's well...

Anyone have success or failure running one of these? tips/tricks/feedback?

[B.M.W Ltd 950]

Where will you fit it and how will it be operated ?? Best go out and have a look under the bonnet and behind the dash

Edited June 6, 2020 by B.M.W Ltd

[tawa 150]

It's remote mount, fair few options I think. vacuum operated and just plumbed in to the existing clutch line.

The real 'issue' is the increased pressure pressure plate.

[M3AN 4016]

I don't know if this is relevant but make sure you don't have spongey clutch lines, it's a big thing to replace the rubber line on E36 M3's with a braided one to solve terrible clutch problems.

[tawa 150]

16 hours ago, M3AN said:

I don't know if this is relevant but make sure you don't have spongey clutch lines, it's a big thing to replace the rubber line on E36 M3's with a braided one to solve terrible clutch problems.

Good point, from memory there isn't much rubber line, but with a bit more pressure in the system it could mask a too stiff pedal/cylinder ratio...

[tawa 150]

9 minutes ago, 3pedals said:

 So there is no "problem as such" the clutch is just a heavier because you installed a pressure plate with more pressure, assuming the mechanics are fine ( good pivot etc)  then two choices:

1. 3 sets of twenty left leg only calf raises every morning for 3 months,  or
2. change the hydraulic ratio and lose a bit of feel and  actuation range.

 

Or put a booster in, hence the thread. Not sure why that seems to be a difficult concept?

[tawa 150]

Cool, as per the title I'm more after people's direct experience than vague doubts about the concept, they've been used in clutches on other cars, similar tech comes stock on a fair number of cars. The unit's operation looks pretty analogue, seems far more like adding a bit more 'free leverage' than being a black hole that eats all your clutch feels.

[Herbmiester 923]

I to am doing a single mass conversion on my 328i. I have gone with a UUC Motorworks lightweight setup. This setup uses a clutch with similar specs to the E34 M5 clutch so I will find out how heavy it is but reviews on this setup dont refer to an unduly heavy pedal. 

 

[B.M.W Ltd 950]

1 hour ago, Herbmiester said:

I to am doing a single mass conversion on my 328i. I have gone with a UUC Motorworks lightweight setup. This setup uses a clutch with similar specs to the E34 M5 clutch so I will find out how heavy it is but reviews on this setup dont refer to an unduly heavy pedal. 

 

That's what I did with M3 master cylinder, slave cylinder, braided clutch hose and valve delete. I was using the G250G gearbox & 3.15: 1 Medium case LSD Diff with the E30 325i MS Axles . It was perfect in my M52B28 Ti

Edited June 8, 2020 by B.M.W Ltd

[M3AN 4016]

If I recall correctly Mark (@sweetm3) got a lightened UUC flywheel and it was woefully out of balance when it arrived. Caveat emptor.

[B.M.W Ltd 950]

17 minutes ago, M3AN said:

If I recall correctly Mark (@sweetm3) got a lightened UUC flywheel and it was woefully out of balance when it arrived. Caveat emptor.

UUC are excellent to deal with. Do you have a link to this or do you know what the outcome was ??

[B.M.W Ltd 950]

I might add ....I was using the UUC flywheel with the E36 M3 pressure plate and the E34 M5 clutch plate (sprung center plate).

Edited June 8, 2020 by B.M.W Ltd

[M3AN 4016]

21 minutes ago, B.M.W Ltd said:

UUC are excellent to deal with. Do you have a link to this or do you know what the outcome was ??

Mark got his flywheel machined and balanced over here, they took off a fair bit to get it right as I understand. I think it was a UUC one, @sweetm3 would need to confirm.  

[Herbmiester 923]

40 minutes ago, 3pedals said:

Assuming you and John (H) have the same flywheel then your combo will be about a kilo lighter as the M5 plate & cover is  well over 8 kgs whereas the M3 plate combo is about 7.4 kg. 

The sub 4kg flywheel with an over 8kg cover is not the best combo as all the mass in the cover is on the outside giving a much higher rotational mass plus the cover will dominate the flywheel in terms of harmonics etc.

That may all be true in theory but the reality is this system has been in use for a number of years now in both street and racing applications and there dont seem to be any skeletons in the closet so to speak so I dont really have any concerns in this respect.  As a bonus should I decide to complete a 3l stroker conversion I will certainly have enough clamping force. It would also seem that the heavy clutch pedal issue is not present with this setup and apart from the flywheel everything else is factory BMW.   

[Herbmiester 923]

8 minutes ago, 3pedals said:

It's not just true in theory , it is also true in practice - basic vibrational and rotational mass physics. Some of us take it into account when we design / engineer, others don't. 

In terms of clamping force the results are within a gnats  I believe the E34 M5 plate is typically rated to 480 Nm - the solution I'm likely to use is rated to 500Nm - (not that it is needed). 

• The UUC combo is 12.2kg  with the mass on the outer ,
• Combo X is 13kg  with a much stiffer flywheel and the mass more centred.

The  4 kg UUC flywheel will  flex and vibrate more as it will have less control over the much higher rotational inertia of the 8kg cover plate. 

Combo X with a 7kg flywheel and 6kg cover is much stiffer as it has (much) more meat around the fixing bolts and is a different grade of alloy -  rough and dirty calcs suggest it will be close to 8 times stiffer than the UUC flywheel.  

As per an earlier comment we 3 should compare when all 3 are done. 

So to be clear, my setup is stiff enough, its balanced, and is no heavier at the pedal than a standard M3, it was affordable and most importantly it's PROVEN.  Using a system that has been working well for a number of years in both road and track applications is good enough for me. So using the assumptions you have made based on the published data may be correct in theory but the application in the real world may be irrelevant, which in this case I suspect it is. I do a lot of work with ballistics and I find people love to fixate on the variables, some of which only have a very minor effect on hit probability, will the Coriolis effect alter my impact point yes it will, will it make a real world difference? 99.99% of the time, No.  

[sweetm3 180]

3 hours ago, M3AN said:

If I recall correctly Mark (@sweetm3) got a lightened UUC flywheel and it was woefully out of balance when it arrived. Caveat emptor.

Hi guys, it was a UUC M3 kit. UUC Stage2/M5 clutch combo (I love it)

3 hours ago, B.M.W Ltd said:

UUC are excellent to deal with. Do you have a link to this or do you know what the outcome was ??

Sorry the info I put on my project has gone. Site went down a few years back and I didnt have the info backed up. 

3 hours ago, M3AN said:

Mark got his flywheel machined and balanced over here, they took off a fair bit to get it right as I understand. I think it was a UUC one, @sweetm3 would need to confirm.  

Dave is right, 

I took Josh advice and gave the unit to an Engineering shop in New Lynn to have it checked.. They did the balancing and said that it was wayyyy out. And I was lucky that I  brought it in.

Thanks again Josh

From UUC web site flywheel weight 8.5 lbs, once balanced I think I was around the mid to high 7's.

Edited June 8, 2020 by sweetm3

[sweetm3 180]

See 6 O'clock to 9, not sure 3pedals, Ron, William  (good to have you back)

Confirming it was 7.9 lbs 

[tawa 150]

7 hours ago, 3pedals said:

So thats three fly wheel swaps on the go you, me and John  all different  combos' so we should compare notes when done. Mine is also going in an E36 328 - John (Tawa) what is swinging off the front of your 220 gearbox? 

M50B28, for now. Though tbh I won't be upgrading the engine without getting a stronger box etc anyway.

[wrs 120]

I purchased a NZAD D1 Racing clutch and flywheel on TM about 5 years ago. It was for the S6S420G box (bigger spline from memory).

It never worked well for me as it would very often not disengage even with the pedal at the floor (with the rubber stopper removed). I had a steel braided clutch line too. I ended up getting a standard M3 clutch plate and pressure plate which works fine and always disengages correctly with the rubber stop reinstalled. It was suspected the D1 pressure plate had the tyne pivots in a different place reducing the amount travel to help reduce the foot force to overcome the stronger springs (never confirmed by measurement). I sold it on TM cheap to someone who was going to use it on a 5-speed and never heard back - don't know if that means it worked well for them or not though.

The flywheel appears to be good with the only issue not having a TDC hole to lock the crank when working on cams... It's around 7.5kg from memory.

The only downside to the light single-mass flywheel is the chatter at idle and meshing noise at low rpms and loads.

Looks like the UCC flywheel has the locking pin hole - interesting the holes drilled for balancing are almost directly opposite it and look like a similar amount of metal has been removed as the lock pin slot.

[Herbmiester 923]

Ok so to do this did you get the position of the steel surfaces (where the weight is) on the UUC flywheels calculated into the equation? Or did you make assumptions? As that will no doubt have an influence on the last two calculations. Also for all we know your calculations could have been tailored to win an argument. Also your calculations on tensile strength have you measured a UUC flywheel, are you familiar with its construction, alloy grade etc? Again this will have a big impact on the torsion numbers as well. Looking at my flywheel if has a number of dimensions in regards thickness and angles plus the torsional strength will change where the friction surface is bolted as of course it will for the ring gear. Have you calculated all these variables because I suspect the calculation will be very complicated, or as you stated in one of your earlier posts used rough calculations. Based on the way you have formulated your arguments over the past number of years perhaps the numbers reflect what you want them to reflect? 

Also re your earlier comment on balance I discussed this with the machinist who is building a motor for me at present and he said that when it comes to balance a light flywheel with a heavier clutch plate is a complete red herring as there are so many other factors that will have a greater influence on balance . As the two are joined and the pressure plate is less likely to be in perfect balance the effects of the crankshaft and the harmonic balancer will have as much influence as the PP and FW, does the car run balance shafts, is it internally or externally balanced? are a few other things he said need to be factored in. He made it clear that the whole rotational assembly needs to be balanced as a unit if perfect balance is required. In his 40 odd years of experience in building race engines, that this step has negligible benefits and the main culprit of a noticeable imbalance is the pressure plate, but this can vary depending on the position of the clutch plate as it obviously never goes back to the same place. As to plane torsion the figures are to a certain extent irrelevant as there is no figure to determine at what power lever rpm etc the torsional deformation has an impact on the performance of the unit, ie once something is strong enough making it stronger serves no purpose.   

Edited June 9, 2020 by Herbmiester

[sweetm3 180]

John, 

"whole rotational assembly needs to be balanced as a unit" 

is this what you mean ?

I dropped off the FW, PP, SD and bolts. All had alignment marks for when being installed.

 

 

 

 

[tawa 150]

4 hours ago, 3pedals said:

For anyone interested in the science - I did a basic comparo chart before selecting the bits I wanted, I've updated it to include the setup Glenn has 

Points of interest: 

UUC combos have lower inertia which means it will spin up quicker however once spun up it has higher kinetic energy,

Most alloy flywheels especially those with the meat removed from the middle are floppy in plane,

Most alloy flywheels have low tensile strength. 

Fly wheel mass is not the significant factor - location of mass is.  

 

 

Few questions, how do the UUC combos have higher kenitic energy if they spin up quicker? surely energy is only conserved...

Why does the Fid&M5 have so much more kinetic energy than UUC&M3 but have near identical rotational inertia?

[B.M.W Ltd 950]

I'd just go to what has been proven to work for DIY applications. It's not like we have to enter F1 specifications to have a bit of fun and enjoy doing it.

[polley 916]

Unless your 328 is making decent power (turbo, supercharged etc) What's wrong with standard clutch?

If you're making decent power then really that just comes with the territory. If you're making standard power just put the standard setup back in and you'll have your nice cushy spongy clutch pedal back again.

 

You put a heavy pressure plate in and complain about pedal effort. To be expected. Storm in a teacup. 

Edited June 9, 2020 by polley

[Herbmiester 923]

59 minutes ago, 3pedals said:

Error in summing the Fid -M5 cover mass levers , also carried into torsional stiffness - revised table attached , have also included Fid with M3 cover. 

 

In response to rotational inertia vs Kinetic energy - the first is essentially treated as a static lever - mass at distance,  the second is a velocity squared based calculation the longer lever with less mass of the UUC produces  higher velocity at 5,000 RPM  the product is higher. 

Agree with Polley -   match the pressure plate to the engine characteristics - you also get some benefits as per above 

Also agree with Glenn - have fun and part of my fun is crash testing the so called proven solutions - the lighter stock  or M3 pressure plates will work  fine  with largely stock or lightly / moderate engine mods. 

 

 

 

I call BS on this as you just dont have enough info to make this accurate. It will either be full of assumptions or so simple because of lack of solid input data that the results are irrelevant.