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VW MKIII-A3/B4 TDIs This is a discussion about MKIII-A3/MkIII Jetta/Golf (<99.5) and B4 Passats (96,97) TDI's. Non TDI related postings will be moved or removed.

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Old February 16th, 2017, 08:50   #1
Join Date: Dec 2014
Location: Central Illinois< US
Default 98 Jetta Clutch/Tranny Upgrade

I've got a 1998 Jetta with just over 200k and some pretty serious driveline clatter, so I'll be pulling them out and replacing shortly.

In addition my clutch has had a slip for quite some time now, so I thought this would be a good time to take care of that as well.

A couple of questions before I tackle the project:

Each time I work on part of this car, I try to upgrade and leave things better than stock and get some more longevity and performance out of the car. I was looking at Single Mass Flywheel and a Stage 2 clutch.
At some point I want to put in a Malone Stage 2 tune and Bosio Injector nozzles but that is a little ways off. But I want a clutch that will handle that torque when I do it.
- What is the advantage of a single mass flywheel?
- I notice they make the flywheels in differing weights, what is the advantage of lighter or heavier and how does it affect performance or fuel mileage?

I'm planning to replace/upgrade the clutch, drivelines, wheel bearings... Is there anything else I should consider tearing into while I have all this apart? Engine mounts were done less than a year ago.

- Also, while the tranny is out, I am considering installing a higher ratio 5th gear. Have any of you guys done that, and were you happy you did? ID parts has a .658 and a .717 ratio set. What do you guys recommend? Is this a job that will be overwhelming for me? I am fairly adept working on these cars and do all my own service work, but have not done much inside a transmission before...

We take this car on some pretty long road trips several time a year, sometimes 5,000+ miles and my main goal would be to lower RPMs at 65-75 mph to increase fuel economy. The car is a daily driver as well, so I wouldn't want it to struggle at 50-55 though. Thoughts?

Whats the best viscosity/brand of oil to run in the manual transmission on this car? I've seen a lot of Redline brand mentioned, is that the best and if so, what viscosity?

Also, just have to say, two thumbs up to this forum in a major way. The level of info available from you guys for these cars is absolutely unparalleled. I've been doing some upgrade/custom work on my ford pickup over the past couple months and can never get as helpful and reliable advice on other forums as I do here. The TDI community is second to none, hope y'all know that!!
paulschmid07 is offline   Reply With Quote
Old February 16th, 2017, 13:06   #2
Veteran Member
Join Date: Oct 2012
Location: waupaca, WI
Fuel Economy: 40-42 with a lead foot.

your car already has a single mass flywheel. dual mass was introduced with the MK4.

Clutches wear out in both eventually but the DMF also can wear out whereas the SMF holds up indefinitely because it has no springs or moving parts.

stage 2 clutch should hold up fine.

you will want the heavier flywheel. lighter flywheels can respond faster but with diesels it leads to vibrations and harshness and the torque overcomes the weight in our TDI's

.658 sounds good for your goals, .622 may be too tall for 50-55 driving. leaves a void between 4th and 5th. 5TH gear swap is fairly straight forward, you should be fine.

keep in mind you will never get back your $$$ in fuel savings but if the noise/RPM reduction is your goal, so be it.

i dunno about oil, i just use the VW stuff. G70 i think it was called???
2003 Jetta TDI - 11mm IP, “stage 1ish” DIY tune.
1996 Passat TDI - "Red Death" RETIRED but still owned. Had a Malone stg 1 tune, 11mm pump, R520, GT15/17 hybrid and more
1997 Passat TDI wagon - Im not really sure why i bought this... anyone want a running donor car??? body is rough.
ketchupshirt88 is offline   Reply With Quote
Old February 17th, 2017, 07:29   #3
Join Date: Dec 2014
Location: Central Illinois< US

Ok, thanks for the advice!

So is there any point in changing the flywheel then? Looking at Stage2 clutches it sounds like many of them need me to use their flywheel. Does that sound right, or should the new stage two clutch bolt up to the stock flywheel.

The clutches I was looking at were the SBC Stage2 sold by ID Parts.

Does anybody know what the weight of the stock flywheel is?

I'm still chewing on the 5th gear upgrade... I realize its hard to get that money back, but we do put on a lot of miles on this car and plan to keep it long term. And on those long trips, sometimes I would rather drive 70-80 mph but don't because its racing the RPMs and really knocks off the fuel mileage. I'm thinking its worth it for those stretches through Wyoming and Nebraska...
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Old February 17th, 2017, 07:49   #4
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Join Date: Aug 2004
Location: South of Boston
Fuel Economy: 50/45/37

Instead of the fifth gear upgrade I'd buy larger tires. 195/60-15s will correct the speedo error and thief things a bit on the highway. Basically a no-cost upgrade if you need tires.
2002 Jetta wagon, 362K, RC3+; 1993 Mercedes-Benz 300D 2.5, 197K; 1997 Passat, 285K; '99.5 Golf, 257K; 2011 335d, 56K; 2015 Golf Sportwagen, 8K. Principal, http://www.idparts.com
Kid's cars: 2002 Golf TDI, 2002 Jetta TDI
IndigoBlueWagon is offline   Reply With Quote
Old February 17th, 2017, 08:46   #5
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Join Date: Mar 2007
Location: Miramar, Ca. (Think Top Gun)
TDI(s): 1996 B4V

A stock VR6 clutch and pressure plate should be more than enough for what you are planning and will save you some money. The South Bend stage 2 Endurance clutch is a bit stronger and will also serve you well. But it is more money. (I have used both clutches).

Quite likely a local machine shop can resurface your existing flywheel, otherwise a new 22/23 Lb stock TDI flywheel is not that expensive.

Transmission 5th gears: I have run longer 5th gears and I have run larger tires for at least 5 or 6 years.

As IBW says, larger tires are your least expensive option (when you need tires). The cost to buy a new 5th gear set will be about $400 - then you have to install it or pay for installation.

With a taller/longer 5th gear you will gain some highway MPG. BUT for me, the reduced engine noise on long trips is the real pay off.

I ran a .622 Fifth gear for about 18 months. Liked the noise reduction a whole lot. Picked up maybe 5% mpg on the highway. But I did not like the big hole between 4th and 5th. Using a .658 or a .68 5th gear would NOT be much better IMHO. But very much worth considering.

For the last 4+ years, I have been running a 6 speed conversion for the stock 5 speed gear box from EuroTuning.cz. This gives me the stock 5th gear and a .59 6th gear for use above 60 mph on the highway. It has been great for me. The cost is about $1300 for the kit only. Yes, not cheap. But it works great for me.

Lastly, I also use larger tires. 195/65 x 15.

Hope this helps.
1996 B4V, Hella E-Codes, GLX leather, EuroTuning.cz 02A 6 speed conversion w/.71 5th and .588 6th gear, A4 shift linkage by Matt-98AHU. 11 mm pump by Oldpoopie. Now, GTC1549VZ turbo by Whitbread. TDtuning, 24 lbs. boost, 162 hp, 285 lb/ft tq. Smoke Free (9/18/15). Koni Yellows and Big Brake 5 lug conversion.
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