1999+ reliable performance potential?

Perhaps that title is confusing...

Anyway, I'm looking to purchase a 1999-2004 Jetta TDI with a manual transmission. I'm getting a job that requires LOTS of driving, and the TDI seems to be the best choice in terms of reliability, comfort, style, and fuel economy.

However, I'm not the sort of person to get a car and leave it stock... I've nearly doubled the horsepower of my 92 Accord, and I don't expect to leave the Jetta alone!

I need the Jetta to be reliable, comfortable, and effecient, but I'd still like to get as much power as I can within those limits.

I've read the FAQ and browsed through the 101 and performance sections of this site. I've seen mention of MANY mods that sound quite interesting. However, I haven't seen much in regards to long-term reliability, effeciency, or specific power gains for any of them.

The Jetta I'll be looking into getting will have 90hp/155lb-ft, I believe. With mods, how much can I expect to increase those numbers, while retaining near-stock relaibility and efficiency?


I'm not new to cars, but I'm new to both VWs and diesels.
I know this is a very vague and noob-ish question, but with my limited knowledge of the motor, I'm not sure how to interpret the effects of various modifications. I've read that diesels don't react in the same was as regular gasoline engines in terms of modification.

RC2 + a modest nozzle upgrade. You'll likely still need to replace the clutch.

Unless your able to find a 1999.5 car which came from the factory with a stronger clutch.

-Jason

You should look at Kermatdi.com, get a set of sprint 520s and a RC1 to see if that's enough...

Yay! Replies!

Wow, the 520s claim a 20hp and 40tq gain... very nice! See, with my current Honda gasser, an upgrade like that would be worthless!

What is RC2? I searched on here, and again it seems to be a term that's so familiar within this group that it's not explained. ECU modification, I assume?

Reprogramming the chip. Look up rocketchip tuning.

Before:



After*:



*RC2 Euro conversion + Kerma Sprint 520 nozzles

Check out this recent thread in the performance section:

http://forums.tdiclub.com/showthread.php?t=152058

I posted an outline of what I recommend to maintain reliability, longevity, and economy. (And I should be at least 130HP/250TQ)



Jason

Wow... I'm still amazed by the massive difference between torque and horsepower with these turbo diesels! I'm making about 170tq with my Honda, but about 230hp (crank). I really need to drive a TDI to understand the difference, I assume. 130hp to me initially sounds wimpy, but those torque numbers are fantastic!

That outline seems quite reasonable... those preparation things are what I would probably do anyway just to keep the car in good shape! Boostvalve... is that a manual boost controller, or a blow off valve?

You got it, Man !

deevergote said:

but those torque numbers are fantastic!

Click to expand...

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Yeah, I hear ya. People just DONT know until they drive it. In actuality I would not be surprised if I put down 140-150 HP and 275+TQ at the wheels. I really need to get on a dyno!


Just think about having that much torque at 2K RPM. That means I have ~ 100HP at 2K RPM (250TQ). When does your Honda reach 100HP? Of course in a drag race peak horsepower is a much more important consideration. It's just plain nice to drive around with all that power on tap, any time, almost any RPM.

I think of the boostvalve as a manually adjusted safety device to control boost spikes. Read on in the performance section and soak up the knowledge. Then think about some goals, then read some more and start making plan.


Jason

Seeing as I can regularly rev to 7500 with the Honda, most of the power is up top. The low end is decent, but I'm sure it doesn't compare. I built it to retain some bottom end, as it is a daily driver... all top end is no fun on the streets! It blows a stock Accord out of the water at any RPM.

From my research, things such as the boost valve found on www.boostvalve.com, it's just a simple manual boost controller. An advanced "bleeder valve" that is actually made for turbo aplications (early turbo modifiers have used fishtank bleeder valves in the past... effective, but not reliable.) How are they used to prevent spiking? I understand the concept of the valve, but I don't see how it does that job.

Also, the RC2 and RC3 (would RC3 be out of my reliable, effecient, easy to drive limitations?)... are they priced as most VW ECU flashes are? My friend has an 04 GLI, and we've been looking into the ECU flash for that. I believe it was $700 or something from a local tuner shop that specializes in VWs (probably where I'll go, if they'll do the TDI ECU as well).

Going by your modifications and estimated power output, Jason, I'm excited about the possibility of making 50-60hp and 100-150tq over stock for $1500 or less! Especially after looking into modifications for my friend's GLI, which put him well over $2000 for similar gains (granted, his car is higher performance... but he doesn't get 45mpg either! )

Go to your local used car dealer and test drive about three of them.

Horsepower is just an esimated figure. The Dyno only measures torque. horsepower is something like (Torque*RPM)/1000=Tq (something like that) so they only measure torque, the higher the RPM the more horsepower it can produce.

Diesels can't go much higher than 5100 RPM, and even then it's like hitting a brick wall. Ever take the rev limiter off of a honda 14D engine and see what it does at 7000 RPM, same feeling with a diesel.

The only way of describing it is like an old V8 from the 60's. It "feels" fast overall, kicks ass around town, and on the highway. It is hands down one of the most fun engines I have ever driven, and I only have the Sprint 520s installed.

I may take a ride tonight to see what I can find. I never thought I'd get excited about a diesel! :lol:

Compared to modifying other VWs, the TDI seems relatively cheap. If it can remain reliable and efficient, while producing numbers like that, I think I'll be extremely pleased!

Would it be too much to hope that graph is from your car with just the 520s? Because those numbers are quite nice I'd even be happy with the lowest one!

The difference between my stock to the sprint 520s (which are the little brother to the PP520s) is like adding about an inch or an inch and a half to the bottom of the pedal.

What do you mean by that?

What exactly do the nozzle upgrades do? (I'm searching around as I ask these questions... but I figure it'll be good to get them written down for future reference!) Do they dump more fuel into the motor, like adding larger injectors? Or do they do something else? If they simply increase the amount of fuel, would that significantly decrease fuel economy?

The nozzles are the tips on the injectors, they inrease the amount of fuel delivered into the combustion chamber.

Most people don't notice any decrease in mpg.

Make sure you buy a 5 speed, unless you want to convert it to a 5 speed later... otherwise, you will be stuck with 36 mpg on the highway.

Yeah, definitely 5 speed. After owning a 5 speed for the past 6 years, I can't stand automatic anymore. With a 5 speed, you're in control. With an automatic, pressing the gas seems more like a suggestion than a command!

What about the PP764? I guess that would probably put my economy requirement out the window, eh?

I think it's time you took a test drive... one stock, and see if there is anyone here in your area with a mildly modded one... you'll enjoy

The boostvalve on a TDI works by actuating the VNT mechanism on the turbo. It responds faster than the N75 valve (when told by the ECU). As I said, just do a ton of reading around this site.


I personally think I am at the limit of the stock turbo. As usuall, person could squeeze a bit out by adding a few things but the big gains are done. The HP per dollar drops off as they say...


Cost might be ~

Tuning - 3-400
Clutch - 450 parts
Nozzles - 300
Gauges - 250
boostvalve - 50

But you must make sure the car is in perfect shape, IMO. Timing belt, fuel filter, etc, etc. Clean the intake of course.


Jason

forget wimpy sprints and rc1. et what you really want. pp520s with an rc3. boost gauge and boost valve for safety. def. gonna need a clutch. after that, if you get that far, look at bigger turbo and upgraded intercooler. pp520s (kerma) and rc3 are reliable, can be economical if you drive easy, and freakin fun!

Well, I found 2 in my area. One is over the river in PA, in an area I'm not familiar with. The other is a 30 mile drive... which I just took

The car 30 miles away looks quite nice. It's a 99, so I'll have to check to see if it's a 99.5 or not (how can I tell? any superficial differences? VIN differences? Dates printed or written anywhere?) They want 9400 for it.
It has pretty much everything I want, aside from being older (I was hoping for an 02 for that price...) The exterior seems decent, aside from a few scratches. I didn't see dents anywhere. Some paint is chipping off the front bumper... but I may swap over my friend's GLI bumpers when he gets a *barf* bodykit Get a decent inexpensive paintjob and it'll be good as new!

Here's the listing It has a sunroof too, which I don't believe it says there. That's a major plus (never had a car with a sunroof... the wife and I are DYING for one!)

Driving easy should be TOO hard... I manage to drive the Honda lightfooted enough to get 30mpg out of it... though most of the power is up top, and I don't ever really NEED to go up there! Staying below 5100 will be a change for me.


The dealership that had the 99 was closed when I got there tonight, so I only got an external view (in the dark). I think I'll get up early tomorrow so I can fit in a test drive!

This is a 1999MY Jetta known as the A3:

This is a 1999.5MY Jetta often referred to as Mk4 or A4:

Theres a pretty reliable way to tell if it has the good clutch. Look at where the shifter cables attach to the transmission. Theres a weight there that looks like a golf club head. If its black it probably has the better clutch. If its silver it probably has the weaker clutch.

Of course you pick the one where my car is covered in salt

-Jason

I wouldn't get RC3 without getting a VNT17 turbo.
An automatic won't need a clutch upgrade, but if you get into the crazy upgrades (like a VNT20 turbo, etc) then you'll need a new torque converter and you'll wish you just had to have a new clutch.

I'd stay its something like this:
Stage 1: 1 nozzle size up, RC1
Stage 2: 1 nozzle size up, RC2, clutch
Stage 3: 2 nozzle sizes up, RC3, clutch, VNT17 turbo, axles
After that its a game of upgrading the chip, nozzles, turbo, clutch again, oil cooler, intercooler, etc.
So you can get modest gains for cheap, or get some crazy power for lots of money. I think someone posted dynos with 380 ft/lbs peak, 225 hp.

Awesome. It's a 99.5 then.

I'm going to do my best to test drive it tomorrow. Are there any major problems I should keep my eyes out for? Anything that can easily be seen on a used car lot? Notorious leaks, important broken plastic or rubber, etc?


Wow... I couldn't imagine 225hp and 380ft-lbs...


So the RC2, PP520, and a clutch if needed... plus the boost valve and guages. Seems like a decent amount of power for a fair price. The car needs to get good mileage and be reliable, so I don't think I should push it further than that. If I didn't modify my Honda as much as I did, I'd probably be driving that for this job!

I've seen claims of over 50mpg with the TDI. What can I realistically look at... both stock, and with my planned mods. I'm DEFINITELY getting a 5 speed model, no doubt about it.