Stage 0 Tune Now Available (Natural Aspiration)

The Stage 0 "SDI" tune is designed for VE and PD TDIs without boost (no turbocharger). We have tuned a MK4 Golf ALH without a turbocharger and it surprisingly keeps up with traffic. No smoke according to the rear view mirror!

The tune appeals to any of the following:

• Industrial applications.
• Simple engine swaps.
• Those who want a potentially lower cost alternative to replacing the turbo.

EDC16 PD engines: The fault code / limp mode associated with a deleted PD VNT "smart actuator" is completely eliminated.

A different exhaust manifold is needed after turbo removal. Stock or aftermarket 4-in-1 exhaust headers for 2.0L gas engines will fit the 1.9L TDI. An air intake from a NA VW is also needed.

Hmm. Could be interesting for people going for max longevity. Doing it right would involve a trans from a 1.8T, to get optimal gearing (code EHA looks about right for gearing), though, IMO.

It'd be interesting to see that on a dyno, and then compare to dyno results from a stock AQM (the factory 1.9 SDI).

(Not interested in it myself, but it's still interesting.)

That is an interesting development, and I'd love to hear feedback from someone who has reverted to "SDI" in this manner!

I think the P-D version of SDI had something like 68 horsepower stock, and it's possible to get a bit more by chip-tuning them.

what do you think would be the mpg change? i'm sure it's take a while to get up to speed, but maybe it would be worth it at the pump?

Would it really be any more efficient to accelerate a weaker "SDI" car to speed (more effort) than gingerly accelerating a more powerful TDIl? I'm not sure I understand why anyone would want to do this.

I thought I had read that turbochargers cost some amount of power to make power. And isn't fuel supposed to burn more efficiently at a higher load? Perhaps it's possible to advance timing further if there is no boost?

Even if it's not more efficient, I can still see some potential for this modification for anyone with a blown turbo who wants to get back on the road cheap. Good thinking!

hmm, is there anything you can do to make the cruise control react slower to acceleration ?

Stealth TDI said:

Would it really be any more efficient to accelerate a weaker "SDI" car to speed (more effort) than gingerly accelerating a more powerful TDIl? I'm not sure I understand why anyone would want to do this.

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Well, the SDI will just have less maximum power than the TDI - it shouldn't overfuel, so it should be about as efficient as a TDI that's accelerating as hard as the SDI is.

(Now, the TDI can accelerate harder. That's the advantage of the TDI.)

The biggest reason to do it has little to do with efficiency, and everything to do with increasing longevity (with no turbo, cylinder pressures are lower, the vanes can't soot up, and the turbo can't blow and dump oil into the intake) and reducing costs if you're an absolute cheapass.

That said, there is a way that an SDI can be more efficient than a TDI. The most efficient modes of operation for the TDI engine are ones in which the turbo can potentially surge, and where the turbo will get sooted up, and therefore those modes of operation are essentially off-limits. An SDI, with no turbo, has no such problems, and therefore is perfectly happy at 1500 RPM.

Look out smart and electric cars! Wicked idea.

Weren't the first VW diesels NA and didn't they smoke like crazy?

abc- I wouldn't say they smoked 'like crazy' but they did make some smoke. They also had relatively primitive fuel injection systems. Unlike the MK4, those early injection pumps were fully mechanical. The point here is that software tuning can produce clean power without turbocharging in the 1.9 It's wonderful that we have access to this setup for many reasnos, but it's not a big surprise- I believe NA direct injection was a stock option in Europe.

They only smoke like crazy when they're not running properly. And, the engine management consists of a bunch of springs, weights, and camplates, that translate RPMs and throttle position into fuel quantity and timing. Note that air isn't take into account.

This is fantastic! I fall into the cheap-ass category with interests in longevity and economy. Sounds like a great alternative to replacing a failed turbo. I have replaced two VNT actuators and one N75 valve allready for a combined total of maybe $400 with shipping to Canada. How much would it cost to delete the turbo? Who will be the first to put together a Turbo Delete Kit for the ALH and price to compete with a replacement VNT15? Very interesting.

Also how is the real world fuel economy on this SDI ALH? What does SDI stand for exactly now?

Someone should just make cartridge block off plates, leave the turbo manifold there, just take out the cartridge, block it and leave the downpipe there

JFettig said:

Someone should just make cartridge block off plates, leave the turbo manifold there, just take out the cartridge, block it and leave the downpipe there

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If I have this correct, the cartridge is the center part with the oil feed and the moving parts? This is a great idea!

JFettig said:

Someone should just make cartridge block off plates, leave the turbo manifold there, just take out the cartridge, block it and leave the downpipe there

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Pulse tuned headers would better IMO.

I just realized the cat and mufflers would need to be returned to any car without them. No turbo to muffle the sound with Stage 0.

JoshJohnson said:

what do you think would be the mpg change? i'm sure it's take a while to get up to speed, but maybe it would be worth it at the pump?

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I would think the SDI is likely to use a little *more* fuel than the TDI that it was developed from.

The extra torque in the TDI allows the engine to pull taller gearing (lower revs at a given road speed) and this reduces engine internal friction, generally by more than whatever slight parasitic loss is associated with flow losses through the turbo (when the turbo is "off boost" it doesn't do anything, it's just a flow restriction).

If you don't change the transmission then you'll have to gear down to get up hills, instead of just letting the TDI come on boost.

By the way, SDI is essentially "suction direct injection" as opposed to "turbo direct injection".

It would be interesting to do some optimizing on the SDI configuration. With the turbo not there, the normal limitations of turbo engines not wanting valve overlap (so the cam might be able to be changed) and the turbo not wanting tuned-length exhaust header pipes are not there. I know the original-equipment SDI used long-runner intake manifolds. Tuning by this method still won't make up for having boost pressure, but it can be better than nothing if done right.

JFettig said:

Someone should just make cartridge block off plates, leave the turbo manifold there, just take out the cartridge, block it and leave the downpipe there

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Then what would you do with the intake? Run the air box directly to the manifold?

GoFaster said:

I would think the SDI is likely to use a little *more* fuel than the TDI that it was developed from.

The extra torque in the TDI allows the engine to pull taller gearing (lower revs at a given road speed) and this reduces engine internal friction, generally by more than whatever slight parasitic loss is associated with flow losses through the turbo (when the turbo is "off boost" it doesn't do anything, it's just a flow restriction).

If you don't change the transmission then you'll have to gear down to get up hills, instead of just letting the TDI come on boost.

By the way, SDI is essentially "suction direct injection" as opposed to "turbo direct injection".

It would be interesting to do some optimizing on the SDI configuration. With the turbo not there, the normal limitations of turbo engines not wanting valve overlap (so the cam might be able to be changed) and the turbo not wanting tuned-length exhaust header pipes are not there. I know the original-equipment SDI used long-runner intake manifolds. Tuning by this method still won't make up for having boost pressure, but it can be better than nothing if done right.

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Wouldn't it be possible that the SDI and TDI would both have advantages for specific loads, (and therefore different terrain/driving style?) I was discussing this about 6 months ago and we never seemed to reach a conclusion.

Please allow me to *only slightly!* disagree with your theory on gear ratios being too tall. The normally aspirated diesels I have driven have always had a top-gear ratio similar to 4th gear in the 02J. Those motors were always screaming at 80mph, while I was getting a consistent 40mpg. The '75 240D was AT redline at 89mph. (near 5K IIRC? no tach...) If I recall correctly, it usually gets about the same average mpg no matter how fast I drove it. (I'm embarrassed to say that I regularly drove well past redline in 4th gear as a 16-year-old...) The point is, even with high, high rpms, (Got her up over 100mph indicated lots of times) I would still average near 36mpg. It looks to me like this SDI has a 4-speed with a generous over-drive.

Perhaps there won't be enough torque down low to climb hills in 5th gear... but I am coming from the perspective where all NA diesels I've driven have been dogs. (36 seconds 0-60 in the 240D... guess how well that climbs hills... ) I'm sure there is a loss of torque at low rpms, but if it really has near 70hp without the turbo, that power/displacement ratio is astonishing.

Geez, I just edited my post because my cell-phone internet was failing earlier.. sent an incomplete post. Wierd!

The gearing in an SDI-equipped Mk4 is, IIRC, about the same as a Mk3 2.0 gasser, which is similar to the tallest factory gearing on a US-spec Mk4 1.8T.

Malone, I'm your biggest fan, but this sounds crazy. 70hp is a 3400 pound car?

TDIMAXIMA, that's more power and less weight than my 240D... I could get that up over 100mph if I needed to.

manual_tranny said:

TDIMAXIMA, that's more power and less weight than my 240D... I could get that up over 100mph if I needed to.

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And that's less power and the same weight as my mkiv though. Why anyone would do this is waaay beyond me. And, if anyone did do this and installed a custom cam and tuned length header to make more power, then they need to seek medical assistance.

Farfromovin said:

And that's less power and the same weight as my mkiv though. Why anyone would do this is waaay beyond me. And, if anyone did do this and installed a custom cam and tuned length header to make more power, then they need to seek medical assistance.

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For people who have had multiple turbo failures, who don't care how fast they go and just want a simple, reliable car, this makes a lot of sense!

For people replacing an 01M auto with another 01M auto, this should be a prerequisite. Those transmissions might prove to be reliable if we reduce maximum torque?

Has anyone actually done this and dyno'd the car?

There could also be a slight, but noticeable, gain in cruising efficiency (MPG) with this tune / setup. Without the turbo and associated plumbing / intercooler, reductions in pumping losses could be significant.

Mark, since you are proposing all sort of wacky ECU tune ideas lately, let me suggest another one:

Additional engine braking through turbo boost at zero throttle, for the people who frequently tow with their TDIs. I sort of accidentally have this mod right now (sticky VNT gets hung up on boost sometimes) and coasting distance is reduced noticeably with only 2-4 lbs of boost at zero throttle. I would imagine that 15 lbs of boost could help slow the car even more. Would have to be switch selectable somehow though.

The 01M's problem isn't too much torque, it's valve body wear causing fluid pressure drops and incorrect behavior, and that results in overheating (which causes more wear) and eventually the transmission tries to go into multiple gears at once, and the hard parts explode.

The 02M isn't really known for any big problems. (It's a 6-speed manual, as used in Mk4 cars, 02Q being the Mk5 version.)

I stand corrected. The use of 02M to describe the 01M was just a brain fart!

Farfromovin said:

And that's less power and the same weight as my mkiv though. Why anyone would do this is waaay beyond me. And, if anyone did do this and installed a custom cam and tuned length header to make more power, then they need to seek medical assistance.

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Yeah, even if you bored out the cylinders to 2.0L, increased compression, installed forged rods, high lift cam, etc. the power output would not even be 100 whp. Not even if the engine was revving to 6K rpm's. Who knows though, this might start an ALH n/a craze. LOL

This kinda reminds me of those nutcases on the DSM forums who ask how they can get 200+ whp from a chrysler 420A with no turbo. It's just not gonna happen.

BTW: No disrespect intended Mark. Just preemptively poking fun at anyone who might try and build an 'all-motor' TDI.