G-Teched my 1.6TD - Part 2

[malone]

I drew a diagram to clarify the LDA control:



A single 3-way dial switch is an option; LDA off, LDA lo, and then LDA hi. It'd have one incoming 12v wire and two outgoing 12v wires for separate solenoids.

Why LDA off? Disabling LDA completely makes a huge difference in torque as low as 2,000 RPM. It would help traction control in very slippery road conditions. It can also be considered as valet mode.

[malone]

I did a couple Gtech runs with GTD injectors installed and no other changes since the Gtech plot above. I didn't feel more power after installing the GTDs and only saw 132 and 135 net hp. Just like the black lines (Oct 30 w/ GTDs) in the above Gtech plot. A little less torque too (approx. 145lb-ft). This is despite having turned up the fuel screw since the above Gtech plot. Not impressed!!

However, I want to get a FMIC in and then do a few more Gtech runs.. then reinstall OEM injectors and do more Gtech runs the same day. While the GTDs are out I'd like to get them pop-tested as well for consistency and spray quality. They only have approx 1,500km on them though.

Perhaps gains from GTDs are more noticable if your original nozzles are old and worn. My OEM injectors (complete, not just nozzles) are brand-spankin' new with approx. 500km on them. I want to see how the GTD injectors perform in a pop-tester first though.

The opening pressure in my GTD injectors (new GTD nozzles in very old TD injector bodies) have been raised to 160 Bar IIRC. The OEM injectors are unmodified.

[BlackTieTD]

thanks for the info malone. what you found is what i was a leary about... there's not much (if anything) to be gained from GTD injectors. i'm watching closely, thanks again for the feedback about the injectors.  

[QuickTD]

The opening pressure in my GTD injectors (new GTD nozzles in very old TD injector bodies) have been raised to 160 Bar IIRC. The OEM injectors are unmodified.

 In my experience, raising the breaking pressure will effectively retard the timing. Advancing the timing a bit may well restore the missing power. Its pretty much impossible to say what amount of advance would be required to compensate for the increase in breaking pressure. To make an accurate comparison you probably should run the stock nozzles at 160 bar or drop the breaking pressure on the GTD nozzles back to stock.

[BlackTieTD]

might not be a bad idea to log another 1000 clicks on the OEM injectors as well to rule out wear variables, athough 1000km shouldn't make any difference.

[malone]

Thanks for the informative responses.

Rather than advance my pump to compensate I'll lower the GTD injectors' breaking pressure to OEM spec while they're being pop-tested (or raise the breaking pressure in OEM injectors.. but would rather try OEM specs first). Will have a pop-tester made eventually.

Cheers,

[QuickTD]

Cool pop tester. Mine is similar, "high end ghetto" . Its constructed from a cab jack pump from a cab-over freightliner truck. Tank is 4x6 steel tubing. The guage is a sweet ashcroft 4" 5000psi unit, princess auto surplus special for $30. I have a "real" pop testor that was donated recently, but I much prefer the ghetto unit, the guage is better quality and it doesn't require bench mounting.

[malone]

That is awesome!! Again the info is appreciated

[VWRacer]

Mark, I am curious as to why the sharp drop off in power and torque at 5250 RPM. Do you know if it's a fueling limitation, airflow dropping off or something else?

And is this with the stock TD cam, or one of 935racer's performance cams?

Thanks!

[malone]

Mark, I am curious as to why the sharp drop off in power and torque at 5250 RPM. Do you know if it's a fueling limitation, airflow dropping off or something else?

And is this with the stock TD cam, or one of 935racer's performance cams?

Thanks!

Stan, I believe that's a fuel cut-off. It feels quite abrupt a lot like a stock TD's fuel cut off at around 4,500 RPM. Still using stock TD cam but will try 935racer's performance cams.

I was hoping the injection pump will continue fueling a little longer because that's where the peak HP is, and the cut-off will especially limit the upper RPM potential with a larger turbo. Will need to check the governor mod.. or send the pump back to Giles for tweaking as I also need a 10mm or 11mm head upgrade.

[VWRacer]

Ah...I was hoping you would identify the governor as the cause. It looks to me as if you can get to over 160 hp at something over 6000 RPM with your present setup if you can address the fuel cutoff issue.

That's pretty radical for a 1.6 diesel...  :lol:

[malone]

If the torque drops off at the same rate without the 5,200 RPM cut-off then I'd likely see 148nhp at 6,000 RPM. That's still usable power in a long gear pull but as you said eliminating the fuel governor completely combined with a 10mm head, 935racer's cam, intercooling, and maybe a more efficient & larger turbo should reduce the rate of torque dropping off during higher RPM.. so an extra 20nhp (160nhp) is plausible If my Gtech calibration is accurate then that might translate into approximately 180 wheel hp. Still need a dyno to verify Gtech #s.

I am glad that I'm not making much torque for the hp, which is easier on the engine (rods have 290 wheel torque limit from what I gather) and so it leaves room for more safe hp. On the other hand, with a single large turbo I won't have much torque in the lower end and that may reduce the fun in daily driving.

Compound turbocharging seems to be the way to go, but that won't happen too soon as I don't have much 'entertainment funds' for the car. While we do the turbo swap we also want to get prechambers ceramic coated, which is cheap. Then there are a few other things we'd like to add, like finally port & polishing the exhaust ports. This means I should get a second back-up vehicle because I work nearly everyday. A friend has a 1.6NA Rabbit that he may sell in a couple months, it starts up like a champ every time while barely needing glowplugs. Good power too. That'll likely be my temporary vehicle.

I'm really itching to get an FMIC installed but 935racer does TIG welding and he prefers to wait until the turbo upgrade because of the differently positioned turbo, which may require a reweld in FMIC piping (only on the hot side).

I can fill my a/w intercooler with ice water (because it does not circulate it will melt quickly) during each dyno run though, so chances are we can still do a dyno with this GT20 turbo soon enough. Instead of waiting for the FMIC I may consider making a ghetto water system with a plastic reservoir in a hatch and perhaps a fuel pump from a EFI big block American car as Brett suggested. A large radiator is cheap and easy to upgrade too. If there's potential for the a/w to be more efficient than FMIC by upgradnig the water pump again later, then I may just keep it and not need the FMIC anymore.

[935racer]

I am making a pop tester like the ones pictured above can't wait for it to be done
I am planning on instaling a 10mm head very soon in marks car It should make a big difference.
Mark all the piping needs to be changed when the new turbo goes on because it is sitting in a completely different spot, the air filter pipe needs to be different, the charge piping needs ot be differnt, you need a differnt downpipe etc. Best to do it once do it right and do it all at once.
I want to try ome cams before the pump and turbo mods though.
I think with the bigger turbo, additional headwork, FMIC, cam, and pump head will get us up to 200whp :twisted:

When I put a bigger head on I can check the governor situation as well, I like to take the pump top off for head swaps anyways so after I reninstall the new head I can see that everything is in place and is as it should be.

[VWRacer]

I agree with your conclusions, Mark. When I lay a straight edge from peak torque to the little torque bump at ~5100 RPM, and continue to to 6000 RPM, I extrapolate the torque to 130 lbs-ft. Using the standard equation, I get:

HP = (Torque*RPM)/5252, so (130*6000)/5252 = 148.5 hp.

Using the same technique for 6500 RPM, I estimate about 120 lbs-ft, so

(120*6500)/5252 = 148.5 again.

Hmm, there appears to be some sort of bottleneck, as I would have expected somewhat greater hp if nothing was cutting off air or fuel. I'm thinking it may not be a fueling issue since the torque drop-off is very linear between 3900 RPM and 5100 RPM.

However, since this is the stock TD cam, with a design peak torque at only about 2000 RPM, I suspect the cam is choking your engine at higher RPMs. If Dave's new cam helps the top end as much as it appears to, then another 10 hp appears very doable to me.

[malone]

Hmm, there appears to be some sort of bottleneck

since this is the stock TD cam, with a design peak torque at only about 2000 RPM, I suspect the cam is choking your engine at higher RPMs.

Thanks.. I'm also willing to bet that the GT20 is also a bottleneck. As stated in one of my posts, blipping the throttle (almost WOT) to 4,500 RPM while in neutral kicks the boost up 15 PSI. That's with 2.5" dia. charge piping too (although shorter than FMIC piping). I also have a 6lb flywheel that reduces rotational mass so revving without boost would have been easy.. but still 15 PSI with no vehicle load :eek: Holds 8.5 PSI while cruising in 5th gear @ 3,000 RPM. The turbo's nice for daily driving but it's almost "too small." The GT20's compressor map also indicates that it may be highly inefficient for this application.

You can say I'm definitely looking forward to 935racer's cam and a turbo upgrade. The 10mm and governor mod too.