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XD3T performance upgrades


Bean

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Any thoughts on the diesel purge they suggest? I've read mixed reviews on the diesel forums...

I used the Lubro Moly Diesel Purge Injector Cleaner back in January when I was first putting my car back on the road after 6 years. It seemed to me to make a noticeable improvement, in smoother running, easier starting and less smoke. This was after running a can of it full strength with a hose from the fuel filter inlet and the injector return in it. The apparent improvement was fairly immediate. I don't know that it would make that big a difference as a routine maintenance procedure as it did to me at that time. Fixing what ain't broke won't make an improvement.

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Thanks Dave! Knowing it works as described is good enough for me, and if it doesn't improve anything I know it's as good as it can get.

I just need to source the filter head filter canister (missed the one on Peugeot-L) and I'll swap it in when I replace the injectors with the rebuilt ones. Once I get the car to stage 0 with all systems functioning as intended - then I'll start tuning the VE pump to see if I can get the car to be just a wee bit faster.

VW IDI guys are getting ~140 HP out of 1.6 and 1.9L engines - so if I can get close that with the 2.5L and retain efficiency and no soot I'll be happy. Really just want it to have decent highway passing capability.

Rabin

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Well I know the XD engines can make some power. A long time ago I was tinkering with my old '82 when I worked at Sunset Coachmen. I turned my boost up to ~16psi and adjusted the max fuel delivery screw on the IP. I went a little overboard at first as I created quite a plume of black smoke, but either way the car really did feel much faster. The soft rear suspension really squatted... ahh good ol semi-trailing arms :P

The head had already developed a small crack by that time, and doing that one acceleration run pressurized the cooling system quite a bit as evidenced by the high coolant temperature and burping from the header tank. As you'd imagine, I returned the car to stock once I returned to the shop.

If I were to tune an XD again, I'd definitely make sure the head and head gasket were in tip top shape as that seems to be the weak link even when running stock. The bottom end doesn't worry me though; Forged parts plus the XD2S and XD3T have oil squirters, and the XD3T goes one step further with small oil galleries under the piston crowns to help distribute the heat load.

Barring head/gasket issues, I'd wager you could get a shit ton of power from an XD3T--probably more HP/displacement than the IDI VW guys can get reliably anyway.

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If I were to tune an XD again, I'd definitely make sure the head and head gasket were in tip top shape as that seems to be the weak link even when running stock. The bottom end doesn't worry me though; Forged parts plus the XD2S and XD3T have oil squirters, and the XD3T goes one step further with small oil galleries under the piston crowns to help distribute the heat load.

Barring head/gasket issues, I'd wager you could get a shit ton of power from an XD3T--probably more HP/displacement than the IDI VW guys can get reliably anyway.

A guy in Finland has told me the car should easily be tunable to 140HP on stock components and intercooling, and still be quite easy to get 160HP with some injector pump modifications. There's a guy named Giles in eastern Canada that is supposed to be a VE injection pump God - he figured 160 HP would be dead easy on the 2.5L mill. That's turbo gas HP and a metric shit ton of torque to go with it - so it'd be PLENTY for what I want. Car was a basket case when purchased and now even with just some basic sorting it spins nicely on gravel or sandy pavement. If they ever do a NICE VNT stand alone controller I'd consider upgrading - but for now the stock turbo should be plenty and have really nice boost response that I want.

Not sure if I should consider the HG as preventative maintenance? If so I'll add that to the list as it's supposed to be easy enough to do. I'm removing the intake and exhaust anyway to fit the euro spec ones I got for it - but I need to modify the intake to plumb in the intercooler first. No space to run the XD3TE set up with the reservoir there - so I'll have to see if I can figure out a different top mount design or squeeze it in the front somewhere.

Rabin

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I'd like to learn more about the electronic Roto-Diesel system used on the XD3TE. I suppose I'd have to somehow source a factory shop manual. I'd like to know if the ECU measured boost electronically and if it measure intake air temperature; Basically I'd like to know if the system compensated for intake air density since the intercooler would presumably make the engine more tolerant to extra fuel with the same boost pressure.

Can you get a ball bearing cartridge for the Garrett units used on the XD3T (TA0302?)

My DD/beater '85 has the 3 speed automatic, and perhaps I've been spoiled by naturally aspirated engines, but the turbo response off the line is pretty poor. I recall my XD2S being a bit zippier, but again it didn't have the super tall 2.88 rear axle like this one does.

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I didn't even know the XD3TE used an electronic Roto-Diesel injection pumps - I assumed it used the VE pump and the only difference was the intercooler with different intake and exhaust manifolds. I assume it used the Garrett TA0302 as well and not the K24 I've read about as well.

As far as I've read any T3 rebuild kit should work with this Turbo - not sure if you can get a new center - but if it's not damaged you shouldn't need it. I've got the turbo on the car, as well as a spare that was supposed to be recently rebuilt. I'll clean up the spare and mount it to the UK manifold after it's all sorted out - then install as a unit. I read lots of MB IDI guys going for gas T3 turbos on their engines and flirted with the idea of using the N9TE .36 AR turbo on it - but it'd be way too laggy with the limited redline I'd want to keep. VW and MB guys push the redline limits going for big power - but I just want improved drive-ability with very little efficiency sacrificed - if any.

My plan was to match port the UK market EGR-less exhaust and intake manifolds with some basic flow cleaning, and possibly getting the exhaust and compressor housings ceramic coated. Any help if can get to keep the heat in should help spool as well as keep under hood temps down in case I do the TMIC. I want working AC in the car and it's likely going to be too tight to get the IC up front.

My car was a total dog when I bought it and I thought the turbo was shot as it simply didn't spool at all. Transmission kick down and throttle linkage set properly though and the car is almost "peppy". I can hear the turbo spool very quickly and it seems to be well into the boost by 2K rpm - but I'll need to fit a boost gauge to know specifics once I start sorting the tuning out.

Since I don't want really massive numbers I think the most the car will ever see is a tuned / modified VE pump, and possibly a hybrid set up with VW AAZ 2stage injectors with a matching modified pump (with the 2-stage injector cam) - there's a marked improvement with the 2 stage set up - but I'd only do it if I found the parts cheap and I was getting Giles to do a performance IP build anyway. If I get to my goals with stock components and some tuning - even better.

Rabin

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Oops kinda highjacked the FS thread. :P

Yeah the XD3TEs had an electronic RotoDiesel FI system. Presumably North America would've gotten the same or similar system in 1987 on the 505 GLS turbodiesel (XD3T); They were in the import catalog as such but I don't think anyone has ever seen one and I believe someone confirmed a while back that none were officially sold here. Nonetheless it was a cool system with an electronic throttle and all.

Given the infinite tuneability of the VE series pumps, I think that all it would take is some patience and trial/error to get one of our cars really churning out some power/torque.

If I ever were the build a powerhouse XD3T from the ground up, I'd make the cam gear adjustable and modify the timing cover to allow easier access. I'd also consider a cam regrind. The XD2 cam had a little more duration than the XD2S cam. And the XD3T cam is like an XD2S cam with more lift. I wonder if taking an XD2 cam but regrinding it with the lift of the XD3T would yield anything useful?

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Yes - it uses a stepped cam plate to properly stage each break point. I e-mailed Giles asking if it was feasible to build a hybrid AAZ for the XD3T, and he responded that he'd had great success with the 2 stage AAZ injectors. Combine that upgrade with his pump tuning tricks and I think these engines would safely approach 160+ HP while retaining efficiency and no increase in particle emissions (IE no visible soot). He did mention 2.5L would be a LOT easier to get numbers out of as the VW are getting the numbers I want out of 1.6 and 1.9 IDI engines of similar design no problem.

I think the VE pump rebuild would cost $1200 - but I'd have to likely supply the AAZ injectors and components from the VE pump for the hybrid to get built. If I could find a decent stand alone VNT controller I think that combo would be the peak of maximizing efficiency and power out of the IDI engine. Should be good for very modern numbers, and exceptional drive-ability - but at a decent cost. (I'd say $3-4000 would get you there assuming a good stock engine)

I know there are DIY VNT controller products - but I just want something that's plug'n play with a parts list and some assembly. :) Until then I'll just use a stock wastegated turbo.

Rabin

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  • 4 weeks later...

The exhaust turbine inlet flange on the XDs looks similar to ones I've seen for other cars. I wonder if it's compatible with the turbocharger from an OM617 Mercedes engine (the 3.0 liter inline 5). As far as I know, that unit had a turbine A/R of .48, and the wastegate was set for over 13psi of boost. If so, that would be an instant bolt-on upgrade. Better exhaust flow and a little higher boost pressure. The I/P would need to be tweaked just slightly to compensate. You'd probably get an XD3T to 100bhp or so that way.

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For some reason Peugeot used a standard T3 flange for the diesels! I do believe the OM617's used the same T0302 Garrett as they pretty much look identical. I checked and the T0302 I have has a .42 cold side AR, but no markings on th exhaust housing I could see what it was. It should be easy enough to measure - just didn't have time.

Found a bunch of posts of guys using the same turbo I want for the N9TEA engine - the Borg Warner EFR6258 is wickedly fast spooling and supposed to be great on diesels as well. A fast spooling turbo and an electronically controlled wastegate might be a nice stage to get to with it. Only problem is the 6258 is a T25 flanged turbo. A GTX2860R Garrett could be done in T3 and still be very fast spooling.

I'm guessing the XD3T and the N9TE's have the same size turbo specs.

Rabin

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Can you get a ball bearing cartridge for the Garrett units used on the XD3T (TA0302?)

BB cartridges can only be used with T31 or T350 exhaust housings, and from trying to see if that would be viable for the N9T** engines it looks like those exhaust housings are at least .63 AR

Since it's a T3 flange though you can bolt whatever you want to it and you're good. T3 is a pretty big flange, so you'd have to spec a GTX2860R with a T3 housing and it should spool almost as fast (faster maybe?) as the stock turbo - but flow way more air. I think doing this is going to be better than trying to go VNT as they seem to have a lot of reliability issues.

A buddy actually got a turbo system for his quad (Yamaha single cylinder 2WD sport quad) as he runs tracks on it in the winter. I was shocked that the kit was a GT2860RS - he said it spools great on the 450cc motor!

Rabin

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  • 2 weeks later...

Nope - not even close. Diesels are low revving, with less exhaust gas energy than a gas motor. That one was also a twin scroll turbo and on a stock manifold it would be a waste - not to mention it'd be too big to even spool.

Personally the best option would be an electronically controlled VNT turbo (If you can find a T3 flanged VNT), second best would be electronic boost controlled GTX2860R, third option would be to just rebuild the stock T0302 as it's well sized for the engine.

Rabin

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ill have to look into the elctronic VNT, that sounds pretty cool to me! its probably a waste for me to do any tuning anyways since my engine rarely goes above 1k rpms

Is that by design? Ideally you should have this engine at it's torque peak when in use. If it rarely sees over 1000 rpm you should pull the turbo and make it a simpler engine... Or put in another transfer case so that you can get your revs into the 2500 range and really have some crawling power. :)

Rabin

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Yeah low rpms is my goal. I already have dual transfercases and that's why I don't ever have to touch the gas. The only time It gets any higher is when I need a little wheel speed to get the tires sticky. Since mine is straight piped from the turbo straigh out of the side, it's fun hearing the turbo spool and the weird looks i get. One day i want to put it on the road but for now it's just a trailer toy

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