850 tdi upgrade project

[martin_r_smith]

It is very hard to find a tuner now, unfortunately most only do modern common rail diesels. We do all the fabrication ourselves and I have a man in Germany do the tuning. He writes the files and sends to me to program the chips and test on dyno, it's a lot of back and forth but was worth it.

Turbo wise, I wouldn't go for a 16T. It was good for low to mid range power but unable to supply enough air for a clean burn past 215bhp. The holset HE221W has been used to produce nearly 300 on several of these engines (with larger 0.280 nozzles).

[mitchyboy01]

I ran the HE221W on my petrol T4 and hit 286bhp at 1.35bar. The stock actuator didn't crack open until nearly 2 bar. These small turbos can hit mega boost and still have plenty low down. I didn't push mine harder because I couldn't find a mapper for my car.

39lbs/min does seem a little optimistic though. From experience I'd say it is about 35lbs at a push. It is very hard to get info on these turbos and a lot of it is contradictory. I hope you push it to the limit and see exactly what it's capable of.

[martin_r_smith]

Yeah you need lots if boost to make the most of them, at 1.35 bar they produce little more than a 16t. I will be running 2-2.2bar at least! I don't think they are particularly well suited for petrol engines, unless you are kitted out for high boost of course.

[martin_r_smith]

This is the compressor map supplied to me for it.

[mitchyboy01]

2.2bar looks like the sweet spot to me! My engine was forged but it was the lack of a mapper for the Siemens ECU that was my stumbling block. I was on a stock map with a maxed MAF and tweaking fuel pressure for the extra boost. I couldn't go any further as it was beginning to run lean up top and midrange was bogging down too rich. I wish I could've pushed mine harder to see what it could do. I look forward to seeing your results.

[martin_r_smith]

I'm looking forward to it too. If I reach the bhp figure you did I'd be happy but as it takes about 30% more air for a diesel to reach the same figures, I won't be too upset if I don't. It is going to require bigger injectors anyway to go past 250 ish, so that will have to wait a little while (they are £400 a set ). But I will get there eventually.

[mitchyboy01]

When you research the diesel turbos it's interesting to find how much the technology has come on compared to petrols. A modern Holset is much more efficient than the tuners favourite Garretts and more reliable too. Great spool, high pressure ratio capability and cheap as chips. The problem most have is finding the correct oil pressure and a big enough drain. I don't think the HE221 needs a huge drain like the HX models though. I didn't run a restrictor and it was fine. I was advised to put one in and when I did the turbo sh&t itself.

[vololic3]

Originally Posted by martin_r_smith

It is very hard to find a tuner now, unfortunately most only do modern common rail diesels. We do all the fabrication ourselves and I have a man in Germany do the tuning. He writes the files and sends to me to program the chips and test on dyno, it's a lot of back and forth but was worth it.

Turbo wise, I wouldn't go for a 16T. It was good for low to mid range power but unable to supply enough air for a clean burn past 215bhp. The holset HE221W has been used to produce nearly 300 on several of these engines (with larger 0.280 nozzles).

I realise now from reading all the posts its more fuel is what I need,I cant seem to find a mapper,not even one in germany,Ive even thought of using the vw t4 ecu, but it seems id have to change the loom.So I will have to use the ronbox,my0.240 nozzles and maybe the auto 12mm pump.I have already brought a gtb2056v turbo and make an adapter like yours with piggy back vnt ecu.I enjoy building things myself, its the only way to learn, 4 years ago I was the first person in the uk to build an upside down passat gearbox for my vw t25.Any surjestions for more fuel would be much appreciated,or you could sell me your old map and t16,id be happy with 215bhp, i understand if you have to keep your source secret,how about some pictures of yours in its present setup? ehaust temp 800* about right? or would it be better to monitor afr?

[martin_r_smith]

0.240 nozzles with a good turbo and supporting mods is enough for over 220. A holset hx27w or HE221W is the way forward. I have just fitted my holset HE221W and a better 3" downpipe and it's running very well but I'm having some boost issues at the moment.

The 11mm pump is good for over 250bhp so no worries there, also the auto has an 11mm too not 12mm.

If you want to keep it simple, a ronbox, decatted, nozzles and upping the boost to 1.4 bar will get you to 190-195. Over 200 cannot be done without a bigger turbo.

Here are a couple of pics I got yesterday.

[vololic3]

thanks martin
is it too much boost or a leak?I noticed you disconected your boost soliod in the picture.Your still on the adapted manifold, I thought that was restrictive for the sort of power you want? I cant rember whon told me about the pump, maybe one of shadows old posts or diesel bob,cant seem to find an auto pump anyway.I also rember reading you need 30% more fuel to get over 200bhp, which I thought the Ronbox wouldnt streatch that far, the reason for needing a map.Last question have you used that exhaust temp feed and what sort of tempretures have you had,it gives a good indication when tuning, is 850deg adout right?